Anaerobic biodegradability and digestion in accumulation systems for concentrated black water and kitchen organic-wastes.

The feasibility of two accumulation-systems (AC) for anaerobic digestion and storage of concentrated black water with (AC1) or without (AC2) urine + kitchen organic-wastes was investigated. The waste(water) was collected by two vacuum toilet/transport systems. The influent-total COD of the AC2 (53,000 mg/L) was more concentrated by four times than that of the AC1. The suspended COD represented the major part (71-73%) of influent total COD of the two systems. The batch-experiments results showed a high anaerobic biodegradability of the waste(water) (> 85%). The AC systems demonstrated stable performance. There was no inhibition effect of NH4 and VFA concentration decreased in time. Total COD removal of 58% was achieved in both systems, after 105 days at 20 degrees C. Moreover, if only the supernatant in AC1 is withdrawn and the settled sludge stays for the next runs, only 20% of the influent total COD will be in the supernatant. In AC2, 74% of influent ortho-P was removed by precipitation. Therefore, the settled sludge in the AC2 had a high total-P concentration of 1,300 mg/L. The C:N:P ratios of the supernatant and the sludge were 26:13:1 and 35:4.5:1, respectively, in the AC1, and were 28:14:1 and 32:2.4:1, respectively, in AC2.     

Enhanced primary treatment of concentrated black water and kitchen residues within DESAR concept using two types of anaerobic digesters.

Anaerobic digestion of concentrated domestic wastewater streams--black or brown water, and solid fraction of kitchen waste is considered as a core technology in a source separation based sanitation concept (DESAR--decentralised sanitation and reuse). A simple anaerobic digester can be implemented for an enhanced primary treatment or, in some situations, as a main treatment. Two reactor configurations were extensively studied; accumulation system (AC) and UASB septic tank at 15, 20 and 25 degrees C. Due to long retention times in an AC reactor, far stabilisation of treated medium can be accomplished with methanisation up to 60%. The AC systems are the most suitable to apply when the volume of waste to be treated is minimal and when a direct reuse of a treated medium in agriculture is possible. Digested effluent contains both liquid and solids. In a UASB septic tank, efficient separation of solids and liquid is accomplished. The total COD removal was above 80% at 25 degrees C. The effluent contains COD and nutrients, mainly in a soluble form. The frequency of excess sludge removal is low and sludge is well stabilised due to a long accumulation time.     

Anaerobic digestion elutriated phased treatment of piggery waste.

The performance of a novel high-rate anaerobic process, the anaerobic digestion elutriated phased treatment (ADEPT) process, for treating a slurry-type piggery waste (55 g COD/L and 37 g TS/L) was investigated. The ADEPT process consists of an acid elutriation slurry reactor for hydrolysis and acidification, followed by an upflow anaerobic sludge bed reactor for methanification. This process provides stable and high system performance with short HRT (7.4 d) and better effluent quality (2 g SCOD/L and 0.68 g VSS/L) due to the alkaline pH condition for hydrolysis/acidification phase, high refractory solids removal and ammonia toxicity reduction. The optimum pH and HRT for hydrolysis/acidogenesis of the piggery waste were 9 and 5 days at both 35 degrees C and 55 degrees C conditions. The hydrolysis and acidification rate in the mesophilic reactor were 0.05 d(-1) and 0.11 d(-1), meaning that hydrolysis was a limiting step. SCOD production by the hydrolysis was about 0.26 g SCOD/g VS(fed) (3.6 g SCOD/g VS reduction). Methane production and content in the system were 0.3 L CH4/g VS(fed) (0.67 L CH4/g VS destroyed) and 80%, respectively, corresponding to 0.23 L CH4/g COD removal (@STP).     

粪便与厨余垃圾地埋式处理工艺研究

根据单元小试数据,设计了一套粪便与厨余垃圾的现场处理工艺,整个系统包括真空收集、固形物的厌氧消化、消化污泥的造粒制肥、混合污水的厌氧-好氧处理等单元,实现了粪便及厨余垃圾的源头收集,现场处理,同时可产出菌肥等产品。     

Risk management in waste water treatment.

