Bio-contact Oxidation Reactor Research Articles

Bioaugmentation using salt-tolerant bacteria in a dual-stage process for high-salinity wastewater treatment: Performance, microbial community, and salt-tolerance mechanism

To address the challenges of nitrogen removal and stability problems in biological treatment of high-salinity wastewater, a new technology based on salt-tolerant aerobic denitrifying (SAD) bacteria to strengthen the two-stage bio-contact oxidation reactor (TBOR) and moving bed biofilm reactor (MBBR) dual-stage process was proposed. The results showed that the NH4+-N removal rate of TBOR and TN removal rate of MBBR increased by 26.05 % and 15.90 %, respectively, after bioaugmentation with SAD bacteria at salinity of 5 %. The COD, NH4+-N and TN removal rates in real wastewater (at salinity of 4 ~ 5 %) treatment were 93.45 %, 97.57 % and 90.83 %, respectively. Microbial analysis showed that at salinity of 5 %, SAD bacteria Halomonas and Truepera were the main functional bacteria responsible for nitrogen removal. Microbial functional analysis and metabolic predictions further revealed that bioaugmentation enhanced the expression of the nir gene, thereby further promoting the process of dissimilatory nitrite reduction to ammonium (DNRA). Furthermore, bioaugmentation can also resist the external high-salinity environment by exporting Na+ extracellularly, promoting extracellular polymeric substances (EPS) secretion and amino acid metabolism. This study demonstrates that bioaugmentation with SAD bacteria is a suitable approach for nitrogen and carbon removal of high-salinity wastewater.

Enhancing efficiency of biological contact oxidation reactors through filaments optimization of basalt fibers bio-carriers: Insights from a pilot-scale study

There has been significant interest in using Modified basalt fibers (MBF) based bio-carriers in biological contact oxidation reactors to enhance biological remediation while minimizing secondary pollution and carbon footprints. These MBF filaments form a unique spherical structure called “bio-nest,” which supports diverse microbial communities and facilitates various biogeochemical processes. However, impact of different structural alignments of the filaments within the bio-nest on system performance has not been fully understood. To address this question, this study investigated the variable spatial structures of MBF filaments using response surface methodology. The MBF carrier media were retrofitted in a pilot-scale bio-contact oxidation reactor (R-MBF) under multiple runs, and optimal parameters for the spatial distribution were identified. The optimal parameters were identified as 17.27 cm for horizontal spacing, 15.04 cm for vertical spacing, and 62.51 % for filling ratio at 6 h of HRT. R-MBF demonstrated successful treatment performance, achieving a total nitrogen removal rate of 0.231 kg/m3/d simulated by the modified Stover-Kincannon model. Denitrifying and decarboxylating bacteria, heterotrophic nitrifying-aerobic denitrifying bacteria, ammonia-oxidizing bacteria, and nitrite-oxidizing bacteria were likely involved in pollutants transformation. The findings of the study emphasize the significance of filament optimization prior to installation as it may improve the efficiency of system's performance.

Succession of fungal communities and fungal-bacterial interactions in biofilm samples within a multistage bio-contact oxidation reactor during the treatment of low-COD and high-salinity produced water

The multistage bio-contact oxidation reactor (MBCOR) has been extensively applicated in the oily wastewater treatment. Nonetheless, the underlying mechanisms, especially the fungal community information during the bioremediation of low-COD and high-salinity oilfield produced water is still poorly understood. In this study, the fungal community succession, and fungi-bacteria interactions of a MBCOR were investigated. The result of Illumina high-throughput sequencing showed that the chemical oxygen demand was the main variable in influencing the community structure within the first tank. Besides, the linear discriminant analysis effect size analysis disclosed the feature fungal taxa at different stages, revealing that the fungal community shift was driven by its functional needs. Additionally, network analysis revealed that fungal and bacterial communities were highly interconnected and possessed cooperative relationships. Furthermore, the equilibrium of fungal-bacterial communities was primarily influenced by species richness and diversity. This study provides a deeper insight into the role of fungi within MBCOR in treating oily wastewater.

