Performance of a pilot scale up-flow septic tank for on-site decentralized treatment of residential wastewater

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• 作者：Gholamreza Moussavi ; Frarough Kazembeigi ; Mehdi Farzadkia
• 关键词：Anaerobic processes ; Residential wastewater ; On-site treatment ; Septic tank
• 刊名：Process Safety and Environmental Protection
• 出版年：2010
• 出版时间：January 2010
• 年：2010
• 卷：88
• 期：1
• 页码：47-52
• 全文大小：612 K

文摘

The aim of this research was to study the on-site anaerobic treatment of a medium-strength residential wastewater in a pilot-scale up-flow septic tank (UST). The effects of three different hydraulic retention times (HRTs) of 24, 12 and 6 h on the UST performance were investigated. The UST removed 85, 77, and 86 % of biochemical oxygen demand (BOD₅), chemical oxygen demand (COD) and total suspended solids (TSS), respectively, at steady state operation and with a 24 h HRT. Decreasing the HRT to 12 and then 6 h resulted in deteriorated effluent quality and significantly reduced reactor performance. The sludge showed a high specific methanogenic activity (SMA) of 15.2 mL CH₄ g⁻¹ VSS d⁻¹ with raw wastewater substrate. The solids accumulated in the tank by the end of the experiment had a VSS/TSS of 0.57, demonstrating significant stabilization. Overall, the UST is concluded to be a technically and economically promising alternative to conventional septic tanks for the on-site decentralized treatment of residential wastewater, particularly in the rural communities of developing countries.