Why do modern reflecting scientists and engineers with two outlets think and produce sanitation based on toilets with one inlet?
Ancient Roman water aquaducts - A monument of long lasting construction but also a monument of bad ecological engineering concerning water management!
Experiences from five Danish projects with ecological sanitation using diverting systems - Reflected development or development as a reflex in designing of sanitary systems and waste products?
Arne Backlund (Corresponding author)
A & B Backlund ApS, Ordrupvej 101,DK-2920 Charlottenlund, Denmark
Tel. +45 39633364 Fax +45 39636455 E-mail email@example.com
Storstrøm County, Technology & Environment, Parkvej 37, DK-4800 Nykøbing F.
Experiences from five Danish projects with ecological sanitation using diverting systems - Gust lecturing at St. Petersburg State Polytechnic University, Rusia 2002
Why do modern reflecting scientists and engineers with two outlets
think and produce sanitation based on toilets with one inlet?
Ancient Roman water aquaducts - A monument of long lasting construction
but also a monument of bad ecological engineering concerning water management!
Figure 1 The Thinker
(Lotte Hilden – copyright A & B BACKLUND ApS)
Experiences from five Danish projects with
ecological sanitation using diverting systems
- Reflected development or development as a reflex in designing of sanitary systems and
Arne Backlund (Corresponding author)
A & B Backlund ApS, Ordrupvej 101,DK-2920 Charlottenlund, Denmark
Tel. +45 39633364 Fax +45 39636455 E-mail firstname.lastname@example.org
Storstrøm County, Technology & Environment, Parkvej 37, DK-4800
Since 1998 A & B BACKLUND ApS has worked on eight wastewater projects concerning
experiences from installing and running of source control, diverting toilet technology and analyses
of the quality of collected human urine mixture and composted human faeces. Storstrøm County
and A & B Backlund ApS have cooperated on four of the projects. Five of the projects will be
presented in the following chapters. The projects were carried out in an Action Plan, managed by
the National Agency of Environmental Protection. The agency is neither responsible for the
conclusions nor the views expressed in the reports.
The collected user experience of the Danish projects show that the diverting technology is accepted
in a housing area, that it functions perfectly in a public place and is most appreciated in allotment
gardens. The following chapters present some of the results from five of the projects.
Key words: No-mix toilets, diverting toilets, composting toilets, biological toilets, separator,
waterless urinals, wastewater treatment, biogas, anaerobic fermentation, wet composting, ecological
engineering, ecological sanitation, sustainable sanitation, human urine, human faeces, nutrients,
heavy metals, pathogens, compost, sludge, manure
REFLECTIONS IN A MODERN RISK SOCIETY
Flushing away human nutrients as waste in a modern risk society is a risk wasting the approach of a
sustainable future. We should stop acting on disposal patterns reflecting as a reflex to150-year-old
hygienic problems, and start reflecting anew. The history of utilising human waste products dates
thousands of year’s back. Ecological engineering and ecological sanitation are ways of developing
safe sanitation systems, protecting water bodies and suitable for producing high quality fertilisers
from human waste products. Wastewater and sludge are risks inherited from disposal technology,
and they are thus not automatically suitable for recycling for agricultural purposes. We cannot solve
the problem on the basis of the pattern, which created the very problem. Flushing and dilution are
not the right solutions to pollution. Modern risks are social factors that should be considered
carefully and not be handled by reflex. Human urine as waste or as a wasted resource – this is one
of the questions.
In modern risk societies wastewater solutions are not only elimination of risks. They can also be
reflected as a production of new risks in structures of knowledge, interests and administration of
rules. The complexity of humans affecting nature by far exceeds the complexity in human
regulative and control systems. Our knowledge is limited and is continuously changed (5), (6), (7),
(20), and (21).
Earlier a large part of nutrients from human urine and faeces was widely returned to farming. A
cocktail of knowledge, new technologies, administrative and business interest have changed this
practice. The historical development has changed the original potential for reuse to a product called
cleaned wastewater and a residual product called sludge. There is a differens between products we
design and excrete in co-operation with our bodies and the residual product sludge from wastewater
treatment plants. Its known that sludges from treatment plant can be a threat.
Regarding the fact that modern societies are populated with reflecting agencies, a modernisation
could be reflected as a reflex or to be reflected. There is a need of reflected modernisation as a
result of open dialogues and decision making and if modernisation more is experienced as a narrow
reflex from existing administrative and business interest one could talk about a need of
modernisation of the modernisation. We can change the wastewater handling by means of changed
systems and different system components but we can also change it with new knowledge and
changed conceptions and definitions: Not only different technologies and knowledge but also
research, administrative and business interest are at stake (5), (6), (7), (20), (21).
Today we flush out the child with the bathing water. We still use a lot of drinking water
producing wastewater getting rid of our nutrients from urine and faeces, and we further more send
the shower water after diluting them. What we meet at the wastewater treatment plant, on the field
or at the incineration plant can't be recognised. It is for sure not the child we originally excreted or
even flushed out. The concept, the paradigm that should flush out infectious risks from the cities
maybe also flushed out the basis for sustainability in the future. Sludge and treated wastewater are
not intended recirculation end products in a concept which from the start is aiming at reuse of
nutrients of high quality in optimal amounts and in high concentration to organic farming. Sludge
and treated wastewater are end products in a source mixing disposal strategy often mixing very
different sources to carry out a common treatment.
The technical installations are drawn up in a way, which makes it difficult to differentiate
different streams according to alternative present wishes and existing knowledge.
There is a need of a catalogue of concepts, systems and system components. In the following
summaries and conclusions from selected projects some technical components and technical
questions and user experiences with technology and handling of urine and faeces will be in focus.
There is a need of a range of systems and components to enable the handling of the streams
originating before the mixing of them into total mixed streams with which we are confronted today.
Successfully diverted source controlled reuse of resources in human excreta, as an alternative to
source mixing disposal of waste, will put up large demands on diverting system components
functionality and reliability
Water and nutrients are fundamentally live giving and water can be used for transportation and
dilution. The ability of water as a mean of transport and dilution has been used as a solution in the
existing mixed disposal systems. In a renewed strategy for reuse of nutrients flush water and
dilution is no longer the solution but a central problem.
The project report reflects on the historical development away from the use of diverted human
residuals as being merely an expressed reflex out of a removal paradigm rather than a reflected
development regarding recirculation of nutrients and organic material to agriculture. There is need
for qualitative modernisation within wastewater handling. New technologies as well as new
conceptions are needed to design the wanted human fertilizer products. There must be a readiness in
the social functional systems and institutions to eventually redesign structural conditions like
regulative and economical management for this process when required.
Ecological sanitation – humane urine and faeces
Among other things, ecological sanitation must be safe, and secure the recycling of human nutrients
of a high quality for agricultural purposes.
Table 1 shows that even if human urine is about 1 % of the volume of household wastewater, it
contains most of the nutrients and only a very small part of the heavy metals.
Parameter Unit Urine Faeces Greywater
Mass kg/year 550 40 40 000
Nitrogen % 80 11 9
Phosphorous % 55 28 17
Potassium % 60 16 24
Copper % 1.407 15.290 83.303
Chromium % 0.333 0.657 99.010
Nickel % 0.347 3.602 96.051
Zinc % 0.099 24.397 75.504
Lead % 0.063 0.662 99.275
Cadmium % 0.579 5.355 94.066
Mercury % 3.030 46.060 50.910
Table 1 Distribution of mass, nutrients and heavy metals in
household wastewater (24)
Table 2 shows the content of heavy metals related to Danish limit values. Especially the values for
urine are far under the limit values.
Parameter Unit Urine Faeces Limit values
Copper mg/kg DM 1.690 22.333 1,000
Chromium mg/kg DM 0.169 0.406 100
Nickel mg/kg DM 0.119 1,500 30
Zinc mg/kg DM 0.731 219,000 4,000
Lead mg/kg DM 0.032 0.406 120
Cadmium mg/kg DM 0.018 0.206 0.8
Mercury mg/kg DM 0.023 0.422 0.8
Table 2 Heavy metals in human urine and human faeces in relation to
dry material (DM,) and compared to Danish limit values (12), (24)
Human urine is only considered a potential health problem due to potential cross contamination by
faecal material. Table 3 shows the values for indicator bacteria in
fresh human faeces.
Indicator bacteria Unit Content in faeces
Total coliforms Cfu/g 10 000 000 – 1 000 000 000
E. coli Cfu/g 10 000 000 – 1 000 000 000
Enterococci Cfu/g 100 000 – 1 000 000
Table 3 Content of indicator bacteria in human faeces (15), (16)
Diverting/No-mix toilets and waterless urinals
Human beings with two outlets for urine and faeces construct toilets with only one inlet. Mixing is
the answer to an often forgotten question. Why mix? No-mix toilets and waterless urinals are no
logical solutions in order to continue where our natural physical process ends. Why not consciously
manufacture and process fertilising products from human waste products?
IMPROVED KNOWLEDGE CONCERNING DIVERTING TOILET TECHNOLOGY TO
ENABLE REUSE OF ENERGY RESOURCES AND NUTRIENTS IN HUMANE URINE
AND HUMAN FAECES
The project was initiated and carried out 1998 – 2002 by A & B Backlund ApS with Arne Backlund
as project manager and partly finansed by the National Agency of Environmental Protection. Basis
for the project is that diverting toilet technology contains interesting system components for
separate collection of urine and faeces. The system components shall, however – be able to collect
the residuals in a function stable way and in a concentration suitable for treatment in e.g. biogas –
and wet composting plants as well as for use as fertilizer in agricultural production.
The project report (XX) reflects on the historical development away from the use of diverted
human residuals as being merely an expressed reflex out of a removal paradigm rather than a
reflected development regarding recirculation of nutrients and organic material to agriculture. There
is need for qualitative modernisation within wastewater handling. New technologies as well as new
conceptions are needed to design the wanted human fertilizer products. There must be a readiness in
the social functional systems and institutions to eventually redesign structural conditions like
regulative and economical management for this process when required.
