| Eutrophication derived from the excess inflow of organics and nutrients into discharge basins results in the mass production of algae, causing other secondary water pollution. Also, toxic algae have been associated with eutrophication in rivers, lakes, and coastal regions and have been implicated in the occrrernce of "red tide" which may lead to paralytic shellfish poisoning. But existing conventional activated sludge systems that are weak in the performance of from 10 to 20 percent N, P removals have not coped with the water pollution owing to eutrophication. Besides, introducing human wastes and livestock wastewater into conventional activated sludge line increasely rises nitrogen and phosphorus level in influent wastewater and decreasingly declines treatment efficiencies, especially, nutrients removal. Hence a viable alternative is to convert existing methods into advanced wastewater treatment system or to encourage and adpot innovation. For better and more effective control of nitrogen and phosphorus effluent limitation should be built up according to wastewater discharges and restricted on the ground of the gross weight. This Research have it that aeration tank in activated sludge system can be readily improved to ASA (Advanced Step Aeration) system, that is advanced wastewater treatment system, and ASA system was well proved to novel advanced wastewater treatment system that is able to more economically strengthen nitrogen and phosphorus removal efficiencies than other existing advanced wastewater treatment system. Though lack of sewer systems into wastewater treatment plants, it is conceivable that influent level could be lower and treatment effect could get worse and soil and groundwater pollution could be continued. Therefore, the expansion of sewer system is urgentlly needful problem. |
|
PDF
