Inhibitory effect of high phenol concentration in treating coal gasification wastewater in anaerobic biofilter

In this paper, the inhibition of methanogens by phenol in coal gasification wastewater(CGW)was investigated by both anaerobic toxicity tests and a lab-scale anaerobic biofilter reactor(AF). The anaerobic toxicity tests indicated that keeping the phenol concentration in the influent under 280 mg/L could maintain the methanogenic activity. In the AF treating CGW,the result showed that adding glucose solution as co-substrate could be beneficial for the quick start-up of the reactor. The effluent chemical oxygen demand(COD) and total phenol reached1200 and 100 mg/L, respectively, and the methane production rate was 175 m L CH4/g COD/day.However, if the concentration of phenol was increased, the inhibition of anaerobic micro-organisms was irreversible. The threshold of total phenol for AF operation was 200–250 mg/L. The extracellular polymeric substances(EPS) and particle size distribution of anaerobic granular sludge in the different stages were also examined, and the results indicated that the influence of toxicity in the system was more serious than its effect on flocculation of EPS. Moreover, the proportion of small size anaerobic granular sludge gradually increased from10.2% to 34.6%. The results of high through-put sequencing indicated that the abundance of the Chloroflexi and Planctomycetes was inhibited by the toxicity of the CGW, and some shifts in the microbial community were observed at different stages.     

An autotrophic nitrogen removal process：Short-cut nitrification combined with ANAMMOX for treating diluted effluent from an UASB reactor fed by landfill leachate

A combined process consisting of a short-cut nitrification (SN) reactor and an anaerobic ammonium oxidation upflow anaerobic sludge bed (ANAMMOX) reactor was developed to treat the diluted effluent from an upflow anaerobic sludge bed (UASB) reactor treating high ammonium municipal landfill leachate.The SN process was performed in an aerated upflow sludge bed (AUSB) reactor (working volume 3.05 L),treating about 50% of the diluted raw wastewater.The ammonium removal efficiency and the ratio of NO 2 N to NOx-N in the effluent were both higher than 80%,at a maximum nitrogen loading rate of 1.47 kg/(m 3 ·day).The ANAMMOX process was performed in an UASB reactor (working volume 8.5 L),using the mix of SN reactor effluent and diluted raw wastewater at a ratio of 1:1.The ammonium and nitrite removal efficiency reached over 93% and 95%,respectively,after 70-day continuous operation,at a maximum total nitrogen loading rate of 0.91 kg/(m 3 ·day),suggesting a successful operation of the combined process.The average nitrogen loading rate of the combined system was 0.56 kg/(m 3 ·day),with an average total inorganic nitrogen removal efficiency 87%.The nitrogen in the effluent was mostly nitrate.The results provided important evidence for the possibility of applying SN-ANAMMOX after UASB reactor to treat municipal landfill leachate.     

Influence of phenol on ammonia removal in an intermittent aeration bioreactor treating biologically pretreated coal gasification wastewater

A laboratory-scale intermittent aeration bioreactor was investigated to treat biologically pretreated coal gasification wastewater that was mainly composed of NH_3-N and phenol.The results showed that increasing phenol loading had an adverse effect on NH_3-N removal;the concentration in effluent at phenol loading of 40 mg phenol/(L·day) was 7.3 mg/L, 36.3%of that at 200 mg phenol/(L·day). The enzyme ammonia monooxygenase showed more sensitivity than hydroxylamine oxidoreductase to the inhibitory effect of phenol, with32.2% and 10.5% activity inhibition, respectively at 200 mg phenol/(L·day). Owing to intermittent aeration conditions, nitritation-type nitrification and simultaneous nitrification and denitrification(SND) were observed, giving a maximum SND efficiency of 30.5%.Additionally, ammonia oxidizing bacteria(AOB) and denitrifying bacteria were the main group identified by fluorescent in situ hybridization. However, their relative abundance represented opposite variations as phenol loading increased, ranging from 30.1% to 17.5%and 7.6% to 18.2% for AOB and denitrifying bacteria, respectively.     