Four selected investigation areas are addressed.
1. The first concerns investigation and consideration regarding establishment of source diverting
vacuum toilets in a housing area in Hannover, Germany with 32 source collecting vacuum
2. The second is investigating the efficiency to separate faeces and paper from water after using
source collecting or source diverting water-flushing toilets.
3. The third area focuses on the functioning and running of waterless urinals as an opportunity for
collecting concentrated urine.
4. The fourth concerns risks of blockages in the urine collection system of source diverting double
flushing toilets and possibilities of avoiding or solving these problems.
Figure 2 WM-Ecovac 2
Central vacuum system in Hannover, Germany
Source diverting vacuum toilets are presented. Connected to the test of a ”Ecovac 2” toilet mounted
on a central plant with 32 source collecting ”Evac” vacuum toilets, this type is also presented and
experiences from the running are given. The investigation is among others carried out in a co-
operation with Stadtwerke Hannover. The investigation points out that with source diverting
vacuum toilets there should be a potential for a more concentrated collection of faeces in blocks of
flats than from source collecting vacuum toilet technology.
The water demand for flushing the source collecting vacuum toilets in 32 flats with a level of 8.2
litres (person-day)(1998), 8.0 litres/p/d (1999) and 9.2 litres/p/d have resulted in water savings of 80
% compared to the former use of toilets with a daily amount of water flush of approximately 40
litres/p/d. The concentration of dry matter from the source collecting toilets is estimated to 1 % DM.
By means of source diverting toilets the DM-% should be able to reach a level of 1.75 – 3.5 %.
The electricity demand 0.006 kWh/(person/day)(2000) as well as the level of noise (sound levels
of 35 – 52 dBa in the living rooms, 43 – 53 dBa in the kitchens and 52 – 60 dBa in the entrances)
could be reduced by using diverting toilet technology.
The diverting vacuum toilet has created a lot of interest in Germany and is as a part of ”Öko-
Technik-Park” Hannover continuously used for demonstrations etc. during EXPO-2000 in
Hannover. A lot of written informative material has been worked out also informing about the
toilet. Though some development of the toilet is needed among others of the vacuum valves of the
faeces outlet. These valves have to be tested for a long period under practical look alike conditions.
Another possibility is taking advantage of the existing use of the source diverting vacuum toilets
establishing a small vacuum system to every single flat. It would have a very positive influence on
the security of running and the consequences of blockages. The individual systems would be able to
transport residuals including grinded food residuals from the individual households in separate pipe
transporting systems with separate vacuum motors and sluice valves to one or more joint
Source collecting as well as source diverting vacuum systems can collect 100 % of human
residuals. Source diversion gives, however a much higher DM-% and a possibility of separate
collection and differentiated use of human fertilizer products.
”Aquatron” separators are presented. Four investigations regarding usage of ”Aquatron”
separators to separate faecal material and paper from the flush water using source-collecting or
diverting toilets are presented and discussed.
Figure 3 “Aquatron” separator Separator with a rotating composting unit
The efficiency of the separation depends on a number of factors such as the speed of the water
reaching the separator, the size of particles at the arrival, the amount of paper in the water, the
amount of flush water and so on. The size of particles is determined not only by the consistency of
the excreted faeces but also depending on the transporting pipes, their length, vertical falls, changes
of directions etc. Highest concentration of dry matter, organic matter and nutrients could be
achieved by using source-diverting toilets in single houses with short pipe lengths and modest
A laboratory test at SPI in Borås, Sweden, resulted in 1 % and 2.4 % of water through the particle
outlet at three-litre clean water flush and respectively one and six metre 110-mm diameter with 5 %
fall. Flushing of seven grams of paper gave 100 % of paper and approx. 12 % of flush water
through the outlet for particles. By flush of rod shaped particles, 2 – 5 mm diameter or split peas 6 –
7 mm, 7.4 % of the 2 – 5 mm particles together with 2.6 % of the flush water and 98.3 of the 6 – 7
mm particles and 2.3 % flush water through the outlet for particles at one metre pipe length (99.8 %
particles and 2.5 % water at six metre pipe).
At the measurements on an installation in a cottage, with a collecting toilet flushing three litres, a
collection was registered of 43.2 % of DM, 57.7 % of VS (organic matter), 11.8 % of N, 29 % of P
and 17.5 % of K and a DM-% of 2.6 and a VS-% of 2.24 in the collected material from the particle
outlet. Estimates concerning the potential concentration in collected material from the particle outlet
by faecal flush of 4.0 – 8.8 % DM and 2.7 – 5.8 % VS shows a great potential by using diverting
Measurements on collected material from 22 source diverting toilets and two parallel separators in a
social building complex with four stores and a basement showed 38 % of DM, 51 % of VS, 55 % of
N as well as of P and 43 % of K through the outlet for particles. However the DM-% was only 0.22
and the VS-% only 0.16. Even if the concentrations of DM, VS and nutrients were low because of a
combination of big vertical falls, long pipes, large and frequent flushes, systematic flushing of
urine, drying paper etc. the collection -% for nutrients were much higher than in the cottage
installation due to source diversion. It is unsatisfactory that about 13 % of the flush water leaves
through the outlet for particles and that the main part of the dry matter including the paper
disappears through the outlet for water. The amount of water through the particle outlet can be
reduced by reducing the water flush from six or nine litres to four litres, by reducing the frequency
of flushing and by refraining from flushing out paper used for urine only using a sanitary bin
It seems furthermore, necessary to reject long vertical falls of up to four floors as these may split
faeces as well as paper into pieces. Until those problems are solved it is advised not to install
separators in large multi store buildings.
At a laboratory test of separation of particular material by flushing collected faecal material, 90
grams wet weight/portion, with 4 litres of water through pipes of 110 mm diameter with one meter
vertical fall and further two meter transport with 5 % fall, showed a result completely different from
the results of the multi store building. At the laboratory test the separation was very efficient.
Approximately 80 % of DM as well as VS were collected from the particle outlet together with
approximately 70 % of N, P as well as K. The DM-% was 10 and only 2.6 % of the flush water
went to the particle outlet. By flushing six litres the DM-% fell to 7.7 %. The flushed faecal
material only contained small amounts of paper. Bigger amounts of paper could, based on tests at
SPI in Borås, have resulted in more water to the particle outlet. Even if 12 % of the flush
water joined the paper by flushing the faeces together with 7 grams of paper the DM-% by four litre
flushes is estimated to be 6.5 – 7 %.
A system consisting of diverting double-flushing toilets in combination with ”Aquatron”
separators has a potential for collection of 80 % of the substances in urine and 70 % of the
substances in faeces. Usage in multi store buildings, however requires a disciplined flushing regime
as well as special pipe installations or many separate systems without big vertical slopes. In the
future it may also be possible to collect coarse grinded food residuals in concentrated form by use
of a separator.
It is concluded that it is possible to collect a product with a rich concentration of organic material
and nutrients. This especially applies to usage of diverting toilets in single households with a faecal
flush of three to six litres and without flush of paper used by urinating only. If paper used by
urinating only is frequently flushed out, the situation will change quickly. If the aim is a
concentrated collection in a closed container, frequent six to nine litre flushes of paper especially in
multi store buildings with pipes to many toilets would create problems. Further tests and
investigations of how to solve the above mentioned problems should be made before installing
separators in multi store buildings.
Fig. 4 “Ernst waterless” “Ernst waterless urinal”
Different waterless urinals based on different principles are presented. The principles are described,
and experiences from using the urinals are reported. The experiences are good. Waterless urinals
should in the future be a decisive component for a cost efficient collection of concentrated urine.
Waterless urinals have a collection of 100 % and secure a maximum concentration of substances. It
would be of interest to investigate whether normal vegetabilic oils as rape oil could be used as a
sealing liquid and whether fresh urine in a liquid lock in combination with natural perfumes would
cause odour problems. There is also need of investigations concerning transport in pipes of
Focus is also put on blockages in the urine system of diverting toilets. The results of analysis and
collections of experiences are presented. Almost all of the investigated toilets had had blockages.
Possibilities of avoiding and solving problems are discussed, among others by means of
electromagnetic water treatment. It is concluded that all of the investigated blockages could be
removed with a mechanical cleaning wire or by using NAOH. An interesting development for
reducing formation of hard crystals as well as securing a better collection of concentrated urine
would be an outlet valve that prevents the flush water for urine to enter the urine pipe. Magnetic
water treatment could possibly be used in connection with irrigation of urine in drip irrigation
systems to prevent blockages related to usage of hard water. It is essential to investigate these
Diverting toilets, vacuum technology, separators and waterless urinals could all be an important
factor in concepts for a sustainable society with collection and recirculation of nutrients and organic
matter in urine and faeces to agriculture. Waterless urinals seems to be the technical system
component which is most easy to establish and run in order to collect big amounts of concentrated
urine. If it can be recommended to establish diverting vacuum toilets or diverting double flushing
toilets in combination with a separator is highly dependent of the concrete place and the users.
VACUUM TOILETS ALLOW THE UTILISATION OF ENERGY AND NUTRIENTS IN
HUMAN RESIDUAL PRODUCTS AFTER TREATMENT IN A BIOGAS OR WET
In the district of Nysted on Lolland two detached houses have had put in vacuum toilets of a new
design in 2000. The toilets were installed as part of a project meant for illustrating the possibilities
of recycling concentrations of "black" wastewater (wastewater from water closets) for agricultural
purposes. The project report describes the experience from the new toilet systems for detached
houses and from earlier common vacuum systems in summer cottage areas on Lolland and Falster.
The new vacuum toilet systems for detached houses, which are continuously developed, have
very low water and electricity consumptions. A great deal of the operating troubles connected to the
earlier vacuum systems has been surmounted. Examinations indicate that vacuum toilets make it
possible to collect a product applicable for co-treatment at a biogas and wet composting works. The
report also includes experience from our neighbouring countries.
Storstrøm County has initiated the project in co-operation with A & B Barklund ApS and is
supported by the National Agency of Environmental Protection through "Action Plan for the
Promotion of Ecological Urban Renewal and Wastewater Treatment".
