Combination of Ozonation and the Fenton Processes for Landfill Leachate Treatment: Evaluation of Treatment Efficiency

Single processes such as ozonation, ozone/hydrogen peroxide, Fenton and several combined treatment schemes were applied for leachate collected from a waste disposal site. The implementation of combined Fenton and ozonation processes resulted in the highest chemical oxygen demand removal (77% from initial value) among all the treatment methods applied, while biodegradability improvement was observed during the Fenton pre-treatment only. Some decrease of chemical oxygen demand was obtained during the single ozonation or combined schemes including ozone resulting in slight if any biodegradability improvement. The addition of hydrogen peroxide to ozonation did not enhance chemical oxygen demand, dissolved organic carbon or biochemical oxygen demand removal compared to ozone alone. Ferric chloride coagulation used as a pre-treatment stage did not improve subsequent chemical oxygen demand removal by ozonation or the Fenton processes. Taking into account the effective chemical oxygen demand, dissolved organic carbon removal and biodegradability improvement the single Fenton process seems to be a preferable treatment method for the leachate treatment. Some reduction in toxicity to Daphnia magna was observed after the application of the studied treatment methods.     

Comparison of different ultrasound support methods during colour and chemical oxygen demand removal of disperse and reactive dyebath solutions by ozonation

In this study, the effects of ozonation, ozonation with ultrasonic bath and ozonation with ultrasonic homogeniser processes on colour and chemical oxygen demand removal properties of disperse (CI Disperse Red 60, CI Disperse Blue 337) and reactive (CI Reactive Blue 171 and CI Reactive Blue 19) dyebath solutions with and without dyeing auxiliaries were investigated. Chemical oxygen demand (in mg/l) and colour (in Hazen) measurements of the studied dyebath solutions were determined. The ozonation process caused simultaneous chemical oxygen demand removal during decolorisation. However, the improvement in chemical oxygen demand reduction was less than of that on decolorisation. The application of the combination of ozonation with ultrasonic homogeniser is the most efficient process and creates a great time advantage over the other process types studied (ozonation alone and ozonation with ultrasonic bath) to reach the same colour and levels of chemical oxygen demand removal.     

工业氧化性废水中COD与TOC的相关性研究

介绍在满足快速测定TOC的条件下快速测定化学需氧量的方法.该法依据化学需氧量与TOC相关性来换算对应的化学需氧量,解决了废水样品受其氧化性环境的影响不能正常测定化学需氧量的问题.     

哈希比色法测定低浓度化学需氧量的改进

用哈希比色法测定化学需氧量,以吸光度对CODcr浓度值绘制标准曲线,输入到哈希分光光度计用户白建程序中,获得一个适合的CODcr测定程序,待水样消解后比色,可直接读出CODcr浓度值。此分析方法能批量测定水样,节省试剂,方便快捷,在大批量水质分析方面优势显著。对哈希比色法测定低浓度化学需氧量的方法作了改进,用改进后的方法测定水样中低浓度化学需氧量,其精密度和准确度均较好,符合测定要求。     

催化消解密封法测定工业废水中的化学需氧量

介绍了用催化消解密封法测定工业废水中化学需氧量的过程 ,与经典重铬酸钾法比较 ,此法缩短了消解时间 ,测定化学需氧量 (COD)值范围广 ,更适合测定化学需氧量较低的地表水和高氯工业废水     

Fenton and Fenton‐like oxidation of CI Basic Yellow 51: a comparative study

When ferric ions are substituted for ferrous ions in Fenton’s reagent, the reactions which occur are called Fenton‐like reactions. This study describes the relative efficiency of Fenton (with ferrous ions) and Fenton‐like (with ferric ions) reactions for the degradation of a basic dyestuff, CI Basic Yellow 51, in aqueous solution. Comparisons were made on the basis of the observed reductions in chemical oxygen demand and visible absorption of the dye solutions at optimum reaction conditions. It was found that the Fenton process with 2.63 mm ferrous ion and 39.96 mm hydrogen peroxide at the optimum pH (3.0) eliminated 92.2% of chemical oxygen demand and 98.9% of colour in 22 min, whereas 43.2% of chemical oxygen demand and 64.6% of colour was eliminated by the Fenton‐like process within the same time period, but at pH 4. The efficiency of the latter was significantly improved (to 96.6% removal of colour and 99.7% removal of chemical oxygen demand) by an increase in temperature of 35 °C (from 15 to 50 °C), while no improvements were observed in the efficiency of the Fenton process by temperature elevations.     

