Study On The Enhanced Treatment Efficiency Of PAM And Biological-iron Oxide Coated Sands To NH₃-N

A homemade iron oxide coated sands (short for IOCS) was to conduct natural bio-film formation and PAM was used for coagulant aids, which was researched for the raw water with micro-polluted raw water of NH3-N, researched on the enhanced coagulation and filtration removing NH3-N of1～8mg/L using IOCS and PAM. Compared with original quartz sand (short for RQS), a mixture of RQS and IOCS on the enhanced filtration quality which combined with biotechnology on strengthening filtering stage:study them on the removal of turbidity, NH3-N, NO2--N, NO3-N, CODMh and the consumption of dissolved oxygen in the initial of formation and the stable of formation, as well as different filter layer variation of head loss.The results show that:1. The experiment results of enhanced coagulation and filtration.(1) Jar test:when only using0.03mg/l PAM for coagulant aids, the removal rate of NH3-N than only using PAC increases by about3.4%,even up to19.8%. The removal rate of NH3-N declined when increased coagulant aids dosage, but the turbidity removal effect improved, up to94.5%.(2) Foshan water group mobile emergency platform coagulation continuity test: changing the raw water concentration of NH3-N, when PAM dosing quantity is0.03mg/L, the best removal effect on turbidity and NH3-N. Different concentration of NH3-N has less removal effect on turbidity. After adding coagulant aid PAM, the removal rate of NH3-N than separate dosing PAC was increased by3%～6%.(3) Foshan water group small mobile emergency platform enhanced filtration test:①When the water concentration of NH3-N before the filter is1～2mg/L, using Bio-RQS, Bio-RQS/Bio-IOCS, Bio-IOCS, the average removal rate were73.8%,79.5%and90.5%respectively. Bio-IOCS removal rate of CODMh is higheast (up to58.3%)②When the water concentration of NH3-N before the filter is3～4mg/L:Bio-IOCS removal rate of NH3-N is as high as95.1%(filter speed is4m/h), Bio-RQS and Bio-RQS/Bio-IOCS removal rate of NH3-N is68.3%and76.2%respectively.③When the water concentration of NH3-N before the filter is5～6mg/L:the effluent of three filter columns are not up to standard,but Bio-IOCS removal rate of NH3-N (filter speed is4m/h) is higherast up to76.1%. (4)When the average NH3-N concentration of raw water is2.0mg/L,5.0mg/L,8.0mg/L:the removal rate of NH3-N is92.9%、90.2%、72.5%respectively by using PAM and Bio-IOCS. PAM and Bio-IOCS removal rate of NH3-N is higher than other two filter material in the same NH3-N concentration.2.The determination of backwash conditions.Bio-IOCS gas-water backwash for parameter optimization:the first gas, qg=7L/(s·m2), t1=3min; gas-water backwash, qg2=10L/(s·m2),qW2=3L/(s·m2),t2=4min; the last water, qw=7L/(s·m2),t3=5min.Backwash cycle is72h.After backwashing, the maturation of Bio-IOCS is40min.The surface of Bio-IOCS is compact structure and its pore is rich.The surface morphology is concave and convex shape which increases specific surface area obviously. After adding the PAM, due to the effect of molecular chain of the polymer, Bio-IOCS filter material surface is covered with a layer of thin film,part of the space is filled and combined with biofilm firmer. Bio-IOCS has strong physical adsorption and biological oxidation,as well as the best filtration performance and the removal effect of NH3-N.