Study On Intermittent Continuous Influent Biofilm Reactor (CIBFR) For Enhanced Biological Phosphorus Removal

Along with the more and more serious pollution of the nitrogen and phosphorus on water environment, and the more and more strict emissions standards on nitrogen and phosphorus, both the newly built wastewater treatment plants (WWTP) and the already built WWTP face more strict phosphorus request. The continuous influent biofilm techniquebecomes the optimal process because of its high removal efficiency for organic compounds and the nitrogen, but its technical bottleneck lies in the low phosphorus removal rate. In view of this question, the paper studied on the phosphorus removal of the continuous influent biofilm reactor, developed three technologies of enhanced biological phosphorus removal(EBPR), which are CIBFR with backflow of rich phosphorus water, influent and effluent alternating CIBFR , and CIBFR with discharging the rich phosphorus water, and also inspected the inffection of DO, intermittent aeration and organic load on the phosphorus removal rate of three system, and finally obtained the best operating parameter of CIBFR. Specially, CIBFR which dischargs rich phosphorus water resolved the contradiction between phosphorus removal and denitrogenation. It has shorter process, simpler operation , and lower costs of chemical phosphorus removal facilities and operating, which possesses a good prospects. The main conclusions are drawn as follows:The experimental results of CIBFR with backflow of rich phosphorus water indicated: with the conditions of the temperature =20℃, DO 5.5mg/l, the intermittent aeration (anaerobic 3h/aeration 6h), the organic load 2.2kgCOD/m³Â·d, CIBFR achieves the highest phosphorus efficiency . The concentration of influent PO₄^3--P is 3.6mg/L and 2.0mg/L respectively, and the effulent PO₄^3--P espectively is 0.7mg/L and 0.4mg/L. the removal rate are 78.44% and 74.4%. Effulent PO₄^3-- P espectively achieves first-level A and first-level B standards in (GB18918-2002).The experimental results of CIBFR with alternating influent and effluent indicated: with the conditions of the temperature =20℃, DO 5.5mg/l, the intermittent aeration (anaerobic 2h/aeration 4h), the organic load 2.2kgCOD/m³Â·d, CIBFR achieves the highest phosphorus efficiency. The concentration of PO₄^3--P influent is 3.0mg/L, effulent PO₄^3--P is 0.9mg/L, the phosphorus removal rate is 69.09%. PO₄^3-- P achieves first-level B standard in (GB18918-2002).The experimental results of CIBFR with discharging the rich phosphorus water indicated: CIBFR achieves the highest phosphorus efficiency under the condition of DO 5.5mg/L, the organic load 1.5kgCOD/m³Â·d, the intermittent aeration (anaerobic 3h/aeration 6h). The The concentration of PO₄^3--P influent is 3.5 mg/L, effulent PO₄^3--P is 0.4mg/L, the removal rate is 88.86%. PO₄^3--P achieves first-level A standard in (GB18918-2002).The treatment results of of CIBFR discharging the urban sewage under long sludge age indicated: under the condition of DO 5.5mg/L, the organic load 1.2kgCOD/m³Â·d, the intermittent aeration (anaerobic 3h/aeration 11h), CIBFR achieves the highest phosphorus efficiency. The concentration of COD,NH4+-N, TN and PO₄^3--P influent are 365mg/L,68.58mg/L,3.63mg/L and 72.93 mg/ L respectively, effulent espectively are 48mg/L,4.66mg/L,0.8mg/L and 20.82mg/L, the removal rate are 86.85%,93.21%,76.69% and71.45%, all achieved first-level B standards in (GB18918-2002).The result of the rich phosphorus wastewater with chemistry processing test showed that, compared with the process of treating all effluent, the costs of Al2(SO4)3 is lower, and also the volume of the wasterwater which needed been treatmented is small,the investment is lower.,and it is more more economicThe above findings will provide the technologies of phosphorus removal of continuous influent biofilm process with new methods, and offer technical support for the upgrading and regeneration of already built WWTP .