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).     

外循环厌氧处理工艺中布水和三相分离的改进研究

污水处理中的布水设备和三相分离设备存在很多缺点,通过旋流配水装置和传统配水装置、小间距斜板三相分离装置和传统三相分离装置的比较试验,研究了旋流配水装置和小间距斜板三相分离装置的性能.研究结果表明:在相同膨胀率的条件下,旋流配水装置所需的回流量小,能耗相对较少;在水力上升流速为8 m/h时,采用旋流配水装置进水时,污泥分布曲线较平缓,污泥在高度上分布较均匀,而采用传统配水装置进水时,污泥主要分布在反应器底部,污泥浓度分布不均匀;在上升流速相同的情况下,采用小间距三相分离装置的反应器出水携带的颗粒污泥浓度较小;在相同的进水COD浓度时,小间距三相分离装置分离的沼气量较多.改进的布水和三相分离装置的性能明显优于传统的布水和三相分离装置.     

UASB反应器处理生活污水的试验研究

采用UASB中试(100 m3/d)对生活污水处理进行了研究。试验结果表明,采用此系统处理生活污水,出水水质良好。COD的去除率在52%~83%,出水的COD值<100 mg/L以下,SS的去除率在95%左右,UASB处理生活污水的最佳停留时间为6 h。产气率在0.1 m3/d。不管停留时间在10 h、5 h,出水的氨氮、乙酸值比进水的高;钙、镁、总氮、总磷、硫酸根和硝酸根离子出水值比进水值低。     

Removal of organic compounds during treating printing and dyeing wastewater of different process units

Wastewater in Shaoxing wastewater treatment plant (SWWTP) is composed of more than 90% dyeing and printing wastewater with high pH and sulfate. Through a combination process of anaerobic acidogenic [hydraulic retention time (HRT) of 15h], aerobic (HRT of 20h) and flocculation-precipitation, the total COD removal efficiency was up to 91%. But COD removal efficiency in anaerobic acidogenic unit was only 4%. As a comparison, the COD removal efficiency was up to 35% in the pilot-scale upflow anaerobic sludge bed (UASB) reactor (HRT of 15h). GC-MS analysis showed that the response abundance of these wastewater samples decreased with their removal of COD. A main component of the raw influent was long-chain n-alkanes. The final effluent of SWWTP had only four types of alkanes. After anaerobic unit at SWWTP, the mass percentage of total alkanes to total organic compounds was slightly decreased while its categories increased. But in the UASB, alkanes categories could be removed by 75%. Caffeine as a chemical marker could be detected only in the effluent of the aerobic process. Quantitative analysis was given. These results demonstrated that GC-MS analysis could provide an insight to the measurement of organic compounds removal.     

Coagulant recovery from water treatment plant sludge and reuse in post-treatment of UASB reactor effluent treating municipal wastewater

In the present study, feasibility of recovering the coagulant from water treatment plant sludge with sulphuric acid and reusing it in post-treatment of upflow anaerobic sludge blanket (UASB) reactor effluent treating municipal wastewater were studied. The optimum conditions for coagulant recovery from water treatment plant sludge were investigated using response surface methodology (RSM). Sludge obtained from plants that use polyaluminium chloride (PACl) and alum coagulant was utilised for the study. Effect of three variables, pH, solid content and mixing time was studied using a Box–Behnken statistical experimental design. RSM model was developed based on the experimental aluminium recovery, and the response plots were developed. Results of the study showed significant effects of all the three variables and their interactions in the recovery process. The optimum aluminium recovery of 73.26 and 62.73 % from PACl sludge and alum sludge, respectively, was obtained at pH of 2.0, solid content of 0.5 % and mixing time of 30 min. The recovered coagulant solution had elevated concentrations of certain metals and chemical oxygen demand (COD) which raised concern about its reuse potential in water treatment. Hence, the coagulant recovered from PACl sludge was reused as coagulant for post-treatment of UASB reactor effluent treating municipal wastewater. The recovered coagulant gave 71 % COD, 80 % turbidity, 89 % phosphate, 77 % suspended solids and 99.5 % total coliform removal at 25 mg Al/L. Fresh PACl also gave similar performance but at higher dose of 40 mg Al/L. The results suggest that coagulant can be recovered from water treatment plant sludge and can be used to treat UASB reactor effluent treating municipal wastewater which can reduce the consumption of fresh coagulant in wastewater treatment.     

