Biogas Potential of Municipal Wastewater Treatment using Up-Flow Anaerobic Sludge Blanket (UASB) reactors under Psychrophilic Condition

Abstract

The operation of two laboratory scale of Up-flow Anaerobic Sludge Blanket (UASB) reactors on treating medium to high strength wastewater (i.e. 500 – 1200 mg COD/l) under psychrophilic conditions (5.5°C) were studied. The reactors were equipped with active granular sludge from three different sources. The aim of this study is to evaluate and investigate capability of anaerobic treatment of medium to high strength municipal wastewater to convert organic matter into methane production using UASB reactors under psychrophilic condition. Hydraulic retention time (HRT) was applied between 6.7 – 1.3 hours with gradually increased organic loading rate (OLR) from 3.11±0.10 – 8.35±0.16 g COD/l.d. The observed results present a fluctuated COD removal efficiency and methane production in the UASB reactors. High effluent COD was also discovered indicating high dissolved concentration of gaseous compounds at low temperatures. Apart from those, COD removal efficiency was able to be achieved a maximum of 58.5% in the reactor I with such a high OLR of 8.9 g COD/l.d with 3.3 h of HRT and yield of 0.62 gCODCH4/ gCODremoved (62% of COD removed converted into methane). Overall methane yields observed were 0.224 l CH4/g COD and 0.186 l CH4/g COD in reactor I and II, respectively. The performance of anaerobic treatment systems using UASB reactor for treating medium to high strength municipal wastewater under psychrophilic conditions show a good alternative as a pre-treatment with some parameters which need to be considered. Keywords: anaerobic treatment, UASB reactor, psychrophilic condition, COD removal efficiency, methane production.