Rotary drum composting of faecal sludge; case of peri-urban areas in Ashanti Region, Ghana
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Date
2017-01-24
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Abstract
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
Description
A thesis submitted to the Department of Civil Engineering, College of Engineering in partial fulfilment of the requirements for the degree of Doctor of Philosophy, 2016