Post-Treatment Of Anaerobically Treated Domestic Sewage Using Coagulation: A Jar Test Approach

Abstract

This study investigates the suitability of coagulation and flocculation processes as an advanced treatment technique for the effluent discharged from Upflow Anaerobic Sludge Blanket (UASB) reactors, which are commonly utilized in the treatment of domestic sewage. The research aims to improve the quality of wastewater treated anaerobically by further reducing organic load and nutrient concentrations. To determine the effectiveness of the treatment, standard jar tests were conducted using two widely adopted chemical coagulants: Aluminium Sulfate (commonly known as Alum) and Polyaluminium Chloride (PAC). The purpose of these tests was to identify the most effective dosage for maximum contaminant removal. Results from the experiment indicated that the optimal dosages for achieving significant pollutant reduction were approximately 500 mg/L for Alum and 600 mg/L for PAC. Both coagulants demonstrated notable efficiency in reducing parameters such as Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), and nutrients including nitrogen and phosphorus. The performance of the coagulation process exceeded that of aeration, particularly in removing phosphorus and nitrogen, where reductions up to 92% and 85% were achieved respectively. Furthermore, coagulation proved highly effective in the removal of pathogenic organisms, achieving up to 99% elimination. Based on these findings, it is concluded that coagulation, particularly using Alum and PAC, is a promising option for the post-treatment of UASB reactor effluent, offering an enhanced level of treatment that meets environmental discharge standards.