炭纤维载体固定床厌氧发酵启动运行效果实验

以开发高效率、抗冲击性能强的高浓度有机废水沼气发酵技术为目的,用传统的 UASB反应器作为对照,研究了以炭纤维为生物膜载体的固定床厌氧反应器的启动运行效果。反应器进口废水 COD 为 5 000 mg/L, 水力停留时间 (HRT) 由213 h 逐步缩短为35 h,进水有机容积负荷(OLR)由0.56 kg COD/ (m³·d)提到3.45 kg COD/(m³·d)。结果表明,固定床反应器厌氧发酵的效率比对照高,出水 pH 值也比对照稳定;运行到第 50 d 时,固定床厌氧反应器和对照的 COD去除率分别由第 7 d 的36.56%和33.58%上升到87.9%和62.6%;固定床厌氧反应器的容积比产气率最高为1.16 m³/(m³·d),累计产气量为415.59 L,而对照的容积比产气率最高值仅为0.31 m³ /(m³·d),累计产气量为 71.66 L,前者最高容积比产气率和累计产气量分别是后者的3.74倍和5.78倍。固定床厌氧反应器的启动速度、COD 去除率和产甲烷效率显著地高于对照反应器。     

Biological treatment of dye wastewaters using an anaerobic-oxic system

Three dye solutions, namely, C.I. Acid Yellow 17, C.I. Basic Blue 3, and C.I. Basic Red 2, were treated in an upflow anaerobic sludge blanket (UASB) reactor followed by a semi-continuous aerobic activated sludge tank. When hydraulic retention time was about 12 hours, no significant color removal was observed in the aerobic stage. In the anaerobic stage, Acid Yellow 17, Basic Blue 3, and Basic Red 2 were removed by 20%, 72%, and 78%, respectively. To treat wastewater from a dye manufacturing factory with COD concentration of 1200 mg/l and Color of 500 degree (dilution factor), an UASB reactor (4.5 liters) and an activated sludge tank (5 liters, adjustable), COD and color were removed by more than 83% and 90% at a COD loading rate of 5.3 kg COD/m³-day in the anaerobic stage, and at the hydraulic retention time of 6-10 hours for the anaerobic stage and 6.5 for the aerobic stage. The anaerobic stage of the A/O system removes both color and COD. In addition, it also improves biodegradability of dyes for further aerobic treatment.     

外循环式UASB反应器处理槟榔废水

在中温（35±2℃）条件下,利用外循环式UASB反应器处理中高有机浓度的槟榔加工废水,并着重探讨了水力停留时间（HRT）对厌氧消化的影响。研究表明,当反应器稳定运行,水力停留时间为1 d,进水COD浓度5 000 mg/L左右,容积负荷在2.53-5.25 kg COD/（m3·d）时,COD去除率在38%以上,出水COD〈3 000 mg/L,平均产气率为0.41 m3/kg COD;若水力停留时间延长至4 d,容积负荷为1.26-1.30 kg COD/（m3·d）,COD去除率可以达到79%,出水COD〈1 200 mg/L,出水可生化性下降,BOD5/COD平均为0.28,实验取得了良好的处理效果,为利用厌氧技术处理槟榔加工废水提供了设计依据。     

Ammonia inhibition on thermophilic anaerobic digestion

This study evaluated both chronic and acute toxicity of ammonia in thermophilic anaerobic digestion of synthetic wastewater over a range of acclimation concentrations. The inhibition effects of ammonia, in terms of total ammonia nitrogen (TAN), under various pH values and acclimation conditions on thermophilic aceticlastic methanogens were investigated. Completely mixed thermophilic anaerobic reactors operated at a chemical oxygen demand (COD) loading rate of 4 g/lday and a solid retention time (SRT) of 7 days were subjected to TAN concentrations of 0.40, 1.20, 3.05, 4.92, and 5.77 g/l. The reactor operations presented a case of chronic inhibition and it was observed that TAN concentrations of 4.92 and 5.77 g/l caused a drop in methane production by as much as 39% and 64%, respectively with respect to control. Batch anaerobic toxicity assays (ATA) were also performed to evaluate the acute toxicity effects of TAN and pH on methanogenesis at thermophilic condition. Modeling based on the results of ATA indicated that aceticlastic methanogens acclimated to high concentrations of TAN were less sensitive to increase in TAN and could tolerate wider pH ranges. TAN concentration causing 100% inhibition occurred in the range of 8-13 g/l, depending on acclimation condition and system pH.     

