The anaerobic biodegradability of municipal sludge and fat, oil, and grease at mesophilic conditions.

The anaerobic biodegradability of municipal primary and secondary sludge with increasing levels of partially dewatered fat, oil, and grease (FOG) was assessed using a mixed methanogenic culture at 35 "C. Under batch conditions with an acclimated and enriched microbial population, the sludge loading was 3 kg volatile solids/m3 and the highest FOG loading tested was 1.5 kg volatile solids/m3, resulting in a methane yield of 245 mL methane/g sludge volatile solids added at 35 degrees C and 1010 mL methane/g FOG volatile solids added at 35 degrees C. Under semicontinuous feeding conditions, the sludge and sludge plus FOG loading tested were 3 and 3.75 kg volatile solids/m3-d, respectively. Within 23 days of operation, the volatile fatty acid concentrations were reduced below 200 mg chemical oxygen demand/L (187 mg/L as acetic acid). Enhancement of sludge digestion was observed in those reactors where codigestion of sludge and FOG took place, which was attributed to a higher level of microbial activity maintained in these reactors as a result of FOG degradation. The results of this study demonstrate that beneficial use of FOG through codigestion with municipal sludge is feasible.     

耐酸厌氧消化污泥处理餐厨垃圾

采用耐酸驯化的厌氧消化污泥处理餐厨垃圾,在酸性条件下（pH=4．5）,对实验装置容积负荷从1．0kgVS／（m3·d）分9次逐级增加到5．0kgVS／（m3·d）的过程进行了跟踪监测,并较深入地研究了驯化污泥代谢活性和处理效果。实验结果表明,pH4．5的耐酸厌氧消化污泥,最佳投加负荷约为4．5kgVS／（m3·d）,此负荷下容积产气率,CH4含量平均值均达最大,分别为1．68m3／（m3·d）,75．0％。耐酸厌氧消化装置持续增料运行46d,产甲烷菌仍能保持较高的活性,其COD去除率范围为40．4％-75．0％,仍能保持pH7．2时处理效果的65．0％-91．8％,表明在低pH、低碱度下实现稳定的产甲烷过程是可行的。     

金属铁铝对混凝强化初沉污泥中温厌氧消化的影响

选取FeCl3和AlCl2·6H2O作为混凝剂对城市污水进行一级强化混凝处理,降低二级生物处理的进水负荷,减少污水生物处理系统的能量消耗。主要研究混凝过程投加的金属盐对一级强化混凝产生的初沉污泥中温厌氧消化的影响。和剩余污泥相比,初沉污泥更适合厌氧消化处理,污泥降解性能和产气性能更高。当采用城市污水一级强化混凝处理时,污泥中的金属和金属盐水解引起的pH降低,使混凝强化初沉污泥的厌氧消化受到一定抑制。随着污泥中铝含量的降低和铁含量的增加,厌氧消化的COD降解率和挥发性固体（Vs）降解率逐渐升高,生物气产量逐渐增大,产气速率加快。当混凝强化初沉污泥只含有铁时（铁含量为10．16mg／L）,混凝强化初沉污泥厌氧消化效果最好,产气稳定,而且产气速率高,生物气产量为237mL,生物气甲烷含量为55．5％,降解单位Vs产气量为0．80L／g,均高于其他含铝的混凝强化初沉污泥。污泥中的铁对初沉污泥厌氧消化的抑制作用远远小于铝的作用,说明铁盐适合用于城市污水的一级强化混凝处理。     

金属铁铝对混凝强化初沉污泥中温厌氧消化的影响简

选取FeCl₃和AlCl₃·6H₂O作为混凝剂对城市污水进行一级强化混凝处理,降低二级生物处理的进水负荷,减少污水生物处理系统的能量消耗。主要研究混凝过程投加的金属盐对一级强化混凝产生的初沉污泥中温厌氧消化的影响。和剩余污泥相比,初沉污泥更适合厌氧消化处理,污泥降解性能和产气性能更高。当采用城市污水一级强化混凝处理时,污泥中的金属和金属盐水解引起的pH降低,使混凝强化初沉污泥的厌氧消化受到一定抑制。随着污泥中铝含量的降低和铁含量的增加,厌氧消化的COD降解率和挥发性固体（VS）降解率逐渐升高,生物气产量逐渐增大,产气速率加快。当混凝强化初沉污泥只含有铁时（铁含量为10.16 mg/L）,混凝强化初沉污泥厌氧消化效果最好,产气稳定,而且产气速率高,生物气产量为237 mL,生物气甲烷含量为55.5%,降解单位VS产气量为0.80 L/g,均高于其他含铝的混凝强化初沉污泥。污泥中的铁对初沉污泥厌氧消化的抑制作用远远小于铝的作用,说明铁盐适合用于城市污水的一级强化混凝处理。     

