Anaerobic-aerobic processes for the treatment of textile dyeing wastewater containing three commercial reactive azo dyes: Effect of number of stages and bioreactor type

In this study, the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewater containing three commercial reactive azo dyes was considered. Two stage processes performed better than one stage ones, both in terms of overall organic and color removal, as well as the higher contribution of anaerobic stage to the overall removal performance, thereby making them a more energy efficient option. The employment of a moving bed sequencing batch biofilm reactor, which uses both suspended and attached biomass, for the implementation of the anaerobic stage of the process, was compared with a sequencing batch reactor that only employs suspended biomass. The results showed that, although there was no meaningful difference in biomass concentration between the two bioreactors, the latter reactor had better performance in terms of chemical oxygen demand (COD) removal efficiency and rate and color removal rate. Further exploratory tests revealed a difference between the roles of suspended and attached bacterial populations, with the former yielding better color removal whilst the latter had better COD removal performance. The sequential anaerobic-aerobic process, employing an aerobic membrane bioreactor in the aerobic stage resulted in COD and color removal of 77.1±7.9% and 79.9±1.5%, respectively. The incomplete COD and color removal was attributed to the presence of soluble microbial products in the effluent and the autoxidation of dye reduction metabolites, respectively. Also, aerobic partial mineralization of the dye reduction metabolites, was experimentally observed.     

印染废水的UV-Fenton氧化处理研究

对光助－Fenton氧化技术处理印染废水的主要操作条件及其对处理效果的影响进行了实验研究：主要考察了Fe^2 和H2O2的投加量及投加比、温度、投加方式等对色度和CODcr去除率的影响。实验结果显示,光助－Fenton氧化反应对CODcr和色度都有比较好的去除效果。在H2O2投加量为1Qth(H2O2理论投加量）,Fe^2 :H2O2=1:20,25℃ ,初始pH为6．0的情况下反应60分析,色度去除率可达95．8％以上。CODcr去除率达到72．7％。针对污染物光助－Fenton氧化反应的特性,建立了相应的动力学模型,这些模型能较好地解释实验结果。     

Combined ozone pretreatment and biological processes for removal of colored and biorefractory compounds in wastewater from molasses fermentation industries

BACKGROUND: The use of ozone combined with biological treatment was investigated for molasses fermentation wastewater containing highly concentrated, brown and biorefractory compounds. These persistent compounds, known as melanoidins, generate disposal issues: in the environment, the color is problematic for aquatic life; and in municipal wastewater treatment plants, the molecules are biorefractory. RESULTS: This paper aims to evaluate the impact of ozone pretreatment, applied in the range 0.1 to 1 g g^?1 consumed ozone doses, on both macroscopic physico‐chemical parameters such as chemical oxygen demand (COD), total organic carbon (TOC), color and UV absorbance, and batch aerobic biodegradability. Then, performances of ozone pretreatment are assessed in terms of biodegradability improvement in batch and semi‐continuous anaerobic processes and, also, in semi‐continuous denitrification as a potential carbon source. Ozonation applied at the ozone dose of 0.5 g O₃ g^?1 COD led to an increase in biodegradability in all bioreactors. On average, the pretreatment resulted in an increased biodegradable fraction from zero to 33% without noticeable toxicity on biomass. This ozone dose also achieved 45% nitrogen removal by biological denitrification. CONCLUSION: Ozone pretreatment is a suitable technique for the biodegradability improvement of molasses fermentation wastewater, in aerobic, anaerobic and anoxic conditions. The pretreatment should be optimized in order to maximize the subsequent biodegradability. Copyright © 2010 Society of Chemical Industry     

Two-Step Wastewater Treatment: Sequential Ozonation - Aerobic Biodegradation

Ozonation of wastewater from olive related industries has been carried out after dilution with synthetic urban wastewater. The advantages of the application of different acidic and basic cycles during the ozonation process have been shown. Biodegradability of the final effluent measured as the biological oxygen demand to chemical oxygen demand ratio has significantly been increased (100–144% for table olive wastewater and 24–60% for olive oil wastewater). Aerobic biological experiments conducted by using non-acclimated microorganisms confirmed the suitability of the biodegradation after the chemical oxidation pre-treatment. A kinetic model based on a free radical mechanism has been used to simulate experimental results. Both chemical oxygen demand and dissolved ozone concentration profiles are well fitted by the model. The aerobic biodegradation process has been modeled by utilizing the Monod equation.     