SH-A工艺处理煤制油废水的研究

采用SH-A强化脱氮除碳工艺处理煤制油废水,进水CODCr<2500mg/L,氨氮<250mg/L,控制一段好氧反应器中水温为33℃,pH值为8.0,溶解氧为2.0mg/L左右的条件下,反应器中生物相丰富,活性强,废水CODCr去除率达70%,氨氮硝化率达60%。     

湘潭地区高锰酸钾法地表水检测分析

为了监测湘潭地区水体受有机物污染程度,采用酸性高锰酸钾法对该地区地表水中化学需氧量数值进行了检测分析。对比近两年来各断面的年平均化学需氧量数值,各断面化学需氧量数值整体呈下降趋势,水体逐渐趋于清洁,且均符合《地表水环境质量标准》(GB3838-2002)Ⅲ类水质标准。但仍有部分地区有机物污染较严重,需继续加强治理。     

Influence of endogenous respiration on the coloration and chemical oxygen demand of biologically purified wastewater

The influence of the endogenous respiration of active sludge on the bichromate oxidizability (chemical oxygen demand) and coloration of coke-plant wastewater is investigated. The high chemical oxygen demand of purified wastewater is due to secondary pollution by the oxidation products of the active sludge.     

化学需氧量测定方法及研究进展

化学需氧量是水质监测的一项重要指标。综述了化学需氧量的测定方法和研究进展。     

活性污泥法处理餐饮废水的动力学研究

通过对餐饮活性污泥法生化处理过程的实验研究,得到了好氧生化处理过程中总化学需氧量与溶解性化学需氧量的浓度变化,确定其降解趋势符合一级反应动力学,降解常数为0,346±0．005h^-1。据此建立了模型并模拟了活性枵泥法处理餐饮废水时溶解性化学需氧量随时阅的变化,确定了达到排污标准所需的最低水力停留时间,为餐饮废水生化处理工程设计提供了依据。     

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.     

金塘水道海域冬季环境现状评价及其指示意义

2011年冬季于宁波镇海与舟山金塘之间海域分大小潮涨落时段进行了海域水体营养盐进行了调查分析。通过主要水质因子的时段比较,结合研究区水文动力背景,得到以下结论：（1）除无机氮超过国家三类海水标准外,其余海水指标均达到或优于三类海水水质要求;（2）无机氮、化学需氧量、石油类的极值均出现在3号站位;（3）无机氮的变化,显示营养盐受涨落潮的影响较大;（4）化学需氧量则与大小潮的相关性明显,其可能是潮流方向变化的原因。     

Ozone applications for after‐clearing of disperse‐dyed poly(lactic acid) fibres

In this study, the effectiveness of the ozonation process, in neutral distilled water at room temperature, as a clearing process for disperse‐dyed poly(lactic acid) fibre fabrics is investigated. The efficiency of simultaneous decolorisation of dyebath effluent and clearing of dyed poly(lactic acid) in the cooled dyebath after completion of the poly(lactic acid) dyeing cycle is also explored. Conventional alkaline reduction clearing with sodium dithionite was chosen as a control clearing process for comparison. Wash fastness, colour difference, colour removal (in Hazen) and chemical oxygen demand values were determined and compared. Long ozone treatment times at high ozone dose resulted in unacceptable colour differences. The colour difference problem was solved by use of lower ozone dose; however, a warm soaping step had to be added to the after‐clearing sequence in order to achieve the desired fastness properties. A 33% reduction on the chemical oxygen demand load of the total process (dyeing + after‐clearing) could be achieved by ozone after‐clearing instead of using a conventional reduction clearing treatment. The addition of the warm soaping step to improve the fastness properties of the ozonated samples increased the total chemical oxygen demand of the process (dyeing + ozonation in water + warm soaping), but a 12–18% reduction on the chemical oxygen demand load of the total process was observed when compared with the conventional treatment sequence (dyeing + reduction clearing).     