Treatment of carbofuran-bearing synthetic wastewater using UASB process

In the present study, fate of carbofuran in anaerobic environments and the adverse effects of carbofuran on conventional anaerobic systems were evaluated. Carbofuran degradation studies were carried out in batch reactors with varying carbofuran concentrations of 0 to 270.73 mg/L corresponding to a sludge-loading rate (SLR) of 2.12 x 10(-6) to 3.83 x 10(-3) g of carbofuran/g of volatile suspended solids (VSS)/d. Carbofuran concentration was reduced to undetectable levels at the end of 8 and 13 days in the batch reactors operated with a SLR of 2.12 x 10(-6) and 3.33 x 10(-5) g of carbofuran/g of VSS/d, respectively. Performances of two anaerobic reactors i.e. upflow anaerobic sludge blanket (UASB) and modified UASB (with tube settlers) were evaluated in the presence and absence of carbofuran using synthetic wastewater. In the absence of carbofuran, the soluble chemical oxygen demand (COD) removal efficiency in the conventional UASB reactor at 8 h and 6 h hydraulic retention time (HRT) was nearly 88% and 76%, respectively, whereas in modified UASB reactor it was increased to 90% at 8 h HRT and 78% at 6 h HRT. When 28 mg/L (SLR of 1.19 x 10(-2) g of carbofuran/g of VSS/d) of carbofuran was introduced in the reactors, the COD removal efficiency was reduced to 41% and 44% in conventional and modified UASB reactors respectively. However, the reactor could maintain around 80% COD removal efficiency at a carbofuran concentration of 7.84 mg/L (SLR of 3.64 x 10(-3) g of carbofuran/g of VSS/d). The reactor efficiency was also measured in terms of specific acetoclastic methanogenic activity (SMA). The toxic effect of carbofuran was reversible to a certain extent. Carbofuran removal efficiency in the conventional UASB reactor at carbofuran concentrations of 7, 13 and 28 mg/L were 40 +/- 3%, 27 +/- 3%, and 11 +/- 3%, respectively. In modified UASB reactor, carbofuran removal efficiency was almost uniform at 7 and 13 mg/L but it was reduced nearly by 56% at 28 mg/L. The major metabolite of carbofuran i.e. 3-keto carbofuran was found in all the reactors.     

Treatment of food industry waste by bench-scale upflow anaerobic sludge blanket-anoxic-aerobic system.

An upflow anaerobic sludge blanket (UASB)-anoxicaerobic system was used for treatment of tomato and bean processing wastewater. At various hydraulic retention times, ranging from 0.7 to 5 days, excellent removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), ammonia-nitrogen (NH4-N), and total Kjeldahl nitrogen was achieved with final effluent BOD/TSS/NH4N concentrations of less than 15/15/1 mg/L. Biogas yield in the UASB reactor varied from 0.33 to 0.44 m3/kgCODremoved. The kinetics of anaerobic treatment were investigated. The yield coefficient was 0.03 gVSS/gCOD; maximum specific growth rate was 0.24 day(-1); Monod half velocity constant was 135 mgCOD/L; and specific substrate utilization rate was 3.25 gCOD/gVSS x d. Nitrification and denitrification kinetics were studied in batch experiments, and the rates were comparable with those in the continuous flow system.     

Enhanced sludge granulation in upflow anaerobic sludge blanket (UASB) reactors by aluminum chloride.

Two upflow anaerobic sludge blanket (UASB) reactors were concurrently operated for 146 days to examine the effects of aluminum chloride (AlCl3) on the sludge granulation process during start-up. Sludge granulation (defined as that over 10% of granules were larger than 2.0 mm) was achieved in the control reactor (R1) in approximate three months. Introduction of Al3+ at a concentration of 300 mg/l reduced the sludge granulation time by approximate one month. Throughout the experiment the AlCl3-added reactor (R2) had a higher biomass concentration, e.g., 13.8 g-MLVSS/l versus 12.8 g-MLVSS/l on Day 146. Granules became visible earlier in R2 compared with R1 (35 days versus 65 days). The average size of granules from R2 was larger than that from R1. The results demonstrated that AlCl3 enhanced the sludge granulation process in the UASB reactors.     

