Halophilic biological treatment of tannery soak liquor in a sequencing batch reactor

Hypersaline wastewater (i.e. wastewater containing more than 35 gl(-1) total dissolved solids (TDS)) is generated by various industrial activities. This wastewater, rich in both organic matter and TDS, is difficult to treat using conventional biological wastewater treatment processes. Among the industries generating hypersaline effluents, tanneries are prominent in India. In this study, tannery wastewater from soak pit was treated in a lab-scale SBR for the removal of organic matter. The characterisation of the soak liquor showed that this effluent is biodegradable, though not easily, and highly variable, depending on the origin and the nature of the hides. TDS was in the range of 21-57 gl(-1) and COD was in the range of 1.5-3.6 gl(-1). This soak liquor was biologically treated in an aerobic sequencing batch reactor seeded with halophilic bacteria, and the performance of the system was evaluated under different operating conditions with changes in hydraulic retention time, organic loading rate and salt concentration. The changes in salinity appeared to affect the removal of organic matter more than the changes in hydraulic retention time or organic loading rate. Despite the variations in the characteristics of the soak liquor, the reactor achieved proper removal of organic matter, once the acclimation of the microorganisms was achieved. Optimum removal efficiencies of 95%, 93%, 96% and 92% on COD, PO4 3-, TKN and SS, respectively, could be reached with 5 days hydraulic retention time (HRT), an organic loading rate (OLR) of 0.6 kg COD m(-3)d(-1) and 34 g NaCl l(-1). The organisms responsible for nitrogen removal appeared to be the most sensitive to the modifications of these parameters.     

A novel sulfate reduction, autotrophic denitrification, nitrification integrated (SANI) process for saline wastewater treatment

This paper reports on a lab-scale evaluation of a novel and integrated biological nitrogen removal process: the sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process that was recently proposed for saline sewage treatment. The process consisted of an up-flow anaerobic sludge bed (UASB) for sulfate reduction, an anoxic filter for autotrophic denitrification and an aerobic filter for nitrification. The experiments were conducted to evaluate the performance of the lab-scale SANI system with synthetic saline wastewater at various hydraulic retention times, nitrate concentrations, dissolved oxygen levels and recirculation ratios for over 500 days. The system successfully demonstrated 95% chemical oxygen demand (COD) and 74% nitrogen removal efficiency without excess sludge withdrawal throughout the 500 days of operation. The organic removal efficiency was dependent on the hydraulic retention time, up-flow velocity, and mixing conditions in the UASB. Maintaining a sufficient mixing condition in the UASB is important for achieving effective sulfate reduction. For a typical Hong Kong wastewater composition 80% of COD can be removed through sulfate reduction. A minimum sulfide sulfur to nitrate nitrogen ratio of 1.6 in the influent of the anoxic filter is necessary for achieving over 90% nitrate removal through autotrophic denitrifiers which forms the major contribution to the total nitrogen removal in the SANI system. Sulfur balance analyses confirmed that accumulation of elementary sulfur and loss of hydrogen sulfide in the system were negligible.     

Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification

In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and hydrogen sulfide. In an aeration pond, the residual COD_organic and the formed dissolved hydrogen sulfide are removed. The biogas, consisting of CH₄ (80-90 vol.%), CO₂ (10-20 vol.%) and H₂S (0.8-1.2 vol.%), is desulfurised prior to its combustion in a power generator thereby using a new biological process for H₂S removal. This process will be described in more detail in this paper. Biomass from the anaerobic bioreactor has a compact granular structure and contains a diverse microbial community. Therefore, other anaerobic bioreactors throughout the world are inoculated with biomass from this UASB reactor. The sludge was also successfully used in investigation on sulfate reduction with carbon monoxide as the electron donor and the conversion of methanethiol. This shows the biotechnological potential of this complex reactor biomass.     

增塑剂生产废水的优化处理及回用

针对某化工企业增塑剂生产废水的特点,提出了对其高浓度COD废水与低浓度COD废水分别进行处理的优化方案.对高浓度COD废水采用隔油一中和调节一两级厌氧好氧一物化工艺处理,平均COD去除率达96.79%,可达到<污水综合排放标准>(GB 8978-1996)的三级标准;对低浓度COD废水采用活性污泥法、纳滤和臭氧氧化工艺处理并回用于生产.该工艺总处理成本为1.78元/m3,实施水回用和资源回收后,收益为1.72元/m3,具有良好的经济及社会效益.     