Performance and kinetics of membrane and hybrid moving bed biofilm‐membrane bioreactors treating salinity wastewater

A pilot‐plant membrane bioreactor (MBR) and two pilot‐plant hybrid moving bed biofilm reactor–membrane bioreactors (MBBR–MBRs), divided into three aerobic and one anoxic chambers, were started up for the treatment of salinity‐amended urban wastewater. The MBBR–MBR systems worked with and without carriers in the anoxic zone (MBBR–MBRanox and MBBR–MBRn/anox, respectively). The systems were operated from start‐up to stabilization, showing high removal of organic matter—a maximum of 90% chemical oxygen demand and 98% biochemical oxygen demand on the fifth day for MBBR–MBRn/anox in the stabilization phase—but low nitrogen elimination—30% maximum for MBBR–MBRn/anox in the stabilization phase. Biofilm attached to carriers reached less than 50 mg L^?1 in the hybrid system. MBR showed faster kinetics than the two MBBR–MBR systems during start‐up, but the opposite occurred during stabilization. Maximum specific growth rates for heterotrophic and autotrophic biomass were 0.0500 and 0.0059 h^?1 for MBBR–MBRn/anox in the stabilization phase. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3329–3342, 2017     

改良型A2/O工艺处理印染废水的研究

阐述了南闸综合污水处理厂废水处理工艺的改良过程,经厌氧＋缺氧/好氧＋絮凝沉淀＋转盘滤池工艺改良后,不仅使出水水质稳定,而且达到了《城镇污水处理厂污染物排放标准》GB18918-2002的一级A标准.     

电气石颗粒在处理焦化废水生物浮动床系统中的作用

电气石是一种价格低廉容易获取的天然矿物。做为一种具有独特表面特性的矿物材料,在水处理领域具有广阔的应用前景。文章针对生物浮动床,对其添加电气石前后对焦化废水的降解特性进行了研究,结果表明,在系统中添加电气石可以有效的提升生物浮动床(MBBR)对化学需氧量(COD)的去处效果。由于电气石自然电极的存在,可以促进废水中有机物的降解,同时,通过显微镜观察可以发现,电气石还可以成为生物载体,提升反应器的处理效果。     

Advanced treatment of textile dyeing wastewater through the combination of moving bed biofilm reactors and ozonation

A four-stage lab-scale treatment system [anaerobic moving bed biofilm reactor (MBBR)-aerobic MBBR-ozonation-aerobic MBBR in series] was investigated to treat textile dyeing wastewater. The MBBRs were operated in a continuous horizontal flow mode. To determine the optimum operating conditions, the effect of hydraulic retention time (HRT) and ozonation time on pollutant removal were analysed by continuous and batch experiments. The optimum operating conditions were found to be 14 h HRT for both anaerobic and no. 1 aerobic MBBRs, 14 min ozonation time and 10 h HRT for no. 2 aerobic MBBR. The average influent concentrations of chemical oxygen demand (COD), suspended solids (SS), ammonia and colour were 824 mg/L, 691 mg/L, 40 mg/L and 165°, respectively. Under these conditions, the average effluent concentrations of COD, SS, ammonia and colour were 47 mg/L, 15.2 mg/L, 5.9 mg/L and 6.1°, respectively, corresponding to total removal efficiencies of 94.3%, 97.8%, 85.3% and 96.3%, respectively. The final effluent could meet the reuse requirements of textile industry. The anaerobic MBBR process improved the biodegradability of the raw wastewater, while the two aerobic MBBRs played an important role in removing COD and ammonia. The ozonation process enhanced the biodegradability of no. 1 aerobic MBBR effluent, and finally, deep treatment was completed in no. 2 aerobic MBBR. The combined process showed a promising potential for treatment of high-strength dyeing wastewater.     

Modeling biological nutrient removal in a liquid–solid circulating fluidized bed bioreactor

BACKGROUND: Both laboratory‐scale and pilot‐scale liquid–solid circulating fluidized bed (LSCFB) bioreactors have demonstrated excellent biological nutrient removal (BNR) from municipal wastewater. In this study, a model for the LSCFB for biological nutrient removal has been developed, calibrated, and validated using pilot‐scale experimental results. RESULTS: An efficient reactor arrangement predicted anoxic–anaerobic and aerobic biofilm thicknesses of 150–400 and 70–175 µm in the riser and downer, respectively. Furthermore, distribution of chemical oxygen demand (COD), NH₄‐N, NO_X‐N, and dissolved oxygen in the biofilm, as well as nutrients removed in the aerobic and anoxic zones, reflect nitrification, denitrification and enhanced biological phosphorus removal in the LSCFB. The model predicted both anoxic effluent and final effluent COD, SCOD, SBOD, NH₄‐N, NO₃‐N, TKN, TN, PO₄‐P, and TP were within the 95% confidence intervals of the experimental data. Model‐predicted simultaneous nitrification/denitrification occurring in the aerobic downer. CONCLUSION: This model developed for LSCFB using the AQUIFAS biofilm diffusion model successfully evaluated the process performance. It is an efficient tool for further research, design, and optimization of the fixed film bioreactor. Copyright © 2010 Society of Chemical Industry     

