Integrated system with microalgae and constructed wetland in vertical flow for urban wastewater treatment

ABSTRACT

The application of integrated systems with microalgae (MA) and Vertical Flow Constructed Wetland Post Microalgae (CWPMA) was performed for campus wastewater treatment assays located in Santa Cruz do Sul (UNISC-RS). Black and yellow waters were fed to systems in batch regime from equalizer university wastewater treatment plant tank, considering hydraulic detention time (HDT) of three days for each unity of the integrated system (MA+CWPMA). The comparison of performances was also made with units involving storage tank wastewater (STW)+Control System (C), only supported with sand and gravel in triple stage, as well as CWs, also triple stage. The supply used load factors in terms of COD 2.4±0.9g m^-1 day^-1 (for STW) and 26.7±11.2 COD m^-1day^-1 for the units of CWs; MA+CWPMA and Control (without the cultivation of Hymenachne grumosa). Reductions of the parameters of pollution loads were more significant in terms of BOD₅ (58%), total phosphorous (63%) and especially in terms of ammonia nitrogen in integrated STW+MA+CWPMA, with a reduction of 100%. In terms of acute toxicity with Daphnia magna, detoxification was effective, with EC₅₀ values ranging from 58 to 100%. The study developed obtained significant results that indicate this is a promising alternative in the treatment of wastewater for decentralized generating units, allowing greater reduction in eutrophic action.

Keywords:
microalgae; constructed wetlands; integrated system; urban effluent