Performance study and kinetic modeling of hybrid bioreactor for treatment of bi-substrate mixture of phenol-m-cresol in wastewater: Process optimization with response surface methodology

Performance of a hybrid reactor comprising of trickling filter(TF) and aeration tank(AT) unit was studied for biological treatment of wastewater containing mixture of phenol and m-cresol,using mixed microbial culture.The reactor was operated with hydraulic loading rates(HLR) and phenolics loading rates(PLR) between 0.222-1.078m3/(m2·day) and 0.900-3.456kg/(m3·day),respectively.The efficiency of substrate removal varied between 71%-100% for the range of HLR and PLR studied.The fixed film unit showed better substrate removal efficiency than the aeration tank and was more resistant to substrate inhibition.The kinetic parameters related to both units of the reactor were evaluated and their variation with HLR and PLR were monitored.It revealed the presence of substrate inhibition at high PLR both in TF and AT unit.The biofilm model established the substrate concentration profile within the film by solving differential equation of substrate mass transfer using boundary problem solver tool ’bvp4c’ of MATLAB 7.1 software.Response surface methodology was used to design and optimize the biodegradation process using Design Expert 8 software,where phenol and m-cresol concentrations,residence time were chosen as input variables and percentage of removal was the response.The design of experiment showed that a quadratic model could be fitted best for the present experimental study.Significant interaction of the residence time with the substrate concentrations was observed.The optimized condition for operating the reactor as predicted by the model was 230mg/L of phenol,190mg/L of m-cresol with residence time of 24.82 hr to achieve 99.92% substrate removal.     

The addition of microbes for treating textile wastewater

Some strains and culture of bacteria which are able to decolorize dyes and degrade polyvinyl alcohol(PVA) were isolated and selected. A pilot scale facultative anaerobic-aerobic biological process was applied for treatment of textile wastewater containing dyes and PVA. Activated carbon adsorption was used as a tertiary treatment stage, and residual sludge from clarifier returned to the anaerobic reactor again. The pilot test were carried out with two systems. One was inoculated by acclimated sludge, and the another was adding the mixed culture of dye-decoloring and PVA-degrading bacteria for forming biological films, the latter was observed to be more effective than the former. The test has run normally for ten months with a COD loading of 2.13 kg/m3/day, a BOD5 loading of 0.34 kg/m3/day in anaerobic reactor; a COD loading of 1.71 kg/m3/day, a BOD5 loading 0.44 kg/m3/day in aerobic reactor. The pollutants removal efficiency by adding microbes was about 20% higher than that by acclimated sludge. The aver     

Removal of anaerobic soluble microbial products in a biological activated carbon reactor

The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable. Focusing on the biodegradation of anaerobic SMP, the biological activated carbon (BAC) was introduced into the anaerobic system. The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors. The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2, i.e., BAC) functioned as a polishing step to remove SMP produced in UASB1. The results showed that 90% of the SMP could be removed before granular activated carbon was saturated. After the saturation, the SMP removal decreased to 60% on the average. Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation. A strain of SMP-degrading bacteria, which was found highly similar to Klebsiella sp., was isolated, enriched and inoculated back to the BAC reactor. When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m 3 ·day), the effluent from the BAC reactor could meet the discharge standard without further treatment. Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective, cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L.     

Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

Anaerobic treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor(ATFBR) with a mesoporous granular activated carbon(GAC)as a support material.The experimental protocol was defined to examine the effect of the maximum organic loading rate(OLR),hydraulic retention time(HRT),the efficiency of the reactor and to report on its steady- state performance.The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/(m~3.d).The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m~3/(m~3·d) of the reactor. With the increase of OLR from 83.7 kg COD/(m~3.d),the COD removal efficiency decreased.Also an artificial neural network(ANN) model using multilayer perceptron(MLP)has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data,the experimental values obtained have been used.The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data.The mean square error(MSE)was found to be only 0.0146.     

