Study On CIBR Process For The Enhanced Phosphorus Removal Of Municipal Wastewater

Contraposing the wastewater quality of low carbon-phosphorus ratio or unstable phosphorus concentration in Zhuankou economic development zones, and based on the limited tolerance to the variety of TP which finally making the effluent TP not reach the discharge criterion steadily in the biochemical technologies, both of the biochemical process and phisico-chemical aided biological process of CIBR was studied, in order to search a method that can make the effluent phosphorus reach the discharge criterion steadily. Besides, the simultaneous removal of phosphorus and nitrogen was also be searched.Through the pilot experiments under four different working conditions of CIBR, it can be drawn that each of the aeration ratio, anaerobic time and the flow of reaction zone during anaerobic time can influence the phosphorus removal. And according to the studies, the phosphorus removal efficiency is well with the aeration ratio of 0.5 or anaerobic time of 2h. Besides, the mixed flow during anaerobic time benefits the phosphorus removal. All of the four working conditions can have a stable and satisfying removal efficiency of COD, but the removal efficiency of phosphorus is influenced by the low carbon–phosphorus ratio. The average removal efficiency of TP and TN can be achieved to 68.30% and 56.38% respectively with the average concentration of influent TP of 3.99mg/L and the carbon–phosphorus ratio of 7.93, and it has obvious advantages. But the phosphorus removal efficiency under conditionⅣwas influenced by the low carbon–phosphorus ratio, and could not achieve a perfect effect.When the carbon–phosphorus ratio is low or the concentration of TP is unstable in the influent of CIBR, a better removal effect can be achieved by the physicochemically assisted CIBR process with a smaller dosage of PAC, and the denitrification effect can also be slightly improved. With the PAC dosage of 20mg/L under conditionⅣ, the average effluent concentration of TP, TN, COD and NH3-N are 0.48mg/L, 9.07mg/L, 30.64mg/L and 3.08mg/L, respectively, which can reach the first degree A level of GB 18918-2002.