The influence of operational conditions in sequencing batch reactors on removal of nitrogen and organics from municipal landfill leachate.

The removal of nitrogen and organics from municipal landfill leachate in sequencing batch reactors (SBR) was investigated in the present study. The influence of hydraulic retention time (HRT), sludge age, manner of leachate dosage (short filling period of SBR and filling during the reaction period), and operational conditions with and without a mixing phase in the SBR cycle was explored. Four series were performed. In each series, the HRT used in the four SBRs was 12, 6, 3 and 2 days, respectively. Series 1 and 2 were characterized by a short leachate filling period, whereas series 3 and 4 were characterized by filling during the 4 h duration of the reaction in the SBR cycle. In series 1-3 SBR reactors worked with mixing and aeration phases, whereas in series 4 they worked only with an aeration phase. The effectiveness of the removal of organics increased with the extension of the HRT of leachate, particularly under operational conditions with the mixing and aeration phases in the SBR cycle. At 12 days HRT, the SBRs with the mixing and aeration phases in the cycle (series 1-3) showed better results than those with only an aeration phase (series 4). However, at 2 days HRT the operational conditions in SBR reactors with leachate filling over the reaction period (series 3 and 4) were more suitable. The highest efficiency of ammonium removal was obtained in series 1 with a short leachate filling period. In this series, at an HRT of 3-12 days, the ammonium concentration in the effluent did not exceed 1 mg NNH4 L(-1). Nitrogen removal proceeded mainly in the aeration phase as a result of ammonium losses and, to a lesser extent, dissimilative nitrate reduction over the mixing phase. The highest percentage of nitrogen removal as a result of ammonium losses was observed in series with a short filling period and long sludge age (series 1) and also in series without a mixing phase and filling over the aeration phase (series 4), whereas the highest nitrogen consumption for biomass production occurred in series 3 with filling during the reaction period and mixing phase of the cycle.     

Treatment of anti-osmotic drug based pharmaceutical effluent in an upflow anaerobic fluidized bed system

During the production of Cephradine (a main constituent of anti-osmotic drug) a large quantity of concentrated effluent was produced. The main polluting compounds in this effluent are osmotic drug, acetic acid and ammonia. The feasibility of using a fluidized bed reactor under anaerobic condition with bioaugmentation to treat anti-osmotic drug based pharmaceutical effluent was evaluated. The main objective of the study was to show that bioaugmentation could be used to promote biological treatment to applications where conventional operation might be difficult or unfavourable. The effluent with chemical oxygen demand (COD) of 14000-18000 mg/l was treated in a fluidized bed reactor with a hydraulic retention time of 3-12 h. The reactor was unable to maintain consistent removal in conventional mode of operation due to an inability to retain and grow biomass. The COD reduction (%) after inoculation from a sequencing batch reactor was related to influent concentration, mass of inoculum and hydraulic retention time characterized by calculating the initial food to microorganism ratio. The role of volatile fatty acid (VFA) as cosubstrate was assessed with respect to COD reduction (%). Continuous COD reduction (%) attained a maximum value of 88.5% using bioaugmentation through periodic addition of acclimated cells every 2 days with 30-73.2 g of cells from an off-line enricher reactor.     

O3氧化法和O3-H2O2氧化法去除水中聚丙烯酰胺

采用O3氧化法和O3-H2O2氧化法去除水中的聚丙烯酰胺（PAM）,分别考察了反应时间、O3质量浓度、n（H2O2）∶n（O3）和溶液pH对PAM去除效果的影响。实验结果表明：O3氧化的最佳操作条件为反应时间30 min、O3质量浓度22.6 mg/L、溶液pH 8.5,O3-H2O2氧化的最佳操作条件为反应时间10 min、O3质量浓度22.6 mg/L、n（H2O2）∶n（O3）=0.1、溶液pH 8.5;在最佳操作条件下,O3氧化和O3-H2O2氧化均可有效降低PAM溶液的黏度和PAM质量浓度,但对COD的去除效果不佳,黏度可降至和蒸馏水相近,PAM的去除率可达80%以上,而COD的去除率分别约为15%和28%;O3-H2O2氧化后的PAM比O3氧化后的PAM更容易被微生物利用,两种氧化预处理方法均有利于后续的生化处理。     

好氧颗粒污泥脱氮性能研究

研究了序批式反应器的污泥沉降时间、曝气速率、水力停留时间、进水方式等参数对好氧颗粒污泥的性能以及COD,NH4^*—N,TN去除率的影响。研究结果表明,在一个运行周期内,反应器运行工艺参数,如DO质量浓度和pH,具有一定的变化规律,并且其变化与反应器内各物质的转化存在严格的对应关系。因此,参照反应器运行工艺参数的特征点,对反应过程进行必要的控制,可达到较理想的处理效果。     