UASB-SBR处理涤纶短纤维废水的实验研究

分别采用水解酸化与好氧（SBR）、厌氧（UASB）与好氧（SBR）工艺对涤纶短纤维废水的生物降解性能进行研究。水解酸化与好氧工艺在进水COD为1 900 mg/L的时候,去除率在80%左右。采用UASB-SBR工艺,进水COD为2700 mg/L时,COD去除率可以达到96%,出水COD〈100 mg/L。实验研究表明,涤纶短纤维废水更适合采用UASB-SBR工艺来处理,并且能够取得较好的效果。     

两级UASB与好氧组合工艺处理城市生活垃圾渗滤液的启动研究

采用两级UASB与好氧组合工艺处理早期城市生活垃圾渗滤液.系统出水按不同比例回流到一级UASB中进行反硝化,同时进行产甲烷反应,有机物在二级UASB中被进一步降解,好氧池完成剩余有机物的去除和氨氮的硝化.启动阶段通过对原渗滤液不同比例的稀释,分5次逐步提高进水浓度,启动结束时完成了对原渗滤液的高效处理.在进水COD浓度从3000 mg/L提高到15000 mg/L,氨氮浓度从250 mg/L提高到1400 mg/L时,最终COD去除率稳定在92%左右,氨氮去除率可达99%以上,一级UASB中反硝化率接近100%,回流比为300%时系统总氮去除率为70%～80%.     

UASB处理硫酸盐有机废水的启动

为了考察上流式厌氧污泥床反应器(UASB)处理含硫酸盐有机废水的特性,采用有效容积为10 L的UASB,研究了启动运行过程中COD和SO2-4降解情况、出水VFA和pH值、产气量及颗粒污泥比产甲烷活性(SMA)变化状况。结果表明,接种厌氧颗粒污泥,保持进水COD为1 500 mg/L,SO2-4浓度为100 mg/L,将HRT由24 h缩短至12 h以提高负荷,经历55 d成功启动了UASB反应器;当HRT为12 h,进水COD和SO2-4负荷为3.0 kg/(m3·d)和0.20 kg/(m3·d),COD和SO2-4的去除率分别达到80%和89%,出水VFA为3 mmol/L,产气量达9.5 L/d,颗粒污泥的SMA为86.4 mL/(g VSS·d)。     

Case studies on biological treatment of tannery effluents in India

This paper presents a comparative assessment of the cost and quality of treatment of tannery wastewater in India by two common effluent treatment plants (CETPs) constructed for two tannery clusters, at Jajmau (Kanpur) and at Unnao in the state of Uttar Pradesh, India. The Jajmau plant is upflow anaerobic sludge blanket (UASB) process-based, while the Unnao plant is activated sludge process (ASP)-based. Investigations indicated that the ASP-based plant was superior in all respects. Total annualized costs, including capital and operation and maintenance costs, for the UASB and ASP plants were Rs. 4.24 million/million liters per day (MLD) and Rs. 3.36 million/MLD, respectively. Land requirements for the two CETPs were 1.4 hectares/MLD and 0.95 hectares/ MLD, respectively. Moreover, the treated UASB effluent had higher biochemical and chemical oxygen demand (BOD/ COD) and considerable amounts of other undesirable constituents, like chromium (Cr) and sulfide, as compared with the ASP effluent, which had lower BOD/COD and negligible concentration of sulfide and Cr. Sludge production from the UASB-based plant was also higher at 1.4 t/day/MLD, in comparison to the sludge production of 0.8 t/day/MLD for the ASP-based plant. Also, the entire sludge produced in the UASB-based plant was Cr-contaminated and, hence, hazardous, while only a small fraction of the sludge produced in the ASP-based plant was similarly contaminated. The results of this study are at variance with the conventional wisdom of the superiority of anaerobic processes for tannery wastewater treatment in tropical developing countries like India.     

