Treatment of bleaching wastewater from pulp paper plants in China using enzymes and coagulants

The treatment of wastewater from pulp-paper plants in China by horseradish peroxidase was investigated in this study. The effects of horseradish peroxidase and coagulants were discussed in detail. The results indicated that enzymes might improve the removal of AOX, TOC and colour for pulp\|paper wastewater and modified chitosan is far more effective than Al\-2(SO\-4)\-3 to remove AOX, TOC and colour.

Mutagenicity of Wastewater Extracts from Pulp and Paper Industry

Wastewater samples were collected from pulp and paper mill located in Kashipur (India) and were extracted using dichloromethane (DCM), chloroform and hexane solvents (all were HPLC-grade). The extracts were assayed for their mutagenic potential using Ames Salmonella mutagenicity assay. TA98 strain was found to be the most responsive, in terms of induction factor (Mi) and slope (m) of the initial linear dose-response curve as determined by linear regression analysis up to the increasing doses indicating the presence of frame shift mutagens in the test samples. Mutagenicity of different extracts is arranged as follows: dichloromethane extracted water samples > hexane extracted water samples > chloroform extracted water samples. Hexane extract exhibited maximum mutagenic index of 13.0 and induction factor (Mi) 2.48 with TA98. The order of responsiveness based on the mutagenic index and induction factor for the test samples was in the following order: TA98 > TA97a > TA100 > TA102 > TA104. Our findings suggest that TA97a, TA98, TA100, TA102, TA104 were sensitive towards the wastewater extracts and showed considerable mutagenicity.

Lipid Production by <i>Rhodotorula glutinis</i>from Pulp and Paper Wastewater for Biodiesel Production

This study investigated the potential of oleaginous yeast Rhodotorula glutinis utilizing pulp and paper wastewater effluents as cultivation media for the sustainable production of microbial lipids as biodiesel feedstock. R. glutinis is oleaginous yeast, which has the ability to produce significant quantities of intercellular lipids in the form of triacylglycerols. Yeast lipids are a promising potential feedstock for biodiesel production due to similar fatty acid composition to plant oils. The effect of various carbon sources on biomass production, lipid accumulation, substrate utilization, and fatty acid composition using R. glutinis in the pulp and paper wastewater media was studied. The pulp and paper wastewater was supplemented with glucose, xylose, and glycerol as carbon sources under nitrogen-limited conditions. The maximum lipid productions of 1.3 - 2.9 g&bull;L–1, which corresponded to the intracellular lipid contents of 8% - 15% cell dry weight (CDW), were obtained under various carbon substrates. A kinetic study of the batch fermentation was performed in a 3 L aerobic batch fermenter to describe the cell growth, lipid accumulation, and substrate utilization process, and the kinetic parameter was estimated. The fatty acid profile of oleaginous yeast was rich in palmitic, oleic, and linoleic acids and comparable to vegetable oils. Thus, the results of this study indicated that pulp and paper wastewater could be used to produce lipids as biodiesel feedstock.

Ecofriendly Remediation of Pulp and Paper Industry Wastewater by Electrocoagulation and Its Application in Agriculture

In the present study pulp and paper industry effluent was treated with the help of aluminum electrode using electrocoagulation (EC) process with feasible sludge management. The influences of pH, time, current density and electrolytes dose were investigated and optimum conditions were established to reduce the maximum amount of Chemical Oxygen Demand (COD) and color. At optimum conditions 70% of COD and 98% of color were removed. Additionally, the behavior of electrolytes (NaCl and Na2SO4) was determined;it has shown that Na2SO4 results in the generation of less secondary pollutants than that NaCl and thereby could be used as better replacement in paper industries for electrocoagulation mediated treatment of wastewater. The residual amount of operational parameters in EC treated water was compared to the World Health Organization (WHO) and Central Pollution Control Board (CPCB) of India. It was found to be safe for utilization in irrigation. Furthermore, sludge produced during the EC process has been analyzed for physicochemical characteristics. To understand the physical and elemental phases of sludge, the analytical technique such as field emission electron microscope coupled with energy dispersive spectroscopy has been used to find out the possible management alternative.

