Anaerobic codigestion of kitchen waste and separated wastewater fraction at different ratios with BMP test

In this study the recovery of energy has been assessed through the utilization of methane produced by anaerobic co-digestion of separated toilet waste fractions, black water (BW) and yellow water (YW) and kitchen waste (KW). One of the first objectives is to determine the optimal mixing composition and temperature to treat KW, BW and YW using methane production as the measure of process performance. The biological methane potential test (BMP test) for monitoring the relative biodegradability of the waste (Owen et al, 1979), was applied. The test was carried out with single and mix substances under two different temperature (thermophilic and mesophilic) conditions. The BMP tests showed that the thermophilic digestion of KW and BW is faster than mesophilic digestion. YW does not produce methane because the concentration of biodegradable organic compounds in urine is negligible, although urine exerts a disproportionately high COD because of the presence of ammonia. The organics mixtures of KW and BW produced high yields of methane than the individual component (220 – 520 Nml-CH4/g-VS). Medium concentrations of urine (approx 700-1400 mg TKN/l) proved to have a positive effect on the methanogenic phase, possibly due to the influence of micronutrients in YW.