Organics removal from landfill leachate and activated sludge production in SBR reactors

This study is aimed at estimating organic compounds removal and sludge production in SBR during treatment of landfill leachate. Four series were performed. At each series, experiments were carried out at the hydraulic retention time (HRT) of 12, 6, 3 and 2d. The series varied in SBR filling strategies, duration of the mixing and aeration phases, and the sludge age. In series 1 and 2 (a short filling period, mixing and aeration phases in the operating cycle), the relationship between organics concentration (COD) in the leachate treated and HRT was pseudo-first-order kinetics. In series 3 (with mixing and aeration phases) and series 4 (only aeration phase) with leachate supplied by means of a peristaltic pump for 4h of the cycle (filling during reaction period) - this relationship was zero-order kinetics. Activated sludge production expressed as the observed coefficient of biomass production (Y(obs)) decreased correspondingly with increasing HRT. The smallest differences between reactors were observed in series 3 in which Y(obs) was almost stable (0.55-0.6 mg VSS/mg COD). The elimination of the mixing phase in the cycle (series 4) caused the Y(obs) to decrease significantly from 0.32 mg VSS/mg COD at HRT 2d to 0.04 mg VSS/mg COD at HRT 12d. The theoretical yield coefficient Y accounted for 0.534 mg VSS/mg COD (series 1) and 0.583 mg VSS/mg COD (series 2). In series 3 and 4, it was almost stable (0.628 mg VSS/mg COD and 0.616 mg VSS/mg COD, respectively). After the elimination of the mixing phase in the operating cycle, the specific biomass decay rate increased from 0.006 d(-1) (series 3) to 0.032 d(-1) (series 4). The operating conditions employing mixing/aeration or only aeration phases enable regulation of the sludge production. The SBRs operated under aerobic conditions are more favourable at a short hydraulic retention time. At long hydraulic retention time, it can lead to a decrease in biomass concentration in the SBR as a result of cell decay. On the contrary, in the activated sludge at long HRT, a short filling period and operating cycle of the reactor with the mixing and aeration phases seem the most favourable.     

Removing cadmium from aqueous solutions utilizing agricultural wastes

The purpose of this study was to determine the cadmium (Cd) biosorption capacities of several agricultural wastes from aqueous solutions. Samples were tested unaltered and after hydrochloric acid treatment. Additional parameters tested include sample dose, contact time, particle size, mixing temperature, and the concentrations and pH of the Cd solutions. Desorption studies were performed to determine if the removed Cd could be recovered. In addition, tests were conducted to determine if the agricultural waste samples (AWS) could be reused for additional Cd biosorption cycles. The results of this study demonstrate a wide range of Cd biosorption proficiencies ranging from 33 to 100% removal. The parameters that resulted in higher Cd removal include higher sample dose, higher pH, and lower Cd solution concentration. Desorption results showed a 36–56% Cd recovery rate. Reused AWS were effective at removing Cd during subsequent trials. Therefore, all AWS types tested in this study can be reused for additional Cd biosorption cycles. Hence, it is possible that using AWS for metal treatment could reduce hazardous waste disposal inefficiencies and costs by avoiding disposing of spent AWS following each Cd biosorption cycle.     

反硝化聚磷菌的培养及其脱氮除磷特性

采用SBR反应器驯化培养反硝化聚磷菌,考察了厌氧-缺氧-好氧和厌氧-缺氧运行模式下反硝化聚磷菌的增殖情况、反应器的脱氮除磷特性及胞内聚合物聚β-羟基丁酸(PHB)和糖原的合成消耗情况。实验结果表明:经过72 d(288个周期)的驯化培养,SBR反应器内反硝化聚磷菌的数量约占全部聚磷菌的84.5%;厌氧-缺氧培养方式下,反硝化聚磷菌的释磷速率为34.5 mg/(L·h),缺氧吸磷速率为23.0 mg/(L·h),缺氧阶段每降解1.0 mg/L的PO_4~(3-)-P需要消耗1.0 mg/L的NO_3~--N;每消耗6.3 mg/L的COD生成1 mg/g的PHB,每降解1 mol的PHB约生成0.73 mol的糖原。     

Biosorption of copper from aqueous solutions utilizing agricultural wastes

The purpose of this study was to determine the copper (Cu) biosorption capacities of several agricultural wastes from aqueous solutions. Samples of agricultural wastes were tested unaltered and after hydrochloric acid (HCl) treatment. Additional parameters tested include sample dose, contact time, particle size, mixing temperature, and the concentrations and pH of the Cu solutions. Desorption studies were performed to determine if the removed Cu could be recovered. In addition, tests were conducted to determine if the agricultural waste samples (AWS) could be reused for additional Cu biosorption cycles. The results of this study demonstrate a wide range of Cu biosorption proficiencies ranging from 0% to 100% removal. The parameters that resulted in higher Cu removal include higher pH and lower Cu solution concentration. Desorption results showed a 58% to 86% Cu recovery rate. Three of the five reused AWS were effective at removing Cu during subsequent trials. Therefore, these AWS types can be reused for additional Cu biosorption cycles. Hence, it is possible that using those AWS for metal treatment could reduce hazardous waste disposal inefficiencies and costs by avoiding disposing of spent AWS following each Cu biosorption cycle.     

