Journal of Korean Society of Water and Wastewater (상하수도학회지)

The Korean Society of Water and Wastewater (대한상하수도학회)
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Co-digestion of food waste recycling wastewater with thermally hydrolized sewage sludge for the improvement of anaerobic treatment efficiency

음폐수의 혐기성 소화 효율 향상을 위한 열가수분해 하수슬러지와 병합처리성 검토

  • Heo Jun (Department of Environmental Engineering, Graduate School of Engineering, Inha University)
  • 허준 (인하대학교 공학대학원 환경공학과)
  • Received : 2022.10.26
  • Accepted : 2022.11.11
  • Published : 2022.12.15
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Abstract

The object of this study is to feasibility assesment for co-digestion efficiency of food waste recycling wastewater(FWR) with thermal hydrolysis process dehydration cake (THP Sludge). As a result of THP pre-treatment experimental conditions to 160℃ and 30 minutes, the solubility rate(conversion rate of TCOD to SCOD) of the THP sludge increased by 34%. And the bio-methane potential in the THP sludge increased by about 1.42 times from 0.230 to 0.328 m3 CH4/kg VS compared to the non-pre-treatment. The substrates of the co-digestion reactor were FWR and THP sludge at a 1:1 ratio. Whereas, only FWR was used as a substrate in the digestion reactor as a control group. The experimental conditions are 28.5 days of hydraulic retention time(HRT) and 3.5 kg VS/m3-day of organic loading rate(OLR). During the 120 days operation period, the co-digestion reactor was able to operate stably in terms of water quality and methane production, but the FWR digestion reactor deteriorated after 90 days, and methane production decreased to 0.233 m3 CH4/kg VS, which is 67% of normal condition. After 120 days of the experiment, organic loading rate(OLR) of co-digestion reactor was gradually increased to 4.5 kg VS/m3-day and operated for 80 days. Methane production during 80 days was evaluated to be good at the level of 0.349 m3 CH4/kg VS. As a result of evaluating the dehydration efficiency of the sludge before/after 150-180℃ THP using a filter press, it was confirmed that the moisture content of the sludge treated before THP at 180℃ was 75% and improved by 8% from 83-85% level. Therefore, it is expected that the co-digestion reactor of FWR and THP sludge will ensure stable treatment water quality and increase bio-methane production and reduction effect of dehydration sludge volume.

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References

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