Effects Of Residual Agents On Performance Of Reverse Osmosis Membrane In Circulating Water Sewage

In order to ensure long-term stable operation of a circulating cooling water system,we need to discharge sewage on a regular basis.Apart from a lot of salt,a variety of water treatment chemicals are still contained in the circulating cooling water sewage for the sake of corrosion prevention,scale prevention and sterilization.If we can do some treatments to the circulating cooling water sewage to make it as the supplementary water for circulating cooling water system or even to the boiler,we can save a lot of fresh water and improve its utilization efficiency,which can bring considerable economic benefits to the company while reducing environmental pollution.According to the characteristics of circulating water sewage,this paper setted up a treatment process(coagulation sedimentation + sand filter + activated carbon adsorption + reverse osmosis),optimized the process parameters of each process and investigated factors each process.Then the effects of single and compound water treatment agents on coagulation effect and the dosages of coagulant had been investigated.In addition,on the basis of it,the effects of single and compound water treatment agents on reverse osmosis membrane and membranes inhibitor had also been investigated,under static and dynamic conditions.The experiments showed that:(1)when the dosages of PAC and PAM were 40 mg/L and 0.8 mg/L,the coagulation effect was best and turbidity removal rate reached 93.49%.Polyaspartic acid(PASP)had a greatest influence on coagulation effect and residual turbidity raged from 0.85 to 1.78 Nephelometric Turbidity Unit(NTU).Dodecyl dimethyl benzyl ammonium chloride(1227)had a greatest influence on the optimum amount of PAC,which ranged from 20 to 70 mg/L.Residual turbidity was greater than 0.98 NTU at the existence of compound agents.(2)Agents in circulating water sewage had a greater impact on membranes inhibitor.In the static experiments,5 mg/L 1227 produced a maximum effect on ZC-R1200 and inhibition rate fell by 88.84%.When the concentration of PASP,HEDP,ATMP and NaClO3 were all 20 mg/L,flux ratios fell by 4.07%,11.45%?11.29%? 3.98%,respectively.When 15 mg/L PASP and 15 mg/L HEDP were compounded,flux ratio felt the most,15.38%.Different agents had a greater impact on the reverse osmosis membrane flux at different concentrations.When the concentration of PASP were 50 mg/L,flux ratio felt the least,5.53%,which was far less than 18.95% of blank.On the contrary,when the concentration of 1227 were 50 mg/L,flux ratio felt the most,46.63%.At the same time,desalination rate was up to 99.59%.