Use of chitosan and Moringa oleifera as conditioners for improved dewatering of faecal sludge

A pilot-scale dewatering research facility was built in Dar es Salaam, Tanzania, and was used to test chitosan and Moringa oleifera as conditioners to improve the dewatering of faecal sludge. Laboratory-scale jar tests were first conducted to determine optimal dosages for the conditioners in faecal sludge samples with varying total solids concentrations. The results for chitosan were 0.5-0.6 mL/gTS, and for Moringa oleifera 5-15mL/gTS. Based on these results, pilot-scale tests were conducted with chitosan, but the use of Moringa was ruled out as it was too resource intensive. Three loading cycles were conducted, and an average of 15.3% reduction in dewatering time was achieved. Based on the laboratory and pilot-scale tests, chitosan is recommended as a conditioner for improved FS dewatering performance. It could be employed at full-scale, but still requires jar tests to determine optimal dosing

Health risks of irrigation with treated urban wastewater

For more than three decades, Waste Stabilization Ponds (WSP) effluent has been used by people of Lemara in Arusha Municipal for irrigation of their farms in order to get better crop yields as source of their food and income. This paper attempt to examine the produce quality from wastewater irrigated areas downstream of WSP. The produce from major market and those, which irrigated by water supplied by approved water authority, were also examined. Results have indicated that despite the wastewater used for irrigation being treated, produce from the irrigated area have shown high level of pollution threatening people’s health. Moreover, there is significant pollution of vegetables taking place in the market probably due to poor hygiene practices. Contrary to research expectation, vegetables irrigated by water supply have also indicated faecal contamination although the water itself is bacteriologically safe