Effectiveness of “Nochar” Solidifier Polymer in Removing Oil from Open Water in Coastal Wetlands

The use of solidifier in oil spill cleanup has been minimal due to lack of practical application method and in situ field testing and evaluation under various coastal and environmental conditions. Solidifiers are dry granular, hydrophobic polymers that react with oil and form a cohesive mass that floats on water. Unlike sorbents, the oil is retained in the solid mass allowing for easy removal. A field test was conducted in coastal Louisiana in which replicated open water enclosures were oiled with South Louisiana Crude. Granular solidifier was spread over oil and the solidified oil was then removed from the plots. Over 70% of the applied oil was recovered. Results demonstrated that solidifier may, under certain conditions, be an option for removing oil from wetlands.     

Improving the two-step remediation process for CCA-treated wood: Part II. Evaluating bacterial nutrient sources

Remediation processes for recovery and reuse of chromated-copper-arsenate- (CCA) treated wood are not gaining wide acceptance because they are more expensive than landfill disposal. One reason is the high cost of the nutrient medium used to culture the metal-tolerant bacterium, Bacillus licheniformis, which removes 70-100% of the copper, chromium, and arsenic from CCA-treated southern yellow pine (CCA-SYP) in a two-step process involving oxalic acid extraction and bacterial culture. To reduce this cost, the nutrient concentration in the culture medium and the ratio of wood to nutrient medium were optimized. Maximum metal removal occurred when B. licheniformis was cultured in 1.0% nutrient medium and at a wood to nutrient medium ratio of 1:10. Also, malted barley, an abundant by-product of brewing, was evaluated as an alternative nutrient medium. Tests were done to determine absorption of metals by barley, and the results indicate that the barley acted as a biosorbent, removing heavy metals from the liquid culture after their release from CCA to SYP. For comparison, tests were also performed with no nutrient medium. Following bacterial remediation, 17% copper and 15% arsenic were removed from an aqueous slurry of CCA-SYP (no medium). When oxalic acid extraction preceded the aqueous bacterial culture, 21% copper, 54% chromium, and 63% arsenic were removed. The two-step process (oxalic acid extraction and bacterial culture with nutrient medium) appears to be an effective, yet costly, way to remove metals.     

蒽醌染料废水处理技术

对蒽醌染料废水分别用混凝沉淀法,微电池法,Ｏ３法进行了预处理试验,用生物膜ＳＢＲ法和活性污泥ＳＢＲ法进行了生化处理试验。试验数据表明,废水经ＰＡＭ混凝沉淀－铁炭微电池预处理和生物膜ＳＢＲ处理后,可达标排放。     

生物滴滤塔处理模拟印刷有机废气

选取甲苯、乙酸乙酯为目标污染物模拟印刷有机废气,采用生物滴滤塔对其进行处理。从某污水处理厂曝气池活性污泥中筛选出3株能够高效降解甲苯、乙酸乙酯的优势菌种,经鉴定分别为枯草芽孢杆菌（Bacillus subtilis）、蜡状芽胞杆菌（Bacillus cereus）和嗜麦芽寡养单胞菌（Stenotrophomonas maltophilia）。实验结果表明：增大乙酸乙酯配比对VOCs去除率影响不大,而增大甲苯配比导致VOCs去除率下降明显;在进气VOCs质量浓度为约800 mg/m³（甲苯与乙酸乙酯的体积比1∶1）、气体空床接触时间为300 s、菌液喷淋量为800 L/h、菌液温度为25 ℃的条件下,VOCs去除率可达约99%。生物滴滤塔运行一段时间后,对菌种进行再鉴定,结果与处理前一致。     

高效石油烃降解菌的筛选及其对原油污染土壤的修复

从陕北原油污染土壤中筛选出7株高效石油烃降解菌,其中黄杆菌属CC-2、不动细菌属SC-5、假单胞菌属SC-6表现出较强的石油烃降解能力。通过单因素试验和正交试验考察总石油烃(TPH)降解效果的影响因素,得出各因素对TPH降解率影响程度的大小次序为:溶液p H降解温度降解菌接种量摇床转速,且在降解菌接种量为7%(φ)、溶液p H为7、降解温度为30℃、摇床转速为150 r/min的最适处理条件下,菌株SC-6的TPH降解率可达61.23%。原油污染土壤生物修复实验结果表明:高效石油烃降解菌的投加有利于土壤TPH降解率和酶活性的提高;"菌株SC-6+营养剂"组修复处理42 d后的TPH降解率可达57.59%。     