Steady-state model-based evaluation of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process

Recently we developed a process for wastewater treatment in places where part of the fresh water usage is replaced by seawater usage. The treatment of this saline sewage consists of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process. The process consists of an up-flow anaerobic sludge bed (UASB) for sulfate reduction, an anoxic filter for autotrophic denitrification using dissolved sulfide produced in the UASB and an aerobic filter for nitrification. The system was operated for 500 days with 97% COD removal and 74% total nitrogen removal without withdrawal of sludge. To verify these results and to understand this novel process, a steady-state model was developed from the COD, nitrogen and sulfur mass and charge balances based on the stoichiometries of the sulfate reduction, the autotrophic denitrification and the autotrophic nitrification. The model predictions agreed well with measured data on COD, nitrate and sulfate removal, sulfide production, effluent TSS, and mass balances of COD, sulfur and nitrogen in the three reactors. The model explains why withdrawal of sludge from the SANI system is not needed through comparisons of the predictions and measurements of effluent TSS and phosphorus concentrations.     

Techno-Economic Assessment Of Biological Treatment And Water Reuse Of Effluent From The Food Industries

Treatment of high strength wastewater generated by food plants requires a development of cost effective wastewater treatment schemes and exploration of viable means for treated water reuse. This paper addresses the techno-economic aspects of a combined biological treatment scheme comprising anaerobic digestion and aerobic biological filters. Advanced water treatment for reuse includes multimedia filtration, activated carbon adsorption and membrane separation. Analysis of the results of the combined performance of the anaerobic/aerobic treatment indicates that treating high strength wastewater could be achieved by an upflow anaerobic sludge blanket (UASB) reactor and high rate trickling filter. Typical biological treatment capital and operating costs are about 1.3 million dollars and 131,000 dollars, respectively, for a treatment facility of about 4000 v m 3 /day to produce effluents of COD about 30 v mg/l. Water reuse costs ranged from US$ 0.034 to US$ 0.38/m 3 based on the salt content and residual dissolved organic matter.     

UASB-A/O工艺处理马铃薯淀粉废水

采用UASB-A/0工艺处理马铃薯淀粉生产废水,介绍了厌氧和好氧反应器的启动方法,分析了各反应器的运行效果,提出工程调试过程中需要注意的问题.沉淀出水部分回流到A段,可以降解水中大部分氨氮.工程运行结果表明:经UASB和A/O工艺处理后,对废水中COD、BOD5、SS的去除率分别可达到99.0%、99.5%和99.5%,系统运行稳定、处理费用较低.     

Removal of carbon and nutrients from domestic wastewater using a low investment, integrated treatment concept

An integrated chemical-physical-biological treatment concept for the low-cost treatment of domestic wastewater is proposed. Domestic wastewater was subjected to a chemically enhanced primary treatment (CEPT), followed by treatment in an upflow anaerobic sludge blanket (UASB) reactor. In addition, a regenerable zeolite was used to remove NH4+, either after CEPT pretreatment or after biological treatment in the UASB reactor. The CEPT pretreatment consisted of the addition of a coagulant (FeCl3) and an anionic organic flocculant and removed on average 73% of the total chemical oxygen demand (COD(t)), 85% of the total suspended solids, and 80% of PO4(3-) present in the wastewater. The UASB system, which consequently received a low COD(t) input of approximately 140 mg/L, was operated using a volumetric loading rate of 0.4 g COD(t)/L. d (hydraulic retention time [HRT]=10 h) and 0.7 g COD(t)/L. d (HRT=5 h). For these conditions, the system removed about 55% of the COD(t) in its influent, thus producing an effluent with a low COD(t) of approximately 50 mg/L. The zeolite, when applied in batch mode before the UASB reactor, removed approximately 45% of the NH4+, whereas its application as a post-treatment cartridge resulted in almost 100% NH4+ removal. The simple design and relatively low operating costs, due to low costs of added chemicals and low energy input (estimated at Euro 0.07-0.1 per m3 wastewater treated), combined with excellent treatment performance, means that this system can be used as a novel domestic wastewater treatment system for developing countries. Therefore, the system is called a Low Investment Sewage Treatment (LIST) system.     