Remediation of Pulp and Paper Industry Effluent Using Electrocoagulation Process

Electrocoagulation of pulp and paper industry effluent with SS-304 electrode has been carried out under varying process variable such as pH, current density, time and dose of electrolyte to find out the optimum conditions. Maximum reduction efficiency of Chemical Oxygen Demand (COD) 82% and color more than 99% from pulp and paper industry wastewater at the following conditions pH = 7, current density = 24.80 mA/cm2 time = 40 min and dose of electrolytes = 1.0 g/L. Moreover, effects of electrolytes dosage on electricity consumption were observed and found to be that NaCl is better in comparison of Na2SO4 in respect of lower down the electricity consumption. But application of NaCl causes the formation of hazardous compounds as secondary pollutants within treated water. Therefore, Na2SO4 could be a potent replacement of NaCl to enhance the conductivity of paper industry effluent treated by EC process. The treated water has been compared with standard of Central Pollution control board (CPCB) and World Health organization, and found to be suitable for the reuse in irrigation.

清洁生产视角下人工湿地与造纸废水处理工艺的融合研究

废水处理是制浆造纸企业日常运营过程中的重要工作,其工艺水平甚至可以直接决定制浆造纸企业是否可以实现绿色可持续发展。以制浆造纸产业的清洁生产为基本出发点,对现有造纸废水处理工艺的现状和难题进行总结,尝试将人工湿地与造纸废水处理的工艺进行融合,并对融合后的废水处理工艺进行测试。结果表明:将人工湿地与造纸废水处理工艺进行融合,可以很好地实现废水无害化处理,综合处理效果优于传统的制浆造纸废水物化处理。

制浆造纸废水处理系统的AOX迁移与赋存

通过研究2家制浆造纸企业的废水与污泥样品,探究了废水处理流程中,可吸附有机氯化物(AOX)去除途径与其在污泥中的微观赋存规律。研究表明,制浆造纸废水末端AOX浓度低于1.0 mg/L;AOX主要通过生化处理去除,剩余污泥是AOX迁移的重要介质。AOX主要赋存于污泥细胞相与胞外聚合物(EPS)中,污泥吸附量达到总AOX处理负荷的21.1%~24.8%。

化学机械法制浆全过程水污染源的等标污染负荷解析

采用等标污染负荷法对化学机械法制浆过程各工序的废水量及主要特征水污染物种类、浓度和存在状态进行定量解析。结果表明,备料工序主要水污染物是COD、悬浮物(SS)和BOD;木片洗涤、挤压撕裂、螺旋压榨、筛选净化浓缩工序的主要水污染物是BOD、COD和SS;主要污染源集中在筛选净化浓缩和螺旋压榨工序,其中筛选净化浓缩工序等标污染负荷比为50.12%~51.17%,螺旋压榨工序为43.40%~44.21%,这2个工序等标污染负荷比累计达到90%以上;全过程主要水污染物为BOD、COD和SS,累计负荷比达到了80%以上,是废水治理的重点关注对象。该研究结果可为典型化学机械法制浆生产全过程水污染物的环境影响程度评价和管理控制提供有效依据。

上流式多相氧化Fenton技术应用于废水提标改造工程

在提标改造工程中采用上流式多相氧化Fenton(UHOFe)技术处理制浆造纸废水二沉出水混合水,设计处理规模为120 000 m^(3)/d。运行结果表明,该工艺运行稳定,抗冲击负荷能力强,去除效率高。当进入系统的污水平均COD、色度、SS分别为276 mg/L、683倍和71 mg/L时,处理后的出水平均COD、色度、SS分别降至19 mg/L、25倍和2 mg/L,对应去除率分别达到93.1%、96.3%和97.2%。出水符合《城镇污水处理厂污染物排放标准》(GB 18918—2002)表1一级A标准,达到提标改造出水要求。项目投资成本约7 000万元,运行成本约1.94元/m^(3)。与提标改造前相比,经系统处理后出水水质实现污染物超低排放,吨水运行成本在制浆造纸废水深度处理领域处于较低水平,在出水水质和运行成本管控方面达到了行业较高水平。