Background and objectives
By the end of the 1960´s and at the beginning of the 1970´s, Storstrøm County established vacuum
toilet systems in many summer cottage areas, where the wastewater cannot move by means of
gravitation, due to the conditions of the ground or because of elevated groundwater level. Instead of
treating this wastewater at sewage works, the content of energy and nutrients is exploited through
treatment at a biogas or wet composting works. The material may be utilised for energy purposes
(the biogas works) or for the generation of heat (the wet composting works). The content of
nutrients in the residual product may be used for agricultural purposes.
The project holds experience gathered from the installation and running of two new types of
vacuum toilets for detached houses, including a source diverting toilet with separate collection of
urine and faeces, as well as the running of large, common vacuum toilet systems in the county.
Based on test results and theoretical calculations, concentrations of organic material/dry matter and
nutrients have been tested with a view to identifying the applicability of the material for biogas or
wet composting treatment. At the same time it has been examined whether it is possible to treat the
collected "black" wastewater at the district biogas works as well. In comparison to this, experience
has been gathered from the establishment and/or the running of vacuum toilet systems and wet
composting works in our neighbouring countries.
The two new vacuum toilet systems were established in 2000 (figure5). The toilets are equipped
with a direct/temporary instead of permanent vacuum, which is generally used. The collected
material is transported to storage tanks by means of vacuum. In the source segregation system the
urine plus 0.1-0.2 litre flush water run to a separate tank by means of gravitation. The users' and the
plumbers' experience from the installations, the running and the use of the toilets have been
gathered during the years of 2000 and 2001.
Figure 5 Sketch of the system for a single vacuum toilet, with the vacuum established only in
connection with the use of the toilet.
Experience has been gathered from the running of large vacuum toilet systems in four districts as
well as from the running of two minor, public systems in Storstrøm County (Figure 6). We have
interviewed both the technological and the administrative staff of the districts as well as the local
plumbing service who have repaired the systems and replaced the toilets. Test results from vacuum
toilet systems in Sweden and Germany as well as the treatment of human residual products in a
Swedish wet composting works have been consulted throughout the entire project period.
Figure 6 Vacuum toilet system with the permanent vacuum close to the toilet.
Toilet with magnetic valves
Collecting tank with flush pipe valves
1. Toilets with a vacuum valve in each house.
2. Vacuum station with vacuum pumps and wastewater pump.
3. Storage tank. Alternatively, the wastewater may be pumped on to another sewage treatment
The examination and the assessment of the collected product's suitability for treatment in a wet
composting or biogas works have been made on the basis of theoretical calculations of its content of
dry matter, organic material and nitrogen, as well as of individual analyses of the material collected
in two vacuum systems in the district of Rudbjerg. Moreover, test results from Swedish works have
been applied. Due to operating troubles it has proved impossible to make representative samples of
the collected wastewater from the new installations.
The costs of the establishment and running of vacuum toilets, including the disposal of the
collected material, have been illustrated on the basis of experience from detached houses in Nysted.
As the economy will depend on the specific, local conditions, no theoretical calculations have been
made concerning the profitability in establishing toilet systems in a major number of houses in
combination with treatment of the material at a biogas or wet composting works. The economy in
connection with works in Norway and Sweden is described.
Vacuum toilet systems can collect material with a high concentration of organic material
and nutrients and with very few substances injurious to the environment
In detached houses with storage tanks the quantity and frequency of the emptying will be
considerably lower than is the case with an ordinary water-flushing toilet. With the pilot
installations, water savings of 40-50% have been obtained. The largest reduction is seen in
connection with source segregation toilets
With the new toilets the electricity consumption is insignificant and considerably lower per
person as for the toilet equipped with a temporary vacuum, compared to the consumption
connected to toilet systems with permanent vacuums
Normally the plumbers are not acquainted with the system and its components, the systems
being not particularly common. It is therefore of great importance that satisfactory
assembling instructions are available to the plumbers
To obtain the optimal function of the toilet systems, sufficient user information is crucial.
The way the users' treat the toilets is important – also as to the quantities and concentrations
led to the storage tank
The toilets require cleaning more frequently than ordinary toilets. The residents of the two
houses, who have chosen the system themselves, do not find it a problem in their everyday
lives, however, when comparing the additional work to the water saving
Experience from Bälinge, Sweden, and Storstrøm County concerning vacuum toilet systems
for many connected households shows that it is possible to run such systems with a
minimum of operating troubles, provided the system is in good repair and the users are well
informed. The systems require more maintenance than the gravitation systems
The concentrations of organic material tested in large systems with permanent vacuums in
Storstrøm County and in Sweden indicate that the material is treatable in a biogas or wet
composting works. The concentrations are not high enough, however, for the works to run
exclusively on this material. Large quantities of organic material with considerably higher
content of dry matter and organic matter must be added. The application of source
segregation vacuum toilets can increase the concentration significantly
It costs 70-150% more to establish a vacuum toilet system combined with one or two
storage tanks, compared to the costs for the establishment of an ordinary toilet system with a
storage tank. On the other hand, the annual expenses for a traditional toilet system are much
higher than those for a vacuum toilet system
At the biogas works in the district of Nysted, the treatment price for organic residual
products is DKK 65-180 per cubic metre, depending on the content of e.g. dry matter. The
profitability of the treatment depends on e.g. the pricing of the protection of the aquatic
environment and the use-value.
Project results - Experience from newly established vacuum toilet systems in two houses in the
district of Nysted
Both installations had problems in the initial phase, i.e. for about six months, but most of them were
overcome. It will thus be possible to make them function perfectly in all houses. Some of the
system components are too fragile and need improvement, however.
The installation of the toilet, including piping, burial of the tank etc. is not more extensive than
that of a traditional system, provided efficient documentation and instruction are available. The
electricity work is more extensive, however, as normally no electric control system is used. As only
a few people are familiar with the technique, good information is crucial to both time consumption
and to the prevention of a number of subsequent operating troubles.
The plumbers found it difficult to adjust the electric control of the vacuum system. The guide plate
and the adjusting screws are produced from a fragile material, which is intolerant to frequent
adjustment. Even during the running-in period the guide plate had to be changed. The adjustment of
the correct sucking-out intervals was done according to the instructions of the firm. The adjustment
depends on a certain flair and several tests, until it functions optimally. The requested 3 metres
between the toilet and the flush pipe valve is too short a distance to ensure a stable operation. Due
to the unstable operation of one of the installations with a short distance, the vacuum toilet system
was replaced after 6 months by a source diverting, double flush toilet, DS.
Flush pipe valve
The flush pipe valves first delivered were of a too fragile structure. After the valves having been
equipped with heavier flaps and stronger fixing, no problems have been noted.
Vacuum pumps, filter and piping
The installations themselves are unproblematic. The filter is indispensable to the motor and to avoid
leaving a repulsive toilet bowl. It is easy for the users to clean the system.
Water consumption and emptying frequency
In the household with the non-diverting vacuum toilet, the water consumption was reduced by
approx. 45% during the project period. In future, the production of "black" wastewater is estimated
to be about 5 m3
annually. This means one or two annual emptyings compared to earlier approx. 6 a
year. The water consumption of the source segregation vacuum toilet was reduced by approx. 40%.
The emptying frequency could be expected to be reduced from approx. 12 times annually (approx.
in 1 tank) to about 2 times (11 m3
in 2 tanks), had the vacuum toilet been retained. Because of
the changing of toilet and because of the varying number of users, it has not been possible to
estimate the production of "black" wastewater.
In the household without source diversion, the power consumption is assessed to total 7 kWh/year
or a little more than 1 kWh per cubic metre, corresponding to an annual expense of DKK 12 at a
price of DKK 1.7/kWh. Using source diversion as an alternative, the annual consumption would
roughly be reduced to approx. 4 kWh in total, i.e. half of the consumption of the non-diverting
system. This corresponds to an annual expense of DKK 7 at a price of DKK 1.7 per kWh.
Using the toilets has caused no problems to the visitors, among whom many children. All users,
irrespective of sex, must sit down during the use of the two-part toilet because of the source
diversion. The family with the diverting toilet have not been missing a child's seat, and the children
using the toilet has caused no faeces landing in the urine bowl nor at the partition between the two
toilet bowls. Apparently it has been no problem, either, to use a sanitary pail for the toilet paper
after a "short visit". The toilets require a little more cleaning than usually, which, however, is
acceptable because of the considerable water saving. It is fairly easy to explain to guests how to use
The motor may make a lot of noise, for which reason it is of great importance where it is placed.
To avoid the noise nuisance, the pump (motor) can be placed at the entrance of the tank.
Treatment of the collected "black" wastewater
It has not been possible to have the collected "black" wastewater treated at the biogas works in
Kettinge in the district of Nysted. This is not due to any environmental requirement, however; it is a
matter of attitude. The biogas works is authorised to treating sludge from sedimentation tanks
(septic tank sludge). The residual products of the works are spread on farmland with farmers who,
due to agreements with Danisco, are not allowed to use residual sludge. Therefore the biogas works
in question accepts no residual sludge and in this case ranks the "human residual products"
alongside with sludge instead of with semi-liquid manure. The collected wastewater has been led to
a district wastewater treatment plant.
Storage tanks and vacuum toilet systems in Storstrøm County
In the County of Storstrøm, only a few houses have storage tanks. In 2001 there were 26,600 houses
with no sewage disposal (Storstrøm County 2002) and of these only 320 houses had storage tanks.
In some cases the "grey" wastewater is percolated, in other cases the "black" and the "grey"
wastewater are both led to the storage tanks.
Vacuum toilet systems
Approximately 30 years ago several major vacuum toilet systems with permanent vacuums were
established in the summer cottage areas of the county. Experience from the running of these
systems in Holeby, Ravnsborg, Rudbjerg and Sydfalster districts is described in the report. The
"black" wastewater is transported by the aid of vacuum to a common wastewater treatment plant for
purification, whereas the "grey" wastewater is percolated at the individual premises. Experience
shows that these 30-year-old transportation systems are somewhat worn and rather maintenance-
requiring, even though the municipalities have reduced the operating troubles considerably through
information and various initiatives. Generally, there are no plans of dismantling the systems.
