Decay Experiments of Effective N-Removing Microbial Communities in Sequencing Batch Reactors

Chen Lv,Jianlong Wang,Shuang Zhong,Lei Wu,Ming Li

doi:10.1155/2017/4878910

Chen Lv, Jianlong Wang + Show 3 more

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https://doi.org/10.1155/2017/4878910

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Abstract

The temporal changes in the compositions of effective N-removing bacterial communities and the decay coefficients of Anammox were studied within the 120-day decay period under anaerobic or aerobic conditions at 25°C. The maximum nitrogen production rate (MNPR) was determined by measuring the temperature, pH, volatile suspended solids (VSSs), and nitrogen-removal efficiency of the microbial communities during the decay period. The decay coefficients under anaerobic and aerobic conditions at 25°C were determined through equation-based fitting to be 0.031 d−1 and 0.070 d−1, respectively. Through molecular biological means and together with quantitative polymerase chain reaction (qPCR), the proportions of AnAOB in the microbial communities dropped from 48.70% to 3.69% under anaerobic condition and from 48.70% to 1.98% under aerobic condition during the decay period.

Highlights

Compared with traditional N-removal processes, the Anammox process is superior with low investment and operation costs, low sludge yield, high processing efficiency, and feasibility to wastewater with low C/N ratio and high ammonia nitrogen [1]
These problems can be overcome if there are abundant favorable bacterial species that can be used for early-phase inoculation or anaphase fed-batch [6]
The air pressure peaked within 24 h, while the N2 production during the whole reaction increased with time, which proves the initial microbes were highly active

Summary

Introduction

Compared with traditional N-removal processes, the Anammox process is superior with low investment and operation costs, low sludge yield, high processing efficiency, and feasibility to wastewater with low C/N ratio and high ammonia nitrogen [1]. The Anammox process is limited by the difficulty in starting, instability after start-up, and difficulty in recovery after destabilization [3,4,5]. These problems can be overcome if there are abundant favorable bacterial species that can be used for early-phase inoculation or anaphase fed-batch [6]. In current activated sludge models of aerobic degradation, the loss of activity and mass of activated sludge is expressed by only one process called decay [7]. The decay coefficient is one of the main variables in the mathematical modeling that is applied to biological wastewater processing. Correct estimation of the decay constant is a key factor to properly model and better understand the Anammox process; it is a parameter that is helpful to design and manage an Anammox reactor [11]

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