Study On Biological Strengthening Purification Of Landscape Stream Water In The Coastal City

There are some problems of the landscape water in Dongying Central City, such as high salinity, severe salt stress phenomenon of river ecosystems, water source contamination, and water shortage. In addition, because of received the mixed sewage water including stormwater and sewage water along the region flowed into the river, the water function atrophied, and the water pollution was serious. The monitoring results showed that the main water quality indicators did not meet the class V standard requirement in surface water environmental quality standards (GB3838-2002). Currently, it is urgent to explore a cost-effective method for improving the quality of the stream water.In this experiment, imitation-type plant packings, AquaMats ecobase and ecological algaes were used as biological carriers, and the returning activated sludge from a sewage treatment plant was used as the inoculation sludge. With the gradual increase of the simulated water salinity, an experiment of salt microbial acclimation and microbial biofilm was conducted. The biofilm and microflora were observed through an electron microscope, and the removals of COD and NH3-N were studied during the biofilm formation period. At the same time, the removals of COD and NH3-N was also studied under different salinities. The microscopic examination results showed that there were much rotifers on the three carriers was much at the beginning of biofilm formation. However, with the increase of salinity, the microbial species and quantities on the three carriers were changed, and the vorticella with strong salt tolerance emerged. When the salinity reached3200mg/L, a little of biofilm on the imitation-type plant packings and ecological algaes fell off slightly.After the completion of biofilm formation, an experiment of biological strengthening purification for salt landscape stream water was conducted. The purification effect under different water quality and quantity conditions were analyzed. Meanwhile, the biofilm on biological carrier were sampled and observed under the electron microscope. It could be found that the biological strengthening purification process using acclimated biofilm achieved a good and stable effect on purification for salt landscape stream water. The removal of COD reached90%-91%, NH3-N reached86%-89%, and the turbidity reached65%-73%.The optimal operating parameters which were obtained from the experiment were DO3.5-4.5mg/L, C/N16, pH6.5-7.5and the water velocity7.2-8.4L/min. Finally, this thesis put forward an initial scheme of biological strengthening purification treatment for landscape water in central city.