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。     

UASB+AF-生物接触氧化工艺处理皂素-酒精综合废水

采用水解酸化-UASB+AF-接触氧化工艺处理黄姜皂素-酒精综合废水,经调试启动和运行研究,结果表明:当进水COD在10 000~12 800 mg/L时,最终出水COD浓度可降低到200 mg/L以下;水解酸化、UASB+AF和接触氧化各阶段的COD去除率分别达到23%、75%和93.5%,系统总的COD去除率可达到98.4%,出水色度在30~50倍之间;同时该工艺具有运行稳定、耐冲击负荷能力强等特点。     

螺旋升流式反应器脱氮除磷系统的运行效果与污泥性能分析

对螺旋升流式反应器脱氮除磷及去除COD的运行效果进行了研究 ,该系统连续稳定运行 6个月的结果表明 ,能保证出水平均质量浓度TN小于 1 0mg/L ,TP小于 0 5 0mg/L ,COD小于 31mg/L ,对TN、TP和COD的去除率分别达 86 %、96 %和 94 %以上。并且对SUFR系统的污泥性能进行了分析 :(1 )螺旋升流特征使本反应系统中的污泥易于颗粒化 ;(2 )SUFR系统中的微生物种群具有多样性 ;(3)污泥在好氧反应器中表现出了同步硝化反硝化功能 ;(4 )污泥在缺氧反应器表现出了反硝化吸磷现象     

Electrochemical degradation applied to the metabolites of Acid Orange 7 anaerobic biotreatment

The electrochemical oxidation of the biotic degradation products of the textile dye C.I. Acid Orange 7 (AO7) was achieved using a boron doped diamond electrode (BDD). Tests were performed with model solutions of the biotic degradation products, sulphanilic acid (SA) and 1-amino-2-naphthol (AN), and also with real effluents obtained in experiments carried out in an up-flow anaerobic sludge blanket (UASB) reactor, fed with a simulated textile effluent containing AO7, working in mesophilic or thermophilic conditions. Bulk electrolysis was studied using two different supporting electrolytes - NaCl and Na(2)SO(4). The influence of initial metabolite concentration and current density on the electrodegradation rates of the biotic products was investigated. For the UASB effluents, oxidation tests were carried out for different electrolytes and at different current densities. Samples were collected at pre-selected intervals and absorbance measurements, chemical oxygen demand (COD) and total organic carbon (TOC) tests and high performance liquid chromatography (HPLC) analysis were performed. Results have shown an almost complete elimination of the persistent pollutants and a COD removal higher than 70% for both AN and SA. For the UASB effluents, COD removals between 45% and 90% and TOC removals varying from 19% to 41% were obtained.     

ClO2三相催化氧化处理硝基苯生产废水的试验

硝基苯(NB)生产废水中含有大量NB及其衍生物,对生物具有毒性,属难生物降解物质.采用ClO2三相催化氧化工艺对NB废水进行处理.结果表明,每升废水投加280、350 mg ClO2,废水在活性炭加载含铜复合金属氧化物的催化剂床层停留56min,NB和色度的去除率均达到95%以上,COD去除率达到90%以上.吨废水处理成本约为10.5元.     

Coagulation and precipitation as post-treatment of anaerobically treated primary municipal wastewater.

The main objective of this study was to investigate the feasibility of coagulation as a post-treatment method of anaerobically treated primary municipal wastewater. Both mesophilic and ambient (20 degrees C) temperature conditions were investigated in a laboratory-scale upflow anaerobic sludge bed (UASB) reactor. In addition, optimization of the coagulant, both in terms of type and dose, was performed. Finally, phosphorus removal by means of aluminum and iron coagulation and phosphorus and ammonia nitrogen removal by means of struvite precipitation were studied. Anaerobic treatment of primary effluent at low hydraulic retention times (less than 15 hours) resulted in mean chemical oxygen demand (COD) removals ranging from 50 to 70%, while, based on the filtered treated effluent, the mean removals increased to 65 to 80%. Alum coagulation of the UASB effluent gave suspended solids removals ranging from approximately 35 to 65%. Turbidity removal reached up to 80%. Remaining COD values after coagulation and settling were below 100 mg/L, while remaining total organic carbon (TOC) levels were below 50 mg/L. Filterable COD levels were generally below 60 mg/L, while filterable TOC levels were below 40 mg/L. All coagulants tested, including prepolymerized aluminum and iron coagulants, demonstrated similar efficiency compared with alum for the removal of suspended solids, COD, and TOC. Regarding struvite precipitation, optimal conditions for phosphorus and nitrogen removal were pH 10 and molar ratio of magnesium: ammonia-nitrogen: phosphate-phosphorus close to the stoichiometric ratio (1:1:1). During struvite precipitation, removal of suspended solids reached 40%, while turbidity removal reached values up to 80%. The removal of COD was approximately 30 to 35%; yet, when removal of organic matter was based on the treated filterable COD, the removal increased to approximately 65%. In addition, nitrogen was removed by approximately 70%, while phosphorus removal ranged between approximately 30 and 45% on the basis of the initial phosphorus concentration. Finally, size fractionation of the organic matter (COD) showed that the various treatment methods were capable of removing different fractions of the organic matter.     

