| The textile industry is one of the larger amount of discharge of industrial waste water sector, annual emissions of more than900million tons of wastewater, which80%of the textile industry wastewater emissions is printing and dyeing wastewater emissions. Printing and dyeing wastewater have some characteristics such as large water volume, high concentration of organic pollutant, deep chromaticity, high alkalinity, poor biodegradability, big change of water quality, complicated composition and so on. With the development of processing technology, for this intractable industrial wastewater, An effective treatment technology which is mainly used in biological and auxiliary used in physico-chemical treatment technology has developed.It’s a comprehensive control technology. Through multistage joint degradation, printing and dyeing wastewater, which can improve the biodegradability, basically can reach the discharge standards.In recent years, there have been many high ammonia nitrogen and low carbon printing and dyeing wastewater appeared in some dyeing factories. Denitrification treatment for this type of printing and dyeing wastewater treatment is another problem.In the denitrification process, compared with traditional biological MBR technology have so long sludge retention time that nitrifying bacteria, nitrification bacteria and other microorganisms have longer generation time. Therefore MBR technology to improve the system of denitrification effect is of great importance.Therefore, this study adopts cheap nylon textile fabric as filter components in fabric bioreactor. Fabric bioreactor in addition to have the characteristics of conventional membrane bioreactor process,such as simple process,small covered area, low sludge production and so on, also has the advantages of a low cost, low power, high strength etc. The new technology for small-scale sewage treatment is a promising technology that has important significance.In this study, the treatment effect of the reactor and membrane fouling examined in the startup phase and long-term operation of the sludge bulking. Subsequent comparative study is to research treatment effect of simulate high ammonia dyeing wastewater under the condition of different operation modes. Under the different operating parameters of MLSS concentration.the conditions of the reactor nitrogen removal, and membrane fouling problems are researched.Some conclusions obtained for the sake of nylon textile cloth bioreactor in practical engineering application laid the foundation experiment.The main results are shown as follows:(1) Reactor start-up in three stages:active sludge cultivation stage, COD loading improvement stage, ammonia loading improvement stage. End of the start treatment,the effect was:the average COD removal rate was65.2%, ammonia concentration in the effluent was substantially less than lmg/L, TN removal rate is low, the average removal rate was only19.03%, because of the reactor appears nitrite accumulation, denitrification is inhibited due to lack of a carbon source. Membrane clogging start in the25days, finally analysis the most likely reason was caused by a mixture of the sludge particle size becomes smaller. The late change to run with a nylon cloth this issue was resolved, the treatment effect was little changed.(2)The long-running phase followed start-up occurs sludge bulking problem.Under the situation of sludge expansion, COD removal rate was not affected, but has increased,the average removal rate was70.53%. Ammonia removal situation was getting worse, and ultimately fell to42.10%. In order to improve nitrogen removal, reduce ammonia concentration to20mg/L, in turn, increased to310mg/L. When ammonia concentration increased to230mg/L, the reactor appears nitrite accumulation. The microorganism is inhibited, COD removal rate with an average of45.76%. Ammonia removal rate rising than before,the average removal rate of95.39%. TN removal efficiency was bad.The higher the cumulative rate of nitrite.the lower removal rate of TN. Under the situation of sludge expansion membrane pollution was more serious than membrane fouling is not caused. And membrane pollution is not caused by the sludge particle size, but EPS concentration.At last.determined the best way of cleaning nylon textile fabric was ultrasonic cleaning.(3)In the continuous FBR, with the MLSS concentration increased, COD removal rate was gradually increased, changed between73.80%-78.15%, COD removal rate increased nearly10percent.when the concentration of MLSS rising to9100mg/L, COD removal rate decreased to77.19%. Ammonia removal efficiency has been increased from91.53%to95.82%,when MLSS concentration rose to6500mg/L. Continued to rise MLSS, ammonia removal rate was decreased due to lack of oxygen. When MLSS concentration of9100mg/L ammonia removal rate was only77.86%.On the occurrence of simultaneous nitrification and denitrification under conditions of high MLSS.When MLSS concentration increased to6750mg/L,TN removal rate rose from 50.34%to82.52%. With continued increase of MLSS concentration, TN removal rate has a tendency to decline due to ammonia removal rate. When MLSS concentration increased to9100mg/L,TN removal rate was68.80%. Considering indices such as organic matter, ammonia nitrogen and total nitrogen removal, MLSS concentration of6500mg/L is the best condition of simultaneous nitrification and denitrification best conditions.(4) In the intermittent FBR, determining optimum operating conditions was aeration2hours and than stopped exposure for2hours. Due to the limitations of dissolved oxygen, the removal rate did not has a very significant upward trend with increasing MLSS concentration.Considering the case processing efficiency and membrane fouling, intermittent FBR run well at MLSS concentration of less than5000mg/L.When MLSS concentration was4000mg/L, denitrification effect best reached76.27%.(5) MLSS concentration not only affects the microbial removal of organic matter, also have an impact on membrane fouling process. In the continuous FBR, with the increase of MLSS concentration, concentration of dissolved EPS is more and more low that the correlation between solubility of EPS and membrane fouling is not big, is mainly associated with adherent EPS. The results show that membrane pollution aggravate when MLSS concentration more than8000mg/L.And protein concentration in EPS made a big effect in membrane fouling. In the intermittent FBR, dissolved EPS and LB-EPS concentration increased with the increasing of MLSS.membrane pollution is becoming more and more serious.The tendency of TB-EPS was similar with continuous FBR. Protein content had the greatest influence on membrane fouling. |
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