Performance and microbial community analysis of a bio-contact oxidation reactor during the treatment of low-COD and high-salinity oilfield produced water

The multistage bio-contact oxidation reactor (BCOR) is a widely used biological strategy to treat wastewater, however, little is known about the performance and microbial community information of BCOR during the treatment of low-COD and high-salinity oilfield produced water. In this study, the performance of a multistage BCOR in treating produced water was investigated. The result suggested the BCOR could efficiently remove COD, BOD5, NH4+-N, and oil pollutants. Besides, high-throughput sequencing analysis revealed that oil content was the main variable in shaping the community structure. The highest total relative abundance of potential pollutants degraders in first BCOR stage suggested significant role of this stage in pollutants removal. In addition, the correlation analysis disclosed the key functional genera during the degradation process, including Rhodobacter, Citreibacter, and Roseovarius. Moreover, network analysis revealed that the microbial taxa within same module had strong ecological linkages and specific functions.

Enhanced performance and microbial community analysis of bioelectrochemical system integrated with bio-contact oxidation reactor for treatment of wastewater containing azo dye

Feasibility and superiority of the bioelectrochemical system integrated with biocontact oxidation (BES-BCO) for degradation and/or mineralization of azo dyes have been confirmed. In this study, the effects of hydraulic retention time (HRT), applied voltage, and dissolved oxygen (DO) concentration at the bioanode on the performance of BES-BCO and traditional BES were investigated. Using the response surface methodology, the optimum values of HRT, applied voltage, and DO concentration at the bioanode of BES-BCO were investigated to obtain the maximum decolouration and COD removal efficiency and minimum specific energy consumption (SEC). The microbial community structure in BES-BCO was studied for analyzing the change following the introduction of oxygen. The optimised solution was an applied voltage of 0.59V, HRT of 12h, and DO concentration of 0.96mg/L at the bioanode. Under such conditions, the DE, COD removal efficiency, and SEC values were 94.62±0.63%, 89.12±0. 32%, and 687.57±3.86J/g, respectively. In addition, after changing from BES to BES-BCO, the bacterial community structure of the bioanode underwent significant changes. Several aerobic aniline-degrading bacteria and anode-respiration bacteria (ARB) were found to dominate the community of the anode biofilm. The results showed that the removal of azo dye degradation by-products was closely correlated with the o-bioanode and the BCO bacterial community structure.

Removal of azo dye in an up-flow membrane-less bioelectrochemical system integrated with bio-contact oxidation reactor

An up-flow membrane-less bioelectrochemical system integrated with bio-contact oxidation (BES-BCO) was developed for degradation and/or mineralization of the Acid Orange 7 (AO7) in wastewater. The performance of BES-BCO was evaluated based on decolorization removal efficiency, chemical oxygen demand (COD) removal efficiency and the concentration of decolorized byproducts in effluent. The study found that the BES-BCO system can degrade AO7 and COD effectively. Further, the toxic decolorized byproducts of azo dye, which are not generally degrade in the traditional BES system, can be further mineralized by the BES-BCO system. In addition, the COD removal efficiency increased with the increase of aeration at BCO. However, higher DO concentration at anode can hinder the electrons transfer between anode and exoelectrogen, resulting in a significant decrease of decolorization removal efficiency. This study provided a novel compact technology for advanced treatment of azo dyes wastewater for engineering applications, and concluded that the integrated BES-BCO system is effective for advanced treatment of azo dye-containing wastewater.

Industrial-scale biological treatment of Chinese nutgall processing wastewater by combined expanded granular sludge bed and bio-contact oxidation

The industrial-scale biological treatment of Chinese nutgall processing wastewater was conducted with a 200 m 3 expanded granular sludge bed reactor and a 900 m 3 bio-contact oxidation reactor. The temperature of the two reactors was controlled under mesophilic conditions (32 - 40˚C), through changing the proportion of the dilution water, which was composed of steam condensation water and residual circulating water. The effluent COD, gallic acid, chroma, total nitrogen, total phosphorus levels and pH of both the expanded granular sludge bed and bio-contact oxidation reactors were monitored. In addition, the redox potential in the expanded granular sludge bed was recorded. The total COD removal efficiency was 87.257% when the influent COD concentration was 14 251±3 148 mg/L, and the ratio of wastewater: dilution water was 1:5. The removal efficiencies of gallic acid, chroma, total nitrogen, and total phosphorus were 72.221%, 43.940%, 64.151% and 39.316%, respectively. The effluent pH increased in either the expanded granular sludge bed reactor or the bio-contact oxidation reactor during the operation. The redox potential in the expanded granular sludge bed varied between -367 mV and -435 mV. The results indicate that the combined process was suitable for treating Chinese nutgall processing wastewater.

