Modified septic tank-anaerobic filter unit as a two-stage onsite domestic wastewater treatment system

• Published in: Environmental technology 2014-09, Vol.35 (17), p.2183-2193
• Main Authors: Sharma, Meena Kumari, Khursheed, Anwar, Kazmi, Absar Ahmad
• Format: Article
• Language: English
• Subjects: anaerobic digesters; Anaerobiosis; Applied sciences; biochemical oxygen demand; Biological and medical sciences; Biological Oxygen Demand Analysis; Bioreactors; Biotechnology; Chemical engineering; chemical oxygen demand; domestic wastewater; environmental technology; Equipment Design; Exact sciences and technology; Filtration - instrumentation; Fundamental and applied biological sciences. Psychology; General purification processes; Hydrodynamics; Hydrodynamics of contact apparatus; indicator organism; indicator species; Methods. Procedures. Technologies; onsite treatment; Others; pathogens; pollutants; Pollution; Reactors; total suspended solids; tracer study; two-stage system; Various methods and equipments; Waste Water - chemistry; wastewater; wastewater treatment; Wastewaters; Water Purification - instrumentation; Water Purification - methods; Water treatment and pollution
• ISSN: 1479-487X; 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2014.896950

This study demonstrates the performance evaluation of a uniquely designed two-stage system for onsite treatment of domestic wastewater. The system consisted of two upflow anaerobic bioreactors, a modified septic tank followed by an upflow anaerobic filter, accommodated within a single cylindrical unit. The system was started up without inoculation at 24 h hydraulic retention time (HRT). It achieved a steady-state condition after 120 days. The system was observed to be remarkably efficient in removing pollutants during steady-state condition with the average removal efficiency of 88.6±3.7% for chemical oxygen demand, 86.3±4.9% for biochemical oxygen demand and 91.2±9.7% for total suspended solids. The microbial analysis revealed a high reduction (>90%) capacity of the system for indicator organism and pathogens. It also showed a very good endurance against imposed hydraulic shock load. Tracer study showed that the flow pattern was close to plug flow reactor. Mean HRT was also found to be close to the designed value.