Integrated application of upflow anaerobic sludge blanket reactor for the treatment of wastewaters

The UASB process among other treatment methods has been recognized as a core method of an advanced technology for environmental protection. This paper highlights the treatment of seven types of wastewaters i.e. palm oil mill effluent (POME), distillery wastewater, slaughterhouse wastewater, piggery wastewater, dairy wastewater, fishery wastewater and municipal wastewater (black and gray) by UASB process. The purpose of this study is to explore the pollution load of these wastewaters and their treatment potential use in upflow anaerobic sludge blanket process. The general characterization of wastewater, treatment in UASB reactor with operational parameters and reactor performance in terms of COD removal and biogas production are thoroughly discussed in the paper. The concrete data illustrates the reactor configuration, thus giving maximum awareness about upflow anaerobic sludge blanket reactor for further research. The future aspects for research needs are also outlined.     

内循环UASB处理酒精废水及其颗粒污泥特性

针对传统UASB反应器在启动时颗粒污泥形成缓慢的问题,采用内循环UASB反应器作为厌氧单元对酒精废水进行处理。其以低负荷启动,启动完成后容积负荷为7.9 kg/(m3.d),对COD的去除率可达80%,整个试验阶段对NH3-N的平均去除率为16.38%。扫描电镜显示颗粒污泥中的优势菌开始为短杆菌,随着培养时间的延长则出现了球菌;而现有UASB反应器中颗粒污泥的优势菌为丝状菌。对沼气成分进行分析,CH4含量最高为81.61%,N2含量则随着颗粒污泥培养时间的延长由3.68%增加至18.59%。     

预处理/厌氧生物处理敌百虫生产废水的研究

对敌百虫生产废水的处理工艺进行了研究,先采用破乳法和电解法进行预处理,然后再采用升流式厌氧污泥床(UASB)工艺进行厌氧处理,试验历时90 d,考察了系统的稳定性及pH值、温度和水力停留时间(HRT)等对反应器的影响。结果表明,当温度控制在30～35℃、pH值为6.8～7.5、进水COD为12 000 mg/L、HRT为72 h时,对COD的去除率可达到73%以上;厌氧处理后采用除磷药剂进行混凝沉淀,出水总磷浓度降为618 mg/L,对总磷的去除率为75.36%。     

污泥调理废水的特性及其处理工艺

采用离子色谱法及化学分析法分析了污泥调理废水的水质特性,在氨吹脱及混凝试验的基础上开展了氨吹脱—厌氧—SBR工艺处理该废水的研究。结果表明,污泥调理废水是一种高浓度含氮有机废水,其中有机污染物主要以溶解态存在,不宜采用混凝处理。该废水具有较好的生物可降解性能,当HRT为24h、进水COD为8658.7~9650.3mg/L时,厌氧对COD的去除率可达62.1%,厌氧/好氧交替运行的SBR对COD、氨氮的去除率分别为92.1%、88.4%。动态运行结果显示,氨吹脱—厌氧—SBR工艺对该废水水质具有良好的适应性,处理出水水质能稳定地达到GB8978—1996的二级标准。     

UASB处理低浓度城市污水的生产性研究

广东某城市污水处理厂采用UASB-好氧工艺处理低浓度城市污水，对UASB的实际处理效能进行了考察。结果表明，在试验的进水水质条件下，当UASB的水力停留时间为6h时，系统对COD和BOD5的平均去除率分别为50％和60％，对TP的去除率为15％～38％。当HRT由5．67h延长至10h时，出水VFA浓度会随之降低，而pH值则始终稳定在6．5～7．5，系统对COD和BOD5的去除率分别增加9％和19％，对溶解性COD和BOD5的去除率分别增加25％和24％。     