Biological nutrient removal of gallic acid processing wastewater by combined expanded granular sludge bed and bio-contact oxidation under mesophilic conditions

AbstractThe biological treatment of gallic acid processing wastewater (GAPW) was carried out with laboratory-scale 30-L expanded granular sludge bed (EGSB) and 60-L bio-contact oxidation (BCO) reactors. The temperatures of the EGSB and bio-contact oxidation reactors were maintained under mesophilic conditions of 35 and 32°C, respectively. The effluent chemical oxygen demand (COD), total nitrogen, total phosphorus, gallic acid levels, and pH values of both the EGSB and bio-contact oxidation reactors, and redox potential of the EGSB were monitored. When the influent COD concentration was 3,000 mg L−1 and the organic loading rate (OLR) was 17.5 kg COD (m3 d)−1, the removal efficiency of COD by the EGSB and bio-contact oxidation reactors was 87.021%. The removal efficiencies of nitrogen, phosphorus, and gallic acid were 70.822, 58.116, and 63.407%, respectively. The redox potential in the EGSB varied between −320 and −350 mV. The effluent pH increased either in the EGSB or the bio-contact oxidation reactor. B...

A novel bamboo fiber biofilm carrier and its utilization in the upgrade of wastewater treatment plant

AbstractA novel biofilm carrier (BFBC) was prepared with bamboo fiber as raw material and its characteristics, including specific surface area, hydrophilicity, and adsorption capacity were investigated. The comparison with conventional combined carrier for the removal of organics, N, and P using bio-contact oxidation reactor (BCOR) was carried out. The application of BCOR filled with BFBC in upgrading the existing activated sludge system of wastewater treatment plant was further studied. The specific surface area of BFBC was 5393 m2/m3, thoroughly saturated with water in 30 min. The BCOR filled with BFBC started up more rapidly than BCOR filled with combined carrier, and the removal efficiencies for chemical oxygen demand (COD), N, and P were significantly higher in BCOR filled with BFBC than combined carrier during start-up period. Moreover, the BCOR filled with BFBC showed higher resistance to pollutants load impact. Compared with the existing activated sludge system, the BCOR was more efficient in poll...

Efficient azo dye removal in bioelectrochemical system and post-aerobic bioreactor: Optimization and characterization

A new process of an up-flow bio-electrocatalyzed electrolysis reactor (UBER) connected with an aerobic bio-contact oxidation reactor (ABOR) was developed for treating azo dye wastewater. Alizarin Yellow R (AYR), used as a model dye, was efficiently decolorized in UBERs (97.5±1.0%) and further mineralized in the subsequent aerobic bio-contact oxidation reactor (ABOR). Decolorization efficiency was improved with increasing cathode size in UBERs, but AYR removal rate and current density were not increased in proportion to cathode size, mainly due to the limitation of anodic reactions. AYR decolorization rate was optimized at a cathode size of 90cm3 in an UBER where the charge transfer resistance Rct (39.5Ω) was minimal. We assessed the effect of hydraulic retention time (HRT: 6.5h, 4.5h, 3.5h, 2.0h) on the removal of residual by-products (p-phenylenediamine (PPD) and 5-aminosalicylic acid (5-ASA) in the ABOR. The concentrations of PPD and 5-ASA decreased down to 0.28±0.01 and 0.27±0.03mgL−1, respectively, in an optimum HRT 3.5h. Decolorization efficiency and COD removal efficiency was 93.8±0.7% and 93.0±0.5% in the combined process of UBER and ABOR in overall HRT 6h (HRT 2.5h in UBER+HRT 3.5h in ABOR). The Chroma in ABOR effluent was 80times.

