Factors affecting simultaneous nitrification and denitrification in an SBBR treating domestic wastewater

Abstract

Recently, researchers have become increasingly interested in the practical application of SND. The reasons are as follows: (1) the products of nitrification including nitrite and nitrate are reactants for nitrification; and (2) the nitrification produces acid and the denitrification produces alkaline. The efficient SND can save money for the construction and operation of wastewater treatment facilities and meet the requirement of carbon resource and alkalinity. Simultaneous nitrification and denitrification in a microbial reactor needs an anoxic condition and a source of carbon. The main control factors for SND are oxygen concentration, carbon and microbial condition [8][9][10].In most experiments, synthetic wastewater was used because the parameters could be controlled easily. Few reports have been found on the SND when real wastewater used in the SBBR.This work aims to determine the feasibility and the factors affecting the SND treatment of real domestic wastewater in an on-site SBBR. The variation of nitrogen, dissolved oxygen, the depth of the biofilm and influent concentration, and the mechanism of SND are evaluated. Finally, a suggestion for the SND operated in the SBBR is provided. Materials and methods Experimental systemThe SBBR for on-site domestic wastewater has been operated for about five years [11]. The sketch of the SBBR is shown in Fig. 1, and its working volume is 200 L, with a dimension of 80 cmx40 cmx110 cm. About 42 cm of the height is packed with Bauer rings with a specific surface area of 219 m 2 /m 3 to attach the biofilm. The filtrating nozzles on the bottom of the reactor are used to collect the effluent and distribute the backwash water. Aeration is performed by perforated pipe. A pump is used for water circulation during reaction and backwash.Abstract An aerobic sequencing batch biofilm reactor (SBBR) packed with Bauer rings was used to treat real domestic wastewater for simultaneous nitrification and denitrification. The SBBR is advantageous for creating an anoxic condition, and the biofilm can absorb and store carbon for good nitrification and denitrification. An average concentration of oxygen ranging from 0.8 to 4.0 mg/L was proved very efficient for nitrification and denitrification. Volumetric loads of TN dropped dramatically and effluent TN concentration increased quickly when the concentration of average dissolved oxygen was more than 4.0 mg/L. The efficiency of simultaneous nitrification and denitrification (SND) increased with increasing thickness of the biofilm. The influent concentration hardly affected the TN removal efficiency, but the effluent TN increased with increasing influent concentration. It is suggested that a subsequence for denitrification be added or influent amount be decreased to meet effluent quality requirements. At optimum operating parameters, the TN removal efficiency of 74%-82% could be achieved.

Simultaneous nitrification–denitrification and phosphorus removal in a fixed bed sequencing batch reactor (FBSBR)

“…The thicker biofilm is advantageous for SND. TN removal rate by SND could be 74-82% if suitable operational parameters are adopted and also if influent NH 4 + -N is less than 110 mg/L [5]. It was reported that simultaneous removal of phosphorus and nitrogen was possible in the biofilm SBR as indicated by the respective removal ratio of around 90% and 57% at a COD loading of 1.00 kg COD/m 3 per day [6].…”

Notice of Retraction: Influence of C/N Ratio on Nitrogen Removal in Sequencing Batch Biofilm Reactor

“…Xu et al studied mechanism on the nitrogen rich leachate by SBBR, and the ammonia nitrogen removal reached 95% [9]. Factors affecting simultaneous nitrification and denitrification in a SBBR treating domestic wastewater was investigated by Li et al [12], and a concentration of average oxygen range from 0.8 to 4.0 mg/L was proved very efficient for nitrification and denitrification.…”

Start-up of sequencing batch reactor with Thiosphaera pantotropha for treatment of high-strength nitrogenous wastewater and sludge characterization

“…In SND, the floc/granule microenvironment provides aerobic conditions towards the exterior favoring nitrification, while denitrification is favored in the interior anoxic zone (Munch et al 1996;Satoh et al 2003). However, the success of this process depends on the conditions prevailing in the reactor (dissolved oxygen (DO), pH, and alkalinity) and diffusion limitations governing transfer of gases, nutrients, and substrate across the flocs/granules (Munch et al 1996;Pochana and Keller 1999;Li et al 2007;Zhang and Zhou 2007). SND may also be achieved using specific strains, such as Thiosphaera pantotropha and Alcaligenes fecalis, that have the ability for heterotrophic nitrification and aerobic denitrification by virtue of their unique enzymes (Robertson and Kuenen 1984a, b;Joo et al 2005;Joo et al 2006).…”

“…Such strains can overcome the requirement for maintaining critical DO levels and substrate diffusion constrains for denitrification. Some studies have explored nitrogen removal in presence of such strains for low-strength wastewater having NH 4 + -N in the range 20-200 mg L −1 (Gupta and Gupta 1999;Pochana and Keller 1999;Lee et al 2001;Li et al 2007;Zhang andZhou 2007, Morita et al, 2008;Singh and Mittal, 2013) and also wastewater containing nitrophenols in the range 2.5-200 mg L −1 (Kulkarni, 2012;Kulkarni, 2013). However, there are only limited studies on application of such strains for nitrogen removal from highstrength wastewater (Kshirsagar et al 1995;Gupta and Gupta 2001;Joo et al 2005;Joo et al 2006).…”