Performance of the hybrid growth sequencing batch reactor (HG-SBR) for biodegradation of phenol under various toxicity conditions

Hybrid growth microorganisms in sequencing batch reactors have proven effective for treating the toxic compound phenol, but the toxicity effect under different toxicity conditions has rarely been discussed. Therefore, the performance of the HG-SBR under toxic, acute and chronic organic loading can provide the overall operating conditions of the system. Toxic organic loading(TOL) was monitored during the first 7 hr while introducing50 mg/L phenol to the system. The system was adversely affected with the sudden introduction of phenol to the virgin activated sludge, which caused a low degradation rate and high dissolved oxygen consumption during TOL. Acute organic loading(AOL) had significant effects at high phenol concentrations(600, 800 1000 mg/L). The specific oxygen uptake rate(SOUR) gradually decreased to 4.9 mg O_2/(g MLVSS·hr) at 1000 mg/L of phenol compared to 12.74 mg O_2/(g MLVSS·hr) for 200 mg/L of phenol. The HG-SBR was further monitored during chronic organic loading(COL) over 67 days. The effects of organic loading were more apparent at 800 mg/L and 1000 mg/L phenol concentrations, as the removal range was between 22%–30% and 18%–46% respectively, which indicated the severe effects of COL.     

An innovative integrated system utilizing solar energy as power for the treatment of decentralized wastewater

This article reports an innovative integrated system utilizing solar energy as power for decentralized wastewater treatment, which consists of an oxidation ditch with double channels and a photovoltaic (PV) system without a storage battery. Because the system operates without a storage battery, which can reduce the cost of the PV system, the solar radiation intensity affects the amount of power output from the PV system. To ensure that the power output is sufficient in all different weather conditions, the solar radiation intensity of 78 W/m 2 with 95% confidence interval was defined as a threshold of power output for the PV system according to the monitoring results in this study, and a step power output mode was used to utilize the solar energy as well as possible. The oxidation ditch driven by the PV system without storage battery ran during the day and stopped at night. Therefore, anaerobic, anoxic and aerobic conditions could periodically appear in the oxidation ditch, which was favorable to nitrogen and phosphate removal from the wastewater. The experimental results showed that the system was efficient, achieving average removal efficiencies of 88% COD, 98% NH 4 + -N, 70% TN and 83% TP, under the loading rates of 140 mg COD/(g MLSS·day), 32 mg NH 4 + -N/(g MLSS·day), 44 mg TN/(g MLSS·day) and 5 mg TP/(g MLSS·day).     

Characteristics of high-sulfate wastewater treatment by two-phase anaerobic digestion process with Jet-loop anaerobic fluidized bed

A new anaerobic reactor, Jet-loop anaerobic fluidized bed （JLAFB）, was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO42 ratio and alkalinity and sulfide inhibition in reactors, were discussed for a JLAFB and a general anaerobic fiuidized bed （AFB） reactor used as sulfate-reducing phase and methane-producing phase, respectively, in two-phase anaerobic digestion process. The formation of granules in the two reactors was also examined. The results indicated that COD and sulfate removal had different demand of influent COD/SO4^2- ratios. When total COD removal was up to 85%, the ratio was only required up to 1.2, whereas, total sulfate removal up to 95% required it exceeding 3.0. The alkalinity in the two reactors increased linearly with the growth of influent alkalinity. Moreover, the change of influent alkalinity had no significant effect on pH and volatile fatty acids （VFA） in the two reactors. Influent alkalinity kept at 400-500 mg/L could meet the requirement of the treating process. The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms. When sulfate loading rate was up to 8. 1 kg/（m^3.d）, the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L, respectively. Furthermore, the granules, with offwhite color, ellipse shape and diameters of 1.0-3.0 mm, could be developed in JLAFB reactor. In granules, different groups of bacteria were distributed in different layers, and some inorganic metal compounds such as Fe, Ca, Mg etc. were found.     