Azo dye removal in a membrane-free up-flow biocatalyzed electrolysis reactor coupled with an aerobic bio-contact oxidation reactor

Azo dyes that consist of a large quantity of dye wastewater are toxic and persistent to biodegradation, while they should be removed before being discharged to water body. In this study, Alizarin Yellow R (AYR) as a model azo dye was decolorized in a combined bio-system of membrane-free, continuous up-flow bio-catalyzed electrolysis reactor (UBER) and subsequent aerobic bio-contact oxidation reactor (ABOR). With the supply of external power source 0.5V in the UBER, AYR decolorization efficiency increased up to 94.8±1.5%. Products formation efficiencies of p-phenylenediamine (PPD) and 5-aminosalicylic acid (5-ASA) were above 90% and 60%, respectively. Electron recovery efficiency based on AYR removal in cathode zone was nearly 100% at HRTs longer than 6h. Relatively high concentration of AYR accumulated at higher AYR loading rates (>780gm−3d−1) likely inhibited acetate oxidation of anode-respiring bacteria on the anode, which decreased current density in the UBER; optimal AYR loading rate for the UBER was 680gm−3d−1 (HRT 2.5h). The subsequent ABOR further improved effluent quality. Overall the Chroma decreased from 320 times to 80 times in the combined bio-system to meet the textile wastewater discharge standard II in China.

Evaluation of decentralized treatment of sewage employing bio-contact oxidation reactor integrated with filter bed

A bio-contact oxidation reactor integrated with filter bed (COR-FB) was developed for decentralized treatment of sewage, which consisted of a biofilm reactor and a gravitational filter bed. It has been investigated to treat municipal wastewater for reuse. The evaluation of COR-FB performance demonstrates that it produced good quality effluent regarding carbonaceous compound, nitrogenous compound, suspended solid and fecal coliform. The efficiencies of COD, NH4+-N, TN, TP and turbidity removal were 90.7%, 81.4%, 64.6%, 60.1% and 96.7%, respectively. The residual geometric mean of fecal coliform counts in the final effluent of COR-FB was only 7.8×103MPN/103ml, corresponding to removal value of 3.8 log10. However, TP removal indicates the necessity of an addition of a bagger and mud valve or an enhanced chemical phosphorus removal prior to treated water reuse. Microfauna communities were monitored in COR-FB, which was found to contain 5 genres and 19 species in the biofilm layer. Also, a simple kinetics model for COR-FB was developed based on the influent, effluent soluble COD concentration and the reaction time by regression simulation. In general, available data proved that COR-FB system can be recommended as a compact and cost-effective technology for decentralized treatment of sewage, especially for developing countries.