新型有机膨润土用于印染废水处理的实验研究

采用二乙烯三胺、环氧氯丙烷合成了一种阳离子型铵盐,用其与十六烷基三甲基溴化铵对钠基膨润土进行复合插层改性,制备得到一种新型有机膨润土;以模拟染料废水和实际印染废水为处理对象,使用改性膨润土进行了吸附脱色实验,吸附完成后加入聚合氯化铝混凝。实验结果表明,与单独投加聚合氯化铝相比,采用改性膨润土吸附后再混凝的方法处理废水,可显著提高脱色率和COD去除率;处理活性艳红X-3B、酸性大红GR与活性艳蓝X-BR三种模拟染料废水时,脱色率分别可达99.4%、84.8%和96.1%;以中试规模处理实际印染废水调节池原水时,COD和色度去除率分别可达51.6%和85.9%;处理实际印染废水好氧生化出水,COD可由121.3mg/L降至65.4mg/L,色度由32倍降至8倍以下。     

印染工业废水处理技术的研究进展

印染工业废水具有成分复杂、碱性大、色度深、TOC含量高、COD含量高、可生化性差等特点,必须采用特定的处理方法对其进行处理,才能达到国家污水排放标准.本文综述了目前国内外印染工业废水处理领域所采取的主要处理方法,有化学法中的湿式催化氧化法、电化学法、Fenton法;物理法中膜分离法、磁分离法、吸附法;生物法中的厌氧法、...     

Treatment and reuse of dyeing effluents by potassium ferrate

The use of potassium ferrate, K₂FeO₄, an environmentally-friendly chemical reagent containing iron in the + 6 oxidation state, has been investigated as a new approach for dyeing wastewater purification.The performance of this product, alone or in combination with a cationic organic polymer and/or power ultrasound, was compared to the traditional biological activated sludge process and a tertiary treatment featuring ozonation.Experimental tests showed that, thanks to its unique properties (high redox potential and simultaneous generation of ferric coagulating species), potassium ferrate can be successfully used in dyeing wastewater treatment. In fact, treatment with ferrate at the optimal dose of 70 mg/L as Fe(VI) was found to allow a high removal efficiency of relevant parameters such as turbidity, total suspended solids and chemical oxygen demand (COD).Whilst potassium ferrate alone had a minor effect on colour, the combination of ferrate with the organic polymer allowed a good decolourisation: this suggested the eventual application of this combined process for reuse of dyeing wastewater, resulting in environmental and economic benefits. The possibility of reusing the purified effluent in textile processes that do not require softened water was demonstrated through dyeing tests.     

Application of A2O moving-bed biofilm reactors for textile dyeing wastewater treatment

A three-stage pilot-scale moving-bed biofilm reactor (MBBRs, anaerobic-anaerobic-aerobic in series) was investigated to treat textile dyeing wastewater. Each reactor was filled with 20% (v/v) of polyurethane-activated carbon (PU-AC) carrier for biological treatment. To determine the optimum operating conditions of MBBRs, the effect of PUAC carrier, its packing percentage (v/v%) and pH control on COD removal were analyzed by batch experiments. The MBBRs were inoculated with activated sludge obtained from a local dyeing wastewater treatment plant. The MBBR process removed 86% of COD and 50% of color (influent COD=608 mg/L and color=553 PtCo unit) using relatively low MLSS concentration (average 3,000 mg/L in biomass attached to PU-AC carrier) and hydraulic retention time (HRT=44 hr). The MBBR process showed a promising potential for dyeing wastewater treatment.     

Catalytic wet-air oxidation of high strength industrial wastewater

Treatment of desizing wastewater, a typical high strength industrial wastewater, by catalytic wet-air oxidation (WAO) is studied. The desizing wastewater sample was obtained from a large textile dyeing and finishing plant. Experiments were conducted to investigate the effects of temperature and catalyst dosage (CuSO₄ and CU(NO₃)₂) on the pollutant (chemical oxygen demand or COD) removal. It is observed that over 80% of the COD removal can be realized in an hour of the catalytic WAO process. A kinetic model was also developed and a two-stage, first-order kinetic expression was found to represent well the treatment reaction. The correlations between the reaction rate coefficients and the temperature and catalyst dosage were also determined.     

