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Anaerobic co-digestion of sanitary wastewater and kitchen solid waste for biogas and fertilizer production under ambient temperature: waste generated from condominium house
Minale, M. & Worku, T.
Abstract
Addis Ababa is one of the fastest growing cities
where high urbanization has become a challenge. Consequently,
housing shortage is a big problem of the city. The
municipality has launched a huge Condominium Housing
Programme in response to the problem. However, sanitary
wastewater and solid waste management are the critical
problems to those houses. The wastes were collected and
evaluated for its biogas production and fertilizer potential
to solve the foreseen waste management problems. The
physicochemical characteristics of the collected wastes
were determined. A laboratory scale batch anaerobic codigestion
of both wastes with different mix ratio of 100:0,
75:25, 50:50, 25:75, and 0:100 by volume [sanitary
wastewater (TS = 7,068 mg/L):kitchen organic solid
waste (TS = 56, 084 mg/L)]were carried out at ambient
temperature for 30 days. The amount of biogas and
methane produced over the digestion period for those
mixing ratios were compared. The highest biogas yield
obtained from a mix ratio of 25:75 was 65.6 L, and the
lowest from a mix ratio of 100:0 was 9.5 L. The percentage
of methane gas in the biogas was between 19.8 and 52.8 %.
From the study results, it is evidenced that the mixing ratio
25:75 produced the maximum quantity of biogas and
methane. With regard to the fertilizer potential of the
digested sludge, composting and sun drying process were
helpful for land application by inactivating the pathogen.
Keywords
Condominium house; Mixing ratio; Biogas; Compost; Fertilizer
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