Concentration reduction of selected pollutants in fish culture effluents using plastic straws and palm kernel shells.

Abstract

Palm kernel shell (PKS) and Polypropylene drinking straw (PDS) were evaluated as biological filter media to evaluate their ability in treating wastewater from fish culture systems. Their effluent treatment ability were evaluated in terms of reduction made to concentration of total ammonia nitrogen (TAN), nitrite nitrogen (NO₂-N), nitrate nitrogen (NO₃-N), total dissolved solids (TDS) and total suspended solids (TSS) in treated wastewater. Culture effluents collected from the fish rearing tanks in African catfish monoculture and African catfish cum Tilapia polyculture systems were run through the biological filters with PKS and PDS as media. Water quality parameters in influent and effluent from each of the biofilter were assessed using standard methods. The percentage reduction in TDS concentration in treated wastewater for PKS is 16.07% and PDS 11.83% in treated monoculture wastewater. PKS performed best in TDS reduction in the polyculture wastewater with a percentage reduction of 13.60%. The highest percentage reduction in TAN of 76.79% was recorded in PDS filter for the monoculture wastewater .Reduction of NO₂-N concentration in treated monoculture wastewater were 3.19 % and 7.45% for PKS and PDS respectively while in treated polyculture wastewater. NO₂-N percentage reduction were 20.83%, and 49.10% for PKS and PDS respectively. Both media filters performed well in reducing pollutants concentration in wastewater from both culture systems.Although PKS performed better in solids removal, both media were efficient in wastewater reduction and maintained water quality parameters within safe limits for discharge.

Keywords: Effluent, Pollution, Biofiltration, Palm Kernel, Drinking Straw