ENHANCEMENT STRATEGY OF METHANE PRODUCTION FROM ANAEROBIC DIGESTION START-UP PROCESS OF GREASE TRAP WASTE

Anaerobic digestion is one of the potential processes of waste lipid recovery for beneficial use to produce methane (CH4). In anaerobic digestion, the utilization of grease trap waste for mono digestion is less reported. This might be due to high lipid content in grease trap waste that may cause inhibition effects which resulted from long chain fatty acids (LCFA) accumulation during the degradation process. This study is intended to investigate the effects of lipid acclimated biomass (LAB) and non-acclimated biomass (NAB) in the anaerobic treatment of grease trap waste over increasing organic loading rate (OLR) in continuous stir tank reactor. The results showed that the resistance of grease trap waste toxicity was higher in LAB while in inhibited reactor (NAB), 9 days lag phase occurred during the start-up process and affected the overall CH4 production. At OLR of 2.2 gCOD/L.day, high CH4 was yielded of 0.22 LCH4/gCODremoved at standard temperature and pressure with 11% CH4 enhancement in LAB. The inoculum acclimatization is one of the strategy to improve CH4 production and the purpose is to provide favorable condition to the methanogens towards build-up of volatile acids and inhibitive components such as LCFA. Thus, the overall enhancement for acclimated to LCFA inoculum strategy was 42%. The induction during the start-up had promoted and enhanced CH4 production when semi-continuous feeding was introduced and remain higher than the other reactors throughout the entire experiment. This indicates that the use of biomass consortium acclimated to long chain fatty acids compounds is a reliable strategy to speed up the start-up of anaerobic digestion process and to enhance the overall CH4 yield.

Pilot-Scale Removal of Trace Steroid Hormones and Pharmaceuticals and Personal Care Products from Municipal Wastewater Using a Heterogeneous Fenton’s Catalytic Process

The pollution of water sources by endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCPs) is a growing concern, as conventional municipal wastewater treatment systems are not capable of completely removing these contaminants. A continuous stir tank reactor incorporating a modified polyacrylonitrile (PAN) catalyst and dosed with hydrogen peroxide in a heterogeneous Fenton’s process was used at pilot scale to remove these compounds from wastewater that has undergone previous treatment via a conventional wastewater treatment system. The treatment system was effective at ambient temperature and at the natural pH of the wastewater. High levels of both natural and synthetic hormones (EDCs) and PPCPs were found in the effluent after biological treatment of the wastewater. The treatment system incorporating the modified PAN catalyst/H2O2decomposed >90% of the EDCs and >40% of PPCPs using 200 mgL−1H2O2, 3 hr residence time. The estrogenic potency EE2-EQ was removed by 82.77%, 91.36%, and 96.13% from three different wastewater treatment plants. BOD was completely removed (below detection limits); 30%–40% mineralisation was achieved and turbidity reduced by more than 68%. There was a <4% loss in iron content on the catalyst over the study period, suggesting negligible leaching of the catalyst.