However, in some cases they have problems percolating the "grey" wastewater, especially in the
wintertime, and therefore there is a wish to dispose of it in a different way.
The systems require inspection more frequently than the gravitation systems. It often happens that a
vacuum valve is leaky, which means that an entire pipe (the passage) may be out of order. In many
cases the valves are not accessible to the personnel; this is e.g. the case if the problem occurs in an
unoccupied summer cottage area. The valves turn leaky for many reasons, e.g. with age or if the
system is left unused all through the winter with a constant vacuum maintained. If the users try to
flush out napkins, cloths etc., which often occurs, the pipes will choke. These obstructions are
caused by a large number of changing tenants during a season, and that these are not familiar with
the system or just do not care about the vulnerability of it. Apart from that, the pipes may choke
because of calcareous sediments.
How to remedy operating troubles
In recent years the municipalities have taken steps to remedy the operating troubles in many
respects. They have established clean out holes on the roads or even on the service pipes to the
houses and made a point out of informing the users. They have reduced the number of operating
stops considerably. Experience from Sweden also shows that the installations can be run
satisfactorily after the running-in period.
Description of collected "black" wastewater
Test samples from two installations in the district of Rudbjerg show a concentration of organic
material of 5.4 mg/l and 5.8 mg/l respectively. These figures make the material suitable for
treatment at a biogas or wet composting works. The concentrations measured correspond to the
ones made in Sweden.
The power consumption of the two installations in the district of Rudbjerg has been estimated at
quite 60 kWh/m3
, which is considerably higher than in two housing sectors in Sweden and
Germany. This is due to the transport distance being much longer in the district of Rudbjerg.
Wet composting and wet composting systems
Wet composting is a thermophilic, biological treatment process, which develops under the supply of
oxygen. In a composting drum the energy content in a biological residual product is used for
producing a high treatment temperature. The surplus heat may be used for external heating. The
treated material (the residual product) is used as a fertilizer. The report mentions the power
consumption during the operation to be 19-35 kWh/m3
treated raw material and possibilities of
using 50-60 kWh/m3
raw sludge for external heating purposes. Moreover, Swedish heat balance
studies are referred to.
Biodegassing and biogas works
Biodegassing/digestion is an anaerobic, microbial decomposition of organic material under
generation of biogas (methane). The treated material (the residual product) is used as an agricultural
fertilizer. There are farm biogas installations, biogas installations at purifying plants or biogas joint
installations with a gas production, based on domestic animal manure, source segregated household
waste, residual sludge and organic trade refuse. Predominant is the domestic animal manure.
Residence time and process temperatures may vary. A distinction is made between mesophilic
digestion (20-52° C) and thermophilic digestion (52-60° C). The biogas potential per year from a
person is assessed to approx. 4 m3
biogas from the faeces and 5.4 m3
from the urine, i.e. a total of
biogas, assessed from the content of organic matter. The high content of nitrogen in urine
can have an inhibitory effect on the thermophilic processes.
Theoretical calculation of the concentration of collected material from vacuum toilets
The report contains calculations of the concentrations of dry matter and organic matter obtainable
through vacuum toilet systems. These results may be used for estimating the dimensions of tanks,
emptying frequencies, expenses for emptying and treatment. They may also be used for an
assessment of whether the material (the "black" wastewater) is suitable for treatment at existing
biogas works or at newly established wet composting works at an acceptable price. The report also
includes the test results of components of material collected through other techniques, e.g.
sedimentation tanks etc.
Expenses for the establishment of vacuum toilet systems in detached houses
Among other things, the preliminary expenses for the vacuum systems depend on whether one or
two storage tanks are in use. The foreseeable expenses are 70-150% higher that those for the
establishment of a conventional system with an ordinary toilet (3/6 litre).
The running of vacuum toilet systems
The running includes emptying the tanks, power expenses and expenses for the maintenance of the
components. The annual expenses for the running of conventional systems with storage tanks are
normally several thousand Danish kroner higher than the expenses for a vacuum toilet system. The
higher establishment expenses for the vacuum toilet system may be recovered within a few years,
provided no repairs have to be made. Another question is if it pays to treat the "black" wastewater at
a biogas works, too. The average county expenses for treatment of wastewater at a wastewater
treatment plant are approx. DKK 30 per cubic metre. The treatment price at the biogas works in
Kettinge is of DKK 180 per cubic metre – an additional price of DKK 150 per cubic metre. It
should be compared to the advantage of using the material for power generation or as a fertilizer
instead of discharging the wastewater, to the detriment of the aquatic environment.
About 15 toilet systems, including the latest changes, have been established in Sweden and Finland.
Here it is possible to take samples. Vacuum systems consisting of a single toilet with a temporary
vacuum system arouse great interest, which is due to the fact that both establishment expenses and
running expenses for systems with permanent vacuums are much higher. The latest changes seem to
have solved the problems that arose in the district of Nysted.
At present we know too little about the willingness of Danish biogas joint installations to receive
"black" wastewater collected from vacuum toilets.
COLLECTION, STORAGE AND APPLICATION OF URINE FROM THE "MØNS
MUSEUMSGÅRD" (The museum farmstead of Møn)
In order to clarify how urine may be recycled in Denmark, Storstrøm County has initiated the
project "Collection, storage and application of urine from the Møns Museumsgård". The project is
funded by the Municipality of Møn, and by the National Agency of Environmental Protection
through the "Action Plan for the Development of Ecologic Renewal of Towns and wastewater
treatment". The initiator of the project is the Møn Museum/the "Museumsgården", Den Grønne
Guide på Møn (the Green Guide of Møn), A & B Backlund ApS (private limited company) and
Storstrøm County. Together they developed and planned the project. The project was carried out
from 1998 – 2002.
The composition of the wastewater of the "Museumsgården" is a high quantity of urine and a
small quantity of an undistinguished substance of wastewater, which makes the separation of urine
by way of source segregation toilets and the utilization of nutrients reasonable. Contrary to a private
house, there will be many different users of the toilets at a museum. This fact makes it possible to
test a segregating wastewater system under somewhat difficult circumstances.
One of the purposes of the project is to collect experience in the installation and use of a source
segregation toilet system, including a waterless urinal, at the "Museumsgården" and to compare this
to experience from Sweden.
Another purpose is to examine the constituents of the urine, including whether the contents of
nutrients, heavy metals, microorganisms and organic substances alien to the environment will
change during storage. Moreover, the collected urine is compared to other urine mixtures and
fertilizers on the basis of these parameters.
Storstrøm County has not put through its own test programme, as the National Agency of
Environmental Protection initiated the project "Assessment of the possibilities and limitations of the
recycling of nutrients from town and country households " (10).
The toilet system of the "Museumsgården" was established in April 1999. Experience from the
installation and operation has been collected during the opening seasons of 1999 and 2000, and
partly during 2001.
The examinations include interviews concerning the installation and operation of the source
segregation toilet system. Apart from that, analytical results are worked up on the basis of the co-
ordinated test programme of the National Agency of Environmental Protection concerning the
content of nutrients in the collected urine, as well as heavy metals, microorganisms and organic
substances alien to the environment.
The "Museumsgården" is described on the basis of its statistic number of visitors and other
relevant characteristics important to the quantity and quality of accumulated wastewater.
Description of human urine
In this chapter, concentrated urine as a fertilizer is characterized. Compared to the content of other
effluent flows from a household, human urine is the kind of effluent flow that contains the main part
of the nutrients. Normally, human urine totals 1-1.5% of the household wastewater, but it
contributes approx. 80% of the nitrogen, 55% of the phosphor and 44% of the potassium in
Although human urine constitutes the main part of the nutrients in household wastewater, urine
contains but a small part of the total content of heavy metals. Heavy metals from human beings are
mainly secreted through the faeces.
Health risks related to the application of urine is generally not looked upon as connected to the
urine itself, but to the mixture of urine and faeces, which has a high content of microorganisms. If
urine is to be utilized as a fertilizer, it is crucial that the source segregation sanitary systems are
established in a way that cross contamination (the mixture of urine and feacal material) is kept at a
minimum. Moreover, to secure a good concentration of ammonium and a high pH factor the supply
of flush water must be limited; this is of great importance to the reduction of microorganisms during
Description of the "Museumsgården"
Today the "Museumsgården" is run as part of the Møn Museum. The "Museumsgården" is open
from May 2nd
till October 31st
. On the average, approx. 4,500 people visit the place every year, of
which 1/3 is children. The production of wastewater is relatively low. Prior to the project start, the
annual water consume constituted approx. 150 m3
, of which 30 m3
are estimated to have been used
outdoors. This consumption corresponds to the consumption of an ordinary household. The
composition of the wastewater differs from ordinary household wastewater, as the majority comes
from flushing-out and wash basins.
Description of the wastewater system
As part of the project, the old porcelain bowls with flushing tanks placed underneath the ceiling
have been replaced. The exact amount of flushing water of the old toilets is unknown, but it is
estimated to be about 9 litres (approx. 2 gallons).
In the gentlemen's lavatory there has been a stand urinal with a stainless steel drain and with
controlled, automatic flush from two cisterns. The urinal has had automatic flush approx. every 15-
20 minutes, using an unknown quantity of water.
With the exception of the sedimentation tank, the existing toilet system has been replaced by a
source segregation system. Four source diverting, double flush, porcelain closets as well as a
waterless, gel-coated, fibreglass wall urinal have been established. The surface of the urinal makes
the urine glance off. Inside the urinal there is a siphon, which constitutes an odour seal in
combination with a sealing liquid.
Figure 7 “Waterless” waterless urinal Siphon with a odour trap
Fig xx WM-DS 3 m3 urine collecting tanks
The diverted urine/flush water of the urinal bowl is led into storage tanks made of polyethylene.
