Integrated constructed wetlands treating industrial wastewater from seed production

Abstract

The performance of an integrated wastewater treatment system composed of a horizontal subsurface flow constructed wetland (HSSFCW), floating constructed wetland (FCW), and anaerobic baffled reactor (ABR) was studied for pollutant removal from seed production wastewater. Cyperus alternifolius (Umbrella Papyrus) plants were used in the HSSFCW, and Vetiveria zizanioides (Vetiver grass) in the FCW. The ABR was fed with 25 /d wastewater from its equalization tank. The average raw wastewater organic loading rate was 0.208 kg-COD/d. Grab wastewater samples were collected twice weekly for three months from each unit's inlet and outlet. The system's performance in removing biochemical oxygen demand (), chemical oxygen demand (COD), total suspended solids (TSS), turbidity, nitrate, phosphate, and ammonium was studied. The average removal efficiencies obtained were 95.5% , 94.6% COD, 86.2% TSS, 76.6% turbidity, 82.4% nitrate, 76% phosphate, and 32.9% ammonium. The results show that integrating ABR, HSSFCW, and FCW improves pollutant removal from seed production wastewater, and the treated water can be used for agricultural purposes. Highlights The performance of wastewater treatment system in treating seed production wastewater was studied.; The system integrated anaerobic baffled reactor, horizontal subsurface flow and floating constructed wetlands.; The system removed COD, BOD5, TSS, turbidity below acceptable limit of Tanzanian national standard for industrial effluent.; The integrated system is promising for pollutant removal from seed production wastewater.;

Keywords

• anaerobic baffled reactor
• floating constructed wetland
• horizontal subsurface flow constructed wetland
• performance evaluation
• seed production wastewater
• wastewater treatment