Performance and kinetic modeling of modified attached-growth anoxic-oxic-anoxic reactor for onsite sanitation system treating septic tank effluent |
Thammarat Koottatep1, Sittikorn Kamngam1†, Chawalit Chaiwong1, and Chongrak Polprasert2 |
1Environmetal Engineering and Management, School of Environment, Resources and Development, Asian Institute of Technology, Pathumthani, 12120, Thailand 2Department of Civil Engineering, Faculty of Engineering, Thammasat University, Pathumthani, 12120, Thailand |
Corresponding Author:
Sittikorn Kamngam ,Tel: +66832830309 , Email: sittikornkam@gmail.com |
Received: November 9, 2020; Accepted: March 29, 2021. |
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ABSTRACT |
This paper investigated a combined process of a modified attached-growth anoxic-oxic-anoxic reactor (AG-AOAR) as a sustainable and effective post-treatment system for septic tank effluent was developed. The AG-AOAR was operated by varying hydraulic retention times (HRTs) from 24 to 72 h. The results showed that the AG-AOAR achieved highest removal efficiencies of 84, 66 and 91% of chemical oxygen demand (COD), total nitrogen (TN) and ammonium nitrogen (NH4-N), respectively, under the HRT of 72 h, resulting its effluent meeting the international and national discharge quality standards for non-sewered sanitation system. The Stover-Kincannon model was applicable to describe the kinetic constants of COD, TN, and NH4-N removal in the AG-AOAR (R2 > 0.85). Accordingly, the maximum utilization rates (μmax) were determined to be 41.1, 0.15 and 0.50 g/(L-d) for COD, TN and NH4-N removals, respectively, while the saturation constants (KB) were 57.7, 0.12 and 0.51 g/(L-d), respectively. These constant values could be applied for the design of the AG-AOAR to produce treated effluent meeting desired standards. |
Keywords:
Attached-growth | Anoxic-oxic-anoxic | Septic tank effluent | Stover-Kincannon model |
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