With the continuous restructuring of the water market due to liberalisation, privatisation and internationalisation processes, the requirements on waste water disposal companies have grown. Increasing competition requires a target-oriented and clearly structured procedure. At the same time it is necessary to meet the environment-relevant legal requirements and to design the processes to be environment-oriented. The implementation of risk management and the integration of such a management instrument in an existing system in addition to the use of modern technologies and procedures can help to make the operation of the waste water treatment safer and consequently strengthen market position. The risk management process consists of three phases, risk identification, risk analysis/risk assessment and risk handling, which are based on each other, as well as of the risk managing. To achieve an identification of the risks as complete as possible, a subdivision of the kind of risks (e.g. legal, financial, market, operational) is suggested. One possibility to assess risks is the portfolio method which offers clear representation. It allows a division of the risks into classes showing which areas need handling. The determination of the appropriate measures to handle a risk (e.g. avoidance, reduction, shift) is included in the concluding third phase. Different strategies can be applied here. On the one hand, the cause-oriented strategy, aiming at preventive measures which aim to reduce the probability of occurrence of a risk (e.g. creation of redundancy, systems with low susceptibility to malfunction). On the other hand, the effect-oriented strategy, aiming to minimise the level of damage in case of an undesired occurrence (e.g. use of alarm systems, insurance cover).     

Anaerobic treatment as a core technology for energy, nutrients and water recovery from source-separated domestic waste(water).

Based on results of pilot scale research with source-separated black water (BW) and grey water (GW), a new sanitation concept is proposed. BW and GW are both treated in a UASB (-septic tank) for recovery of CH4 gas. Kitchen waste is added to the anaerobic BW treatment for doubling the biogas production. Post-treatment of the effluent is providing recovery of phosphorus and removal of remaining COD and nitrogen. The total energy saving of the new sanitation concept amounts to 200 MJ/year in comparison with conventional sanitation, moreover 0.14 kg P/p/year and 90 litres of potential reusable water are produced.     

低温下富铁填料对BAF处理效果及细菌群落的影响

为探究低温下富铁填料影响曝气生物滤池(BAF)处理效果的微生物机制,通过对比试验考察了使用富铁填料的试验组和未使用富铁填料的对照组中硝化细菌数量和细菌群落的多样性变化。结果表明：温度由14℃降为12℃时,对照组对COD、NH⁺₄—N、TN和TP的去除率分别减小了4.17%、4.67%、4.87%和10.86%;14℃时,试验组对COD、NH⁺₄—N、TN和TP的去除率分别比对照组高2.35%、2.37%、10.86%和52.34%;温度由14℃降为12℃时,试验组对TN、TP的去除率分别由45.98%和97.74%减小至42.33%和91.55%,比对照组在12℃时TN、TP的去除率高12.08%、57.01%,也比对照组在14℃时TN、TP的去除率高7.21%、46.15%;14℃时,试验组中部生物膜中亚硝化单胞菌目(Nitrosomonadales)、黄单胞菌目(Xanthomonadales)和红环菌目(Rhodocyclales)的丰度比对照组分别高了3.1%、2.3%和2.9%。温度降低使...     

人工快速渗滤系统处理高速公路服务区污水

利用人工快速渗滤系统(CRI)处理高速公路服务区生活污水,工程试验结果表明:在水力负荷不小于1m/d的条件下,CRI系统对服务区生活污水具有较强的抗冲击负荷能力和较好的污染物去除效果。其对SS、COD_(Cr)和NH_3—N的平均去除率分别为92.74%、91.12%和84.34%;处理出水中SS、COD_(Cr)和NH_3—N的平均浓度分别为5.25mg/L、25.7mg/L、4.32mg/L。     

Anaerobic digestion of gelatinous water at laboratory and pilot scale and nitrogen inhibition.

The anaerobic digestion of the liquid residue (gelatinous water) coming from the production of fat from animal residue, was studied at laboratory and pilot scale. Biodegradability (>98%) and biogas potential (675 mL of biogas/g of COD(applied)) of this wastewater are very high. However, due to the high content on nitrogen, an inhibition of the anaerobic activity was observed for quite low concentrations of N-NH(3). Dilution of the wastewater and pH regulation in the reactor around 7.3 are the 2 solutions which were investigated to overcome the nitrogen inhibition at industrial scale. These two solutions were validated at laboratory scale in an anaerobic SBR and then onsite at pilot scale in a continuous reactor. A stable anaerobic digestion was observed in both reactors showing that no nitrogen inhibition was obtained when N-NH(3) concentration in the reactor was kept low.     

