Comparison of the MBBR denitrification carriers for advanced nitrogen removal of wastewater treatment plant effluent

Abstract

The moving bed biofilm reactors (MBBRs) were used to remove the residual NO3(-)-N of wastewater treatment plant (WWTP) effluent, and the MBBR carriers for denitrification were compared. The results showed that high denitrification efficiency can be achieved with polyethylene, polypropylene, polyurethane foam, and haydite carriers under following conditions: 7.2 to 8.0 pH, 24 to 26 °C temperature, 12 h hydraulic retention time (HRT), and 25.5 mg L(-1) external methanol dosage, while the WWTP effluent total nitrogen (TN) was between 2.6 and 15.4 mg L(-1) and NO3(-)-N was between 0.2 and 12.6 mg L(-1). The MBBR filled with polyethylene carriers had higher TN and NO3(-)-N removal rate (44.9 ± 19.1 and 83.4 ± 13.0%, respectively) than those with other carriers. The minimum effluent TN and NO3(-)-N of polyethylene MBBR were 1.6 and 0.1 mg L(-1), respectively, and the maximum denitrification rate reached 23.0 g m(-2) day(-1). When chemical oxygen demand (COD)/TN ratio dropped from 6 to 4, the NO3(-)- N and TN removal efficiency decreased significantly in all reactors except for that filled with polyethylene, which indicated that the polyethylene MBBR can resist influent fluctuation much better. The three-dimensional excitation-emission matrix analysis showed that all the influent and effluent of MBBRs contain soluble microbial products (SMPs)-like organics and biochemical oxygen demand (BOD), which can be removed better by MBBRs filled with haydite and polyethylene carriers. The nitrous oxide reductase (nosZ)-based terminal restriction fragment length polymorphism (T-RFLP) analysis suggested that the dominant bacteria in polyethylene MBBR are the key denitrificans.

Comparative Study of Denitrifying-MBBRs with Different Polyethylene Carriers for Advanced Nitrogen Removal of Real Reverse Osmosis Concentrate

“…Q-PCR technology is widely used to investigate the gene richness of the total bacteria and the richness of denitrifying bacteria in the biofilm of MBBRs [21]. In this study, the bacterial 16S rRNA gene, 16S Archaea (for total bacteria), and the narG, nirS, nirK genes (for denitrifiers) were applied as primers [37,38].…”

“…The suspended carrier is the core of the MBBR process and provides a place for microorganisms to attach and grow. There are many types of suspended carries used in MBBR practice such as polyethylene (PE) [18,19], polypropylene (PP) [20], polyurethane (PU) [21], ceramsite [22], diatomite [23], and Poly (vinyl alcohol) hydrogels (PVA gel) [24]. Among these, PE has been widely used due to its good performance.…”

“…Zhang et al [19] used PE (inclination angle 60 • , filling rate 50%) as the MBBR carrier to treat ammonia nitrogen wastewater with 71.4 ± 26.9% being obtained. Yuan et al [21] used denitrification-MBBR to treat the WWTP effluent with PE, PP, PU, and ceramsite as the carriers. In the stable operation stage, performances of denitrification, organic matter removal, biomass, and microbial characteristics on different carriers were compared.…”

Simultaneous Biological and Chemical Removal of Sulfate and Fe(II)EDTA-NO in Anaerobic Conditions and Regulation of Sulfate Reduction Products

“…The MBBR process principle is based on the basic principle of the biofilm process, making full use of the advantages of the activated sludge process and overcoming the shortcomings of the traditional activated sludge process and the fixed biofilm process. Yuan et al found that while the NO 3 − -N was 12.6 mg·L −1 , the highest NO 3 − -N removal rate of MBBR filled with polyethylene carriers was 96% [19]. The sulfur-oxidizing autotrophic denitrification in MBBR achieved the nitrogen removal efficiency of 94% at the volumetric loading rate of 0.18 kg N·m −3 ·d −1 [17].…”

Long-term performance evaluation of an anoxic sulfur oxidizing moving bed biofilm reactor under nitrate limited conditions

“…Moving bed biofilm reactors (MBBR) have been widely used for the treatment of domestic and industrial wastewaters due to their effective biomass retention. [12][13][14] However, few studies focused on the operation of anoxic MBBRs for treating sulfur contaminated wastewaters. Full-scale sulfuroxidizing bioreactors may experience fluctuations in the influent NO 3 − concentration as well as an unexpected increase or decrease of sulfur loading, which can lead to severe NO 3 − limitation in the system.…”