A Low Cost Constructed Wetland Alternative for Improving the Effluent Quality of a Lagoon Wastewater Treatment Plant

摘要

Fisherman Bay Sewer District (FBSD) owns and operates an aerated lagoon wastewaterrntreatment plant with a hypochlorite calcium tablet system for plant effluent disinfection. Highlyrnvarying level of solids in combination with nitrite in the lagoon effluent presented a significantrnchallenge for the plant operator to maintain appropriate chlorine dosage for ensuring consistentrncompliance with plant effluent limits for total chlorine residuals (TRC) and fecal coliform. Studyrnshowed that solids in the lagoon effluent were products of the treatment process including oldrnsludge, biomass and algae. Majority of the solids were erratically varying algae that werernidentified as the primary contributing cause for effluent chlorine residual noncompliance andrnoccasional fecal coliform, TSS and CBOD5 violations for individual samples. A constructedrnwetland with shredded tire media was built for removing lagoon effluent solids. The performancernof the wetland for CBOD5, TSS, fecal coliform removals is reviewed.