Oily wastewater treatment using a novel hybrid PBR-UASB system

In this study, anaerobic treatability of oily wastewater was investigated in a hybrid reactor system consisting of a packed bed reactor (PBR) followed by an upflow anaerobic sludge blanket (UASB) reactor at 35 degrees C. The system was operated using real pet food wastewater at different hydraulic retention times and loading rates for 165 d. The PBR was packed with sol-gel/alginate beads containing immobilized enzyme which hydrolyzed the oil and grease (O&G) into free long chain fatty acids, that were biodegraded by the UASB. The hybrid system was operated up to an oil loading rate of 4.9 kg O&Gm(-3)d(-1) (to the PBR) without any operational problems for a period of 100 d, with COD and O&G removal efficiencies above 90% and no sludge flotation was observed in the UASB. Beads supplement to the PBR was less than 2 g d(-1) and the relative activity was about 70%. Further increment in O&G loading to 18.7 kg O&Gm(-3)d(-1) caused destabilization of the system with 0.35% (v float/v feed) sludge float removed from the UASB.     

苯酚的厌氧生物处理

采用不断增加苯酚浓度而降低葡萄糖浓度的方法可驯化厌氧污泥中的微生物,使厌氧污泥最终以苯酚为唯一碳源生长,可显著提高厌氧污泥降解苯酚的能力;对苯酚间歇厌氧降解过程进行了分析。苯酚浓度在0～1.680 mg/L范围内,其厌氧降解过程符合一级动力学。Aiba模型、Haldane模型和Teisser 模型均可很好地描述处于对数期时厌氧污泥的比生长速率与初始底物浓度之间的关系,其中以Teisser 模型模拟的效果最好。将驯化污泥接种于UASB中可实现对含酚废水处理的连续运行,最大的有机负荷达2 g COD/（L·d）,稳定运行时苯酚的去除率可维持在96%以上。     

Comparative mesophilic and thermophilic anaerobic digestion of palm oil mill effluent using upflow anaerobic sludge blanket

The effects of organic loading rate and operating temperature on the microbial diversity and performances of upflow anaerobic sludge blanket (UASB) reactors treating palm oil mill effluent (POME) were investigated. The following two UASB reactors were run in parallel for comparison: (1) under a mesophilic condition (37 degrees C) and (2) under a mesophilic condition in transition to a thermophilic condition (57 degrees C). A polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) analysis showed that the microbial population profiles significantly changed with the organic loading rate (OLR) and the temperature transition from the mesophilic to the thermophilic condition. Significant biomass washout was observed for the mesophilic UASB when operating at a high organic loading rate (OLR) of 9.5 g chemical oxygen demand (COD)/L.d. In contrast, the thermophilic UASB can be operated at this OLR and at a temperature of 57 degrees C with satisfactory COD removal and biogas production. The PCR-based DGGE analysis suggested that the thermophilic temperature of 57 degrees C was suitable for a number of hydrolytic, acidogenic, and acetogenic bacteria.     

絮凝剂对高速厌氧反应器污泥颗粒化的强化作用

以考察絮凝剂对厌氧反应器中活性污泥性能的影响为目的,将聚合氯化铝(PAC)、聚丙稀酰胺(PAM)、聚季铵盐3种不同类型絮凝剂以不同投加量添加到反应器中,采用生物化学甲烷势(BMP)和厌氧毒性测定(ATA)分析方法,评价了3种絮凝剂的厌氧生物可降解性以及3种絮凝剂对厌氧污泥产甲烷活性、沉降性能等方面的促进或抑制作用。确定以聚季铵盐作为厌氧污泥颗粒化促进剂,建议采用多次投加方式,反应器中聚季铵盐质量浓度以10-50mg／L为宜。     