不同氮源下好氧反硝化菌Defluvibacter lusatiensisstr.DN7的脱氮特性

PDF HTML阅读 XML下载 导出引用 引用提醒 不同氮源下好氧反硝化菌Defluvibacter lusatiensis str.DN7的脱氮特性 DOI: 10.5846/stxb201203090318 作者: 作者单位: 浙江农林大学,浙江农林大学环境与资源学院,浙江农林大学环境与资源学院 作者简介: 通讯作者: 中图分类号: 基金项目: 水体污染控制与治理重大科技专项(2008ZX07101-006-08);浙江省重大科技专项(2009C03006-3) Denitrification characteristics of an aerobic denitrifying bacterium Defluvibacter lusatiensis str. DN7 using different sources of nitrogen Author: Affiliation: Zhejiang Agriculture and Forestry University,,Zhejiang Agriculture and Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究了不同氮源下好氧反硝化菌Defluvibacter lusatiensis str.DN7的脱氮特性。结果表明:菌株均能以硝酸盐和亚硝酸盐为唯一氮源进行好氧反硝化作用。反应4 h,NO3--N和NO2--N的去除率分别达83.35%和85.72%。亚硝酸盐完全还原比硝酸盐提前42 h。硝酸盐还原过程中基本无亚硝酸盐积累,而亚硝酸盐还原过程中则检测到明显的硝酸盐积累,反应4 h,NO3--N积累量达到21.83 mg/L。培养液中同时存在硝酸盐和亚硝酸盐时,菌株优先选择硝酸盐作电子受体。亚硝酸盐共存对硝酸盐还原无显著影响,但培养液中残留的NO2--N随亚硝酸盐比例上升而增加,当亚硝酸盐比例从10%升至50%时,NO2--N残留量由3.38 mg/L增至7.60 mg/L。少量硝酸盐的加入对亚硝酸盐的还原产生抑制作用。当硝酸盐比例为10%时,72 h NO2--N的去除率仅为74.79%,远低于以亚硝酸盐为唯一氮源情况(去除率100%)。以氨氮为唯一氮源时,菌株同时进行异养硝化和好氧反硝化反应,72 h,NH4+-N去除率达85.66%,且基本无硝酸盐或亚硝酸盐积累。少量氨氮共存(氨氮比例<30%)有利于促进菌株的好氧反硝化作用,反之亦然。 Abstract:An aerobic denitrifying bacterium DN7 was isolated from the bio-contact oxidation reactor treating bamboo processing wastewater. Cellular morphology demonstrated that strain DN7 was a gram negative bacillus with an average size of 0.5 μm×1.5 μm and the colony was ivory. Based on the homologic analysis of the 16S rDNA sequence and physiochemical properties, the strain was identified as Defluvibacter lusatiensis str.. The denitrification characteristics of strain DN7 with different sources of nitrogen were investigated. Results showed that the strain could use either nitrate or nitrite as the sole source of nitrogen for aerobic denitrification, and the removal efficiencies of nitrate and nitrite were 83.35% and 85.72% in 4 h, respectively. The completely reduction of nitrite was 42 h before the nitrate. Almost no nitrite accumulation was observed in the aerobic denitrification process with nitrate as the sole nitrogen source, whereas nitrate accumulation was detected with nitrite as the sole nitrogen source, in which the maximum amount of nitrate reached 21.83 mg/L in 4 h. The strain preferred nitrate to nitrite in the nitrate-nitrite mixed system. Coexistence of nitrite and nitrate had no significant effect on nitrate reduction, however, the residual concentration of nitrite increased with the ratio of nitrite to nitrate. As the ratio of nitrite to nitrate increased from 1∶9 to 5∶5, the residual nitrite concentration increased from 3.38 mg/L to 7.60 mg/L. Little amount of nitrate would inhibit the nitrite reduction significantly. When the ratio of nitrate to nitrite was 1∶9, the nitrite removal efficiency dropped to 74.79%, much lower than that with nitrite as the sole nitrogen source. The strain was capable of using ammonium nitrogen as the sole nitrogen source, in which both heterotrophic nitrification and aerobic denitrification occurred. Nitrate accumulation was observed in the heterotrophic nitrification and aerobic denitrification process, and the maximum value was 18.92 mg/L. In 72 h, the removal efficiency of ammonium nitrogen reached 85.66%, and neither nitrate nor nitrite accumulation was observed. The aerobic denitrification of the strain could be promoted in the presence of little amount of ammonium nitrogen. When the ammonium to nitrate ratio was 1∶9, nitrate was completely reduced in 48 h, 24 h before that with nitrate as the sole nitrogen source. Coexistence of nitrate and ammonium nitrogen also enhanced the heterotrophic nitrification. When the nitrate to ammonium ratio was 1∶9, removal efficiency of ammonium nitrogen reached 87.50%, 7.05% higher than that with ammonium nitrogen as the sole nitrogen source. 参考文献 相似文献 引证文献

Anaerobic ammonium oxidation in constructed wetlands with bio-contact oxidation as pretreatment

Anaerobic ammonium oxidation (ANAMMOX) may provide an effective nitrogen removal pathway for constructed wetlands with low C/N influent. In a study of domestic sewage treatment, anaerobic ammonium oxidation process was identified in the pilot-scale constructed wetland of a bio-ecological process which was composed of a bio-contact oxidation reactor and a horizontal subsurface flow constructed wetland (CW). To investigate the ANAMMOX establishment in the bio-ecological process, two new CWs (planted and unplanted) were developed to be a control for the pre-existing CW. Under operational conditions of DO 2–3mg/l, HRT 3.5h for the bio-contact oxidation reactor, HRT 3days for CWs, and domestic sewage as influent, the process achieved more than 90% TN removal rate after the ANAMMOX was established. The ANAMMOX bacteria on the media of the constructed wetlands were analyzed by specific polymerase chain reaction (PCR) with ANAMMOX specific primer set AMX818F-AMX1066R. The result of the genetic sequencing showed that the PCR product was related to Candidatus B. anammoxidans (AF375994.1) with 98% sequence similarity. Copy numbers of 16S rRNA gene of ANAMMOX bacteria in the pre-existing CW, the new planted CW and new unplanted CW were 3.47×105, 3.02×105 and 1.30×105, respectively. These results demonstrated that the ANAMMOX process was successfully established and operated consistently in the constructed wetlands with a bio-contact oxidation reactor as a pretreatment, and that vegetation positively affected the growth and enrichment of ANAMMOX bacteria.

