Integration of continuous biological and chemical (ozone) treatment of domestic wastewater: 1. Biodegradation and post‐ozonation

The continuous treatment of domestic wastewater by an activated sludge process and by an integrated biological–chemical (ozone) oxidation process were studied in this work. Chemical oxygen demand (COD), biochemical oxygen demand (BOD), absorbance at 254 nm (UV₂₅₄) and nitrogenous compound content were the parameters followed in order to evaluate the performance of the two processes. Experimental data showed that both UV₂₅₄ and COD reductions are improved in the combined biological–chemical oxidation procedure. Thus, reductions of 59.1% and 37.2% corresponding to COD and UV₂₅₄, respectively were observed after the biological process (hydraulic retention time = 5 h; mixed liquor volatile suspended solids concentration = 3142 g m⁻³) compared with 71.0% and 78.4% obtained when a post‐ozonation step ( D _O3 = 41.7 g m⁻³) was included. During conventional activated sludge treatment, appropriate nitrification levels are only achieved with high hydraulic retention time and/or biomass concentration. Ozonation after the secondary treatment, however, allows improved nitrogen content reduction with total nitrite elimination. Post‐ozonation also leads to a higher biodegradability of the treated wastewater. Thus, the ultimate BOD/COD ratio goes from 0.16 after biological oxidation to 0.34 after post‐ozonation with 41.7 g O₃ m⁻³. © 1999 Society of Chemical Industry     

Combined effects of sucrose and copper(II) ions on the growth and copper(II) bioaccumulation properties of Candida sp

A microbiological process using Candida sp was developed for the removal of copper(II) ions in the presence of molasses as nutrient. The combined effects of sucrose (in molasses) and copper(II) ions on the growth and copper(II) bioaccumulation properties of adapted Candida cells was tested under laboratory conditions as a function of initial pH and single‐sucrose and dual‐sucrose and copper(II) ion concentrations. The optimum pH value for maximum growth and metal ion accumulation was determined as 4.0 for the microorganism. At a constant copper(II) concentration, growth and copper(II) bioaccumulation increased with increasing concentrations of molasses sucrose up to 15 gdm⁻³. Although increased initial copper(II) concentration increased the copper(II) uptake capacity of the microorganism, inhibition by copper(II) ions of the growth of Candida sp was observed at all the concentrations of copper(II) at all the sucrose concentrations studied. The non‐competitive inhibition kinetics (assuming copper(II) ions as the toxic inhibitory component) were used to define the relationship between the specific growth rate and molasses sucrose and copper(II) concentrations and model parameters were determined by using experimental data. © 2000 Society of Chemical Industry     

Mono- and multi-component biosorption of lead(II), cadmium(II), copper(II) and nickel(II) ions onto coco-peat biomass

The potential of using coco-peat biomass (CPB) has been assessed for the removal of Pb(II), Cd(II), Cu(II) and Ni(II) ions from single and quaternary solutions. According to Langmuir isotherm, the maximum biosorption capacity of CPB was 0.484, 0.151, 0.383 and 0.181 mmol/g for Pb(II), Cd(II), Cu(II) and Ni(II) ions, respectively. Scanning electron microscopy along with energy-dispersive X-ray spectroscopy and Fourier-transform IR spectroscopy confirmed changes in the biosorbent functionality after metal sorption. Through quaternary isotherm experiments, 16.1%, 48.2%, 32.3% and 46.5% decrease in experimental uptakes were observed for Pb(II), Cd(II), Cu(II) and Ni(II), respectively, in the presence of other metal ions.     

化学法处理高浓度含钒碱性工业废水

针对高浓度含钒碱性工业废水的特点,经多次比较试验得出最佳处理方法:还原-中和-絮凝法.详细探讨了还原剂用量、还原反应的最佳pH、还原反应时间、中和沉淀过程的pH、助凝剂等因素对废水中钒残留量的影响.实验结果表明,在最优实验条件下,处理后废水中钒<0.001 g/L,出水达到国家废水排放标准.     

微气泡臭氧催化氧化深度处理化工园区废水研究

以酸/碱改性和Cu负载活性炭为催化剂,采用微气泡催化臭氧氧化深度处理化工园区废水。结果表明,经该工艺处理后,出水COD降至20 mg/L以下,发光抑制率降至-1.2%~-7.3%,B/C升至0.29~0.37,消除了废水生物毒性,并提高了废水可生化性。硝酸改性并负载Cu组分活性炭具有更强的催化活性,COD去除率和去除负荷分别可达70.8%和0.478 kg/(m~3·d),臭氧利用率为97.5%,催化臭氧氧化反应效率为0.554 mg COD/mgO_3。     

臭氧氧化法深度处理造纸废水试验研究

首先采用复合混凝剂对造纸废水二级出水进行了预处理,再用臭氧进行氧化处理.研究了在不同臭氧量、pH条件下,臭氧氧化法对造纸废水中COD和色度的去除效果,及不同臭氧产生速率和反应时间对COD与色度的去除效果,分析了臭氧氧化污染物的机理.结果表明,臭氧氧化效果随臭氧量、反应时间的增加而增强,但增强幅度越来越小;臭氧投加速率为13.98 mg/min、停留时间为30 min时,COD和色度去除率分别可达62-3%和99.5%,去除效果明显.     