林可霉素生产废水的厌氧生物处理工艺

采用单相中温升流式厌氧污泥床(UASB)反应器厌氧生物工艺处理含有有毒难降解有机物的林可霉素生产废水.当进水COD 8000～14000 mg/L,HRT约10h时,COD容积负荷可达20～35kg/(m³·d),COD去除率为50%～55%.适时调整并维持较高的表面水力负荷[0.2～0.4 m³/(m²·h)]、较高的进水有机基质浓度(COD为2000～3000mg/L)和污泥COD负荷[0.2～0.5 kg/(kg·d)],并适当延长启动驯化时间可培养出沉降性好、污泥活性较高的颗粒污泥.废水厌氧生物降解动力学符合Monod方程,动力学常数V_max=1.3 d^-1,K_s=8133mg/L.废水中不可生物降解物质占总COD的比例约为30%,这是废水COD去除率偏低的重要因素.     

上流式多级厌氧反应器（UMAR）处理木薯淀粉废水的研究

对自行研制的上流式多级厌氧反应器（UMAR）处理木薯淀粉废水的启动和运行特性进行了研究.结果表明,UMAR反应器启动周期短,易培养出活性高的颗粒污泥,经过40 d的运行,COD去除率可达84%,VSS/TSS由78%增加到90.4%.UMAR处理效率高,水力停留时间（HRT）为4 h,进水COD为6 250 mg/L,容积负荷为24 kg/(m³·d)时, COD去除率在75%以上.UMAR反应器对负荷提高、低pH冲击、进水水质的改变表现出良好的耐受能力.     

微压流化式复合生物反应器处理含酚废水效能的研究

通过连续动态试验,对新型微压流化式复合生物反应器(MP-FHBR)处理模拟苯酚废水的效能进行研究.结果表明,MP-FHBR的COD容积负荷可达4.86kg/(m3·d)、苯酚容积负荷可达1.96kg/(m3·d),出水COD低于200mg/L、出水苯酚浓度低于1mg/L,COD和苯酚去除率分别达到90%和99%以上.当苯酚容积负荷达到2.04kg/(m3·d),苯酚在反应器中逐渐累积,反应器内微生物的TTC-比脱氢酶活性下降.当MP-FHBR进水苯酚浓度为800mg/L时,最佳水力停留时间为9～10h.水力负荷对反应器沉淀池的泥水分离效果影响较大,限制了反应器的进水量,所以MP-FHBR主要适用于处理较高浓度的含酚废水.     

Degradation of phenol in an upflow anaerobic sludge blanket (UASB) reactor at ambient temperature

IntroductionPhenolistherawmaterialforthecommercialproductionofawidevarietyofresins ,includingphenolicresinsasconstructionmaterialsforautomobilesandappliances,expoxyresinsasadhesives ,andpolyamideforvariousapplications.Inaddition ,phenolsareoftenfoundinwas…     

Degradation of phenol in an upflow anaerobic sludge blanket(UASB) reactor at ambient temperatureKE

