IC反应器技术的发展

扼要介绍IC反应器的基本结构和原理,并从工艺思想的角度对该反应器进行了分析,即IC反应器是现有废水处理工艺成果与内循环技术相结合的产物.最后总结了IC反应器的应用特点.     

生物除磷过程中乙酸盐厌氧代谢机理的研究

本文研究了生物除磷过程中乙酸盐厌氧代谢机理。结果表明,在厌氧条件下,活性污泥的聚-β-羟基丁酸盐含量,无机磷酸盐释放量分别随乙酸盐吸收量的增加而呈线性关系上升。      

Effect of coplanar PCB concentration on dechlorinating microbial communities and dechlorination in estuarine sediments

The effect of concentration of coplanar PCB on the dechlorinating microbial community and dechlorination were investigated in anoxic estuarine sediment collected from Er-Jen River and enriched with 10 and 50 mg L⁻¹ of 3,4,4′,5-tetrachlorobiphenyl, 3,3′,4,4′,5-pentachlorobiphenyl, and 3,3′,4,4′,5,5′-hexachlorobipheny. Dechlorination rates were similar in the cultures enriched with 10 and 50 mg L⁻¹ of 3,4,4′,5-tetrachlorobiphenyl, whereas significantly higher dechlorination rates were observed in cultures enriched with 10 mg L⁻¹ of 3,3′,4,4′,5-pentachlorobiphenyl. No dechlorination was observed in sediment slurries enriched with 3,3′,4,4′,5,5′-hexachlorobipheny. Para dechlorination occurred prior to meta dechlorination during reductive dechlorination of 3,4,4′,5-tetrachlorobiphenyl and 3,3′,4,4′,5-pentachlorobiphenyl. GC-MS and denaturing gradient gel electrophoresis (DGGE) were used to detect dechlorination products and dechlorinating microorganisms in the enriched sediment cultures during the process of degradation. Two Chloroflexi phylotypes observed in DGGE were responsible for para and meta dechlorination respectively. Phylotype Cp-1 has 98% similarity to uncultured bacterium N5-12. Phylotype Cm-1 has 99% similarity to uncultured dechlorinating bacterium m1 or SF1 belonging to the ο-17/DF-1 group of PCB-dechlorinating bacteria.     

Occurrence of polycyclic musks in wastewater and receiving water bodies and fate during wastewater treatment

The occurrence of cashmerane (DPMI), celestolide, phantolide, traesolide (ATII), galaxolide (HHCB) and tonalide (AHTN) in sewage and surface waters and their fate during wastewater treatment and anaerobic sludge digestion is investigated. AHTN and HHCB are the most important representatives and influent concentrations of 0.41-1.8 and 0.9-13 μg L⁻¹ are observed. DPMI is detected in influent and effluent samples but in notably lower concentrations than AHTN and HHCB. Major sources of polycyclic musks are households, whereas industrial emitters seem to be of minor importance. This conclusion is supported by the analysis of selected industrial wastewaters (metal, textile and paper industry). Specific emissions of 0.36 ± 0.19 and 1.6 ± 1.0 mg cap⁻¹ d⁻¹ for AHTN and HHCB are calculated. Overall removal efficiencies between approx 50% and more than 95% are observed during biological wastewater treatment and removal with the excess sludge is the major removal pathway. Log K_D values of 3.73-4.3 for AHTN, 3.87-4.34 for HHCB and 2.42-3.22 for DPMI are observed in secondary sludge. During sludge digestion no or only slight removal occurred. Mean polycyclic musk concentrations in digested sludge amounted to 1.9 ± 0.9 (AHTN), 14.2 ± 5.8 (HHCB), 0.8 ± 0.4 (ATII) and 0.2 ± 0.09 (DPMI) mg kg⁻¹ dry matter. In the receiving water systems a comparable distribution as during wastewater treatment is observed. AHTN, HHCB and DPMI are detected in surface waters (ND (not detected) - < 0.04, ND - 0.32 and ND - 0.02 μg L⁻¹) as well as AHTN and HHCB in sediments (ND - 20, ND - 120 μg kg⁻¹). For HHCB an apparent K_OC value of 4.1-4.4 is calculated for sediments. Major source for polycyclic musks in surface waters are discharges from wastewater treatment plants. For HHCB and DPMI 100% of the load observed in the sampled surface waters derive from discharges of treated wastewater.     

Semi-continuous anaerobic co-digestion of thickened waste activated sludge and fat, oil and grease

Co-digestion of thickened waste activated sludge (TWAS) and fat, oil and grease (FOG) was conducted semi-continuously under mesophilic conditions. The results showed that daily methane yield at the steady state was 598 L/kg VS_added when TWAS and FOG (64% of total VS) were co-digested, which was 137% higher than that obtained from digestion of TWAS alone. The biogas composition was stabilized at a CH₄ and CO₂ content of 66.8% and 29.5%, respectively. Micronutrients added to co-digestion did not improve the biogas production and digestion stabilization. With a higher addition of FOG (74% of total VS), the digester initially failed but was slowly self-recovered; however, the methane yield was only about 50% of a healthy reactor with the same organic loading rate.     