污泥与餐厨垃圾联合厌氧发酵产氢余物产甲烷条件优化研究

研究了21、37和47 d产甲烷物料代替新鲜污泥接种于污泥与餐厨垃圾联合厌氧发酵产氢余物的厌氧发酵产甲烷情况,发现接种47 d产甲烷物料的消化系统在最佳接种量50%条件下的产甲烷效能显著优于接种新鲜污泥的消化系统,不仅提高了产甲烷率,还大大缩短了消化时间。并且3种消化系统产甲烷率和比产甲烷率均为47 d37 d21 d,分别为3.78、3.88、6.15 mL/g和0.172、0.277、0.559 mL/(g·d),完成产甲烷过程的消化时间为47 d37 d21 d。在一定的消化时间范围内,产甲烷菌被驯化时间越长,接种于产氢余物中的产甲烷效能越好。     

耐酸厌氧消化污泥处理餐厨垃圾简

采用耐酸驯化的厌氧消化污泥处理餐厨垃圾,在酸性条件下（pH=4.5）,对实验装置容积负荷从1.0 kg VS/（m³·d）分9次逐级增加到5.0 kg VS/（m³·d）的过程进行了跟踪监测,并较深入地研究了驯化污泥代谢活性和处理效果。实验结果表明,pH 4.5的耐酸厌氧消化污泥,最佳投加负荷约为4.5 kg VS/（m³·d）,此负荷下容积产气率,CH₄含量平均值均达最大,分别为1.68 m³/（m³·d）,75.0%。耐酸厌氧消化装置持续增料运行46 d,产甲烷菌仍能保持较高的活性,其COD去除率范围为40.4%~75.0%,仍能保持pH 7.2时处理效果的65.0%~91.8%,表明在低pH、低碱度下实现稳定的产甲烷过程是可行的。     

臭氧预处理—厌氧消化工艺促进剩余污泥减量化的研究

主要研究了臭氧氧化对剩余污泥的破解效果及污泥厌氧消化效率的影响.结果表明,随着臭氧投加量的增加,悬浮物(SS)、可挥发性悬浮物(VSS)逐步减少,而剩余污泥上清液中的溶解性COD(SCOD)、总有机碳(TOC)、蛋白质和多糖则明显增加.经臭氧预处理(臭氧投加量为0.050 g(以每克SS计))后,剩余污泥中温(35℃)厌氧消化效率明显提高,经65d稳定运行后,总挥发性固体(TVS)去除率为67.58％,与未经臭氧预处理的剩余污泥相比提高50.61％;甲烷平均产率为0.303 L(以每克TVS计),与未经臭氧预处理的剩余污泥相比提高54.59％.可见,臭氧预处理能有效促进污泥厌氧消化,从而达到污泥减量的目的.     

A rational procedure for estimation of greenhouse-gas emissions from municipal wastewater treatment plants.

Municipal wastewater treatment may lead to the emission of greenhouse gases. The current Intergovenmental Panel on Climate Change (Geneva, Switzerland) approach attributes only methane emissions to wastewater treatment, but this approach may overestimate greenhouse gas emissions from the highly aerobic processes primarily used in North America. To better estimate greenhouse gas emissions, a procedure is developed that can be used either with plant-specific data or more general regional data. The procedure was evaluated using full-scale data from 16 Canadian wastewater treatment facilities and then applied to all 10 Canadian provinces. The principal greenhouse gas emitted from municipal wastewater treatment plants was estimated to be carbon dioxide (CO2), with very little methane expected. The emission rates ranged from 0.005 kg CO2-equivalent/m3 treated for primary treatment facilities to 0.26 kg CO2-equivalent/m3 for conventional activated sludge, with anaerobic sludge digestion to over 0.8 kg CO2-equivalent/m3 for extended aeration with aerobic digestion. Increasing the effectiveness of biogas generation and use will decrease the greenhouse gas emissions that may be assigned to the wastewater treatment plant.     

超声与次氯酸钠耦合预处理剩余污泥的中温厌氧消化效果

以某城市污水处理厂剩余污泥为对象,通过实验研究了超声与次氯酸钠预处理对污泥的溶胞效果,以及对后续厌氧消化的影响。结果表明,超声与次氯酸钠耦合作用最优操作条件为超声声能密度1.0 W/mL,作用时间50 min。在此条件下,次氯酸钠投加量为4.023 mg/g SS时,对污泥厌氧消化改善效果最明显,剩余污泥产气率及甲烷含量较对照组分别提高了69.73%和10%。同时污泥VSS去除率由11.11%提高到21.24%,在一定程度上实现了污泥减量。     

