Evaluating the Performance of Water Hyacinth and Soft Stem Bulrush in the Treatment of Brewery Wastewater Effluent Using Constructed Wetland Technology

The discharge of untreated brewery wastewater into the environment poses serious environmental and public health concerns due to its high organic load, suspended solids, nutrients, and heavy metal concentrations. Conventional wastewater treatment systems are often expensive and energy-intensive, creating the need for cost-effective and sustainable alternatives. This study evaluated the performance of water hyacinth (Eichhornia crassipes) and softstem bulrush (Schoenoplectus tabernaemontani) in the phytoremediation of brewery wastewater using a laboratory-scale constructed wetland system. Wastewater samples were collected from Nigerian Breweries Plc, Kaduna State, Nigeria, and analyzed for selected physicochemical parameters and heavy metals before and after treatment. The parameters investigated included pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, total suspended solids (TSS), ammonia, sulphate, nitrate, total phosphorus, biochemical oxygen demand (BOD), chemical oxygen demand (COD), and heavy metals such as copper (Cu), lead (Pb), zinc (Zn), iron (Fe), and cadmium (Cd). Two separate wetland systems planted with water hyacinth and softstem bulrush were monitored over a treatment period of twenty-five (25) days. The results revealed that both macrophytes significantly improved the quality of brewery wastewater. Water hyacinth achieved removal efficiencies of 71% for EC, 68% for TDS, 99% for TSS, 100% for ammonia, 99% for turbidity, 87% for sulphate, 100% for nitrate, 100% for total phosphorus, 88% for COD, 90% for BOD, and 100% removal of heavy metals (Cu, Pb, Zn, Fe, and Cd). Similarly, softstem bulrush recorded 69% for EC, 90% for TDS, 99% for TSS, 100% for ammonia, 98% for turbidity, 88% for sulphate, 100% for nitrate, 100% for total phosphorus, 88% for COD, 90% for BOD, and 100% removal of the selected heavy metals. At the end of the treatment period, the pH values were reduced from 9.82 to 7.10 and 7.23 for water hyacinth and softstem bulrush, respectively, bringing the treated wastewater within acceptable standards established by NESREA and FAO. Comparative analysis showed that water hyacinth performed slightly better in turbidity reduction and electrical-conductivity removal, while softstem bulrush demonstrated superior efficiency in total-dissolved-solids reduction. The study concludes that both macrophytes are highly effective in the phytoremediation of brewery wastewater and offer environmentally friendly, low-cost, and sustainable alternatives for industrial wastewater treatment. Their application in constructed wetland systems can significantly improve effluent quality and contribute to effective environmental pollution control and sustainable wastewater management.