Aerobic treatment of oilfield wastewater with a bio-contact oxidation reactor

This paper investigated the use of Bacillus coagulans W-15 immobilized on carriers in a bio-contact oxidation reactor to treat oilfield produced water. It researched the effect of hydraulic retention time (HRT) on the removal efficiencies of chemical oxidation demand (COD) and total organic carbon (TOC). The results showed that, when the HRT was 24 and 32 h, the COD of effluent water were less than or equal to 352 mg/L, the removal efficiencies of COD and TOC were greater than or equal to 75% and 68%, respectively. The degradation efficiencies in the bio-contact oxidation reactor immobilized with W-5 were estimated to be 73% for total oil, and 86% for the gas chromatography resolved compounds. The quality of the effluent water met the professional emission standard of petrochemical industry of China.

Wastewater treatment by alkali bacteria and dynamics of microbial communities in two bioreactors

In this study, an alkali bacterial consortium was obtained by enrichment cultivation and was used to treat printing and dyeing wastewater (PDW, pH 11–12). The treatment effects and dynamic changes were evaluated in a biocontact oxidation reactor (BOR) and a sequencing batch reactor (SBR). During 3months of continuous operation, the two bioreactors had similar treatment efficiencies (polyvinyl alcohol, PVA, 74.5–81.3%; COD, 73.5–77.4%; 2.15 pH decreases). Molecular biological analysis indicated that the microbial communities underwent dramatic changes during the operation, in which the SBR was superior to the BOR in retaining the alkali bacteria at the start-up stage, however, the BOR seemed to be more advantageous when the frequently changing influents were considered. The bacterial communities in BOR and SBR were diverse and included Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria and an unidentified cluster. Among these only Paracoccus sp. was successfully isolated and confirmed to have the ability to degrade PVA.

Two-stage biodegradation coupled with ultrafiltration for treatment of municipal landfill leachate

The municipal landfill leachate was treated in a hydrolysis–acidification reactor (HAR)/aerobic bio-contact oxidation reactor (ABOR) following a pretreatment with ultrafiltration (UF) membrane. Experiments were conducted continuously for 44 days at a constant flow rate of 20 l d −1 and organic loading rates (OLRs) from 0.75 to 1.5 kgCOD m −3 per day. The results showed that COD of the leachate steadily decreased from 20,015 mg l −1 to less than 3000 mg l −1, and NH 4-N decreased from 368.6 mg l −1 to 259.3 mg l −1 in the UF process. The COD and NH 4-N removal efficiency of HAR was 56.7% and 27.7%, and that of ABOR was 94.6% and 86.7%, respectively. The total COD and NH 4-N removal efficiency reached 99.6% and 93.2%, respectively. UF and HAR played a critical role in raising the biodegradability of the landfill leachate, while ABOR had an important function on removing the dissolved NH 4-N in leachate.

Removal of dichloromethane from waste gases with a bio-contact oxidation reactor

Dichloromethane (DCM) is a kind of volatile organic compound (VOC), and many biological technologies have been studied and applied to meet the treatment of the waste gases. In this paper, a new bio-contact oxidation reactor, in which biofilm attached on the assembly semi-soft plastic media filled in column, was set up to removal DCM from waste gases. The influences of empty bed residence time (EBRT), temperature, pH and organic load on the removal efficiency (RE) and the elimination capacity (EC) of DCM were investigated and discussed. The optimum operation conditions were obtained as the temperature of 20–30 °C, pH 6.0–7.0 and EBRT of 28.3 s for the inlet gas concentration range of 500–1260 mg/m3. Under the optimum operation conditions, the average removal efficiency of DCM was higher than 82%, at the inlet concentration of DCM lower than 1260 mg/m3. The maximum elimination capacity (ECmax) of DCM in the bio-contact reactor was higher than that in the biofilters reported in the literature under the same operation conditions.