Demonstration of anaerobic stabilization of black water in accumulation systems under tropical conditions.
The anaerobic digestion of "human waste" was studied at Mlalakuwa residential settlement in Dar-es-Salaam, Tanzania at ambient tropical temperatures (24-31 degrees C). This settlement experiences a high water table with flooding during the rainy season, resulting in a very costly emptying of the latrines once per month. To improve the situation, two plastic tanks (while one is in use, the other one is on stand-by) of 3000 l capacity each, named as Improved Pit-Latrines Without Urine Separation (IMPLWUS), were used as latrine pits. They received faeces+urine+wash water; basically, an accumulation system. Septic tank seed sludge was used. The dissolved chemical oxygen demand (COD(dis)) remaining when the reactor was closed after 380 days was about 8 g COD/l, volatile fatty acids were 100 mg COD/l and total ammonium nitrogen was about 2.8 g N/l, implying the possibility of methanogenesis inhibition. Stability results indicated a need for more degradation time after reactor closure. Estimated biogas production from wastewater generated by 10 people was 544 g COD-CH(4)/day, not enough for cooking purposes.
Chaggu
Esnati J
EJ
Environmental Engineering Department, University College of Lands and Architectural Studies, Dar-es-Salaam, Tanzania. chaggu@uclas.ac.tz <chaggu@uclas.ac.tz>
Sanders
Wendy
W
Lettinga
Gatze
G
D000641:Ammonia / Q000737:chemistry / Q000378:metabolism; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D005243:Feces / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000378:metabolism; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D013636:Tanzania; D013696:Temperature; D014038:Toilet Facilities; D014329:Tropical Climate; D014556:Urine / Q000737:chemistry; D018508:Water Purification
D012722:Sewage; D000641:Ammonia; D010100:Oxygen