Thermophilic adaptation of a mesophilic anaerobic sludge for food waste treatment

As opposed to mesophilic, thermophilic anaerobic digestion of food waste can increase the biogas output of reactors. To facilitate the transition of anaerobic digesters, this paper investigated the impact of adapting mesophilic sludge to thermophilic conditions. A 5L bench scale reactor was seeded with mesophilic granular sludge obtained from an up-flow anaerobic sludge blanket digester. After 13 days of operation at 35 degrees C, the reactor temperature was instantaneously increased to 55 degrees C and operated at this temperature until day 21. The biomass was then fed food waste on days 21, 42 and 63, each time with an F/M (Food/Microorganism) ratio increasing from 0.12 to 4.43 gVS/gVSS. Sludge samples were collected on days 0, 21, 42 and 63 to conduct substrate activity tests, and reactor biogas production was monitored during the full experimental period. The sludge collected on day 21 demonstrated that the abrupt temperature change had no pasteurization effect, but rather lead to a biomass with a fermentative activity of 3.58 g Glucose/gVSS/d and a methanogenic activity of 0.47 and 0.26 g Substrate/gVSS/d, related respectively, to acetoclastic and hydrogenophilic microorganisms. At 55 degrees C, an ultimate gas production (Go) and a biodegradation potential (Bo) of 0.2-1.4 L(STP)/gVS(fed) and of 0.1-0.84 L(STP) CH(4)/gVS(fed) were obtained, respectively. For the treatment of food waste, a fully adapted inoculum was developed by eliminating the initial time-consuming acclimatization stage from mesophilic to thermophilic conditions. The feeding stage was initiated within 20 days, but to increase the population of thermophilic methanogenic microorganisms, a substrate supply program must be carefully observed.     

Overcoming the toxicity effects of municipal wastewater sludge and biosolid extracts in the Yeast Estrogen Screen (YES) assay

For nearly two decades, the Yeast Estrogen Screen (YES) has been used as a valuable tool for determining the total estrogenic potency of various environmental samples, including influent and effluent streams at municipal wastewater plants. However, applying the YES assay to wastewater sludges and stabilized biosolids has been problematic. This is due to co-extracted compounds from the solids either proving toxic to the yeast or masking the presence of estrogenic substances. The present research describes the development and validation of sample preparation steps that mitigate the toxicity effects of municipal wastewater sludge and biosolid samples in the YES assay, while allowing for reliable dose-dependent expression of estrogenic activity. A copper work-up for sulfur removal and chromatographic cleanup with silica and alumina were required in addition to solid-phase extraction to adequately remove interfering compounds. Sample stabilization methods such as autoclaving, lyophilization and formaldehyde treatment were found to be detrimental to the assay. Hence, heat-drying is recommended to prevent cytotoxicity and the degradation of estrogenic substances.     

Mass balance of anionic surfactants through up-flow anaerobic sludge blanket based sewage treatment plants

The outcome of a 21-month monitoring study on anionic surfactants (AS) at five (27–70 ML/d) up-flow anaerobic sludge blanket (UASB) based sewage treatment plants (STPs) is described. The average removals of AS were around 8–30%. Appreciable concentrations of AS were being discharged to the watercourse (average 4.30 mg/L; range 3.60–4.91 mg/L). On an average dried sludge contained 1452 mg AS/kg dry weight. Mass balance at three STPs indicated that, AS load of the order of 5–17% and ≈12% is removed by adsorption in UASB reactors and polishing ponds (PP) respectively. Biodegradation of AS under anaerobic conditions in UASB reactors and PP does not seem to take place. In the sludge stream, appreciable biodegradation (≈46%) of adsorbed AS under aerobic conditions on the sludge drying beds takes place. If influent AS mass flux is normalized to 100 units, than average of ≈74 and ≈7 units are discharged with treated effluent and dried sludge respectively, while 12 and 6 units are adsorbed/settled in PP and aerobically biodegrade on sludge drying beds respectively. At two STPs (34 and 56 ML/d), the filterable fluxes in UASBR increased so that the mass balance could not be computed.     

浙江江山化工股份有限公司污水站一期调试运行

通过对浙江江山化工股份有限公司污水站一期工程3个多月的调试,证明复合厌氧反应器(HAR) 多段好氧工艺处理高浓度有机废水是切实可行的.新型HAR污水站常温下100 d左右可以顺利启动,在进水量675 m3/d、平均容积负荷(以COD计)2.72 kg/(m3·d)条件下,平均COD去除率为35.47%,平均有机胺转化率为39.50%.启动后组合系统COD去除率可达90%以上,出水达到<污水综合排放标准>三级标准.化学沉淀去除NH3-N是出水顺利达标和好氧池稳定、高效运行的关键.尽可能控制并减少磷酸盐等加药量,以防止剩余磷的二次污染.     

味精废水厌氧氨氧化生物脱氮的研究

采用厌氧氨氧化工艺(ANAMMOX)处理味精废水,结果显示,总氮容积去除负荷可达457 mg·L-1·d-1,高于传统硝化-反硝化工艺,可成为传统硝化-反硝化工艺的替代技术.厌氧氨氧化菌对NO2--N的耐受范围为96.5～129 mg·L-1.受基质NO2--N抑制后,厌氧氨氧化反应器难以自行恢复,将基质浓度稀释到临界浓度以下则可恢复效能.反应器对进水cNO2-N/cNH4 -N比值有一定的适应能力.在所试的进水cNO2--N/cNH4 -N比值(1.0～1.4)范围内,出水基质浓度基本保持不变.