Microbial activity in a combined UASB-activated sludge reactor system

A combined upflow anaerobic sludge bed-activated sludge (UASB-AS) reactor system with consistently wasting of excess biomass was used to treat suspended-solids pre-settled piggery wastewater (COD=2000 mg l(-1), total Kjeldahl nitrogen TKN=400 mg l(-1), suspended solids=250-400 mg l(-1)). Thus, the activity of nitrogen-related microbial groups in each individual bioreactor was investigated. When the granules retention time (GRT) of 20-50 d in the UASB reactor, the solids retention time (SRT) of 10-25 d in the AS reactor and the recycle-to-influent ratio (Re) of 1 were maintained, the combined system removed 95-97% of chemical oxygen demand (COD), 100% of TKN and 54-55% of total nitrogen (TN). Denitrification and methanogenesis occurred in the UASB reactor so that both biochemical processes contributed to most of the COD removal and, complete nitrification (most of the TKN removal) occurred in the AS reactor. Compact granules with good settling abilities developed in the UASB reactor, and rapid rates of granulation of break-up granules in the UASB reactor were confirmed by experiments. The activity of nitrifiers and denitrifiers (an=0.68-0.87; adn=0.55-0.70) and the calculated specific nitrification and denitrification rates (qn=0.26-0.47 mg NH4+ -N mg VSS(-1)d(-1); qdn=0.046-0.076 mg NOx- -N mg VSS(-1)d(-1)) significantly increased with decreasing SRT and GRT, respectively. Accordingly, the combined UASB-AS reactor system should be regarded a promising alternative for the removal of organic carbon and nitrogen from piggery wastewater.     

Analysis of the syntrophic anaerobic digestion of volatile fatty acids using enriched cultures in a fixed-bed reactor

Volatile fatty acids (VFAs) are key intermediates in anaerobic digestion. Enriched acetogenic and methanogenic cultures were used for the syntrophic anaerobic digestion of VFAs in a continuous fixed-bed reactor at mesophilic conditions. The interactive effects of propionic (HPr), butyric (HBu), and acetic (HAc) acids were analyzed. Furthermore, hydraulic retention time (HRT) and methanogen-to-acetogen ratios (M/As) were investigated as the key microbiological and operating variables of VFA anaerobic degradations. Experiments were carried out based on central composite design (CCD) and results were analyzed using response surface methodology (RSM). Effluent concentrations of HPr, HBu, HAc, and biogas production rate (BPR) were directly measured as responses. The optimum conditions were found to be HPr = 1122.9 mg/L, HBu = 1792.4 mg/L, HAc = 1735.4 mg/L, HRT = 21 hours, and M/A = 2.4 (corresponding to the maximum VFA removal and BPR). The results of verification experiments and predicted values from fitted correlations were in close agreement at a 95% confidence interval.     

Effect of limited aeration on the anaerobic treatment of evaporator condensate from a sulfite pulp mill

Serious inhibition was found in the regular up-flow anaerobic sludge blanket (UASB) reactor in treating the evaporator condensate from a sulfite pulp mill, which contained high strength sulfur compounds. After applying the direct limited aeration in the UASB, the inhibition was alleviated gradually and the activity of the microorganisms was recovered. The COD removal rate increased from 40% to 80% at the organic loading rate of 8kgCODm(-3)d(-1) and a hydraulic retention time of 12h. Limited aeration caused no oxygen inhibition to the anaerobic microorganisms but instigated sulfide oxidization and H(2)S removal, which was beneficial to the methanogens. The experiment confirmed the feasibility of applying limited aeration in the anaerobic reactor to alleviate the sulfide inhibition. It also proved that the anaerobic system was actually aerotolerant. SEM observation showed that the predominant microorganisms partly changed from rod-shaped methanogens to cocci after the UASB reactor was aerated.     

Improvement of upflow anaerobic sludge bed performance using chitosan.

Chitosan, with a degree of deacetylation of 85% and a molecular weight of 2.5 x 10(5) Da, yielding high flocculation efficiency (85 to 100% flocculation) and a broad flocculation region (2 to 45 mg/g suspended solids), was selected for accelerating granulation in a 30-L upflow anaerobic sludge bed (UASB) used to treat wastewater from a tropical fruit-processing industry. Compared with other studies, smaller amounts of chitosan were applied (two injections with 2 mg chitosan/g suspended solids in the reactor at each injection). Comparison with the UASB without chitosan addition, the UASB had a 24 to 37% larger particle size and a 6 to 41% longer solids retention time. In addition, the reactor performances were also enhanced. The UASB with chitosan addition had a 9 to 59% lower effluent chemical oxygen demand (COD), 4 to 10% higher COD removal, up to 35% higher biogas production rate, and a 16 to 68% lower biomass washout. The paired t-test analysis indicated that these performance parameters were significantly different (P < 0.05).     

