Pollution Mechanism Research On Pharmaceutical Wastewater Nitrogen And Phosphorus Zero Discharge Treatment System In Membrane Unit

Selecting proper technology is the key to realize the zero emissions of N and P in waste water.Based on the study on the zero-emission technology,it is suggested that pretreating,film and evaporating are the main options,but the processing efficiency is influenced by film contamination,which leads to lower water quality,shorter film lifetime.Therefore,it is necessary to study whether this system is capable of removing nitrogen and phosphorus,polluting reverse osmosis membrane and cleaning efficiency.A/O+MBR+two stage RO+evaporation process is used in this paper to investigate whether or not the system can achieve zero nitrogen and phosphorus removal by adding carbon sources and adjusting p H.In reverse osmosis membrane fouling,the compound fouling of reverse osmosis membrane caused by residual aluminum and calcium in the front section and organic matter,the causes of membrane fouling and the effect of calcium and aluminum on the formation of membrane fouling were discussed in combination with the concentration of calcium and aluminum and p H of water,and the cleaning effect of cleaning agent after the formation of membrane fouling was investigated.In order to solve the N and P zero-discharge in medical waste water,this paper uses two stage A/O+MBR+two stage RO+evaporating technology.The results showed that COD,TP,NH₃-N could be used to treat COD,TP,NH₃-N,and above90%,but the efficiency of TN removing was less.The removal rate of TN was up to88%after the addition of carbon.To get better therapeutic results,TP could satisfy the demands of the first stage RO.But NH3-Nwas not achieved.Following a second inverse osmosis,NH₃-N is in the range of detection.Through adjustment of p H value and PH adjustment,NH₃-N achieved discharge criterion.Residual liquid was transferred to vaporizer.The effects of structure,morphology,composition and characterwastics of reverse osmoswas membrane fouling were investigated by an effluent with different Ca/Al ratios of membrane bioreactor in a biopharmaceutical enterprwase.The results demonstrated that calcium and aluminum combined with organic matter formed a composite fouling layer on the membrane surface,and the change of Ca/Al ratio resulted in significantly different membrane fouling characterwastics.It had a far greater effect on the formation of membrane fouling than the Ca component.According to the extended Young’s equation,the total surface tension of the system was calculated as:53.0 m J/m²（low Ca low Al）,55.3 m J/m²（high Ca low Al）,69.5m J/m²（low Ca high Al）,70.4 m J/m²（high Ca high Al）.It showed that the change of aluminum content mainly affected the polar force between the solution and the membrane material,and the change of the calcium content had almost no corresponding effect.The PH of Influent has great influence on the Ca and Al forms in water.Compared with the condition of acid or neutral p H,the contamination degree is the highest when the PH of the Influent is alkaline,and the concentration of Ca and Al is the highest on the membrane.At this time,calcium and aluminum in the water mostly exist in the form of Ca（OH）₂and Al（OH）₄-.The effect of the polar force was far more significant than the static force.Six detergents are arranged on the paper for purification of polluted reverse osmosis membrane to examine the purification performance of polluted film.It was found that Q5 had the best washing efficiency,and it was up to 94 percent of the original film flux.When Q1 and Q2 were washed by acidic solution and alkaline solution,there was a certain amount of fouling on the film surface.The SDBS was obviously less efficient compared to EDTA.The purification efficiency of SDBS is enhanced significantly when the concentration is raised.It is also found that the contamination of Ca and Al in the inlet water is layered in spatial structure,and aluminium is tightly bound to the base of the membrane by the polarity of the molecular interactions at the surface of the membrane,creating an irreversible contamination which is hard to remove;Ca is mostly removed from the polluted filtration cake layer,which can be readily reclaimed by means of chemical treatment.