IWA Publishing

Treatment of domestic wastewater by a hybrid natural system

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The present study addresses performance evaluation of a hybrid natural system comprising of settling tank, sand-gravel filter (SGF), aerated constructed wetland (ACW) and vermifilter (VF) for the treatment of domestic wastewater. The sequential batch experiments were conducted in a pilot-scale experimental set-up. The biochemical oxygen demand (BOD5) was varied from 20 to 120 mg/L and the hydraulic retention time (HRT) used was from 1 to 3 d. The BOD5 removal efficiency was found to be in the range 20–40%, and 40–70%, for 3 d HRT in SGF and ACW/VF, respectively. The efficiency of the system for BOD5 removal was observed to be 80–90% at 3 d HRT and the system was found to be adequate for reducing BOD5 to a value less than 20 mg/L. The effluent can be recycled and used for non-potable purposes in a household. The developed system is a potential option for the decentralized wastewater treatment.

Customer comments

  1. By Geoff Salthouse on

    This seems like an overly complex system. We have 30+ years of experience with hundreds of systems operating with just a primary settling tank and recirculating sand/gravel filter (and more recently other engineered media to reduce size) to reduce domestic strength wastewater (i.e. BOD5>350 mg/L) to better than 10 mg/L BOD5 with about 3 days total HRT. This is a common solution in decentralized wastewater management; case studies can be seen at www.orenco.com/systems.