制浆造纸废水污染物处理工程中排放量估算方法研究

当前废水污染物排放量估算方法采用灰色关联分析法,但该方法受废水处理工程不同处理工序污染物属性变化影响,导致估算误差大。提出制浆造纸废水污染物处理工程中排放量估算方法。通过废水各污染物来源分析,基于污染物排放审定数据,根据废水排放环境的阈限值分析污染物排放属性,确定排放环境目标值,利用平衡法求取各污染物排放因子,实现污染物排放量估算。以实际废水污染物处理工程为研究案例,对所提方法估算性能测试。结果表明,所提方法准确估算污染物排放量,相对误差在0.2以下,有应用价值。

白腐菌处理草浆造纸废水研究

利用8株不同的白腐菌处理造纸废水,通过考察其对废水COD_(Cr)值、色度、pH值等指标的影响,优选出一株处理效果最好的白腐菌L02。进一步对菌株L02处理造纸废水时较适宜的工艺条件(处理时间、反应温度、废水初始浓度和pH值、通氧量等)进行了优化。结果表明,白腐菌L02可以直接应用于造纸废水的处理,可大幅度降低废水COD_(Cr)含量(降低84%以上)和废水的色度(降低93%以上),并可以降低废水的pH值,显示出了良好的工业化应用前景。

非均相光-Fenton法处理废纸制浆废水

为有效处理废纸制浆废水,对针铁矿催化的非均相光-Fenton法处理废纸制浆废水进行了研究.结果表明,针铁矿与H2O2对有机物的降解具有很好的协同效应,在针铁矿200mgFe/L,H2O21500mg/L,pH3.0和35℃的条件下,经过90min的处理,废水TOC可去除67%.针铁矿用量存在饱和点;H2O2用量不宜超过1500mg/L;最佳pH为3.0;升高温度有利于有机物的降解;重复使用针铁矿仍可取得很好的处理效果.反应中,主要进行非均相反应,处理后无需增设后续除铁工序.当针铁矿和H2O2按200mgFe/L和500mg/L配比时,表观速率常数最大,半衰期最短.实验证明非均相光-Fenton法可有效处理废纸制浆废水.

辣根过氧化物酶处理酚和氯酚的催化特性研究

为了研究辣根过氧化物酶处理酚和氯酚的动力学过程，采用人工配水试验，测定了ｐＨ对酶催化反应的影响、Ｈ２Ｏ２抑制酶催化反应的动力学参数和不同底物的酶催化反应动力学参数．结果表明，在试验的ｐＨ范围内，ｐＨ为９时过氧化物酶对苯酚和对氯苯酚的去除效率最高，分别达到９９．５％和９５％．在较低浓度时污染物去除效率随Ｈ２Ｏ２浓度的升高而增加，较高浓度Ｈ２Ｏ２对酶催化反应有一定的抑制效应，但这种抑制作用对酶促反应的影响不大．对氯苯酚、苯酚和间氯苯酚的酶催化反应米氏常数Ｋｍ依次增加，对酶的亲和性逐渐降低，间氯苯酚最难去除．根据酶反应动力学特征判定，辣根过氧化物酶催化酚形成自由基的氧化反应属于乒乓双双反应机制．

铁碳微电解-H_2O_2耦合联用的类Fenton法处理制浆造纸废水

采用铁碳微电解-H2O2耦合联用的类Fenton法处理制浆造纸废水,研究了Fe/C、pH、H2O2投加量、反应时间等因素对处理效果的影响和优化.结果表明,pH值为3,Fe/C质量比为1∶1,H2O2投加量0.0146 mol·L-1,曝气反应时间75 min为最优反应条件,对COD的去除率达到75.43%,也显著降低了色度和悬浮颗粒物,大大减少了运行费用,是一种深度处理造纸废水的有效方法.此外,还与铁碳微电解进行对比,结果表明,铁碳微电解/H2O2耦合联用的类Fenton法对制浆造纸废水COD去除具有明显的加强作用.