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。     

Evaluation of TCDD biodegradability under different redox conditions

Polychlorinated dibenzo-p-dioxins have been generated as unwanted by-products in many industrial processes. Although their widespread distribution in different environmental compartments has been recognized, little is known about their fate in the ultimate environment sinks. The highly stable dioxin isomer 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been called the most toxic compound known to man. In this laboratory microcosm study, TCDD bioavailability was evaluated under five reduction/oxidation (redox) conditions including aerobic biodegradation, aerobic cometabolism, methanogenesis, iron reduction, and reductive dechlorination. Activated sludge and aquifer sediments from a TCDD and a pentachlorophenol (PCP) contaminated site were used as the inocula. Acetate, sludge cake, and cane molasses were used as the primary substrates (carbon sources) in cometabolism and reductive dechlorination microcosms. After a 90-day incubation period, microcosms constructed under reductive dechlorination conditions were the only treatment showing promising remediation results. The highest TCDD degradation rate [up to 86% of TCDD removal (with an initial concentration of 96 microg/kg of soil)] was observed in the microcosms with anaerobic activated sludge as the microbial inocula and sludge cakes as the primary substrates. Except for reductive dechlorination microcosms, no significant TCDD removal was observed in the microcosms prepared under other conditions. Thus, application of an effective primary substrate to enhance the reductive dechlorination process is a feasible method for TCDD bioremediation. Bioremediation expense can be significantly reduced by the supplement of some less expensive alternative substrates (e.g., sludge cakes, cane molasses). Results would be useful in designing a scale-up in situ or on-site bioremediation system such as bioslurry reactor for field application.     

污泥同时浓缩消化新型反应器的开发研究

针对污泥厌氧处理的问题,对污泥浓缩消化一体化反应器进行了开发研究,提出了ICSTD、MISTD和TISTD 3套反应器,反应器由内外2个反应室组成,采用沼气搅拌或机械搅拌。3套反应器的试验结果表明：在中温条件下,进泥含水率98.3%～99.8%,VS/TS 0.52～0.69时,排泥含水率87.4%～97.3%,VS/TS 0.23～0.51,产气量8.2～76.6 L/d,其浓缩和消化效果优于其他反应器。     

Steam-explosion pretreatment for enhancing anaerobic digestion of municipal wastewater sludge.

This study evaluated the use of steam explosion as a pretreatment for municipal wastewater treatment sludges and biosolids as a technique for enhancing biogas generation during anaerobic digestion. Samples of dewatered anaerobic digester effluent (biosolids) and a mixture of thickened waste activated sludge (TWAS) and biosolids were steam-exploded under differing levels of intensity in this study. The results indicate that steam explosion can solublize components of these sludge streams. Increasing the intensity of the steam-explosion pressure and temperature resulted in increased solublization. The steam-explosion pretreatment also increased the bioavailability of sludge components under anaerobic digestion conditions. Increasing the steam-explosion intensity increased the ultimate yield of methane during anaerobic digestion. Batch anaerobic digestion tests suggested that pretreatment at 300 psi was the most optimal condition for enhanced biogas generation while minimizing energy input. Semicontinuous anaerobic digestion revealed that the results that were observed in the batch tests were sustainable in prolonged operation. Semicontinuous digestion of the TWAS/biosolids mixture that was pretreated at 300 psi generated approximately 50% more biogas than the controls. Semicontinuous digestion of the pretreated biosolids resulted in a 3-fold increase in biogas compared with the controls. Based on capillary suction test results, steam-explosion pretreatment at 300 psi improved the dewaterability of the final digested sludge by 32 and 45% for the TWAS/ biosolids mixture and biosolids, respectively, compared with controls. The energy requirements of the nonoptimized steam-explosion process were substantially higher than the additional energy produced from enhanced digestion of the pretreated sludge. Substantial improvements in energy efficiency will be required to make the process viable from an energy perspective.     

Effect of solids concentration on bacterial leaching of heavy metals from sewage sludge

Microbial metal leaching from sewage sludge (2-9% w/v) was carried out with the iron-oxidizing bacterium Thiobacillus ferrooxidans. Measurements of pH, oxidation-reduction potential, and concentration of Fe2+ indicated that T. ferrooxidans was effective in removing metals from an incubation bath containing less than 5% sludge solids concentration. Specifically, Cu leaching was completely suppressed at a high solids concentration of 9% (w/v). Results indicated that the deactivation of T. ferrooxidans at a high sludge content was mainly due to the presence of inhibiting materials such as organic matter. A mixed culture of sulfur-oxidizing bacteria was obtained by enrichment from anaerobically digested sewage sludge to enhance the efficiency of the microbial leaching process. These bacteria were much more effective in metal leaching than was iron-oxidizing T. ferrooxidans. At 9% (w/v) solids concentration, the leaching efficiencies of Zn and Cu were 78% (2.66 g/kg dry sludge) and 59% (1.36 g/kg dry sludge), respectively. Therefore, when removing heavy metals from the anaerobically digested sewage sludge, the indigenous sulfur-oxidizing bacteria isolated in the current study were more efficient than T. ferrooxidans, especially at high sludge solids concentrations.     

