Rotary drum composting of faecal sludge; case of peri-urban areas in Ashanti Region, Ghana

The main objective of the study was to design and demonstrate the applicability of the rotary drum composter for treating faecal sludge from peri-urban Ghana. The specific objectives were to assess faecal sludge practices and management, assess the perception of peri-urban farmers on faecal sludge compost and its utilization, determine the characteristics of faecal sludge, test the effect of bulking materials and mixing ratios on the quality of peri-urban faecal sludge compost and measure the performance of rotary drum composter on the die off of Ascarisand Trichuriseggs. The study was conducted in six (6) communities (3peri-urban and 3 rural used for comparison) randomly selected from Bosomtwe District, Ejisu-Juaben Municipal and Kumasi Metropolitan Assemblies. The study used desk studies, responses from household surveys, key informant interviews, field observations and experiments to address the objectives. The study showed poor faecal sludge management in both peri-urban and rural areas with no designated locations for faecal sludge treatment and disposal. 63% and 76% of peri-urban and rural areas respectively used public toilet as their main mode of defaecation (p=0.0172). Majority of farmers (about two-thirds) were not aware of the many advantages associated with the use of faecal sludge to fertilize their farms and the benefits that the reuse of faecal sludge has on sanitation issues. Only 34% of the farmers were aware that faecal sludge is a useful source of fertilizer and only 4% use it to fertilize their farms. Farmers seemed to be more concerned about how society will react towards them if they use faecal sludge compost. Generally, the values for electrical conductivity, chemical oxygen demand, biochemical oxygen demand, ammonia-nitrogen, nitrate-nitrogen, total Kjeldahl nitrogen, nutrients, some heavy metals and microbial quantities analysed in both peri-urban and rural sludge were generally high compared to that found in literature. During the testing of bulking materials in different mixing ratios, all the experimental trials were not adequately exposed to high temperatures (above 45 o C) for a sufficient period to guarantee pathogen die off. Faecal sludge in peri-urban areas of Ashanti region of Ghana was highly contaminated with Ascaris and Trichuris eggs. The population of Ascaris and Trichuris decreased significantly in all the rotary drum experimental set ups during the composting process. The study on the assessment of faecal sludge management showed poor faecal sludge management in both peri-urban and rural areas. From the study, the characteristics of faecal sludge varied between peri-urban and rural areas. Maize cobs as bulking material in 1:2 ratio produced best compost during the testing of bulking materials in different mixing ratios. The type of composter had significant impact on the die off of Ascaris and Trichurispopulation with plastic drum with rotating paddle mixer performing best. This research bridges a gap in faecal sludge management as it demonstrates the applicability of the rotary drum technology in faecal sludge composting in peri-urban areas where farming is the main economic activity of majority of the inhabitants

Source: KNUST