Inhibition Of Eutrophication Of Reclaimed Wastewater By Ruppia Maritima In Coastal Scenic Watercourse

This paper studies on inhibition of eutrophication of reclaimed wastewater by submerged aquatic vegetation Ruppia maritima in the scenic watercourse in the northern coast of China. By employing monitoring and various experimental methods in the field and in the laboratory, the study focused on: 1) investigate the relationship between the water quality and seasonal growth changes of Ruppia maritima in the reclaimed wastewater of the coastal scenic watercourse 2) investigate effect of Ruppia maritima on removing nutrients in the reclaimed wastewater and its removal mechanism 3) investigate allelopathic effect of Ruppia maritima on Chlorella vulgaris which is dominative algae in the reclaimed wastewater of the coastal scenic watercourse and its allelopathic mechanism 4) develop an ecological water purifier which was a combination of membrane technology and submerged aquatic vegetation reactor(SAVR).The results showed that the distribution trend of submerged aquatic vegetation with the decrease of the water body salinity was the community of Ruppia maritima, community of Potamogeton pectinatus, community of Myriophyllum spicatum; community of Ceratophyllum demersum; and community of Potamogeton crispus in the coastal wetland of Tianjin. The order of the salt tolerance was Ruppia maritima > Potamogeton pectinatus > Myriophyllum spicatum > Ceratophyllum demersum > Potamogeton crispus > Potamogeton pusillus > Potamogeton malainus > Hydrilla verticillata > Vallisneria asiatica.It was found that there were two seasonal growth peaks of Ruppia maritima each year in the coastal reclaimed wastewater. The contents of the nitrogen and phosphorus of Ruppia maritima varied with the season. The most contents of nitrogen and phosphorus in the tissue of Ruppia maritima were up to 5.042% and 0.956%, respectively. It was observed that the community of Ruppia maritima was replaced gradually by the community of Potamogeton pectinatus in the coastal scenic watercourse of reclaimed wastewater from April 2004 to October 2005. But biomass of the submerged aquatic vegetation had a remarkable influence on the growth of algae in the watercourse.The laboratory studies indicated that Ruppia maritime could efficiently remove nutrients of reclaimed wastewater. The net removal rates of ammonia, nitrate, and phosphate by Ruppia maritima were 51.84%, 28.88%, and 79.86%, respectively,...