Co-digestion of fruits and vegetable waste (FVW) with palm oil mill effluent (POME) for biogas production

Abstract

Biogas is one of the most important sources of renewable energy and considered as an environmental friendly energy source. In this research, biogas produce from fruit and vegetable wastes (FVW) co-digest with palm oil mill effluent (POME). Biomethane Potential (BMP) Test, and quality improving effects for biogas production were studied. For this purpose, the BMP test was carried out in batch mode at mesophilic temperature (38°C). Substrates were pretreated and divided into 2 group: in slurry (Test1) and liquid form(Test2) before co-digest with POME for 10 days. In this study, the biogas yield of inoculum (mono digestion) and substrate (Co-digestion) using BMP test was measured to compare the biogas yield of two different form of co-substrates. Then, the composition of methane (CH4) and carbon dioxide (CO2) of the biogas produced were examined. The BMP method used to check the biogas potential, based on a volumetric test, which was measured by the displacement of a liquid. The influences of total solid(TS), volatile solids (VS) and pH were also evaluated. Biogas yields obtained were between 241 ml/day to 316 ml/day for test 1 while 301 ml/day to 326 ml/day for test2. The result demonstrate slightly increases in methane production when co-digesting FVW with pretreatment (liquid) with POME which contain 41% methane compared to co-digesting FVW without pretreatment (slurry) with POME which contain 37% methane. This may have been attributed to the pre-treatment of the substrate. The particle size of substrate influenced methane production rates during BMP tests. The results indicated that smaller particle size of substrate, yield higher amount of methane.