Water quality and ecological impacts of treated sewage effluent on a peri-urban stream

![CDATA[The purpose of this study was to assess the water quality of a small STP at North Richmond (NR), NSW and investigate the impact of the treated effluent being released into a local creek, Redbank Creek. Salinity levels increased significantly from 560 μS/cm upstream to 704 μS/cm downstream of the STP. There was a significant increase in nitrate concentrations from 960 μg/L upstream to 1900 μg/L downstream. Water temperature was more than 1° C higher downstream of the STP. Higher mean SIGNAL scores of the macroinvertebrates were found upstream compared to downstream. A NSW EPL license (license number 190) for North Richmond STP (NR STP) does not include any discharge limits for salinity but does permit the discharge of highly elevated phosphorous and nitrogen concentrations in the wastewater. The license specifies 90th percentile concentration limits of 5mg/L (P) and 15mg/L (N). This is surprising as chronic eutrophication levels contribute to regular problematic blue-green algal blooms in the Hawkesbury River.]]