Oxidative treatment characteristics of biotreated textile-dyeing wastewater and chemical agents used in a textile-dyeing process by advanced oxidation process.

The oxidative treatment characteristics of biotreated textile-dyeing wastewater and typical chemicals such as desizing, scouring, dispersing and swelling agents used in the textile-dyeing process by advanced oxidation process were experimentally studied. The refractory organic matters remained in the effluent of biological treatment process without degradation may be suitable for the improvement of biodegradability and mineralized to CO2 by combined ozonation with and without hydrogen peroxide. On the other hand, the refractory chemicals contained in the scouring agent A and swelling agent may not be mineralized and their biodegradability may not be improved by ozonation. However, the BOD/DOC ratio of scouring agent B increased from 0.3 to 0.45 after ozonation. Based on the results described above, advanced treatment process involving the ozonation without and with the addition of hydrogen peroxide, followed by biological treatment was proposed for the treatment of refractory wastewater discharged from the textile-dyeing process.     

Recalcitrant COD degradation by an integrated system of ozonation and membrane bioreactor.

In order to treat wastewater to a low residual COD-concentration such as 125 mg/L, classical biological treatment is not sufficient for many types of industry. This research focused on the integrated treatment of the wastewater of the paper industry, with a membrane bioreactor (MBR) and an oxidation step. The optimal configuration was examined. Screening tests with different types of oxidation showed that ozonation after biological treatment could reduce the COD with 40% with an ozone dose of 0.4-0.8g O3/g COD. BOD/COD ratio could be increased up to 0.19. Neither combination of ozone with UV and/or hydrogen peroxide nor the process H2O2/UV or (photo-)Fenton reagents gave any improvement in COD reduction or BOD increase, unless the doses were very high. Based on these results, an integrated system MBR-ozonation was designed, with recirculation of MBR effluent over ozonation. This test showed that reduction of COD up to 125 mg/L immediately behind the MBR required a lot of ozone. A technically feasible solution was to discharge the water after an extra ozonation step, which resulted in a high total ozone dosage. The alternative, the consecutive treatment activated sludge-ozonation-activated sludge, did not give a better COD-removal with the same ozone dose as the integrated concept. The economic evaluation proves that the integrated chemical and biological treatment is expensive for the paper industry if a low discharge limit of COD has to be complied with.     

酸析—微电解—Fenton氧化预处理亚麻脱胶废水的研究

高浓度亚麻脱胶废水CODCr、色度都很高,不宜直接进行生物处理.试验采用酸析-微电解-Fenton氧化的预处理工艺,并对反应的影响因素进行了研究,试验结果表明,在pH=3,微电解90 min,H2O2投量1 500 mg/L,Fenton氧化120 min的条件下,CODCr去除率可以达到71.4%,色度去除率超过90%.同时该方法提高了废水的可生化性,有利于后续的生化处理.     

Application of a combined process of moving-bed biofilm reactor (MBBR) and chemical coagulation for dyeing wastewater treatment.

A combined process consisted of a Moving-Bed Biofilm Reactor (MBBR) and chemical coagulation was investigated for textile wastewater treatment. The pilot scale MBBR system is composed of three MBBRs (anaerobic, aerobic-1 and aerobic-2 in series), each reactor was filled with 20% (v/v) of polyurethane-activated carbon (PU-AC) carrier for biological treatment followed by chemical coagulation with FeCl2. ln the MBBR process, 85% of COD and 70% of color (influent COD = 807.5 mg/L and color = 3,400 PtCo unit) were removed using relatively low MLSS concentration and short hydraulic retention time (HRT = 44 hr). The biologically treated dyeing wastewater was subjected to chemical coagulation. After coagulation with FeCl2, 95% of COD and 97% of color were removed overall. The combined process of MBBR and chemical coagulation has promising potential for dyeing wastewater treatment.     