Anaerobic treatment of organic chemical wastewater using packed bed reactors.

The studied organic chemical wastewater had a high COD, 20-45g/L, and low TSS, less than 200 mg/L, making anaerobic bio-filtration a suitable treatment method. The organic matter consisted of alcohols, amines, ketones and aromatic compounds, such as toluene and phenol. Granulated activated carbon (GAC) and a porous stone called tezontle, widely available in Mexico, were used as a bio-film support. Once inoculated, the mesophilic reactors with granulated activated carbon (GAC-BFs) reached stability with 80% COD removal in 40 days, while the reactors with tezontle material (tezontle-BF) required 145 days. Biodegradation of more than 95% was obtained with both support media: at organic loads less than 1.7 kg m(-3) d (-1) in tezontle-BF and with loads of up to 13.3 kg m(-3) d(-1) in GAC-BFs. The bio-filters with GAC allowed COD removal efficiency of 80% at a load as high as 26.3 kg m (-3) d(-1), while the same efficiency with tezontle was obtained at loads up to 4.45 kgm (-3d) (-1). The use of GAC as support material allows greater biodegradation rates than tezontle and it makes the bio-filters more resistant to organic increases, inhibition effects and toxicity. Methanogenic activity was inhibited at loads higher than 1.7 kg m(-3) d(-1) in bio-filters with tezontle and 22.8 kg m(-3) d(-1 ) in bio-filters with GAC. At loads lower than the previously mentioned, high methane production yield was obtained, 0.32-0.35 m(3) CH4/kg COD removed. The biomass growth rates were low in the bio-filters with both kinds of material; however, a sufficiently high biomass holdup was obtained.     

生活垃圾填埋场渗滤液超临界水氧化试验研究

采用间歇式超临界水氧化反应装置,用过氧化氢为氧化剂,对生活垃圾填埋场渗滤液进行处理,考察了反应温度、压力、停留时间等因素对氧化效果的影响。结果表明:超临界水氧化对渗滤液COD和TOC的去除率随着反应温度、压力、停留时间的增加而显著提高。当渗滤液原水COD、TOC和BOD的质量浓度分别为8 119、2 289和971 mg/L时,在反应温度405℃,压力25 MPa,停留时间37.1 s的条件下,经超临界水氧化反应后,渗滤液中COD和TOC的去除率分别达到了98.8%和97.6%。此外,超临界水氧化反应能明显改善渗滤液的可生化性,反应后渗滤液的生化比由0.12提高到0.55。     

被动处理技术SAPS处理酸性矿山废水实验研究

酸性矿山废水(AMD)的排放不但造成矿山资源的流失,而且会造成受其影响的陆地和海洋生物量的严重减少,直接威胁人类生存.国外应用被动处理技术处理AMD在过去20年间有了很大发展,已从实验室规模发展到大规模地实际应用.本文研究了被动处理技术SAPS(Successive Alkalinity Producing System)对AMD处理效果、影响因素及净化机理,创新性的应用锯屑与鸡粪混合物的发酵产物作为硫酸盐还原菌的碳源.实验结果表明:AMD在实验装置内停留一定时间后获得充足的碱度,Fe2 和Cu2 的去除率均超过90 %,SO42-的浓度也有大幅度降低,但对Mn2 的去除效果一般.当处理效果以净碱度衡量时,净碱度的产生与废水在装置中的停留时间和废水中Fe2 的浓度有关.停留时间越长,Fe2 的浓度越大,产生的净碱度越大.     

UASB reactor for domestic wastewater treatment at low temperatures: a comparison between a classical UASB and hybrid UASB-filter reactor.

The performance of an upflow anaerobic sludge blanket (UASB) reactor and a hybrid UASB-filter reactor was investigated and compared for the treatment of domestic wastewater at different operational temperatures (28, 20, 14 and 10 degrees C) and loading rates. For each temperature studied a constant CODt removal was observed as long as the upflow velocity was lower than 0.35 m/h. At these upflow velocities similar removals were observed for both reactor types at 28 and 20 degrees C, 82 and 72% respectively. However, at 14 and 10 degrees C the UASB reactor showed a better COD removal (70% and 48%, respectively) than the hybrid reactor (60% and 38%). COD removal resulted from biological degradation and solids accumulation in the reactors. At 28 degrees C, a constant 200 g sludge mass was observed in both reactors and COD removal was attributed to biological degradation only. At lower temperatures, solids accumulation was observed in addition to biological degradation with an increase in reactor sludge as the temperature decreased. The decrease in biological degradation at lower temperatures was offset by solids accumulation and explains the similar overall COD removal efficiency observed at 28 degrees C, 20 degrees C and 14 degrees C. The decrease in temperature was also followed by an increase in the effluent TSS concentration in both reactors. At 14 and 10 degrees C a lower effluent TSS concentration and better performance was observed in the UASB reactor.     