MUCT工艺不同硝化液内循环比的PHA和磷代谢

以低C/N比污水为处理对象、基于物料平衡分析,研究了在MUCT工艺中硝化液内循环比与COD降解转化、PHA的代谢、磷的转移以及氮的转化等4个过程的关系。进水COD浓度恒定为(290±10)mg/L,TN浓度恒定为(55±0.5)mg/L,TP浓度恒定为(7.0±0.5)mg/L,改变硝化液内循环比,测定各反应段及出水COD、TN、TP浓度以及污泥中的PHA含量。试验结果表明:厌氧段去除的COD的63%~67%左右转化为PHA,在第二缺氧段和好氧段,PHA被消耗用于吸收污水中的磷,硝化液内循环比对第二缺氧段的消耗量有较明显的影响;硝化液内循环比对磷的释放过程影响较小,是第二缺氧段的吸磷过程的主要影响因素。     

紫薯色素生产废水的生化处理研究

高紫色素品种的紫薯加工出的天然食用色素可以代替人工合成色素,在食品工业中已得到广泛的应用。但从紫薯中提取色素所产生的废水具有化学需氧量(COD)质量浓度高、色度大等特点,必须处理达标后才能排放。通过对特定微生物的驯化,使其降解该类废水,探讨其生化降解特性。实验结果表明,在好氧反应器内p H值约为5、COD的初始质量浓度约为1 600 mg/L条件下,利用好氧生物接触氧化法处理6 h后,废水的COD质量浓度可降至200 mg/L以下。     

Investigation of a homogeneous activating ozonation method in the rinsing procedure of cotton fabric dyed with reactive dye

The textile dyeing process requires the consumption of large quantities of water, which includes huge amounts of coloured wastewater. Usually the rinsing of dyed fabric and the treating of the dyeing house wastewater are separated. The two independent processes not only increase the difficulty of wastewater treatment but also increase the costs of the treatment. In this paper, the ozone/tetraacetylethylenediamine active oxidation technology was employed to rinse dyed fabric and to decolorise the rinsing wastewater simultaneously. The effects of the rinsing conditions on the decolorisation ratio and the chemical oxygen demand Cr value of treated wastewater, and the K/S value, colour difference, tensile strength and fastness of dyed samples were investigated. The results indicated that the decolorisation ratio of the rinsing effluent was greater than 80% and the chemical oxygen demand Cr value decreased more than 58% by the ozone/tetraacetylethylenediamine rinsing process compared with that of traditional rinsing processes. Furthermore, the curve of decolorisation kinetics was in good agreement with a pseudo‐first‐order kinetic model. In addition, the decolorisation mechanism was also discussed after ultraviolet–visible and ultra performance liquid chromatograph–mass spectrometry analyses of the degraded dye molecule.     

物化+三级生化法处理浆染厂生产废水

浆染厂生产废水具有高浓度、高色度和含有大量难降解有机物的特点,用单一的化学法或生物法处理效果不好。广州某浆染厂采用物化+三级生化处理浆染生产废水,设计处理能力800m3/d,废水进水ρ(CODCr),ρ(BOD5),ρ(SS)和色度分别为3500mg/L,800mg/L,500mg/L和12000倍,经处理后,COD,BOD,SS和色度的去除率分别达98%,97%,90%和99.6%,出水稳定并达到污水排放一级标准。     

新型海藻式膜生物反应器处理印染废水的应用研究

针对印染废水成分复杂、色度大、浓度高且生物难降解物质多等特点,采用了混凝沉淀法对印染废水进行预处理,然后采用新型海藻式膜生物反应器(MBR)对印染废水进行活性污泥法处理试验研究.通过对COD、BOD、NH_3-N、TN、TP、色度、浊度等水质指标连续进行测定、分析与处理,考察MBR对印染废水的降解效果,并观察系统运行情况和膜组件污染状况.试验结果表明,海藻式MBR对印染废水的处理效果良好,出水浊度低于0.3 NTU,对COD、BOD、色度、NH_3-N、TN的去除率分别可达90%、94%、91.4%、87.8%、86.4%.海藻式MBR能够降低MBR膜丝根部的污染,清洗更方便、更有效.     

挡板式水解酸化法处理印染废水的中试试验研究

对印染废水进行了挡板式水解酸化中试试验。结果表明,调节原水pH值为10左右,污泥质量浓度为20g/L,水力停留时间为9～10h的条件下,处理后的废水COD去除率平均为38．6％,进出水的BOD／COD比值由0．285升高至0．447,废水可生化性能得到明显改善。挡板式水解酸化法作为印染废水好氧生物处理的前处理在技术上和经济上都是可行的。