组合工艺控制有机物及消毒副产物前体物的特性研究

通过XAD-8树脂将水中有机物分成疏水性、亲水性两部分,对传统常规处理工艺(混凝气浮、过滤)和深度处理工艺(臭氧氧化、生物活性炭)出水的DOC,UV254THMFP,HAAFP指标以及疏水、亲水有机物去除率进行了检测分析。结果表明,生物活性炭(BAC)单元工艺能同时去除疏水性和亲水性两种有机物,且两者去除率均为最高。其次去除效果较好的是传统的常规工艺。臭氧工艺具有将天然的疏水性有机物氧化成可生化降解的亲水性小分子有机物的特点,在预臭氧+常规以及O3-BAC组合工艺中,起到了强化去除有机物和消毒副产物前体物的效果。     

Catalytic oxidation with Al-Ce-Fe-PILC as a post-treatment system for coffee wet processing wastewater

The effluent from the anaerobic biological treatment of coffee wet processing wastewater (CWPW) contains a non-biodegradable compound that must be treated before it is discharged into a water source. In this paper, the wet hydrogen peroxide catalytic oxidation (WHPCO) process using Al-Ce-Fe-PILC catalysts was researched as a post-treatment system for CWPW and tested in a semi-batch reactor at atmospheric pressure and 25 °C. The Al-Ce-Fe-PILC achieved a high conversion rate of total phenolic compounds (70%) and mineralization to CO(2) (50%) after 5 h reaction time. The chemical oxygen demand (COD) of coffee processing wastewater after wet hydrogen peroxide catalytic oxidation was reduced in 66%. The combination of the two treatment methods, biological (developed by Cenicafé) and catalytic oxidation with Al-Ce-Fe-PILC, achieved a 97% reduction of COD in CWPW. Therefore, the WHPCO using Al-Ce-Fe-PILC catalysts is a viable alternative for the post-treatment of coffee processing wastewater.     

Phenol wastewater remediation: advanced oxidation processes coupled to a biological treatment.

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. Wet air oxidation and Fenton process were tested batch wise, while catalytic wet air oxidation and H2O2-promoted catalytic wet air oxidation processes were studied in a trickle bed reactor, the last two using over activated carbon as catalyst. Effluent characterisation was made by means of substrate conversion (using high liquid performance chromatography), chemical oxygen demand and total organic carbon. Biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) were obtained from respirometric tests using activated sludge from an urban biological wastewater treatment plant (WWTP). The main goal was to find the proper conditions in terms of biodegradability enhancement, so that these phenolic effluents could be successfully treated in an urban biological WWTP. Results show promising research ways for the development of efficient coupled processes for the treatment of wastewater containing toxic or biologically non-degradable compounds.     

Using ozone to reduce recalcitrant compounds and to enhance biodegradability of pulp and paper effluents.

The effect of ozone based oxidation on removing recalcitrant organic matter (ROM) and enhancing the biodegradability of alkaline bleach plant effluent was investigated. A bubble column ozonation tower was used in the study. The experiments were carried out at different temperatures (20 degrees C and 60 degrees C) and pH (9 and 11), with a number of biological and chemical parameters being monitored including BOD5, COD, TC, pH, color, and molecular weight distribution of organics (nominal cut off of 1,000 Da). Biodegradability of the effluent was determined based on BOD5/COD of the wastewater throughout the process. For all the experiments, ozonation enhanced the biodegradability of the effluent by 30-40%, which was associated with noticeable removal of ROM including high molecular weight (HMW) and color-causing organics by about 30% and 60%, respectively. While the biodegradability of HMW fraction increased by about 50%, there was no biodegradability improvement for low molecular weight (LMW) portion, which was originally readily biodegradable (with BOD5/COD of about 0.5). Statistical analysis of variance (ANOVA) revealed neither pH nor temperature played significant role on the ozonation process at 95% confidence level.     

草甘膦废水预处理研究与工程应用

某草甘膦废水处理站已无法达到处理要求,需要进行改造.为了减轻后续的生化处理负荷,强化对草甘膦废水的除磷预处理,选用电絮凝氧化、Fenton氧化和电磁-Fenton氧化3种工艺作为草甘膦废水预处理工艺,进行了比选试验.试验结果表明,Fenton氧化为本工程的草甘膦废水最佳预处理工艺,可达到预期效果.     

An overview of the integration of ozone systems in biological treatment steps.

