Biofilters By Ammonium Oxidizing Bacteria And Reverse Osmosis Treating Wastewater From Wastewater From Wastewater Treatment Plants

From the situation of water environment in our country, NH₃-N pollution has become the main question, and has the possibility to become the most important question of water pollution, but at present sewage treatment plant regardless industrial waste or the sanitary sewage nitrogen removal proportion and the efficiency are very low. Wipe off nitrogen by shortcut nitrification realizing low concentration waste water, using high-effect Ammonium oxygen bacteria which screened from sludge of settlement pool in sewage treatment factory. Ammonium oxygen bacteria was sieved by the silica gel flat, 6 kinds of Ammonium oxygen bacteria are picked out and fostered ultimately. The DNA sequence similarity searches showed that the strain YB—2 shares 98% sequence homology with Nitrosomonas sp. GH22. According to these results, the strain in phylogenetic framework of bacteria was classified.The Ammonium oxygen bacteria YB-2 can effectively degrade ammonia nitrogen which concentration no more than 250 mg/L, degradation speed increases with , ammonia nitrogen concentration, but after degradation 3 days, degradation effect is no longer obvious. The best pH for bacterium is at the range of 8. Ammonium oxygen bacteria remove the ammonia nitrogen effectively at the range of 25- 30℃. Ammonium oxygen bacteria demands comparatively minor dissolvied oxygen. Adopting long time culture of carrier can gain stable bacterium biomembrane and accelerate the ammonia nitrogen removing speed, the experiment proved ceramicite suitable for the growth Ammonium oxygen bacteria, and have good machinery intensity for long time using.Aerated/anoxic biofilters treatment system using in advanced treating effluent from wastewater treatment plant has been constructed. It consists of aerated biofilter and anoxic biofilter. The aim of aerated biofilter is essential to remove organic matter and achieve nitrification, then anoxic biofilter remove nitrite and nitrate by denitrification. At the beginning, first biofilter were seeded with ammonium oxidizing bacteria (AOB) from laboratory and aerated for 3 days without water inflow. After 3 days, water feed in biofilters by controlling low air/water ratio in first biofilter and methanol were added in the second biofilter. During the operation, the system has show stable and high nitrogen removal effect, whose air/water ratio is 0.25:1 in first biofilter. In order to effectively remove ammonia nitrogen, air/water ratio 0.5: 1 may realize the maximal nitrite accumulation, simultaneously avoids increasing of the nitrate, realizes the total nitrogen good removal effect. The counter- flushing is advantageous to the nitrite accumulation, but is obstacle to COD removal. The research indicated the reason which influence shortcut nitration mainly was the nitrobacteria growth. Adopts the ammonium oxidizing bacterium ahead of time and moderate air/water ratio may cause ammonium oxidizing bacterium stable maintenance activeness, and realize ammonia nitrogen and the total nitrogen good remove effect.To further research the biofacies character in biofilters, samples of each reactor were withdrawn and observed by microscope and SEM. It is clearly observed the acicula structure of heterotrophic bacteria covering the surface of the underlayer media in the first biofilter. The ellipsoid structure of the AOB is shown in the middle or upper media in the first biofilter. In the secondary biofilter, mostly spheriform bacteria were observed different from AOB and heterotrophic bacteria in first biofilter.Recently, reverse osmosis (RO) membrane technology has drawn attention because of its advantages over other processes.Reverse osmosis (RO) is a useful process that has potential for the removal of ionic and organic pollutants for recycling wastewater. Low pressure reverse osmosis (LPRO) membranes appear to be most desirable because of their high permeate flux and rejection.The objective of this research is reduction of conductance in water by using reverse osmosis (RO) technology for resulting to the standards of hardness, alkalinity, carbon dioxide, oxygen and SiO₂.Water treatment units with desalination can be divided into a pre-treatment part and desalination part. Pre-treatment of the source water plays a significant role in efficiency, the economical aspects and life-span of a desalination unit. The set-up of the pre-treatment depends on the type of source water. The aim of the desalination and pre-treatment parts of water treatment plants is to reach a composition of the water according to regulations for the type of low pressure boiler.The integrated and safe application of the reuse of treated municipal wastewaters from WWTP in various uses in urban areas dictates the development of a comprehensive environmental plan, which will take into consideration all parameters relative to such reuse, qualitative characteristics of wastewater.An experimental study was undertaking over 6 months in a one-stage reverse osmosis module in the WWTP. The wastewater was treated by reverse osmosis to eliminate the water solutes. The obtained results showed that the reverse osmosis process is well adapted for this treatment; the removal effect is more than 99% for the totality of solutes (the total conductivity decreased from 670-740μs/cm to 11μs/cm). This RO system leads to a recovery of 34%.