1. The burningfossilfuels are: More expensive; Increasegreenhousesgases; Introduce more carbondioxideinto the atmosphere Toresolvethisproblemwe can usewastewithanaerobicdigestion. This system recyclingmanureto produce methanefor industrial purposes. Thisisanefficient and ingenious way to reduce greenhousegases, hence riduce global warming, whileproducingenergyfromwaste BURNING FOSSIL FUELS

3. FERMENTATIVE BACTERIA: convertsugar and aminoacidsintoorganicacids;

4. ACIDOGENIC BACTERIA: convert the acidsintohydrogen, carbondioxide and acetate;

5. METHANOGENIC BACTERIA: produce biogas fromacetic acid, hydrogen and carbondioxide.ANAEROBIC DIGESTION

6. Biogas iscomposedby: 55-70% METHANE CARBON DIOXIDE PLUCE TRACE AMOUNT OF WATER HYDROGE SULPHIDE (H2S) AMMONIA (NH3) BIOGAS

7. Digestiondipendby: pH; Water/solidratio; Carbon/ nitrogenratio (20/1 – 30/1) Particlesizeof the material beingdigested and its mixing; Amountofantibiotic in livestoockfeed.

8. There are 3 typesofdigester: COVERED LAGOON; COMPLETE MIX DIGESTER; PLUG-FLOW TYPE OF DIGESTER

9. They are: Environmentfriendly; Economicprofitable; Improvequalityof the air; Reducesodour and toxicgases (reducesodour 97%); Weedseed more than 90% of the patogens are destroyed. ADVANTAGES

10. COVERED LAGOON . Itconsistof a manurestoragelagoonwithan air-tight impermeabile floating cover of industrial fabricthattraps the gas producedduringcompositionof the manure and a suction pipe withextract the gas foruse. Digestmanurewhichcontainslessthan 3%. Itmaynot produce allyear round, because gas flow can beaffectedby low temperature. Itis the CHEAPEST.

11. COMPLETE MIX DIGESTER. Convertsorganicwasteto biogas in a heated tank above or belowground. Mixer keep the solids in suspension. Concentrationsolidis 3-10%. The reactoris a circular steel or poured concrete container. Itis the MOST EXPENSIVE.

12. PLUG-FLOW. Concentrationsolidis 11-13%. Itincludes a manurecollection, system, a mixing pit and the digesteritself. DIGESTER ITSELF: a long rectangularheated container, builtbelowgroundwithan air-tight. MANURE COLLECTION and MIXING PIT: where water can beaddedtoadjust the proportionofsolids in the manureslurry.Inside the digesterthere are suspendedheatingpipeswhichallow hot water tocirculate-the hot water keeps the slurry at 25-40°c necessaryformethanproducingbacteria. Whennew material isaddedtoone end of the tank itpushesolder material out of the dicharge end: the coarsesolids in the manureform a thicksticky material as the are digested, limitingseparationofsolids ad forming a “plug”. The manureremains in the digesterfor 20-30 days.