UV-Fenton法处理草浆造纸废水的研究

采用UV-Fenton法对自偶氧化清洁制浆造纸废水进行处理。考察了废水pH、H2O2投加量、Fe2+投加量、反应时间以及紫外光强等对废水中CODCr去除率的影响,得到了最佳的工艺条件为pH3.53、H2O2投加浓度46.19mmol/L、Fe2+投加浓度3.06mmol/L,反应60min后CODCr去除率达到67.13%,出水CODCr降到428mg/L,改善了废水的可生化性,有利于进一步进行生化处理。

制浆造纸废水处理新技术

随着制浆造纸工业的发展以及人们对环保意识的不断提高,要求造纸废水排放需达到GB3544—2008排放标准,因此,制浆造纸废水处理新技术的研究及应用成为热点。本文主要介绍了酶处理、复合仿生酶处理、营养剂生物处理等生物新技术以及高级氧化技术、新型膜技术在深度处理制浆造纸废水中的研究与应用情况,以期对今后制浆造纸废水处理提供有价值的参考。

废纸制浆废水在光-Fenton反应中的降解

在太阳光模拟灯的照射下,采用光-Fenton反应对废纸制浆废水进行了处理。结果表明,在Fenton试剂最佳物质的量比为10∶1、最佳pH值为2.8的条件下,光-Fenton反应处理废纸制浆废水效果显著,H2O2用量、催化剂种类和反应时间对TOC的去除也均有很大影响。在H2O2和Fe(Ⅱ)的用量分别为1883 mg/L和310 mg/L、pH值2.8及30℃的条件下,经过90min的处理,废水的TOC可去除66%以上。

造纸中段废水的混凝—臭氧氧化深度处理研究

就混凝-臭氧氧化组合工艺对造纸中段废水生物处理出水的净化效果进行了研究。结果表明，Ca（OH）2对废水色度、TOC、COD和254nm的紫外吸收值（UV254）的去除效果均优于聚合氯化铝／聚丙烯酰胺（PAC／PAM）；Ca（OH）2O3组合工艺的处理效果也优于PAC／PAM—O2工艺。当Ca（OH）2投加量为1g／L、臭氧投加量为50mg／L时，废水色度降低至10倍以下，COD小于150mg／L。经Ca（OH）2混凝处理后，相对分子量在0．5～1．0ku和10．0ku以上的有机物显著减少；进一步臭氧氧化处理后，除0．5～1．0ku范围的有机物大幅度增加外，其余分子量有机物显著减少。由于对色度贡献很大的大分子量物质的去除，废水的色度显著下降直至无色。

制浆造纸废水复合仿酶深度处理技术反应机理研究

针对制浆造纸废水的复合仿酶深度处理技术,通过对复合仿酶处理前后的总有机碳(TOC)、Fe元素变化,对复合仿酶处理废水的反应产物与废水有机污染物凝胶渗透色谱(GPC)、气相色谱-质谱(GC-MS)、红外光谱图(IR),以及对复合仿酶处理废水反应产物的X射线光电子能谱(XPS)的分析研究,明晰了复合仿酶处理体系对自由基反应的控制、引导和终止路径,揭示了"适度氧化-反应沉淀"的反应机理。

废纸制浆废水光催化降解条件的优化

从多方面优化了废纸制浆废水的光催化降解条件。结果表明,在photo/H_2O_2/FeSO_4体系中,Fe^(2+)催化分解H_2O_2和光分解H_2O_2之间存在着协同效应,处理效果显著。在[Fe(Ⅱ)]100mg/L,H_2O_21000 mg/L,pH值3.0和35℃的光照条件下,废纸制浆废水经过60min的处理,TOC去除率65%。增加光强及让废水和空气有效接触均可提高光催化效果,但无需动力曝气。FeSO_4光催化体系的效果较FeCl_2体系的好,三价铁盐光催化体系去除废水TO C的顺序为:Fe(NO_3)_3>Fe_2(SO_4)_3>FeCl_3。采用光-Fenton工艺处理废水的成本约为3.8元/t。