Research Article:

Wisam S. Al-Rekabi
Civil Engineering Department, Engineering College, university of Basrah

Email address: wesam752014@gmail.com

ABSTRACT

continuous up-flow moving bed biofilm reactor (MBBR) were used to treat
4m3/d of domestic wastewater in Chongqing city at Southwest China .Both the
anoxic and aerobic reactors were filled to 50 %( v/v) with Kaldnes (K1)
biofilm carriers. After developing the biofilm on the carriers,the effect of
nitrate recycle ratio on biological nutrients removal from domestic wastewater
was investigated by operation of reactors under 3 different nitrate recycle
ratios ranging from 50% to 150% (50%, 100%, and 150%) through changing
the value of this parameter every one week. During this operation mode, the
MBBRs was operated under the optimal value of gas/water ratio which equal
to 7/1 and hydraulic retention time (HRT) equal to 6.2 hours. The experiment
results showed that optimum value of the nitrate recycle ratio for simultaneous
organic carbon and nutrients removal was equal to 100%. In this nitrate recycle
ratio, the average removal efficiencies were 92.16 %, 98.84 %,71.23 % and
91 % for COD, NH4+-N,TN and TP respectively, while the average dissolved
oxygen concentration (DO) in aerobic and anoxic MBBRs were 4.35 mg./L
and 0.19 mg./L respectively .

Keywords:  Ammonium nitrogen, Autotrophic, Carrier, Heterotrophic, Nitrate, Nitrite, Nitrogen, Moving Bed Biofilm
Reactor, Phosphorus

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