Despite the well-known potential and performance of combined biological and ozonation processes for wastewater treatment, only few full-scale applications are published. Beside the synergistic effects of such process combination, which lead to oxidation of recalcitrant and inhibitory compounds or intermediates by enhancement of their biodegradability, the key for raising applicability is the improvement of the ozonation efficiency. An overview about the history and progress of full-scale applications, which deals with combined ozonation and biological treatment is given. Recently more than 40 applications exist, but many of them are not published. Therefore, a couple of selected not yet published applications have been mentioned in this paper. Landfill leachate and industrial wastewater treatment were mostly applicated, while treatment of municial wastewater treatment plant (WWTP) effluents are of increasing interest due to several advantages such as disinfection, decolourisation and removal of persistent dissolved organic carbon (DOC) for water re-use and groundwater recharge.     

多级串联接触氧化法处理漂染废水

漂染废水处理的主体工艺流程可以采用气浮法预处理→水解酸化 接触氧化法生化处理→氧化脱色后处理工艺 ,出水水质可以达到《纺织染整工业水污染物排放标准》(GB4 2 87- 92 )一级标准。工程实践与工艺分析表明 ,多级串联接触氧化法中 ,各级微生物数量及形态保持相对独立 ,表现出类似于AB工艺的特征 ,结合预处理及后处理措施处理漂染废水具有效果好、运行稳定、投资少及占地面积省等优点。在具体工艺设计上 ,依水流方向 ,各级接触氧化池负荷由高至低分布 ,宜采取较低的有机负荷及较长的反应时间     

臭氧技术在污水处理中的应用

臭氧作为一种强氧化剂,主要用于污水的深度处理。本文介绍了臭氧氧化的机理,探讨了臭氧及臭氧高级氧化在污水深度处理以及降解痕量有机物方面的应用,并在此基础上对今后的研究方向进行了展望,提出如何避免副产物的产生将是今后的研究重点。     

微电解-Fenton联合工艺处理拉米夫定废水的试验研究

研究了铁炭微电解-Fenton联合工艺对高浓度难生化处理的拉米夫定制药废水的预处理效果.结果表明:在微电解2 h, Fenton 1 h,pH为3,H_2O_2(30%)投量5 mL/L条件下,COD_(Cr)去除率可以达到76%,色度去除率超过98%,BOD/COD由0.15提高到0.52,有利于后续的生化处理.     

Integration of chemical and biological oxidation in a SBBR for tannery wastewater treatment.

This paper reports the results of an investigation aimed at evaluating the laboratory-scale performance of an innovative process for treating tannery wastewater. In this process, biological degradation, carried out in a sequencing batch biofilm reactor (SBBR), is combined with chemical oxidation by ozone. Tannery wastewater treatment was carried out, at laboratory scale, on a real primary effluent coming from a centralised plant treating wastewater produced by a large tannery district in Northern Italy. SBBR performance both without and with ozonation, was assessed with very satisfactory results. In particular, in the latter instance the recorded COD, TKN and TSS average removals, (96%), (92%) and (98%) respectively, allowed the maximum allowable concentration values fixed by the Italian regulation in force to be achieved without any additional polishing step. During the investigation biofilm properties (biofilm concentration and biofilm density) and flow dynamics aspects (head loss, shear stress, bed porosity) were also studied. A major feature of the process is that, with or without ozonation, it was characterised by very low specific sludge production (0.05 kgVSS/kgCODremoved) and high biofilm density (i.e. 87-122 gVSS/Lsludge) both contributing to a rather high biofilm concentration (i.e. 31-44 gTSS/Lfilter).     

Application of membrane bioreactor system with full scale plant on livestock wastewater.

A full-scale plant of an MBR system treating livestock wastewater has shown impressive results. The Cheorwon County Environmental Authorities adopted the MBR process with UF membrane for retrofitting the old plant, which removes organic matter, nitrogen and phosphorus at a high level. According to 6 months operation data, BOD and SS removal were about 99.9% and COD(Mn), TN and TP removal were 92.0%, 98.3% and 82.7%, respectively. It is considered that the temperature at the bioreactor has to be controlled to be below 40 degrees C so as to ensure sufficient nitrification. It appeared that the MBR system is competitive with other conventional technologies for treatment of livestock wastewater such as piggery waste.     