A synthetic wastewater containing phenol as sole substrate was treated in a 2.8 L upflow anaerobic sludge blanket(UASB) reactor at ambient temperature. The operation conditions and phenol removal efficiency were discussed, microbial population in the UASB sludge was identified based on DNA cloning, and pathway of anaerobic phenol degradation was proposed. Phenol in wastewater was degraded in an UASB reactor at loading rate up to 18 gCOD/(L·d), With a 1:1 recycle ratio, at 26(1℃, pH 7.0-7.5. An UASB reactor was able to remove 99% of phenol up to 1226 mg/L in wastewater with 24 h of hydraulic retention time(HRT). For HRT below 24 h, phenol degradation efficiency decreased with HRT, from 95.4% at 16 h to 93.8% at 12 h. It further deteriorated to 88.5% when HRT reached 8 h. When the concentration of influent phenol of the reactor was 1260 mg/L(corresponding COD 3000 mg/L), with the HRT decreasing(from 40 h to 4 h, corresponding COD loading increasing), the biomass yields tended to increase from 0.265 to 3.08 g/(L·d). While at 12 h of HRT, the biomass yield was lower. When HRT was 12 h, the methane yield was 0.308 L/(gCOD removed), which was the highest. Throughout the study, phenol was the sole organic substrate. The effluent contained only residual phenol without any detectable intermediates, such as benzoate, 4-hydrobenzoate or volatile fatty acids(VFAs). Based on DNA cloning analysis, the sludge was composed of five groups of microorganisms. Desulfotomaculum and Clostridium were likely responsible for the conversion of phenol to benzoate, which was further degraded by Syntrophus to acetate and H2/CO2. Methanogens lastly converted acetate and H2/CO2 to methane. The role of epsilon-Proteobacteria was, however, unsure.     

太阳光Fenton氧化对含酚废水生物降解影响研究

研究了太阳光Fenton氧化预处理对含酚废水生物降解性的影响及太阳光Fenton氧化-生化法联合工艺对煤气含酚废水的处理效果。结果表明,煤气含酚废水和模拟含酚废水的生物降解性均较差,太阳光Fenton氧化预处理可明显提高含酚废水的生物降解性,随着H2O2投加量的增加,废水的BOD5/COD比值逐渐增大,生物降解性明显增强。煤气含酚废水直接进行生化处理的COD和挥发酚去除率均较低。当太阳光Fenton氧化过程H2O2用量为22.5%理论投加量时,采用太阳光Fenton氧化-生化法联合工艺可使煤气含酚废水的COD由1357mg/L降低至104mg/L,挥发酚由198.2mg/L降低至0.47mg/L,COD和挥发酚均达到国家二级排放标准。     

硫酸盐生物还原法处理含锌废水

研究了用硫酸盐还原菌处理含锌废水的污泥床工艺及影响运行的主要因素,结果表明,该工艺可在进水ＣＯＤ和锌浓度分别为３２０ｍｇ／Ｌ与１００ｍｇ／Ｌ时有效运行,有机物和Ｚｎ＾２＋的去除率分别以７３．８％和９９．６３％,大水力滞留时间降至６ｈ时,Ｚｎ＾２＋的去除率仍可达９４．５５％,进水Ｚｎ＾２＋浓度低于５００ｍｇ／Ｌ,时装置可以稳定运行,而当浓度达到６００ｍｇ／Ｌ时,硫酸盐原菌受到Ｚｎ＾２＋的明显毒害。当     

三相生物流化床处理高浓度丙烯酸丁酯生产废水

采用三相生物流化床工艺处理模拟丙烯酸丁酯生产废水,考察了进水丙烯酸浓度、对甲基苯磺酸浓度、容积负荷、水力停留时间对废水处理效果的影响.结果表明,该工艺适合于丙烯酸丁酯废水的高负荷处理.进水中100 mg/L丙烯酸及50 mg/L的对甲基苯磺酸对生物流化床中未经驯化的微生物具有明显的毒害作用,经过2周左右的驯化,毒害作用...     

酸化大豆蛋白废水的厌氧处理

对有机质浓度高,成分单一,蛋白质、总氮浓度较高,易酸化,且已酸化程度较高的大豆蛋白废水,确定以新型内循环厌氧反应池为主的处理工艺,在原废水ρ(COD)为11809~15040mg/L时,总出水浓度192~350mg/L,去除率达到96.2%~97.5%。新的内循环厌氧反应池具有高度小、结构简单、污染物去除率高的特征,COD运行负荷达6.0~7.5kg/(m3.d),COD去除率达88%~93%。当COD运行负荷5.0~7.0kg/(m3.d)时,该池内循环管道形成了连续的较强内回流。