The remaining wastewater is still led into the sedimentation tank. The cycle of the application of the
tanks was planned to be 6 months' collection in tank 1, and after that 6 months' storage during the
filling of tank 2. The 2 tanks are emptied once a year with 6 month's interval. The capacity of the
tanks, however, has turned out to be larger, i.e. a possible storage period of more than 12 months.
The Act on installation and spreading of urine
Systems for handling wastewater fall within the Act of Environmental Protection and the Building
Act. This chapter contains a short comment on the legislation relevant to the establishment of a
source segregation wastewater system. When the permission is given to the establishment of a
wastewater system including the collection of human waste products in a collection tank, it must at
the same time be made sure that emptying; transportation and final use take place in a proper way.
No general test and approval conditions are laid down for urine segregation toilets. Therefore,
each installation must be granted separate approval. This also applied to the urinal at the time of
establishment, but later a VA approval has been achieved. The pipe installations of a wastewater
system must be made in accordance with the Discharge Code DS 432.
Wastewater, including human waste products with agricultural value, may be used for
agricultural purposes according to the Sludge Regulations (regulation no 49 of January 20th
the application of waste products for agricultural purposes). The county may give permission to
make use of these products. The applications of urine and other human waste products depend on
the way they have been treated. Basically, they are comparable with night soil; but in case of further
treatment of the products to the effect that they no longer may be considered as night soil, they can
be used in farming and private gardening (according to the guidance of the National Agency of
Environmental Protection, no 5/1999 for the regulations on wastewater permissions etc.). The
treated end product may be compared with residual sludge as for application restrictions laid down
for sanitary reasons (cf. appendix 3 of the Sludge Regulation).
Experience from installation and operation
The experience from the establishment of the source segregation wastewater system at the
"Museumsgården", as well as the experience from the operation during the seasons of 1999, 2000
and partly 2001 is summarised in this chapter. No problems arose in connection with the
establishment of the system or with the adjustment of the flush. Due to a mistake, the storage tanks
for urine were not properly fixed in connection with their burial. The light tanks rose because of the
water pressure, and they have later been fastened. Moreover, the part connecting the shanks and the
tanks was not properly sealed, to begin with. This meant initial problems with water leaking in from
Functional performance and reliability of the system components
The overall experience has been positive – maybe even surprisingly positive, when you think of the
fact that there are many, different toilet users at the "Museumsgården".
No problems with the flush mechanism of the toilets have been reported, and no odour problems
because of the toilets have been observed. The staff has noticed no faeces in the small urine bowl or
at the section between the urine bowl and the faeces bowl. This indicates that no major cross
contamination has taken place.
The staff has observed that the toilets demand a little more cleaning than traditional toilets. The
short flush has not been able to keep the urine bowl completely clean, using a flush of about 2
decilitre. Approx. every 3 weeks the staffs has poured a mixture of water and acetic acid into the
water seal to prevent it from choking, among other things because of the crystallisation and deposit
To use the toilets correctly, sufficient instructions for use are a prerequisite. This precondition is
apparently met, as printed instructions on the lavatory doors and walls tell how to use the toilets.
After 3 seasons, the inside surface of the urinal is intact and smooth, so that the urine still glances
off. There are no visible remains of urine in the bowl. The surface has not been vandalised, and it
has so far not been necessary to polish the surface with car-polish, as recommended by the
manufacturer. Nor have there been any odour problems. Even though the manufacturer recommends
replacement after 5,000 – 7,000 times of use or at least once a year, there has been no need for the
siphon to be replaced since it was fitted in 1999.
The visitors' experience
No inquiry has been made into the visitors' experience from the toilet system of the
"Museumsgården". Interviews with the staff and the impression of the Green Guide's conversations
with visitors imply that the visitors have generally approved of the new system and have expressed
their satisfaction with the functioning. Even during the annual event, the fair day, with up to 600
visitors the system functioned impeccably, without odour problems or other problems.
A few have expressed their dislike for the toilet paper to be put into a bin – in connection with a
"quick visit". In this case you may abstain from following the instructions and put the paper into the
large bowl and activate "full flush" instead.
The special exhibition about the subject along with the establishment of the new system has
proved a good idea. The exhibition has given rise to many formal conversations about toilet systems
in general. It is the impression that the exhibition has reduced the surmounting of trying something
so completely different.
Results and comparison with other fertilizers
During the season of 1999 (from May 2nd
– October 31st
) approx. 1,830 litre (about 40 gallons) of
urine mixed with water was collected in tank 1. The number of visitors during the season was 4,320.
During the period from November 1st
1999 till September 1st
2001, 2,640 litre of urine mixture was
collected in tank 2; the number of visitors was 6,856. The analyses of the co-ordinating test
programme have been carried out for the urine mixture in tank 1. Chapter 8 deals with the results of
the analyses of the constituents of the stored urine mixture. The results are compared to the analyses
of other fertilizers.
The urine mixture from the "Museumsgården" has a percentage of dry solid matter of 0.3384, and
contains approx. 3,300 g nitrogen (N), approx. 135 g phosphorus (P) and approx. 1,250 g potassium
(K). Potassium is normally the best indicator of the concentration of the urine mixture. If the ratio
between urine and flush water is based on the concentration of potassium, it means a urine content
of 35%, corresponding to a ratio of 641 kg of urine and 1,189 kg of flush water. The collected urine
mixtures are not only diluted because of the flush water: it is not possible to retain the total quantity
of urine in the source segregation toilets. The percentage of collected urine through the source
segregation toilets on Møn is unknown, too. Examinations of toilets in Swedish apartments have
proved a collection percentage from 50 to 80 (16), (24). A further development of the toilets will
probably result in the collection of a more concentrated fertilizer.
The test results of Møn have been compared to test results from urine tanks of similar source
segregation toilets in the rented dwellings of "Hyldespjældet" in Albertslund near Copenhagen, and
from the Svanholm Estate. Moreover, they have been compared to a test from ten allotment garden
houses equipped with source segregation dry closets with only little or no manual flushing. All the
projects belong to theme 3 of the action plan. The analyses show that urine mixtures have a
considerable content of nitrogen, and that the content of phosphorus is low – lower than in the
concentrated urine. The lowest content of phosphorus was demonstrated in the urine mixture from
The nutrient of the urine mixture from the "Museumsgården" is compared to the content of
concentrated urine and to residual sludge, compost, and liquid manure, used as fertilizers. The
content of nutrients (N, P, K) of the urine mixture is "thin" compared to the other fertilizers, but the
low concentration of dry solid matter makes the urine mixture most suitable for spreading through
Parameter Unit Møn T0 Møn T4 Møn T6 Hyldes. Svanh. Allotm.
El.conductivity ms/m 1 500 1 500 1 400 1 400 1 730 3 000
Nitrogen mg/l 1 800 1 500 1 600 2 000 2 500 5 400
Phosphorous mg/l 74 77 68 100 170 360
Potassium mg/l 680 670 590 430 1 200 1 100
Ammonium mg/l 1 800 1 500 1 600 1 500 2 200 5 100
Calcium mg/l 36.6 20.4 9.67
Magnesium mg/l <1.80 <1.80 0.2 <1.8
Sodium mg/l 616 756 1 700
Table 4 The electrical conductivity and the content of nutrients in EPA projects (3), (11), (12), (18)
T(x): Months of storage without further supply
In table 5 the content of nutrients in ”Møn” is compared to the content in other organic fertilisers. It
is obvious that especially the concentration of P is very low in ”Møn”
Parameter Unit Urine Møn, T0 Wastewater
DM percent. % 3.98 0.3384 13.648 66.434 6.739 11.899
Nitrogen mg/kg mass 7 300 1 800 5 897 5 944 9 058 7 377
Nitrogen mg/kg DM 130 000 532 544 43 500 9 000 127 000 55 000
Phosphorous mg/kg mass 670 74 4 297 1 399 1 812 857
Phosphorous mg/kg DM 16 700 21 893 30 300 2 000 28 000 11 000
Potassium mg/kg mass 2 000 680 421 2 448 3 261 6 188
Potassium mg/kg DM 35 000 201 183 3 600 3 500 72 000 50 000
Table 5 The content of nutrients in collected urine mixture ”Møn”, compared to other organic
fertilisers (11), (12), (24)
Heavy metals and organic substances alien to the environment
As part of the co-ordinated test result programme, the content of heavy metals and organic
substances in the urine, alien to the environment, has been tested. The results have been compared
to the content in the urine mixtures from the other examined segregation systems including
concentrated urine, and to results from similar analyses of other fertilizers. The results prove that
the content of heavy metals and substances alien to the environment in urine mixtures is low. Thus,
the content of concentrated urine and of urine from the "Museumsgården", on the basis of dry solid
matter, is down to thousandths of the marginal values which apply to the spreading of residual
products allowed for agricultural purposes (according to regulation no. 49 of January 20th
The analyses moreover show that the content of heavy metals in the urine mixture is considerably
lower than in the other fertilizers. The concentration of Cadmium (Cd) in the urine mixture, in
relation to the dry solid matter from the "Museumsgården", constitutes but a couple of per cent of
the concentrations found in liquid manure and but a couple of thousandths of the content in residual
sludge and compost. The differences are more evident if the content is calculated in relation to the
content of nitrogen and phosphorus and is most evident for nitrogen.
The content of substances alien to the environment in the urine mixture, calculated on the basis of
the content of nitrogen and phosphorus, is down to thousandths of the content in residual sludge and
composted household waste. The content of PAH and NPE in liquid manure is at the same level as
that of the urine mixture. This is not surprising, as the sources of these substances are primarily the
Table 6 shows the content of heavy metals compared and related to Danish limit values on the
basis of dry material. The content in ”Møn” is by far the lowest.
