Estimated inorganic nutrient inputs to the coastal waters of Jersey from catchment and waste water sources

Concern over nutrient levels and eutrophication in the north-east Atlantic sea area has required a reduction in inputs at several urban centres. Imple mentation of a best European Practice by the States of Jersey has necessita ted an assessment of the impact of the Islands waste water treatment works (WwTW) on inorganic nutrient inputs to the coastal zone. Inorganic nutrient concentrations in stream and sewage effluent Inputs into St. Aubin's Bay J ersey, were monitored during the phytoplankton growing season. Inorganic nu trient input budgets were calculated using estimates of runoff based on hyd rological data for an instrumented catchment. Results indicated that the Ww TW accounted for 54% of the inorganic nitrogen load and 98% of the inorgani c phosphorus load over the survey period. The remaining inputs from catchme nts are driven by the seasonality of flow and nutrient concentrations. Inst allation of nutrient removal technology at the WwTW would reduce the total inorganic nitrogen load by 33% and the inorganic phosphorus load by 86%. Im plications for the WwTW and compliance with the European urban waste water treatment Directive 91/271/EEC are discussed, (C) 2000 Elsevier Science Ltd . All rights reserved.