Phenol degradation and microbial characteristics in upflow anaerobic sludge blanket reactors at ambient and mesophilic temperatures

A synthetic wastewater containing phenol as sole substrate was respectively treated at temperatures of 26±1°C and 37±1°C in 2.8 litre upflow anaerobic sludge blanket (UASB) reactors. At the two temperatures, pH 7.0–7.5, with a 1:1 effluent recycle ratio, phenol in wastewater was efficiently degraded in a UASB reactor. Microbial community analysis using denaturing gradient gel electrophoresis (DGGE) showed that less shift in the microbial community occurred with the temperature changing. Phenol degradation in wastewater was recommended to select ambient temperature in UASB reactors. The optimal HRT was 12 to 16 hours corresponding to 6.0–4.5 g COD/(l.d) loading rate at ambient temperature in UASB reactors. The distribution of archaeal and bacterial populations in the UASB granular consortium was revealed using fluorescence in situ hybridisation (FISH) technique.     

Anaerobic degradation and toxicity of commercial cationic surfactants in anaerobic screening tests

Anaerobic biodegradability and toxicity on anaerobic bacteria of di(hydrogenated tallow) dimethyl ammonium chloride (DHTDMAC) and two esterquats have been investigated. A batch test system containing municipal digester solids as a source of anaerobic bacteria, based on the method proposed by the ECETOC, has been applied. To evaluate the potential toxicity of such surfactants on anaerobic sludge, a co-substrate, an easily biodegradable compound in anaerobic conditions, has been added to the samples to test and the effects on biogas production have been determined. For the esterquats studied high biodegradation levels were obtained and no toxic effects on anaerobic bacteria were observed even at the highest concentrations tested, 100 and 200 mg C/l, respectively. On the contrary, DHTDMAC was not degradated at the same test conditions. However, no inhibitory effects on the biogas production were detected for this surfactant at concentrations <100 mg C/l.     

外循环式UASB反应器处理高浓度酒精废水

利用改进型上流式厌氧污泥床反应器在中温条件下处理高浓度酒精废水,研究反应器的启动影响因素及颗粒污泥形成过程,分析反应器运行特性。在容积负荷为10.39 kg COD/(m3.d),COD去除率达90.2%,VFA在300 mg/L以下,平均产气率为0.328 m3/kg COD,取得最佳的运行效果,为高浓度酒精废水的处理应用提供科学依据。     

高氯离子味精尾母液废水厌氧处理研究

味精尾母液废水COD浓度极高同时含有大最氯离子.采用UASB反应器对味精尾母液废水进行处理,其中接种污泥来自啤酒厂UASB反应器.实验表明:当氯离子浓度在4 500 mg/L以下时,对厌氧微生物没有明礁的抑制作用;5 000 mg/L的氯离子浓度可以看作一个抑制限值,但经过驯化后,仍可获得较好的COD去除效果;当氯离子浓度达到8 000mg/L左右时,COD平均去除率在80%以上.     

2种UASB的ANAMMOX与反硝化协同作用对比研究

采用2套UASB-ANAMMOX反应器处理垃圾渗滤液,其中反应器2具有生物膜,对反应器在有机环境下的ANAMMOX与反硝化协同作用进行对比研究。在稳定期,反应器1和反应器2对氨氮、亚硝氮、TIN、COD的平均去除率分别为95.7%、95.9%、77.3%、70.3%和97.4%、96.4%、87.2%、74.8%。反应器1对TIN和COD最大容积去除率为112.2和107.7 g/(m3.d),反应器2对TIN和COD最大容积去除率为120.5和119.9 g/(m3.d)。结果表明,过高的负荷会对反应器产生抑制作用,且当抑制产生后协同作用难以恢复到原来水平。在厌氧氨氧化与反硝化协同作用良好时,pH值和碱度均存在特征性变化。总体上,反应器2比反应器1具有更强的厌氧氨氧化与反硝化协同作用和抗负荷冲击能力。