Effect of Fenton's reagent on the degradability of CI Reactive Yellow 15

As an advanced oxidation method, Fenton's reagent has an advantage that it combines both oxidation and coagulation techniques. The aim of this study was to efficiently operate Fenton's reagent oxidation to degrade a reactive dye, CI Reactive Yellow 15, which is non-biodegradable and has high chemical oxygen demand. In addition, performance of the Fenton oxidation process for dye solution was determined by measuring the chemical oxygen demand and colour removal. The influence of the main operating parameters, iron sulphate and hydrogen peroxide concentration, pH, temperature and dye concentration have been studied, in a batch-type operation. The results obtained show that the best pH value for decolorisation was pH 3, with an average decolorisation of 98.7% and average removal of chemical oxygen demand ca. 93.3% at 15 °C for a 0.065 molar ratio of Fenton's reagent. An increase in temperature resulted in higher removal rates.     

用混凝-微电解-催化氧化工艺预处理含拉开粉的丁腈橡胶废水

采用混凝-微电解-催化氧化工艺预处理含拉开粉的丁腈橡胶废水,通过静态和动态放大试验探讨了微电解时的pH值、反应时间、铁炭比、气水比以及催化氧化时的pH值、反应时间、氧化剂和催化剂用量等对化学需氧量、悬浮物及拉开粉去除率的影响。结果表明,在微电解反应时pH值为3～4、铁炭比为2/1(质量比)、反应时间为30min、气水比为12/1(体积比),以及催化氧化反应时pH值为5左右、催化剂质量浓度为0.75g/L、氧化剂质量浓度为5g/L、反应时间4h的条件下,处理后废水的悬浮物去除率可达到90%以上,化学需氧量去除率达到45%以上,拉开粉的去除率达到90%以上。生物化学需氧量与化学需氧量比值由0.08提高到0.16,废水可生化性得到提高,水中悬浮物得以大幅度降低,水质得到改善,为后续处理奠定了基础。     

Decolorisation and mineralisation of CI Reactive Black 8 by the Fenton and ultrasound/Fenton methods

The effects of pH, ferrous ion and hydrogen peroxide dosage on the decolorisation and mineralisation of CI Reactive Black 8 by the Fenton process with/without ultrasonic irradiation were investigated. It was verified that the presence of ultrasonic irradiation did not enhance the decolorisation of CI Reactive Black 8 significantly by Fenton's reagents, but it enhanced the chemical oxygen demand removal efficiency. The enhancement was more pronounced for lower (<0.89 mm) or higher (>1.78 mm) ferrous ion dosage. The optimal pH for chemical oxygen demand removal was 3.0. Chemical oxygen demand removal efficiency increased with the increasing H₂O₂ dosage and reached the highest level at 5.88 mm, but further increase in H₂O₂ dosage would not increase removal efficiency significantly.     

影响COD测定精度因素初探

根据化学需氧量（COD）这一条件性指标国家规定的测定的条件出发,在实验中改变原工艺中单一条件进行测量,通过测试数据的变化找出各因素对测量化学需氧量（COD）精度的影响。     

灭多威农药废水预处理技术研究

采用NaClO氧化工艺处理灭多威农药废水,考察了反应pH值、NaClO溶液投加量、反应温度和反应时间对化学需氧量(COD)去除率的影响.结果表明:当水样初始pH值为6～9,在V(NaC1O)∶ V(废水)为15∶100,反应温度为20～30℃,反应时间为2h,COD去除率达到70％,废水恶臭气味有明显的减轻.     

Biogas Production of Ozone and/or Microwave-Pretreated Canned Maize Production Sludge

The production of canned maize is accompanied by formation of large volumes of waste water, with high contents of starch, and high chemical- and biochemical oxygen demand. In our work the effects of acidic, microwave and ozone pretreatment on the biogas production and aerobic biodegradability of canned maize production sludge were examined and the energy balance of the processes were determined when different sludge pretreatments were used. It was found that ozone treatment decreased the chemical oxygen demand, while the biochemical oxygen demand and the aerobic biodegradability increased. The combination of microwave and ozone treatment increased the biodegradability relative to ozone treatment alone.