Parameter Unit WW
Møn T0 Danish
Cadmium Mg/kg DM 2.0 0.3 0.5 0.6 >0.0118 0.8
Mercury Mg/kg DM 1.4 0.1 <0.1 <0.1 - 0.8
Lead Mg/kg DM 71 32 3 4 0.49 120
Nickel Mg/kg DM 23 9 14 8 1.25 30
Chromium Mg/kg DM 32 11 10 3 0.49 100
Zinc Mg/kg DM 760 150 1.500 150 45.86 4 000
Copper Mg/kg DM 262 50 630 65 3.05 1 000
Table 6 The content of heavy metals in organic fertilisers, compared to”Møn” and Danish limit
values (3), (11), (12)
In table 7 the levels are compared on the basis of N, which would be the interesting parameter in
using urine mixture as a fertiliser. The values for urine mixture are far below the values for other
Parameter Unit Møn T0 WW
Cadmium mg/kg N <0.02 32.9 35 3.6 8.5
Chromium mg/kg N <0.91 929 1 118 72 45
Copper mg/kg N 5.72 17 857 5 588 2 640 1 097
Mercury mg/kg N 31.4 12
Nickel mg/kg N 2.34 571 1 000 96 116
Zinc mg/kg N 86.11 7 000 16 471 6 120 1 742
Lead mg/kg N 0.92 24 58
Table 7 Heavy metals in urine mixture ”Møn” compared to other organic fertilizers.
Concentrations in mg/kg N. (11), (12)
Unit Møn T0 Møn T4 Møn
PAH ug/l 0.000 0.069 0.34 0.094 <10 0.85
DEHP ug/l 2.4 20 5.4 3.0 29.0 20
NPE ug/l 0.0 9.8 11 0.0 <15 27
LAS ug/l <20 <20 <20 <20 <0.030 <0.02
Table 8 The content of PAH, DEHP, NPE and LAS in human urine mixtures in EPA projects (11),
In table 9 contents of organic compounds are compared and it is shown that urine mixture is far
below sludge and compost and at the same level as manure.
LAS mg/kg N <12.5 61 429 2 353
PAH mg/kg N 0 - 0.2 143 59 0.16 0.32
NPE mg/kg N 0 - 6.9 357 59 8 16
DEHP mg/kg N 1.3 - 13.3 857 1 176
Table 9 The content of LAS, PAH, NPE and DEHP in ”Møn”, compared to content in sludge,
compost and manure. Concentrations in mg/kg N (3), (12)
The results of the microbiological analyses
The results of the microbiological analyses of the co-ordinated test programme are compared to the
content of the urine mixtures of the other theme 3 projects. The number of Enterococci serves as an
indicator of feacal pollution of the urine mixture. The quantity of Enterococci in the urine mixture
from the "Museumsgården" had already been reduced to less than 10 per 100 ml after 2½ months.
The quantity of Enterococci and Escherichia coli would typically fall under the limit of detection
after 3-4 months' storage of the urine mixture, with some individual modifications in the projects
(Dalsgaard & Tarnov, 2001). The bacterial count of the urine mixtures at 37º has also been reduced
considerably during the first month of storage.
The disintegration rate of the bacteria depends on the pH and temperature conditions in the
storage tanks. The pH should be min. 8.8, and the temperature rather 20 than 4 (Jönsson et al., 2000,
Höglund, 2001). During the last part of the test period, the temperature of the storage tank has risen,
and the pH factors registered have not been quite up to the mark. It may be due to the fact that the
urine mixture has a relatively low concentration of urine.
The microbiological analyses show that no Salmonella or Camphylobactor have been found.
After 2½ months' storage, the content of Enterococci in the urine mixture from the
"Museumsgården" is less than 100/g. In this respect the urine mixture meets the hygienic
performance criteria in force, laid down in the sludge regulation (regulation no. 49 of January 20th
2000 concerning waste generation for agricultural purposes). The treatment of the urine mixture,
however, does not quite correspond to the definition of the controlled sanitising laid down in the
regulation. These demands must be met before spreading.
Dalsgaard & Tarnov (2001) conclude that by 4 months' storage of separately stored urine mixture
a considerable reduction of bacterial infectious matters is obtained. "Utilisation of stored urine as a
fertilizer seems to constitute an insignificant risk of bacteria-based gastrointestinal infection with
animals and human beings in the handling of urine, and in the consumption of urine-fertilized
The presence of the parasite Chryptosporidium parvum (10) has been demonstrated, whereas the
parasite Giardia duodenalis has not been found in the urine mixture of the "Museumsgården". The
Danish Environmental Protection Agency has, among other things for this reason, started an
analysis of risks of the collected urine (Linda Bagge, personal information).
In table 10 the content of microorganisms in urine mixtures are compared
Parameter Unit Time
Møn Hyldespj. Allotment
cfu/100 ml (mg) T0
E.coli cfu/100 ml T0
Enterococci cfu/100 ml T0
1 500 000
c/10 g (ml) T0-T2 neg. neg. neg.(T0-T1)
Salmonella c/10 g (ml) T0-T2 neg. neg. i.p. (T0-T1)
(antal pr. ml.)
pos./neg. neg. Neg. neg.
pos./neg. neg. Neg. neg.
Table 10 The content of micro-organisms in urine mixture ”Møn” and other urine mixtures (3),
In table 11 the content of microorganisms in ”Møn” is compared to the content in manure, sludge
and treated biomass. It is shown that the content in ”Møn” was far lower.
2 000 000
32 000 000
24 500 000
43 000 000
1 300 000
48 000 000
29 000 000
1 400 000
83 000 000
Neg. pos. in
53.5 % of
50 % of
Neg. up to
pos. in 4 out
of 53 sampl.
Neg. 0 – 300 0 – 100
0 – 200 0 – 100
Table 11 The content of microorganisms in ”Møn”, compared to manure, sludge and treated
biomass (1), (3),(8), (9), (12), (26)
Source diverting toilet systems and the application of collected urine in Sweden
In this chapter, a number of examples of and experience from installations of source diverting toilet
systems in various types of housing in Sweden is introduced in order to be able to compare with the
Danish experience. The application of urine in Sweden as well as the recommended regulations
concerning the utilisation, given by the "Smittskyddsinstitutet" (epidemiological institute) in
Stockholm and the Swedish Agricultural University, SLU), are discussed.
In Sweden the ”Swedish institute for Infectious Disease Control” recommends a storage time for
urine mixture of minimum 1 - 6 months, depending on storage temperature and fertilised crop. No
storage should be necessary for urine produced by the families for private gardening purposes (14)
Here, some of the important questions related to the recycling of urine are discussed, i.e. the
reliability and efficiency of the waste water systems in relation to the collection of urine, the
concentration of nutrients in the urine mixture as well as the problems concerning cross-
contamination. An important subject is the quality of the collected nutrients of the urine mixture
concerning both the content of nutrients, substances alien to the environment, and microorganisms.
COMPOSTING AND MATURING OF HUMAN RESIDUAL PRODUCTS CONTAINED IN
DRAINED “BLACK” WASTEWATER
In the autumn of 1998 The County of Storstrøm in a co-operation with A & B BACKLUND ApS
initiated the project "Composting and maturing of human residual products contained in drained
"black" wastewater". The project is partly financed by Miljøstyrelsen (Danish EPA)
In order to illustrate how human residual products, through composting, can be re-cycled in
Denmark, Storstrøm County has initiated a project funded by the action plan of the Danish
Environmental Protection Agency for furthering ecological urban renewal and sewage treatment.
The originator of the project is the Kjær family in the district of Stubbekøbing, A & B Backlund
ApS and Storstrøm County. Together they developed and planned the project.
One of the objects of the project is to collect experience on establishing and using a source
diverting compost toilet system in a one-family house. Another object is to collect experience on
using a source uniting compost toilet system including many users, experience from both operation
staff and users. The intention is moreover to survey the composting process in the two toilet
systems, e.g. in order to assess the quality of the compost material. Only the experiences from the
diverting system are reported in this resume.
In the autumn of 1998, a new wastewater system was established in Stubbekøbing. The system is
built up of system assemblies, commercially available in Denmark, but not yet tested in this
country. The examinations of the system have been made during the period of November 1998 till
The examination program is described. Based on interviews and supervision, the examinations
include the experience gained from the installation and working of the source diverting.
Furthermore, the measurements taken from the compost of the source diverting system are worked
up. The analyses focus on the examination of the functionality and stability of the systems as well
as on the demonstration of the content of nutrients and special microorganisms in the compost
Human urine and faeces
Urine and faeces are characterised on the basis of the constituents. Even though urine and faeces
normally constitute but approx. 1-1.5% of the household wastewater, they account for 91% of the
discharge of N, 83% of P, and 60% of K. Urine alone accounts for 80% of N, 55% of P, and 44% of
K contained in the household wastewater (23), (24). Standard urine production is indicated to be
365-550 kg per person per year according to source. The annual standard amount of faeces varies
from 33 kg per person to 110 kg per person (13). The content and composition of nutrients in the
faeces make them suitable as fertilisers, even though the content of N is somewhat lower compared
to the need. It is, however, not the output variables of the faeces, but the nutritive content of the end
product, which is decisive for the manorial value.
Composted faeces may also be useful as soil improving material. It may have great effect on
especially barren lands containing much clay or sand. Composting will increase the content of
carbonaceous organic material of the soil, which leads to an increase of the water-retaining capacity
and the accessibility to nutrients. Humus produced during the composting process also creates good
conditions for a healthy population of organisms in the soil, protecting the plants from earthborn
Human faeces contain a large amount of bacteria, which does not necessarily involve a large
quantity of infectious matters, however. Infected persons do, however, secrete large quantities of
infectious matters with the faeces. In the composting process of faeces it is therefore important that
the amount of indicator bacteria and actual infectious matters are reduced to an acceptable/defined
Compost making and compost toilet systems
The chapter holds a short description of compost making, composting processes and compost toilet
systems. It is merely an overall presentation of the material, but the indicated references will be able
to give an overview of concrete models and experience gained from the running.
Making compost is a process in which the material is transformed by the aid of oxygen. The
organic part of the wet residual/waste products is mineralised or transformed into solid humus by
the aid of oxygen-consuming microorganisms, releasing carbon dioxide and water in the process. A
humidity percentage of 45-70% in the compost substance is ideal to the process. The composting
process can be divided into three phases: The decomposition, the rebuilding and the construction.