厌氧系统中碱处理对污泥减量的影响

碱解预处理污泥和原污泥按一定比例进行混合后,投入厌氧反应器中进行消化,研究其对污泥减量化的影响。结果表明,该处理既可以提高污泥减量率,又能改善污泥厌氧消化性能,提高污泥产气量。当碱处理污泥和原污泥混合比为1∶3时,在混合初期由于稀释作用和水解中和作用,溶液的pH能迅速恢复到中性。SS减少48%,较对照组提高了10%;SCOD减少约80%,较对照组提高20%,而空白对照组因未发生溶胞作用,各参数值均处于较低水平,降解率也维持在较低水平。     

Priority organic pollutant assessment of sludges for agricultural purposes

A comprehensive characterization of five of the seven priority organic pollutants listed in the draft of the "Working document on sludge" [EU, 2000. Working Document on Sludge 3rd Draft. Unpublished, 19 p] has been carried out during 2001-2003 in sludge samples from Catalonia (NE Spain). One hundred and thirty-nine samples belonging to 20 Waste Water Treatment Plants (WWTPs), seven sludge treatment (thermal drying) and three composting sludge plants were taken in order to determine the concentration of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs), di-2-(ethyl-hexyl)-phthalate (DEHP), nonylphenol and nonylphenol ethoxylates with one or two ethoxy groups (NPE), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). PCDD/F concentrations were in general lower than the 100 ng I-TEQ/kg limit suggested in the above-mentioned document. In the same way, 98.5% for PCBs, 97% for PAH and 92.8% for DEHP of the samples presented concentrations lower than 0.8 mg/kg dm, 6 mg/kg dm and 100 mg/kg dm, respectively. In contrast, the vast majority of samples contained NPE concentrations much higher than 50mg/kg dm limit. The values ranged from 14.3 to 3150 mg/kg dm (median value=286.6 mg/kg) being composted sludge samples the less contaminated ones (17.9-363.4 mg/kg dm; median value=89.3 mg/kg). Special attention should be paid to the Catalan sludge NPE contamination owing to the high levels detected.     

An observation on sludge granulation in an enhanced biological phosphorus removal process

A sequencing batch reactor (SBR) seeded with flocculated sludge and fed with synthetic wastewater was operated for an enhanced biological phosphorus removal (EBPR) process. Eight weeks after reactor startup, sludge granules were observed. The granules had a diameter of 0.5 to 3.0 mm and were brownish in color and spherical or ellipsoidal in shape. No significant change was observed in sludge granule size when operational pH was changed from 7 to 8. The 208-day continuous operation of the SBR showed that sludge granules were stably maintained with a sludge volume index (SVI) between 30 to 55 mL/g while securing a removal efficiency of 83% for carbon and 97% for phosphorus. Fluorescent in situ hybridization (FISH) confirmed the enrichment of polyphosphate accumulating organisms (PAOs) in the SBR. The observations of sludge granulation in this study encourage further studies in the development of granules-based EBPR process.     

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。     

炼厂"三泥"的生物处理研究

从大港油田筛选和分离出3株以原油为碳源的石油降解菌,初步鉴定为假单胞菌属(Pseudomonas sp.),用这3株菌混合处理某炼厂的"三泥",在适宜的降解条件下,仅需投加混合菌液,无需添加营养物(N,P),可使含油污泥A的残油量从67g/kg降至7.7g/kg,混合油泥试样AB的残油量从19.7g/kg降至3.1g/kg,平均去除率为84%以上,可以实现含油污泥的较为经济的、有效的处理.经生物处理后含油污泥的恶臭味完全消失.     

碳氮比对鸭粪中温厌氧消化的影响

在中温(35±1)℃、6%的料液浓度、pH为中性条件下,采用10 L玻璃瓶作为反应器对碳氮比(C/N)分别为15、20、25和35的4组鸭粪溶液进行厌氧消化实验,系统运行30 d,分析了厌氧消化过程中的COD(化学需氧量)、pH、VFA(挥发性脂肪酸)和产气量的变化。结果表明,碳氮比是影响鸭粪厌氧消化过程的重要因素,调节鸭粪碳氮比至25,可以使其厌氧消化获得最佳的产气效果,COD去除率为24.06%,原料干物质产气率为0.178 m3/kg,产气中甲烷含量为71.5%,产甲烷率为0.127 m3/kg。