Research On Optimization Of The Operation By The Multi-loop Reactor In Low Carbon-resource Condition

At present, the contamination of nitrogen and phosphorus is serious in our country, and many WWTPs use complex processes which have too many structures, complex feedback system and need strict working condition, all of those result in the sewage treatment establishments have high costs of construction and operation, fussy condition and high technique need for keepers and so on. Those problems will inevitably influence the development of environment protect project in our country. So highly efficient, energy-saving and simply running Combined Triple Circle Technology is invented in prophase study, but this process dosen't have good nitrogen and phosphorus removal effect for insufficient carbon source sewage. Based on analysis of spacial relationship of several continuous removal phosphorus and denitrification process, integration of the advantage of many continuous flow nitrogen and phosphorus removal process, such as the inverse A2/O, subsection influent removal phosphorus and denitrification process, OCO process, Orbal oxidation ditch, and integrated oxidation process and so on, combination with new theory on removal phosphorus and denitrification, adoption of basic form of Combined Triple Circle process model, a kind of new simple wastewater treatment technique called multi-loop reactor to improve the treatment effect of actual low-concentration influent is brought forward in paper. Four parameters were selected in multi-loop reactor:SRT,HRT,feedback ratio and DO in aerobic zone, and each parameter has three levels. The results show that: SRT is the first important parameter, successively is HRT,feedback ratio and DO in aerobic zone, and long SRT,HRT, big feedback ratio and low DO in aerobic zone is advantaged for nitrogen and phosphorus removal under low-concentration influent. Based on this result, the complemental test of SRT=30d,HRT=16hr is carried through and confirm that long SRT,HRT are really advantaged for nitrogen and phosphorus removal, COD,TN,TP of effluent is up to waste discharge standard, and the removal ratios of TN and TP is 81.24%and 71.09%. The result of simultaneous nitrification and denitrification (SND) in outer loop shows that: the nitrogen removal rate of SND is about 34% at the condition of SRT=20~25d,HRT=12hr,feedback ratio=400% and DO=0.5~1mg/L. Besides, the result show that: those parameter levels are not only advantaged for low-concentration influent, but for common-concentration sewage. The running mode and parameter levels for nitrogen and phosphorus removal could effectively resolve problem of low removal effect under low-concentration influent, have practical meaning.