Organic matter removal in combined anaerobic-aerobic fixed-film bioreactors

A combination of two fixed-film bioreactors (FFB) with arranged media, the first anaerobic and the second aerobic, connected in series with recirculation was fed continuously for 133 days with wastewater from a poultry slaughterhouse. Oxidation of the organic carbon compounds and nitrification were carried out in the aerobic FFB and methanogenesis and denitrification were performed in the anaerobic FFB. The average organic loading rate was 0.39 kg COD/m3d and 92% removal efficiencies of organic matter were achieved. COD-removal occurred mainly in the anaerobic FFB, increasing when the recirculation ratio rose from 1 to 6 due to the increase in the anoxic denitrification. The influence of the C/N ratio of the raw wastewater over the proportion in which the COD-removal was carried out by oxidation in the aerobic FFB, methanogenesis or denitrification in the anaerobic FFB was studied. When the volume of the aerobic FFB became smaller than that of the anaerobic one the fraction of organic matter removed in the anaerobic FFB increased, but also the ratio between the respective volumetric rates (rCODan/rCODae) increased. High recirculation and low C/NO-N ratio in the anaerobic FFB feed favoured the denitrification to the detriment of the methanogenic process. Regarding nitrogen removal for nitrogen applied loads around 0.064 kg TKN/m3d the removal efficiency was of 95%, which decreased to 84% for 0.14 kg TKN/m3d. The stability of the nitrification process was the controlling factor of the nitrogen removal. High ammonia concentration caused by high recirculation ratio, specially when the aerobic FFB volume was smaller, caused nitrification inhibition which destabilised the system.     

某城市污水处理厂改造工程的中试研究

采用厌氧塘/预曝气/絮凝沉淀/好氧生化工艺对工业废水所占比例较高的城市污水进行中试研究.结果表明,厌氧塘出水经30 min的预曝气后进行絮凝沉淀,当FeSO4投加量为150mg/L、聚合氯化铝(PAC)投加量为100 mg/L时,对COD的单元去除率能够达到52%,且BOD5/COD值由0.4提高到0.6;对好氧系统采用周期性改变反应池内溶解氧浓度和外加碳源的措施,能够提高生物脱氮效果;经该工艺处理后,出水水质能够达到GB 18918-2002标准的一级B标准;经核算,该工艺的直接运行成本为0.65元/m3(不合污泥处理费).     

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30 degrees C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52-64% was obtained at HRT between 6 and 16 h. The UASB reactor removed 22-30% and 15-21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0.18 and 0.28 kg COD/(kg VS d).     

生物强化厌氧/好氧组合工艺处理模拟冰淇淋废水

从餐饮业下水道污泥中分离筛选出菌株B3，对模拟冰淇淋生产废水的厌氧水解过程进行生物强化，并考察其在厌氧阶段对COD去除率的影响及对后续好氧处理的影响。试验结果表明，经B3菌强化厌氧处理8h后对COD的去除率比未投菌的高31％，并有效促进了后续的好氧处理，尤其是对NH3-N的去除率提高了约40％，说明该菌具有很强的硝化功能。     

Study on the treatment of the sulfite pulp CEH bleaching effluents with the coagulation-anaerobic acidification-aeration package reactor

The coagulation-anaerobic acidification-aeration package reactor was designed for the treatment of pulp CEH bleaching effluents, the efficiencies in CODcr, BOD(5), AOX and toxicity removal achieved were 88.1%, 81.0%, 98.4% and 92.0%, respectively, with 15 h HRT. The toxicity and AOX were removed mainly through coagulation and anaerobic process, while the COD and BOD(5) were removed mainly through coagulation and aerobic process. The pretreatment of coagulation precipitation decreased the following organic load, which decreased the following treatment retention time and increased the stability of the system.The results of GC-MS showed: pollutants of wastewater were mainly chlorinated organics, most of AOX and the toxicity were removed by reductive dechlorination and acidified hydrolysis in anaerobic unit, the high COD removal in aerobic unit showed further degradation of pollutants. Chlorine atoms in the ortho position were preferentially dechlorination, that in para position were difficult to remove from chlorinated phenols during biological treatment.     

UASB工艺在啤酒废水处理中的应用

安徽某大型啤酒厂的工程实践证明，采用内循环UASB反应器＋好氧工艺处理啤酒废水是可行的。因设计了出水内循环并加装了斜板分离器，在实际调试与运行中UASB系统适应pH值和温度的范围较宽，运行稳定、处理效率高、能耗低，在春季时系统重新启动可很快得以恢复。     

高浓度化纤废水的处理及回用

高浓度化纤废水处理难度大、费用高，采用UASB厌氧处理，可将难降解的大分子有机物分解为小分子有机物，再通过多级接触氧化和生物炭池处理，出水COD浓度〈50mg／L（对COD的去除率高达99％），达到《污水综合排放标准》（GB8978-1996）一级标准。工程实践表明，UASB的实际容积负荷超过设计值，而多级串联接触氧化池中各级微生物的数量及形态保持相对独立，表现出类似于AB工艺的特征，具有处理效果好、运行稳定、投资少等优点。