No abstract

A wastewater treatment pond covered with water hyacinth (Eichhorniacrassipes) was first tested in Bahia in an attempt to treat sewage from an urban area in Salvador, Bahia, Brazil. This pond, which receives a high organic load with an average of 750 kg BOD/ha.day, after a short detention time of as little as 5 days, exhibited a removal rate efficiency of 90.7% of BOD and 96% of suspended solids. The problems related to the operation of this plant and its limitations, mainly regarding removal of nutrients, are discussed.