The substance is reduced considerably during the process, which at best results in a compost
substance of a characteristic dark colour and with a smell of earth. The microorganisms use more
than one third of the energy contained in the material, while the large, remaining quantity is
released as heat.
The system assemblies forming part of the composting systems, toilet stools, filters/separators
and the collecting/composting units are described. The parts may be assembled in batch composting
systems or continuous composting systems. A batch composting system consists of two or more
containers or chambers. While the toilet being used, one container or one chamber is filled. The
material in the filled-up unit is then composted without further supply of fresh faecal material. The
composting systems examined in this project are batch systems. Continuous systems may consist of
large one-chamber systems with flat or sloping bottoms. Fresh material is supplied continuously at
the top of the compost container. The amount depends on the frequency of the use and possibly on
the supply of organic household waste and admixtures. A minor amount of composted material will
typically be removed from the bottom after 2-4 years for the first time, and after that once a year.
Description of the wastewater systems in the project
Here, the assemblies forming part of the two composting systems of the project are described. One
of them is a source segregation batch composting system with water flush, which is installed at each
household. It consists of a toilet with very scarce water flush (1-2 decilitres for urine and 0.5 litres
for faeces) and of two “Kaggen” containers with filters, used for drainage and composting
respectively. In addition to this there is a compost container – the “Quick Composter” – used for the
maturing stage. The other composting system is the public source collecting batch compost toilet
system without flush, placed at the Skelsnæs Pavillonen. Here there is a toilet building with two
separate rooms containing a source-collecting privy. When you use the toilet you sit on a kind of
cut-out wooden bench. In the room there is a bucket of sawdust to be used as an admixture (for
sprinkling after stools). By simple gravitation, faeces etc. will sink into the underlying chamber.
The system is meant for alternating batch running, using and filling one chamber at a time. After
one chamber having been filled up, the substance can enter the maturing stage without further
supply of faeces and urine.
Figure 8 “WM-Ecovip” “WM-DS”
Figure 9 "Quick-composter" Two "Kaggen" containers for dewatering and composting
The chapter gives a short presentation of legislation relevant to the establishment of a compost
toilet, together with legislation related to the application of the compost as manure. Finally the
legislation of other countries in this area is outlined.
Wastewater systems are comprehended by the Act on Environmental Protection as well as by the
Housing Act. The plumbing must be performed according to the basic standards of waste pipe
installations (DS 432, 2000). Human residual products (urine and faeces) may be used for
agricultural purposes according to the sludge regulation (no. 49 of January 20th
2000 concerning the
application of residual products for agricultural purposes). The possible applications of urine and
other humane residual products depend on how they are treated (cf. guideline no. 5 of 1999 of the
Environmental Protection Agency for the regulation on sewage permission etc., chapter 13.2.2).
Experience gained from installation and running
A short presentation is given of the experience gained from the installation and running of the
compost toilet in the one-family house in Stubbekøbing.
Experience from the running of the compost toilet system at Stubbekøbing
The toilet has posed great problems with the tilting device of the “Ecovip” toilet and so the flush of
the faeces. The backward pressure of the spring was not sufficiently strong to keep the system tight,
and consequently the toilet was changed into a DS toilet, which produces a larger flush (3-5 litres
for faeces). The material collected and composted in the “Kaggen”, of which tests have been made
for various analyses, has been collected from flushes with the “Ecovip”. Apart from one single
choking, which could be mended by way of a cleaning wire or caustic soda, no problems with the
“DS” toilet have been registered here. The family found that cleaning the faeces unit of the
“Ecovip” toilet was considerably more difficult than cleaning an ordinary toilet. In return, they have
been very satisfied with the “DS” toilet.
The filter in the first “Kaggen” was not properly installed; the filter bag was placed too far down
the container. It would have been more convenient with more suspension points than the four ones
in the corners, and even better if an unambiguous way of suspension meant the correct fitting of the
filter. In spite of this it was, however, possible to supply faeces from the four persons having a high
home frequency, for almost 13 months from the beginning of November 1998 to November the 26th
1999. The assembled batch containing approx. 600 litres stayed untouched about one year, without
stirring, digging over or supply of admixtures. A shovel of compost containing worms was added in
In connection with the testing it was obvious that the compost substance was rather compact
during long periods of the composting process. After one year of composting in the “Kaggen” the
material was shovelled from the filter bag into the garden compost unit, the “Quick Composter”.
The bottom 10-20 cm of the “Kaggen” material is still not properly transformed; there are a lot of
worms in the compost material, however. Ten months later the material seems totally transformed.
It looks like sphagnum and it smells good. The total reduction of volume during the two composting
phases is approx. 88%.
Figure xx Material collected during 1 year Material transferred to and composted
and composted for 1 year in Kaggen in "Hurtig-komposteren" for 8 months
Results of analysis and comparison to other compost and manure material
Tests have been made frequently during the composting period, from the “Kaggen” and from the
“Quick Composter”; during the composting period of just under 2 years the TS percentage rises but
moderately from 18.2 to 23.0. The humidity percentages of 81.8 – 77.0 are far from the 60%, which
are considered ideal.
It appears from the analyses that considerable reduction of the total compost substance and the
constituents take place. The total reduction of organic material is 88%. The results compared to an
assessment of the volume indicate a considerable reduction of the nutrient content. During the
composting and maturing stages the original content of N is reduced to 16%, P to 31%, and K to
42%. The output variables of the content of N and P seam rather high compared to standard figures
of excreted faeces.
The content of nutrients in the compost from Stubbekøbing is compared with the content in the
compost substances from other compost toilet systems as well as with the content in sludge from
household containers (sedimentation tanks), and in the separated faeces fraction in connection with
Temperatures measured in the “Kaggen”
In the “Kaggen”, temperatures have been measured during the composting period, but not during
supply and draining periods. The temperature development seams more determined by the exterior
temperature conditions than by any increase of temperatures caused by heat generating biological
activity in the compost substance. The lowest registered temperature is 3° C, which indicates that
there have been periods of insignificant microbiological activity. Temperatures may have been even
lower during the period from January 16th
to April 30th
2000, when temperatures were not measured.
The highest temperature, registered in July 2000, is 21.4°C. The temperatures measured are
compared to the temperature development in the compost material of other compost toilet systems.
Results from microbiological analyses
During the composting and maturing stages 5 tests have been made, which have been analysed for
content of microorganisms. The results prove that the number of thermo tolerant coliforms has been
reduced to 10 cfu/g (colony forming units) about one year after having stopped the supply of faeces.
At this time, the material still is in the “Kaggen”. It has not been ventilated, shovelled or treated in
any way. Ten months later, after the material having been transferred to the compost container, the
next analysis proves a content under detection level (<10 cfu/g). Analyses of presumptive E-coli
show the same results. The number of enterococci is 12,000 cfu/g after approx. one year, and 10
months later, at the next measuring, it is under level of detection (<100 cfu/g. No salmonella or
campylobacter have been found in any of the tests. All tests contain Cryptosporidium parvum, but
the amount is too small to quantify. The results are compared with the content of selected
microorganisms in other compost substances showing an equivalently large reduction.
Experience gained from similar composting systems
This chapter is among others about the experience from the “Kaggen” used in Sweden.
On the basis of the experience gained from the use of the composting system, the possibilities of
optimising both the components and the running of the systems are discussed. Furthermore, the
quality of the compost material is discussed on the basis of the content of nutrients and
The capabilities of the system are assessed. The source diversion system of "Kaggen" is found a
splendid alternative to other composting systems and other low-technology sewage facilities,
especially in the countryside where you find the greatest interest in using the compost for garden
purposes. There is, however, a need for analyses of the content of heavy metals and organic
substances injurious to the environment, as well as for an assessment of the risk in connection with
the utilisation of the compost product as manure, both with a view to the possible content of these
substances and to microorganisms, also including bacterial infectious matters.
ECOLOGICAL HANDLING OF URINE, FAECES AND GREYWATER FROM
ALLOTMENTGARDENS BY MEANS OF NO-MIX TOILET SYSTEMS AND
EVAPOTRANSPIRATION WILLOW BEDS
- A big success in Danish allotment gardens
The project is the biggest ever carried out concerning diverting toilet systems in allotment gardens.
It was initiated by the Danish Allotment Garden Association and A & B Backlund ApS and carried
out in co-operation with Danish Technological University and the municipalities Ballerup and
Herlev with Arne Backlund from A & B Backlund ApS as project manager in the period 1998 -
2002. The project is partly financed by the National Agency of Environmental Protection.
89 no-mix/diverting toilet systems without water flush were establish to test and demonstrate
organic and sustainable sanitation systems as alternatives to systems with chemicals or water flushing
closets in combination with collecting tanks or sewers.
Many Danish gardeners have stopped using pesticides and wants to develop a more ecological
behaviour also in sanitation. Water flush toilets in combination with collection tanks are very
expensive resulting in economical and social problems. Trucks collecting wastewater destroys the
often primitive roads. Establishing sewage is also very expensive and often resulting in different
problems. Both solutions with water flushing toilets also works against the idea of allotment gardens
as only being used half of the year and without some of the features known from permanent living. No
mixing toilets/diverting toilets were introduced to implement ecological and sustainable behaviour
with a high sanitary comfort
Participation is free for organisations and members and the choice among a range of toilets and
containers are free. Information about the systems, the handling and the ideas are presented on
arrangements. The participants are free to contact the project manager concerning questions. The
participants are responsible themselves for mounting and running of the systems. Written
questionnaires play a minor role. Information about among others expectations and experiences
with installation and running are collected. All participants are personally interviewed by phone or
at a visit. Many of the installations are inspected. Samples of collected urine are taken from 10
allotment gardens and analysed for among others nutrients, heavy metals, organic compounds and
microorganisms. The participants delivering urine are especially interviewed concerning questions
relevant for the quality of the urine. Sample of faeces/composted faeces are not taken and analysed
in this but in another project.