水环境中PPCPs的臭氧氧化和高级氧化技术

药物和个人护理用品(PPCPs)是最近十年引起关注的一类新型有机微量污染物,其对人类健康和生态环境安全的影响受到了越来越多的关注.传统的给水处理和污水处理工艺都不能有效去除水中的PPCPs,因此有必要采用臭氧氧化、高级氧化等工艺进行深度处理.臭氧是选择性氧化剂,其与PPCPs的反应受PPCPs的基团电子特性和溶液pH的影响;高级氧化技术产生的羟基自由基·OH氧化能力强,与PPCPs的反应没有选择性,主要包括O_3/H_2O_2、UV/H_2O_2、UV/TiO_2、芬顿和光芬顿氧化等.这些深度处理工艺的采用受一些因素的限制,同种工艺或不同工艺的组合能达到更高的去除效率.     

化学除磷在城市污水处理中的应用

阐述了城市污水处理中除磷的重要性和迫切性,而在普遍采用的生物除磷技术不能满足出水磷的排放标准时可考虑采用化学除磷技术.系统分析了化学除磷的原理、方法、工艺、研究进展及应用前景,并指出了现阶段化学除磷技术研究与发展的目标.     

Comparison of AOPs for the removal of natural organic matter: performance and economic assessment.

Control of disinfection by-products during water treatment is primarily achieved by reducing the levels of organic precursor species prior to chlorination. Many waters contain natural organic matter at levels up to 15 mg L(-1); therefore it is necessary to have a range of control methods to support conventional coagulation. Advanced oxidation processes are such processes and in this paper the Fenton and photo-Fenton processes along with photocatalysis are assessed for their NOM removal potential. The performance of each process is shown to be dependent on pH and chemical dose as well as the initial NOM concentration. Under optimum conditions the processes achieved greater than 90% removal of DOC and UV254 absorbance. This removal led to the THMFP of the source water being reduced from 140 to below 10 microg L(-1), well below UK and US standards. An economic assessment of the processes revealed that currently such processes are not economic. With advances in technology and tightening of water quality standards these processes should become economically feasible options.     

影响反硝化除磷与厌氧氨氧化耦合的因素

氧对厌氧氨氧化菌有毒,但在颗粒污泥和生物膜中的厌氧氨氧化菌对氧有较高的耐受能力,并且聚磷菌能消耗影响氧氨氧化菌生长的氧。厌氧氨氧化菌的生长无需有机物的参与,聚磷菌释磷需要吸收有机物,少量有机物的加入对厌氧氨氧化菌的活性影响不大。亚硝酸盐是厌氧氨氧化菌氧化氨的电子受体,较高浓度的亚硝酸盐对反硝化聚磷有抑制作用,但合适浓度的亚硝酸盐(该浓度可以通过驯化来提高)可以作为反硝化聚磷菌吸磷的电子受体。厌氧氨氧化过程中有硝酸盐生成,反硝化聚磷菌能利用这部分硝酸盐。另外,两类菌都适宜于中温略偏碱性的环境。因此,通过创造同时对厌氧氨氧化菌和反硝化聚磷菌有利的微生态环境,发挥两者在脱氮除磷方面的协同耦合作用,达到高度脱氮除磷,是极有前景的废水厌氧(缺氧)处理研究方向。     

Application of vibration milling for advanced wastewater treatment and excess sludge reduction

As a new sludge reduction technology with a phosphorus removal mechanism, a vibration milling technology that uses iron balls have been applied to the wastewater treatment process. Three anaerobic-aerobic cyclic activated sludge processes: one without sludge disintegration; one disintegrated sludge by ozonation; and the other disintegrated sludge with the vibrating ball mill were compared. Ozonation achieved the best sludge reduction performance, but milling had the best phosphorus removal. This is because iron was mixed into the wastewater treatment tank due to abrasion of the iron balls, leading to settling of iron phosphates. Thus, the simple means of using iron balls as the medium in a vibrating ball mill can achieve both a sludge reduction of half and excellent phosphorus removal. Material balances in the processes were calculated and it was found that carbon components in disintegrated sludge were more resistant to biological treatment than nitrogen.