Upgrading of waste water treatment plants by cloth-filtration using an improved type of filter-cloth

In order to reach in the effluents of wastewater treatment plants values for phosphorous below 0,5 mg P/l and for the suspended solids below 5 mg SS/l, a filtration stage is necessary in almost all instances. Apart from conventional deep-bed porous media filters (gravity filters), cloth filtration systems offer a viable alternative because of the low head loss, and their low price. The use of pile fabrics instead of conventional needle felt solves the crucial problem of cloth filtration: the considerable increase of cloth resistance due to the irreversible soiling. Cloth filtration plants equipped with this filter media allow for considerably higher hydraulic strains and for higher surface loads with a separation performance on the same level as reached by conventional systems. If the problem of clogging is solved as well, it should be possible to use pile fabrics with even finer filaments on a pile of micro-fibres, which would further increase the effluent quality.     

Grey water treatment in upflow anaerobic sludge blanket (UASB) reactor at different temperatures

The treatment of grey water in two upflow anaerobic sludge blanket (UASB) reactors, operated at different hydraulic retention times (HRTs) and temperatures, was investigated. The first reactor (UASB-A) was operated at ambient temperature (14-25 degrees C) and HRT of 20, 12 and 8 h, while the second reactor (UASB-30) was operated at controlled temperature of 30 degrees C and HRT of 16, 10 and 6 h. The two reactors were fed with grey water from 'Flintenbreite' settlement in Luebeck, Germany. When the grey water was treated in the UASB reactor at 30 degrees C, total chemical oxygen demand (CODt) removal of 52-64% was achieved at HRT between 6 and 16 h, while at lower temperature lower removal (31-41%) was obtained at HRT between 8 and 20 h. Total nitrogen and phosphorous removal in the UASB reactors were limited (22-36 and 10-24%, respectively) at all operational conditions. The results showed that at increasing temperature or decreasing HRT of the reactors, maximum specific methanogenic activity of the sludge in the reactors improved. As the UASB reactor showed a significantly higher COD removal (31-64%) than the septic tank (11-14%) even at low temperature, it is recommended to use UASB reactor instead of septic tank (the most common system) for grey water pre-treatment. Based on the achieved results and due to high peak flow factor, a HRT between 8 and 12 h can be considered the suitable HRT for the UASB reactor treating grey water at temperature 20-30 degrees C, while a HRT of 12-24 h can be applied at temperature lower than 20 degrees C.     

生物接触氧化法-人工湿地处理常低温生活污水

采用生物接触氧化法(BCO)-人工湿地组合工艺处理常低温生活污水,当BCO的气水比为7∶1、回流比为100%、人工湿地的水力停留时间(HRT)为9 h,人工湿地的水力负荷(HLR)为3. 65 m3/(m2/d)时,在常温下(22~27℃),组合工艺出水COD、NH_4~+—N、TN和PO_4~(3-)—P分别为14. 60、1. 40、12. 70和0. 43 mg/L,出水满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准;而低温下(7~12℃),组合工艺出水COD、NH_4~+—N、TN和PO_4~(3-)—P分别为29. 60、9. 90、19. 90和0. 88 mg/L。保持气水比和回流比不变,控制低温下BCO的HRT为12 h,人工湿地的HLR为2. 74 m3/(m2/d)时,组合工艺出水COD、NH_4~+—N、TN和PO_4~(3-)—P为18. 40、6. 17、14. 17和0. 66 mg/L,去除率分别为90. 60%、87. 80%、75. 40%和85. 30%。结果表明:常、低温下该组合工艺均能够实现污染物的良好去除,为实际工程应用提供参考。     

臭氧生物活性炭深度处理饮用水中抗生素的研究

介绍了饮用水中抗生素污染的来源及潜在危害,阐述了臭氧氧化及生物活性炭技术处理微量抗生素污染的机理,概括了最近几年国内外关于饮用水中抗生素物质控制技术的研究成果,指出臭氧生物活性碳技术在抗生素微污染水处理领域的广泛应用前景。     

Anaerobic membrane bioreactor for treatment of synthetic municipal wastewater at ambient temperature.