Diverting dry toilets are good alternatives. Mounting, cleaning as well as emptying of the toilet are
all found easy to carry out.
The project participants in the investigation are very positive and have had very few problems
which have all been solved
The daily use of the toilet is generally without problems but some women find it difficult to hit
the urine bowl. After a period of getting accustomed to the system only two women still had
Inconveniences in the shape of flies, noise and smells have been minimal and the users have
solved the few problems occurring themselves
The urine is very concentrated because the users if they manually add water after urinating only
uses small amounts
Concentrations of heavy metals and organic compounds are low much lower than the limit
values in the sludge regulation. The urine is well suited to be used as a fertiliser. The project
participants would have liked to use of mixture of collected urine and water as a fertiliser in
their individual garden
In the investigation neither bacterial nor parasitic infectious micro organisms of the types:
Campylobacter, Salmonella, Cryptosporidium parvum, Giardia duodenalis or other intestinal
parasites have been found
Diverting toilet systems without water flush is a good ecological alternative to chemical closets
as well as an economical and an ecological alternative to water flushing toilets with collection
tanks or sewage.
Characteristics of allotment gardens and participants
The methods for collection of user experiences are described. The average size is 390 – 400 m2.
The ten allotment garden associations are characterised through numbers and sizes of the gardens.
Garden sizes were generally 390 – 400 m2. The age and the sex of the users, and distribute among
the allotment gardens, are stated. 80 allotment garden houses have altogether 176 permanent users,
slightly more women than men. 27 permanent users are under 18 years of age and 13 of those under
the age of six. Answering a questionnaire, 34 participating gardens responded that they use the
allotment garden 60 – 230 days a year. The gardens are in average used 145 days a year. The water
demand including water for irrigating the garden was in 5 allotment gardens from 4 - 20 m3 with an
average of 11m3. Finally the focus is on the toilets previously used in the allotment garden houses.
The most commonly used toilet was a chemical toilet. 55 out of 81 toilets had been chemical.
Choice of toilet and urine container
The participants could choose between 4 toilet models in plastic 2 in wood, one in metal and one in
sanitary porcelain. The toilet stool in porcelain has a collection unit under the floor to collect faeces;
all other models collect faeces in the toilet above the floor. Fans are available for 12V or 220V with
an effect from 1W to 19W. Most frequently a ”Separett Weekend”, 37 out of 89, was chosen. 80
participants preferred 25-litre urine containers and only 9 the big 220-litre containers
Figure 9 “Separett Weekend” “WM ES” ES + 2 container collection unit
Characteristics of the collected urine
The 10 households delivering urine mixture for sampling and analysis are described. The
households are described regarding numbers of permanent users, age, sex, type of toilet, urine
container, efficiency of the source diverting system and the frequency of emptying the urine
container. The results of the chemical and microbiological analysis are presented.
The urine mixture is very concentrated with a concentration of nutrients of 5400-mg N, 360 mg P
and 1100 mg K per litre. The concentrations of heavy metals were very low, much lower than the
limit values given in the sludge directive and also much lower than the contents found in other
organic fertilisers. The concentrations of the investigated organic compounds were also low, much
lower than the limit values.
There were no findings of bacterial infectious matters, such as Campylobacter or Salmonella or
parasitic infectious matters such as Cryptosporidium parvum, Giardia duodenalis or other intestinal
parasites, in the urine mixture from any of the 10 households. Amounts of thermo tolerant coliforms
were already at the first sampling below the detection level (10-cfu/100 ml) for 9 of the 10 urine
mixtures. The sample, in which thermo tolerant coliforms could be detected, was under the
detection level at the second analysis approximately one month after sampling in the allotment
garden. Amounts of enterococcus were below detection level (10-cfu/100 ml) for five of the urine
mixtures at the second analysis approximately one month after sampling. At the third analysis
approximately two months after sampling additional four samples were below detection levels. In
the last urine mixture the amount of enterococcus was not detectable at the fourth analysis after
approximately three months. pH was from 8.8 – 9.2.
Experiences from mounting and running
Installation of toilets, ventilation systems, and urine systems with 25-litre containers were generally
easy. To dig down 220-litre containers demanded more work and efforts. Experiences from the
running of the faeces system, the urine system and the ventilation system are reported. The
experiences have been positive.
Comfort of sitting
The comfort of sitting on the toilets is reported in only positive terms by 63 users (nine users has
provided foot stools on their own). All of the participants using toilet models with sitting heights of
40, 42 and 46 cm are satisfied. More different opinions are expressed regarding sitting heights of
49, 50 and 53 cm without stools, 18 of these users would prefer a stool.
Figure 10 ”Separett Villa” ”Backlund H 66”
The function concerning diversion of the urine to the urine collecting system was only reported
inconvenient for two women. Though it is reported that 11 women had to get acquainted with and
adjusted to the system in order to achieve a god diverting functioning. Men and children at the age
of seven or older had no problems. Experiences from children under the age of seven were varied. 5
out of 24 children had problems to divert properly. The 5 children were; a 15-month-old boy, three
girls of three and a half, four and five years and a child at the age of six with unspecified sex. 7
children at the age of 5 or less managed fine. A special child seat can be used on 3 of the models.
Figure 11 Sight trap Child seat
Cleaning, noise, smell and flies
3 out of 77 users only reported cleaning of the toilets as slightly difficult or difficult. The rest of the
participants found cleaning to be trouble free. Regarding problems with noise, only 1 participant
could occasionally hear an irritating sound from a 19 W fan. Nobody with fans had problems with
smell in the toilet room. Some users without fans could have some smell problems, but not enough
to make them install a ventilation system. 2 users had had big problems with flies, but the problems
had been solved by means of continuous running of the fan, as prescribed in the manual and by use
of a fly net at the end of the ventilation system and on the inlet to the urine container.
Handling of urine and faeces
Reported experiences with the handling of urine and faeces showed no problems concerning urine
and 76 characterised emptying of the faeces container as unproblematic. One participant found the
smell unpleasant but acceptable. The frequencies of emptying the faeces container are reported for
the different models. The frequencies were from every third to sixth day to once a season depending
on toilet model, size of the household and use of the toilet.
Over all impression
Generally the interviewed participants characterised the impression of the toilet system as positive
or very positive.
Reactions from visitors
49 participants have had positive or very positive reactions from guests, neighbours or others. 3
participants had had negative reactions.
The participants are engaged in the project and on request 26 participants propose amendments, 9
participants with sitting heights of 50 cm or more, wish for lower sitting height.
Willow evapotranspiration bed without outlet for grey water
As a part of the project a willow evapotranspiration bed after a new concept developed by A & B
Backlund ApS has been constructed. Grey water from 10 allotment gardens evaporated from a
common bed. Each individual garden could also have been equipped with its own bed. The system
almost only evaporates wastewater as rainwater is discharged from the surface by means of a plastic
folio. The system is ideal for allotment gardens. Only few m2 are needed for an allotment garden
with limited water demand limited to the growing season. The experiences will be gathered and
Diverting/no-mixing toilets were installed in 89 allotment gardens in the municipalities of Ballerup,
Herlev and Slagelse. The purpose was to allow the users to evaluate the system regarding
installation, diverting, usage, cleaning, emptying, and possible inconveniences. A wide
representative section of the inhabitant regarding age has participated in the tests. The users have
been very positive and have only had very few problems; all of them were solved during the project.
Installation, cleaning and emptying of the toilets are considered easy to manage. 1 user has had
problems with installation of a 220-litre container due to high ground water level.
The daily use of the toilets is without problems, but some women find it difficult to hit the urine
bowl. After a period of training, only two women still had problems. Inconveniences like flies,
noises and smells have been minimal and the users have solved the few problems themselves. There
has been some smell problems at special wind directions, at five of the users who had decided to
take the ventilation out of the wall instead of up through and over the roof. Only two users
considered the problem big enough to make it worth changing the ventilation system.
The collected urine was very concentrated due to limited use of water. At the same time the
concentrations of heavy metals and organic compounds were far under the limit values given in the
sludge directive. The collected urine is well suited as a fertiliser.
In the analysis of the collected urine mixture no bacterial or parasitic infectious microorganisms
were found. The following species were investigated: Campylobacter, Salmonella,
Cryptosporidium parvum, Giardia duodenalis and other intestinal parasites. Thermo tolerant
coliform bacteria were only present in one of the 10 samples from the 10 different urine containers
and disappeared after 1 month. The amount of enterococcus is below the detection level for in this
urine mixture after 3 month of storage.
Usage of stored human urine, as a fertiliser, seems to involve a very small risk for bacterial
related stomach intestinal infections to animals and human beings by handling of human urine and
by consumption of crops fertilised with human urine.
The test of diverting/no-mixing toilets in the allotment gardens has been a great success and the
systems are excellent alternatives to traditional systems. The advantages by establishing diverting
toilets to solutions with sewers are among others water savings and recycling of nutrients.
Furthermore there are considerable economical advantages for the allotment gardens, compared to
installation of much more expensive solutions with sewers. The results from the microbiological
analysis indicate that the urine can be used as a fertiliser in the garden instead of being dug down.
Established together with willow evapotranspiration beds a well functioning complete solution to
black as well as to grey wastewater can be established in allotment gardens
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Reuse of Energy Resources and Nutrients in Humane Urine and Human Faeces. Ecological Urban
Renewal and Wastewater Treatment.The National Danish Agency of Environmental Protection.
3. Backlund, A., Eilersen, A. M., Larsen, I., Hagelskjær, M., Jensen, I. 2002: Ecological Handling
of Urine, Faeces and Greywater from Allotment Gardens by means of No-Mix Toilet Systems and
Evapotranspiration Willow Beds. Ecological Urban Renewal and Wastewater Treatment.The
National Danish Agency of Environmental Protection. Denmark.
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willow coppice fertilized with nutrient from municipal wastewater (BWCW).
Ed. Stig Larsson in report with the same tittle. Sweden.
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6. Bech., U. 1988: Gegengifte. Die organisierte Unverantwortlichkeit. Frankfurt am Main.
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