Abstract:
The water hyacinth (Eichhornia crassipes (Mart.) Solms), a floating aquatic plant, is able to absorb both the organic and the inorganic content of water which it can utilise for its growth. It has been effectively used to reduce pollutants in wastewater from domestic sources. The purpose of this research was to study the potential of water hyacinths for treating wastewater from pig farms. The experiments were conducted in 57x58x50 centrimeter acrylic tanks. The study showed that water hyacinths, with a density of 4 kilograms wet weight per square meter, can normally grow in wastewater from the pig farm with a biochemical oxygen demand (BOD) of less than 110 mg/L. Water hyacinths withered in wastewater with a BOD of 110-130 mg/L and the plants completely died with a BOD of more than 130 mg/L. The study also showed that water hyacinths caused significant reductions of BOD, chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), phosphate, total dissolved solids, and suspended solids, with average values (n = 8) of 29.56, 25.83, 24.14, 18.90, 27.32, and 24.86%, respectively, over the first week. The average (n = 8) reduction of the same parameters during the second week was 37.28, 37.43, 41.77, 23.55, 34.64, and 39.09%, respectively. It was noted that water hyacinths could not reduce sulfide in pig farm wastewater.