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.     

铁炭内电解-厌氧-好氧工艺处理阿维菌素废水的试验研究

血清瓶毒性试验表明 ,AVM对厌氧消化产生强烈的抑制作用。AVM废水经铁炭内电解预处理后 ,COD和AVM的去除率分别达到 19.5 %和 6 8.5 % ,可大大降低废水的毒性。预处理出水再经UASB +生物接触氧化反应器进一步处理 ,当生化系统进水COD为 6 0 0 0— 6 5 0 0mg/L时 ,出水COD为 2 5 0— 2 80mg/L ,总COD去除率达到 95 .6 % ,出水达到生物制药行业排放标准     

Anaerobic mesophilic treatment of cattle manure in an upflow anaerobic sludge blanket reactor with prior pasteurization

Different autonomous communities located in northern Spain have large populations of dairy cattle. In the case of Asturias, the greatest concentration of dairy farms is found in the areas near the coast, where the elimination of cattle manure by means of its use as a fertilizer may lead to environmental problems. The aim of the present research work was to study the anaerobic treatment of the liquid fraction of cattle manure at mesophilic temperature using an upflow anaerobic sludge blanket (UASB) reactor combined with a settler after a pasteurization process at 70 degrees C for 2 hr. The manure used in this study came from two different farms, with 40 and 200 cows, respectively. The manure from the smaller farm was pretreated in the laboratory by filtration through a 1-mm mesh, and the manure from the other farm was pretreated on the farm by filtration through a separator screw press (0.5-mm mesh). The pasteurization process removed the pathogenic microorganisms lacking spores, such as Enterococcus, Yersinia, Pseudomonas, and coliforms, but bacterial spores are only reduced by this treatment, not removed. The combination of a UASB reactor and a settler proved to be effective for the treatment of cattle manure. In spite of the variation in the organic loading rate and total solids in the influent during the experiment, the chemical oxygen demand (COD) of the effluent from the settler remained relatively constant, obtaining reductions in the COD of approximately 85%.     

Fenton-水解酸化-接触氧化处理模拟磷霉素钠制药废水

对模拟磷霉素钠制药废水进行Fenton-水解酸化-接触氧化小试处理实验,考察了COD、有机磷的去除效果,并对处理前后的废水进行了GC-MS分析。结果显示,增加了Fenton预处理后磷霉素钠制药废水的COD和有机磷分别降低到100和2 mg/L,去除率均可达87%以上,出水COD满足化学制药行业污染物排放标准(GB 21904-2008);Fenton过程对制药厂废水中的复杂有机物去除效果明显,GC-MS结果表明,出水中基本检测不到复杂有机物。与制药厂采用的水解酸化-接触氧化处理效果相比,增加Fenton预处理可以提高废水的可生化性和系统的处理效率。     

Case Studies on Biological Treatment of Tannery Effluents in India

Abstract

This paper presents a comparative assessment of the cost and quality of treatment of tannery wastewater in India by two common effluent treatment plants (CETPs) constructed for two tannery clusters, at Jajmau (Kanpur) and at Unnao in the state of Uttar Pradesh, India. The Jajmau plant is upflow anaerobic sludge blanket (UASB) process-based, while the Unnao plant is activated sludge process (ASP)-based. Investigations indicated that the ASP-based plant was superior in all respects. Total annualized costs, including capital and operation and maintenance costs, for the UASB and ASP plants were Rs. 4.24 million/million liters per day (MLD) and Rs. 3.36 million/MLD, respectively. Land requirements for the two CETPs were 1.4 hectares/MLD and 0.95 hectares/MLD, respectively. Moreover, the treated UASB effluent had higher biochemical and chemical oxygen demand (BOD/COD) and considerable amounts of other undesirable constituents, like chromium (Cr) and sulfide, as compared with the ASP effluent, which had lower BOD/COD and negligible concentration of sulfide and Cr. Sludge production from the UASB-based plant was also higher at 1.4 t/day/MLD, in comparison to the sludge production of 0.8 t/day/MLD for the ASP-based plant. Also, the entire sludge produced in the UASB-based plant was Cr-contaminated and, hence, hazardous, while only a small fraction of the sludge produced in the ASP-based plant was similarly contaminated. The results of this study are at variance with the conventional wisdom of the superiority of anaerobic processes for tannery waste-water treatment in tropical developing countries like India.