Hydrogen production from alcohol wastewater by an anaerobic sequencing batch reactor under thermophilic operation: Nitrogen and phosphorous uptakes and transformation

The objective of this study was to investigate hydrogen production from alcohol wastewater using an anaerobic sequencing batch reactor (ASBR) under thermophilic operation and at a constant pH of 5.5. Under the optimum COD loading rate of 68 kg/m³d, the produced gas contained 43% H₂ without methane and the system provided a hydrogen yield and specific hydrogen production rate of 130 ml H₂/g COD removed and 2100 ml H₂/l d, respectively, which were much higher than those obtained under the mesophilic operation. Under thermophilic operation, both nitrogen and phosphate uptakes were minimal at the optimum COD loading rate for hydrogen production and most nitrogen uptake was derived from organic nitrogen. Under the thermophilic operation for hydrogen production, the nutrient requirement in terms of COD:N:P was found to be 100:6:0.5, which was much higher than that for the methenogenic step for methane production under both thermophilic and mesophilic operations and for the acidogenic step for hydrogen production under mesophilic operation.     

MP-EBGP网络技术应用研究

BGP MPLS VPN是未来VPN技术的主流,随着企业信息化进程的加快,越来越多的用户要求能够跨市、跨省甚至跨国进行通信.以不同AS域的BGP MPLS VPN为基础,通过在ABSR之间配置它们互连接口的IP地址、为VPN配置VRF的Import/Export Target以及在ASBR上对MP-EBGP的特殊配置,实现了MP-EBGP组网方式,并分析了这种组网方式的性能.     

厌氧序批式活性污泥工艺(ASBR)特性研究

通过正交试验,探讨了ＡＳＢＲ工艺最为重要的两个操作参数即充水时间和负荷率对ＡＳＢＲ工艺过程的影响。试验表明,充水时间和负荷率明显影响着ＡＳＢＲ的工艺过程,如出水水质、循环周期等。而且,充水时间和负荷率相互之间也存在着制约关系。     

Enhanced treatment efficiency of an anaerobic sequencing batch reactor (ASBR) for cassava stillage with high solids content

Cassava stillage is a high strength organic wastewater with high suspended solids (SS) content. The efficiency of cassava stillage treatment using an anaerobic sequencing batch reactor (ASBR) was significantly enhanced by discharging settled sludge to maintain a lower sludge concentration (about 30 g/L) in the reactor. Three hydraulic retention times (HRTs), namely 10 d, 7.5 d, 5 d, were evaluated at this condition. The study demonstrated that at an HRT of 5 d and an organic loading rate (OLR) of 11.3 kg COD/(m³ d), the total chemical oxygen demand (TCOD) and soluble COD (SCOD) removal efficiency can still be maintained at above 80%. The settleability of digested cassava stillage was improved significantly, and thus only a small amount of settled sludge needed to be discharged to maintain the sludge concentration in the reactor. Furthermore, the performance of ASBR operated at low and high sludge concentration (about 79.5 g/L without sludge discharged) was evaluated at an HRT of 5 d. The TCOD removal efficiency and SS in the effluent were 61% and 21.9 g/L respectively at high sludge concentration, while the values were 85.1% and 2.4 g/L at low sludge concentration. Therefore, low sludge concentration is recommended for ASBR treating cassava stillage at an HRT 5 d due to lower TCOD and SS in the effluent, which could facilitate post-treatment.     

SRB法处理高浓度硫酸盐废水的试验研究

研究了在厌氧序批式反应器(ASBR)中,利用硫酸盐还原菌(SRB)处理含高浓度SO42-的酸性钛白粉废水的技术可行性及ASBR处理工艺的最佳运行参数。试验结果表明:SRB法处理含高浓度SO42-的酸性钛白粉废水是可行的,在选定试验条件下,模拟废水和钛白粉废水的SO42-去除率分别为92.7%和88.3%,且出水硫酸盐浓度在250mg·L-1以下,达到了国家地面水环境质量标准(GB3838-83)。     

接种污泥对厌氧氨氧化反应器启动特性的影响

采用两套相同的ASBR系统,分别接种好氧硝化污泥和自养反硝化污泥,在模拟废水的pH值为7.6～7.9、温度为32 ℃的条件下,分别运行176 d和170 d后,均成功启动了厌氧氨氧化反应器.在稳定运行阶段,其总氮容积负荷分别为0.147和0.11 kgN/(m3·d),对总氮的平均去除率分别为84.81%和81.57%.两组反应器内氨氮和亚硝态氮的减少量与硝态氮的生成量之比分别为1:1.08:0.31和1:1.18:0.33.接种了好氧硝化污泥的反应器启动更快,且对氨氮的去除效果更好.     

