Investigating the Applicability in Emergency Situations of Terra Preta Sanitation System using Lactic Acid Bacteria

LAB failed to keep lacto-fermented sludge’s pH (6.7) and TAN (11.8mg/l) below 4.2 and within 15-30 mg/l respectively. This is despite registering promising results in pH (9.6) and TAN (16.6mg/l) for urine. The results challenged on-site LAB procedure in terms of stabilizing and sanitising faecal sludge possibly due to differences in sludge age, charcoal addition and different environmental factors. Therefore TPS combined with LAB inoculation could not be the best sanitation option for an immediate phase but rather second and third stages of emergency situations.  Malawi experiences emergency situations whose response does not prioritize faecal sludge management challenges. This research adopted a redefined Terra Preta Sanitation (TPS) system that replaced vermicomposting with Lactic Acid Bacteria (LAB) inoculation. The research aimed at determining possibility of on-site LAB procedure upscalling and safe separation of urine and lacto-fermented sludge as useful agricultural by-products. The study site was Crown Ministries, Blantyre, Malawi. A fermented mixture of15L pasteurized milk, 30ml of Yakult and 1.5g cane molasses was added to a 200L faecal sludge collection drum before use. After defecation, 100cm3 charcoal and 2g molasses were added. Urine was anaerobically collected in 50L drum. Random grab samples results indicated that COD for urine (868.4mg/l) and Lacto-fermented sludge (431.2mg/l) were above 60mg/l Malawi Standard and E. coli (1.05 x107) and Total coliforms (2.18 x 107) for Lacto-Fermented Sludge went above <103 CFU/100ml.