Non-woven fabric filter and poly-tetrafluoroethylene (PTFE) composite membrane were investigated to determine their applicability to treat low strength wastewater in an anaerobic membrane bioreactor (AMBR). Sludge cake resistance of the membrane was quantified using pure water flux of anaerobic sludge cake accumulated on the glass fiber filter of similar pore size. It is hypothesized that the formation of thin cake layer on the porous medium, e.g. non-woven and PTFE acts as a dynamic membrane. Thus, the capture of thin sludge cake inside the non-woven fabric matrix and accumulation on the PTFE membrane surface forms a membrane system equivalent to a commercial membrane system. The permeate quality was found to improve as the cake became more dense with filtration time. The PTFE composite membrane coated with thin PTFE film on the non-woven fabric filter enhanced the filtration performance by improving flux and minimizing the propensity of bio-fouling. The membrane flux was restored by back-flushing with permeate. The AMBR coupled with PTFE laminated membrane was operated continuously during the experiment at a cross flow velocity (CFV) of 0.1-0.2 m/sec and a transmembrane pressure (TMP) of 0.5-3 psi. Although about a month of acclimation was required to reach steady state, the effluent chemical oxygen demand (COD), volatile fatty acids (VFAs) as acetic acid, and suspended solids (SS) concentrations were below 30, 20 and 10 mg/L, respectively, during 90 days of operation with intermittent back washing. The lower operation TMP and CFV were subjected to less shear stress on the microbial community during continuous AMBR operation. In addition, thin sludge film accumulated on the membrane surface also acted as a biofilm bioreactor to remove additional COD in this study.     

Innovative conception and performance evaluation of a compact on-site treatment system.

The purpose of this study was to develop a new configuration for a compact on-site treatment system, which could become an attractive alternative, from technical, economic, social and environmental viewpoints, to the technologies that are currently employed. The treatment unit consists of a cylindrical tank, where half of the volume is used as a modified septic tank and the other half is divided between an anaerobic hybrid reactor and a trickling filter. An intermittent feeding system was used, with minimum, mean and maximum flowrate settings (Qmin = 0.25l.s(-1), Qmean = 0.50l.s(-1) and Qmax = 1.00l.s(-1)), to reflect the actual operating conditions of a compact on-site treatment system serving a typical dwelling. An average 24-hour hydraulic detention time was used, corresponding to a flowrate of 750l.d(-1). High removal efficiencies and low concentrations of COD, BOD and TSS in the final effluent were achieved, even when the unit was exposed to hydraulic loading peaks during feeding periods at maximum flowrate.     

Biodegradation of phenol at low temperature using two-phase partitioning bioreactors.

Two-phase partitioning bioreactors offer many advantages for the removal of toxic pollutants. In particular, such systems can be loaded with very large quantities of pollutants without risks of microbial inhibition, they are self-regulated and they prevent the risks of hazardous pollutant volatilisation during aerobic treatment. However, their potential has never been tested at low temperatures. Phenol biodegradation by a cold adapted Pseudomonas strain was therefore tested at 14 or 4 degrees C using 2-undecanone, diethyl sebacate or 2-decanone as organic phases in a two-phase partitioning bioreactor. The three solvents were biocompatible at 14 degrees C but evidence was found that diethyl sebacate was biodegraded by the bacteria and this solvent was not tested further. Although only 2-decanone was suitable at 4 degrees C, phenol biodegradation was more efficient in 2-undecanone at 14 degrees C, reaching a maximum volumetric rate (based on the volume of aqueous phase) of approximately 1.94 g/L.day after 47 h of cultivation. In 2-decanone at 14 degrees C, evidence was found that phenol degradation was limited by the release of biosurfactants, which increased the solubility and toxicity of the solvent in the aqueous phase inhibiting microbial activity. This study therefore shows that pollutant removal at low temperature is feasible but that the production of biosurfactants can have a negative impact on the process and must be taken into consideration when selecting the organic solvent. Future work should therefore focus on the selection of solvents suitable for use at temperatures below 14 degrees C.