Relationship between phenol degradation efficiency and microbial community structure in an anaerobic SBR

Phenol is a common wastewater contaminant from various industrial processes, including petrochemical refineries and chemical compounds production. Due to its toxicity to microbial activity, it can affect the efficiency of biological wastewater treatment processes. In this study, the efficiency of an Anaerobic Sequencing Batch Reactor (ASBR) fed with increasing phenol concentrations (from 120 to 1200 mg L⁻¹) was assessed and the relationship between phenol degradation capacity and the microbial community structure was evaluated. Up to a feeding concentration of 800 mg L⁻¹, the initial degradation rate steadily increased with phenol concentration (up to 180 mg L⁻¹ d⁻¹) and the elimination capacity remained relatively constant around 27 mg phenol removed?gVSS⁻¹ d⁻¹. Operation at higher concentrations (1200 mg L⁻¹) resulted in a still efficient but slower process: the elimination capacity and the initial degradation rate decreased to, respectively, 11 mg phenol removed?gVSS⁻¹ d⁻¹ and 154 mg L⁻¹ d⁻¹. As revealed by Denaturing Gradient Gel Electrophoresis (DGGE) analysis, the increase of phenol concentration induced level-dependent structural modifications of the community composition which suggest an adaptation process. The increase of phenol concentration from 120 to 800 mg L⁻¹ had little effect on the community structure, while it involved drastic structural changes when increasing from 800 to 1200 mg L⁻¹, including a strong community structure shift, suggesting the specialization of the community through the emergence and selection of most adapted phylotypes. The thresholds of structural and functional disturbances were similar, suggesting the correlation of degradation performance and community structure. The Canonical Correspondence Analysis (CCA) confirmed that the ASBR functional performance was essentially driven by specific community traits. Under the highest feeding concentration, the most abundant ribotype probably involved in successful phenol degradation at 1200 mg L⁻¹ was affiliated to the Anaerolineaceae family.     

Effect of the presence of the antimicrobial tylosin in swine waste on anaerobic treatment

An anaerobic sequencing batch reactor (ASBR), seeded with a biomass inoculum that previously had not been exposed to the macrolide antimicrobial tylosin (mixture of Tylosin A, B, C, and D), was operated for 3 months with swine waste without Tylosin A and for 9 months with swine waste containing Tylosin A at an average concentration of 1.6 mg/L. When swine waste with tylosin was fed to the ASBR, methane production and volatile solids removal did not appear to be inhibited and a methane yield of 0.47 L methane per gram volatile solids fed to the ASBR was observed. Throughout the operating period, Tylosin A levels in ASBR biomass and effluent were below the detection limit of 0.01 mg/L. However, during the first 3 months of operation, the levels of macrolide-lincosamide-streptogramin B (MLSB)-resistant bacteria in the ASBR biomass increased substantially as determined by hybridizations with oligonucleotide probes designed to target MLSB-resistant bacteria. Since no Tylosin A was present in the swine waste during the initial 3 months, the presence of MLSB-resistant bacteria in the swine waste was likely the reason for the increase in resistance. Subsequently, the levels of MLSB-resistant bacteria in ASBR biomass stabilized with an average of 44.9% for the 9 months of operation with swine waste containing Tylosin A. The level of MLSB-resistant bacteria in the swine waste fed to the ASBR during this period averaged 18.0%. The results indicate that anaerobic treatment of a waste stream containing tylosin was effective (based on reactor performance) and that the level of resistant bacteria in the ASBR was substantially higher than in the waste stream fed to this system.     

Influence of the agitation rate on the treatment of partially soluble wastewater in anaerobic sequencing batch biofilm reactor

This work reports on the influence of the agitation rate on the organic matter degradation in an anaerobic sequencing batch reactor, containing biomass immobilized on 3 cm cubic polyurethane matrices, stirred mechanically and fed with partially soluble soymilk substrate with mean chemical oxygen demand (COD) of 974+/-70 mg l(-1). Hydrodynamic studies informed on the homogenization time under agitagion rates from 500 to 1100 rpm provided by three propeller impellers. It occurred very quickly compared to the total cycle time. The results showed that agitation provided good mixing and improved the overall organic matter consumption rates. A modified first-order kinetic model represented adequately the data in the entire range of agitation rate. The apparent first-order kinetic constant for suspended COD rose approximately 360% when the agitation rate was changed from 500 to 900 rpm, whereas the apparent first-order kinetic constant for soluble COD did not vary significantly.     

曝气气浮+ASBR+SBR+Fenton+混凝沉淀处理化学储运废水

针对某企业运营的化学储运废水,采用"曝气气浮+ASBR+SBR+Fenton氧化+混凝沉淀"工艺进行废水处理。工程运行结果表明,出水水质能稳定达到广东省水污染物排放限值(DB44/26-2001)第二时段一级排放标准要求,实际运行成本为4.61元/m^3,实现了化学储运废水稳定达标排放。