Vermifilter and zooplankton-based reactor integration as a nature-based system for wastewater treatment and reuse

Abstract The performance of an innovative, decentralized, nature-based wastewater treatment system composed of modular units (vermifilters and zooplankton-based reactors) on a pilot scale level (10 p.e.) is presented here. The efficiency of this system was evaluated over a 10-months period under controlled conditions at different flow-rates (750, 1,500 and 3,000 L·d-1). Vermifiltration alone delivered average removals of 88 ± 7%, 89 ± 8%, 91 ± 8% and 85 ± 19% for COD, TSS, NH4+ and BOD5, respectively. Zooplanktonbased reactor provided an important polishing stage that allowed the achievement of removal efficiencies above 95% for TSS, NH4+ and 91% for COD and BOD5, respectively. As the main function of zooplankton-based reactor is to filter fine particles (