国外膜生物反应器在污水处理中的研究进展

系统地论述了国外膜生物反应器在污水处理中的研究进展。国外膜生物反应器在污水处理中的应用范围和规模不断增加，然而，膜污染依然是其推广应用的主要障碍。值得注意的是，采用空气喷射方式在中空纤维膜内形成活塞流，可有效减轻膜污染和提高膜通量。经济分析表明中小规模的污水处理厂可能采用膜生物反应器更便宜，但大规模的污水处理厂宜采用常规工艺。现代分子生物技术为研究和了解膜生物反应器中的微生物群落提供了新的方法和手段。     

磁絮凝去除工业废水中铜离子的试验研究

采用磁絮凝对工业废水中重金属铜离子进行试验研究,讨论了聚合硫酸铁(PFS)投加量、静沉时间、温度、pH值、磁粉投加量对处理效果的影响.试验结果表明PFS投加量为100mg/L,pH值为8.0,静沉时间为20min,磁粉投加量为400mg/L时对含铜废水有良好的处理效果,铜离子去除率超过了97%,出水铜离子的质量浓度低于...     

发电厂含油废水处理系统的改造

根据含油废水的特性，对应用物化隔油-破乳浮选-混凝气浮-粗粒化过滤-活性炭吸附工艺处理发电厂含油废水的情况进行了详细的介绍。多年的运行经验证明，在进水石油类为54．3～207．9mg／L的情况下，出水可降至0．6～1．6mg／L，去除率达99．2％。     

改性粉煤灰在难降解工业废水处理中的应用

改性粉煤灰与原始粉煤灰相比,其物理化学性质发生显著改变,不仅具有吸附能力强、对废水处理效果好和可去除污染物范围广等优点,而且灰水分离能力强、处理污泥数量少,废水处理经济性大大提高.毋容置疑,改性粉煤灰是粉煤灰在工业水处理中应用的必然趋势.作者对改性粉煤灰技术在工业水处理中的应用做了概述,着重阐述了改性粉煤灰的一些工程实际应用及其现状,并提出改性粉煤灰在处理工业废水中一些亟待解决的问题、研究方向和应用前景.     

膜生物反应器在水处理中的应用与新发展

综合论述了膜生物反应器的分类、结构、特点，介绍了近年来各国学者应用膜生物反应器去除废水中有机物、氮、磷等污染物所取得的研究成果、面临的问题以及膜生物系统在实际废水处理中的应用。简要阐述了膜污染的成因、机理及其对策，并指出了现阶段限制膜生物技术在我国发展的原因，展望了未来膜生物技术在我国广阔的发展前景。     

水蚯蚓在污水处理与污泥减量中的应用

微型动物污泥减量技术作为一种生态工程技术由于能耗低,不产生二次污染而受到关注,成为污水处理中研究的热点。该文介绍了水蚯蚓对污泥减量化的贡献及它所具有节约成本、环境友好的优势,同时也指出了水蚯蚓在污水处理中对出水水质的影响及存在的一些问题,并总结了污水处理中水蚯蚓的化学控制、物理控制、生物控制方法等措施。     

An oblique rotating barrel electrochemical reactor for removal of copper ions from wastewater

An experimental study was performed using an oblique rotating barrel cathode to recover copper from a simulated wastewater, which initially contained 100 parts per million (ppm) of cupric ions. The barrel was a perforated cylindrical polypropylene basket having several axial and circumferential fins on its exterior surface. It was partially filled with copper Raschig rings and was partially submerged in the wastewater at a tilted angle from the horizontal position. During the operation, the barrel was slowly rotating about its axis and the copper rings were made as the cathode by connecting them to a d.c. power supply through a dangler contact. The movement of exterior fins and tumbling motion of copper rings provided a high mass transfer rate and a large cathode area for copper electrodeposition reaction. The cupric ion concentration in the wastewater was reduced to less than 1.0 ppm, permitting discharge of the treated wastewater to the drain system. With an operating cell voltage of 2.5–5.0 V, the overall cathode current efficiency was 53–20%, and the electric energy requirement was 4 to 21 kWh per kilogram of copper recovered from the wastewater. An apparent first order reaction rate constant for copper electrodeposition reaction on the Raschig rings was measured as a function of process variables including cell voltage, barrel rotational speed, percentage barrel loading, barrel tilt angle and percent barrel immersion.     

