Effect of influent c/n and c/p ratios on nutrients removal investigated via chemical and microbial analyses in a novel bnr-ic process

Haiming Zout1,2,3, Xiwu Lu2,3, Abualhail Saad2,3,4

1 Department of Resource and Environment, Anhui Science and Technology University, Donghualu Road, Fengyang 233100, PR China
2 School of Energy and Environment, Southeast University, Sipailou Road, Nanjing 210096, PR China
3 School of Energy and Environment, Southeast University, Sipailou Road, Nanjing 210096, PR China
4 Department of Civil Engineering, College of Engineering, University of Basrah, Basra, Iraq

Abstract


This work describes the variations in nitrogen (N) and phosphorus (P) removal performances and bacterial population dynamics in response to different influent C/N and C/P ratios in a novel BNR-IC process combining biological nutrients removal (BNR) with induced crystallization (IC). A good nutrients removal performance was achieved at 7.8 of C/N ratio and 23.3 of C/P ratio, where P and TN removal efficiencies were 94.0 2.4% and 90.5 4.3%, respectively. Moreover, significant changes of microbial community structure were found with the variations of influent C/N and C/P ratios. Increasing influent C/N and C/P ratios favored the development of DPAO, thus enhancing the TN and P removal efficiencies and causing a decrease in microbial community biodiversity. However, excessive P load in the influent strongly influenced the P removal performance when C/N ratio was maintained at appropriate levels. PCR-DGGE showed that microbial populations in sampled sludge were classified into five different phylum or class (Alpha-, Beta-, and Gammaproteobacteria, as well as Firmicutes, Actinobacteria).

Keywords


denitrifying polyphosphate accumulating organisms; enhanced biological phosphorus removal; nutrients removal; polymerase chain reaction-denaturing gradient gel electrophoresis; wastewater treatment

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