石油污染海岸线生物修复技术研究进展

介绍了生物修复、生物强化和生物刺激的基本概念。综述了基于生物强化和生物刺激技术处理石油污染海岸线的研究进展,并指出不同处理技术的优势与不足。分析了影响溢油污染海岸线生物修复的重要因素,包括石油类型、波浪和水流能量、温度、盐度、氧气含量等。对今后研究的主要方向进行了展望。     

电渗析法脱除氨法烟气脱硫浆液中的氟离子

利用异相膜电渗析装置去除氨法烟气脱硫浆液中的F~-。考察了脱硫浆液p H、F~-初始质量浓度、Cl~-初始质量浓度、膜堆两端电压、浓缩室和淡化室循环流量等操作参数对F~-去除效果的影响。实验结果表明:在酸性条件下,F~-去除率更高;脱硫浆液中F~-初始质量浓度越高,F~-去除率越高;Cl~-初始质量浓度较低时会增加F~-去除率,过高时又会降低F~-去除率。优化的操作条件为:膜堆两端电压25 V,浓缩室和淡化室循环流量300 L/h。一级电渗析进行100 min后,Cl~-去除率接近100%,F~-去除率只有47.3%。二级电渗析进行100 min时,F~-去除率达92.2%。一、二级电渗析F~-累积去除率达96.1%。     

微生物菌剂强化处理油砂

研究了微生物菌剂对油砂的处理效果,并通过第15天和第30天两次追加微生物菌剂和营养物质来加速分解石油类污染物。试验结果表明,经过56d的处理,菌剂强化处理单元最终油去除率达到47．4％;添加营养物质和农家肥的对照单元油去除率为23．6％,证明土著菌种在得到适宜的营养和共代谢基质后降解了部分石油;未做任何处理的原始油砂单元含油量基本没有变化。通过气相色谱一质谱联用分析表明,微生物菌剂对于较少碳原子数的有机物质有较好的降解效果。处理单元中随着石油分解过程的进行,系统pH会有一个明显的下降过程。通过对照单元细菌数的检测发现,改善营养物质和氧含量,可以提高土著菌种的石油降解件能。     

旋流气浮除油装置预处理含油污水

在河南油田开展旋流气浮除油装置的现场试验,考察进水流量和曝气量对旋流气浮除油装置除油效果的影响。试验结果表明:在进水流量为1.8 m³/h、曝气量为0.5 L/min时,除油率最高达到96.03%;在不添加任何药剂的条件下,装置处理效果稳定;连续运行6 d内,进水含油量为174.57~1 193.15 mg/L时,出水含油量可以保持在137.38 mg/L以下,除油率为58.58%~94.53%。     

催化臭氧氧化对生化尾水中典型有机物的去除特性

系统深入地分析了Fe-Ce/AC催化臭氧氧化对化工园区污水厂生化尾水中典型有机物的去除特性。与单独臭氧氧化相比,催化臭氧氧化可将TOC去除率从7.89%大幅提升至17.54%。120 min时UV_(254)和特征紫外吸光度(SUVA)的去除率分别高达66.80%和59.73%,证明了催化臭氧氧化可有效去除含共轭结构或芳环结构的不饱和有机物。催化臭氧氧化对生化尾水中腐殖酸类(HA)、溶解性微生物产物类(SMP)和疏水性腐殖酸类(HOA)3种荧光组分的去除过程均符合一级动力学模型,且由一级动力学速率常数可知,与生化尾水色度直接相关的HA和HOA被优先去除。40 min时HA、SMP和HOA的去除率即高达95.24%、93.21%和92.96%。     

改性累托石复合絮凝剂处理油漆废水

采用改性累托石-天然高分子多糖复合絮凝剂处理油漆废水。在改性累托石质量浓度为80mg／L、天然高分于多糖质造浓度为4mg／L的条件下,COD、悬浮固体和色度的去除率分别较传统絮凝剂三氯化铝和聚丙烯酰胺提高了43．1％,6．4％,22．6％和19．1％,3．4％,21．8％;吨废水药剂成本分别下降了16．9％和30．7％,处理后的油漆废水均达到国家二级污水排放标准。     

液膜法处理含硝基酚废水试验研究

采用液膜法对含硝基酚废水进行了处理试验研究。对低浓度废水选取了适宜的工艺条件：油相中表面活性剂的质量分数为2％；内水相中NaOH的质量分数为2％；乳液中油相与内水相的质量比为2：1；外水相：pH为2；乳液与外水相的体积比为1：3。在进水总酚质量浓度分别为1050、6700mg／L的条件下，出水总硝基酚的去除率均高达99．9％以上，同时废水中的硝基苯和COD也有较好的去除效果。