利用电镀酸铜废渣修复碱铜阳极的方法

以9 mol/L硫酸溶解某电镀公司废水处理所产生的酸铜渣(含铜35%~43%),将所得含铜溶液经过滤后作为电解液,采用电解法修复作为阴极的破损碱铜阳极,探讨了阳极类型,电流密度,镀液中硫酸和铜离子含量,以及温度对铜沉积速率的影响。分析了阳极修复前后的纯度和孔隙度,并通过赫尔槽试验对比了修复后的阳极与完好阳极的性能。结果表明,修复后的阳极虽然孔隙度分布不均,但是能够满足碱铜电镀的需要,为处置含铜浓废液、含铜泥渣提供了新的思路。     

Scale-up of an electrochemical reactor for treatment of industrial wastewater with an electrochemically generated redox mediator

This paper presents the results of a study on the scale-up, from a batch to a continuous flow unit, of an electrochemical reactor applied for the treatment of textile wastewater. Decolourisation of the wastewater bearing a reactive dye Red Procion H-EXGL proceeded via indirect electro-oxidation, mediated by “active chlorine”. The kinetics of decolourisation in a single-cell reactor under different operating conditions were second order, with the highest apparent rate constant (k = 0.523 l mol⁻¹ s⁻¹) achieved at 40 °C. A low Hatta number (Ha = 0.03) indicated that the reaction occurred totally in the bulk solution, hence homogeneous reaction kinetics were used successively to scale-up a continuous flow electrochemical unit: a once-through filter-press reactor. Its hydrodynamic characteristics were defined by the residence time distribution (E(t)) function using a pulse injection method. The decolourisation efficiency experimentally determined in a continuous flow reactor was further compared with that predicted on the basis of the knowledge of the E(t) of the reactor and the homogeneous phase kinetic expression, obtained from the batch study and corrected for the geometric parameters of the reactors. A complete segregation of the fluid inside the flow reactor was assumed. For different applied flow rates, the experimentally defined conversion of the dye was close to the calculated value.     

生物预酸化处理明胶废水对活性污泥减量化的作用

明胶废水具有高钙、高COD等特点而难于处理。通过对明胶废水进行生物预酸化处理,研究了活性污泥法处理明胶废水过程中COD去除率、MLSS、MLVSS以及无机灰分的变化。结果表明,经过生物预酸化处理后,明胶废水的p H由11.8降至7.4左右,COD由1 058 mg/L降至671 mg/L。后续活性污泥法处理过程中,与未进行生物预酸化处理相比,MLSS、MLVSS呈明显下降趋势,最终COD去除率达到90%;同时由于反应器维持在较低的p H下运行,避免了曝气生成CaCO_3沉淀,污泥无机灰分减少。生物预酸化处理对污泥减量化有明显贡献。     

CAST工艺在处理果汁加工废水中的应用

介绍了运用循环式活性污泥法（CAST）工艺处理果汁加工废水的工程实例。经过该工艺处理后．出水水质达到《辽宁省沿海地区污水直接排人海域标准》（DB21-59-1989）中一级标准,运行结果表明该工艺具有抗冲击负荷,运行稳定及污染物去除效果好等特点。     

Improvement of domestic wastewater primary sedimentation through ozonation

The use of ozone as an aid for flocculation‐coagulation of domestic wastewaters has been studied. Jar tests of ozonated and non‐ozonated wastewater at different coagulant (hydrated aluminum and ferrous sulfate salts) and flocculant (calcium hydroxide and A‐201 polyelectrolyte) doses have been conducted to obtain optimum floc size. Settling experiments have then been carried out to follow changes of total COD conversion and surface area of a primary settling tank needed to reach a given percentage particle separation. The results show that the use of preozonation provides beneficial results to both improve COD conversion and reduce the sedimentation surface area.     

城市污水处理厂温室气体的排放及减排对策

近年来,我国污水处理事业得到了大力的发展,污水处理厂污染物减排能力逐年提升。然而,污水及剩余污泥处理处置过程中温室气体的排放问题却没有得到应有的重视。本文系统阐述了城市污水处理厂温室气体的来源,并从污水处理工艺的选择、工艺运行参数的科学调控、剩余污泥的处理处置和资源化、处理水的回用等方面提出了温室气体的减排对策,从而为开展污水处理厂温室气体减排的研究及低碳运行的实践提供借鉴。