2. Partially based on a research
Sludge Reuse from Mega-Cities – A
Southern India Case
Elisabeth Kvarnström, Vectura Consulting, Inc.
Joep Verhagen, IRC
Mats Nilsson, MN Context
Vishwanath Srikantaiah, Biome (responsible for this slide show)
Karan Singh, Biome
Shubha Ramachandran, Biome
4. India Sanitation (Census 2011)
Septic Tanks Pit toilets
• (million) • (million)
• Urban 30.09 • Urban 55.97
• Rural 24.67 • Rural 17.68
• Total 54.76 • Total 73 .65
• Grand Total 128.41
5. Septic tanks and Pit Latrines
Another 113 million rural households
and 14 million urban households will
build toilets and mostly pit toilets in
the future
This represents a massive sludge
management challenge
7. Current Drivers of Sanitation
The employment of Manual Scavengers and Construction of Dry
Latrines (Prohibition) Act 1993
• Karnataka has adopted this Act in 1997
• All toilets should have a water seal of at least 20cm.
• No removal of human waste by human hands
• 208,323 + 586,087 = 794,410 engaged in the practise
8. The city utilities response
• Only 400 MLD out of 1000 MLD sewage
generated is collected
• Of the 400 MLD collected only around 180
MLD is treated
• Sanitation is subsidized. People pay Rs 15 a
month as sewage charges .
• The externality is pollution of rivers
33. BWSSB (Guidelines for discharging domestic waste water from soak pits/
mobile toilets into Board Sewers in the premises of BWSSB STP)
• Non refundable deposit amount equivalent to 6 months as
indicated by the applicant at the rate of Rs 50/kl
• Rs 50/kl charge per month
• Domestic wastewater which will be disposed to the Board
sewer in the premises of STP shall comply for BWSSB
standards fixed for discharging trade effluent
• Till now 75 permits have been issued for 1mld. ( Contrast with
494,221 households having septic tanks or pit toilets.)
39. Fertilizer value of sewage sludge
Kind of Nutrient Average nutrient content in
1000 kg of sewage sludge 1000 kg of farm yard
(10% TS) grams manure grams
N 5.5 17.5
P2O5 17.5 17.5
K2O 0.75 65
S (Total) 12.5 25
MgO 30 15
Cu (Total) 1.2 0.03
Zn (Total) 1.5 0.15
Mn (Total) 0.6 0.4
Mo (Total) 0.01 0.001
B (Total) 0.03 0.035
Source: Ludwig Sasse, BORDA, 1998, DEWATS Decentralised Wastewater Treatment in Developing Countries
46. The Economics
For the truck
• A Honeysucker costs Rs 800,000 /-
• Charges Rs 1500 / per trip
• Can do 5 trips in a day
• Income Rs 7500 a day Rs 225,000 a month
• Income in a year Rs 2.7 million
• Expenditure for O and M - Rs 400,000
• Simple Return on Investment 6 months
• One truck can service a population of 20,000
assuming a 2 year pit emptying cycle
47. The Economics
for the household
• Rs 1500 / every 2 years
• Rs 60 / a month approx
• Rs 15 a month if you are connected to the
sewage
48. The Economics
for a farmer
• Free compost
• On labour - expenditure Rs 5000 /
• Savings per acre Rs 20,000 to Rs 50,000 /- on
manure alone (10 to 25 tractor load per acre
per year )
49. Land required to absorb nutrients
• 250 tanker loads per Hectare
• 2500 peoples nutrients can be absorbed by 1
Hectare of land
• 50000 population town needs 20 Hectares of
land
• 100,000 - 40 Ha.
• 1 Million 400 Hectares
50. Way forward…
• Better understanding, from a business and
sanitation perspective, of existing practices
around the country
• Embedding of current practices as an officially
accepted option to sanitation service delivery
for all urban dwellers
51. Way forward
• Developing a protocol for the inclusion of non-
sewerage based or on-plot sanitation systems in
India
• Developing a protocol and a legal frame-work for
handling, transportation, composting and
application of nutrients from septage and on-plot
systems
• Research on understanding nutrient – pathogens
and safe application for nutrient reuse
52. Way forward
• Civic authorities to incorporate sewage
disposal systems in building plan approvals
• Land use plans to earmark space for solid and
liquid waste composting .
• Separate systems for toilets and grey-water
• Understanding the pit / groundwater interface
and designing systems for non-pollution.
53. Guidelines for the safe use of
wastewater, excreta and grey water
Cost-effective strategies for controlling negative health impacts
• Treatment of wastewater, excreta and greywater is used to prevent the contaminants
from entering the environment.
• Crop/produce restriction is used to minimize health risks to product consumers.
• Waste application techniques (e.g. drip irrigation) and withholding periods aim to reduce
contamination of the products or allow sufficient time for pathogen dieoff in the
environment prior to harvest.
• Exposure control methods (e.g. protective equipment, good hygiene) will prevent
environmental contamination from reaching exposed groups.
• Produce washing/rinsing/disinfection and cooking reduce exposures for product
consumers.
• Vector control reduces exposures for workers and local communities.
• Chemotherapy and immunization can either prevent illness for those who are exposed or
treat those who are ill and thus reduce future pathogen inputs into the
wastewater, excreta or greywater.
Source: WHO 2006