Improving the stability and biogas production of UASB reactor; parametric and microbial study

Abstract

In areas without sewer collection infrastructure, decentralized treatment is regarded as being necessary to provide sewage management and sanitation. Organic matter can be degraded anaerobically with Up-flow Anaerobic Sludge Blanket (UASB) digesters resulting in biogas production that is used in a wide range of uses (i.e., for heating, electricity, and fuel). Under decentralized operations, traditional aerated wastewater treatment can be expensive and readily overloaded by high-strength effluent or changes in the environment's temperature. High-strength wastewater can be treated with UASB digesters, which can also produce biofuel and reduce the high costs of aeration. Operations can be stabilized and granule formation improved by adding supporting components such as microbial communities and biochar made from Phragmites Australis to the UASB. The first stage of this study statistically investigates the optimization of anaerobic treatment conditions of cattle wastewater in a batch study. In the second stage, continuous treatment processes will be planned using data obtained as a result of the batch study. The COD concentrations used in the present study ranged between 1850 mg/L to 2050 mg/L while the BOD concentrations range between 450 mg/L to 1250 mg/L. The effects of operating parameters on the chemical oxygen demand (COD) removal efficiency and the methane production rate were evaluated. COD removal efficiencies of 72.43% -92.70% were obtained for the cattle wastewater using a 3-14 d hydraulic retention time. The maximum COD removal was found in batch experiment 7, where the type of bacteria was actinobacteria, biochar dose was 20 g/L, pH was 7.5 and no inoculum dose was added this resulted in 92.70% COD removal efficiency. Hence, the batch study recommended using actinobacteria as a type of bacteria and Phragmites Australis biochar for continuous UASB reactors.