Hydraulic Condition of Up-Flow Thermophilic Septic Tank (UTST) for Treatment of Blackwater

Authors

  • Pimchanok Prapasriket Asian Institute of Technology 58/9 Klong Luang, Klong nueng, Pathum Thani 12120
  • Thammarat Koottatep Department of Energy, Environment & Climate Change, School of Environment, Resources and Development, Asian Institute of Technology, Thailand
  • Tatchai Pussayanavin Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand
  • Chongrak Polprasert Department of Civil Engineering, Faculty of Engineering, Thammasat University, Thailand

Keywords:

Hydraulic Condition, Up-Flow Thermophilic Septic Tank, HRT, Blackwater

Abstract

The treatment performance of septic tanks can be affected by many factors. Hydraulic conditions can affect the treatment performance of septic tanks. The characteristics of hydraulic patterns such as residence time, dead zone, short circuiting and mixing can influence on the reactor performance. According to Stanmatelatou et al. (2004), the microorganisms were disrupted to produce biogas production that resulted from the inappropriate mixing in the sedimentation tank. Average COD removal efficiencies of the laboratory-scale UTST operating at 8, 16, 24 and 32 h at the temperature of 50 °C were 53, 67, 77 and 75%, respectively. The effluent BOD5 concentrations of the laboratory-scale UTST were in the same magnitude of about 190- 300 mg/L. The result showed that the UTST operating at HRT of 24 h could remove COD and BOD5 better than those unit operating at 8, 16 and 32 h. The intermittent feeding mode was conducted with HRT of 24h to compare the treatment performance of different mode feeding. The experimental results showed that intermittent feeding mode could remove COD and BOD5 better than continuous feeding. Average COD and BOD5 removal efficiencies of intermittent feeding at 24h HRT were 87 and 79%, respectively with significant differences (p<0.05). The hydraulic condition in the UTST at optimum HRT of 24h was studied. NaCl was used as a tracer chemical with a single shot impulse. The normalized resident time distribution (RTD) curves resulting from the results of tracer study indicated that the dispersion numbers of continuous and intermittent feeding were 0.203 and 0.326, respectively indicating the reactors approaching the completed-mix pattern.  

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Published

2018-04-30

Issue

Vol. 1 No. 1 (2018): January - April

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Original Articles

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