造纸工业节水技术

总结了近年来的造纸业基本节水技术，并进一步提出了其技术发展的趋势与最新动态。     

草制浆造纸中段废水处理及回用技术分析研究

中段废水是制浆造纸工业的主要污染源之一，从工程设计的角度出发，对草制浆造纸中段废水处理及回用提出一套可行适用的工艺方案；对主要工艺环节参数、设备备有说明，以供同行借鉴。     

造纸制浆废水中回收木质素的技术线路评述

造纸制浆废水是造成我国水域污染的主要污染源之一,其不仅有机物含量高、色度深,还有酸碱度严重超标的问题,俗有“一个造纸厂污染一条河”的说法.因此,制浆废水的处理一直是环保工作者关注的课题,综合治理、变废为宝、走废物资源化道路是被公认的可取之举,其中碱回收和木质素回收是两大主要治理方案.在此,我们针对制浆废液木质素回收的主要技术线路进行评述.     

草制浆造纸中段废水处理及回用技术分析研究

中段废水是制浆造纸工业的主要污染源之一,从工程设计的角度出发,对草制浆造纸中段废水处理及回用提出一套可行适用的工艺方案;对主要工艺环节参数、设备备有说明,以供同行借鉴.     

杭州市制浆造纸工业污染现状和防治对策研究

调研了杭州市现有的３２０家制浆造纸企业概况，针对广大散在的制浆造纸废水的污染状况，提出了分浆种集中制浆集中治理控制污染等对策。     

中国制浆造纸行业污染排放现状及其环境政策研究

立足于国内制浆造纸行业的污染排放现状,分析了该行业与发达国家在生产规模、原料结构、生产工艺和碱回收率及资源利用等方面存在的差距,针对国内造纸工业污染现状,提出了中国造纸工业可持续发展的环境政策建议：淘汰落后企业、强制推行清洁生产审核、优化原料结构、修订排放标准、提高环保准入门槛、上大压小和加强环保监测等。     

制浆造纸废水生化出水的混凝处理研究

研究了硫酸铝和三氯化铁对制浆造纸废水生化出水的处理效果.研究发现,不调节原水pH值,硫酸铝投加量为600 mg/L或三氯化铁投加量为300mg/L时,混凝后废水的COD＜150 mg/L,色度＜50倍,出水均符合现阶段排放标准.混凝剂比较发现,在最佳反应条件下,2种混凝剂的处理效果相当,但硫酸铝混凝的成本低于三氯化铁....     

预氧化-混凝沉淀法处理制浆造纸废水的研究

采用预氧化-混凝沉淀法处理制浆造纸废水。研究了以氯化铁、聚丙烯酰胺为混凝剂，氢氧化钙为助凝剂的混凝沉淀法和KMnO4预氧化的最佳实验条件。实验结果表明，预氧化-混凝沉淀法对造纸废水的处理有较好的效果，其CODCr的去除率达93．42％，比混凝沉淀法提高了26．8％。     

预氧化-混凝沉淀法处理制浆造纸废水的研究

采用预氧化 混凝沉淀法处理制浆造纸废水。研究了以氯化铁、聚丙烯酰胺为混凝剂 ,氢氧化钙为助凝剂的混凝沉淀法和KMnO4预氧化的最佳实验条件。实验结果表明 ,预氧化 混凝沉淀法对造纸废水的处理有较好的效果 ,其CODCr的去除率达 93.4 2 % ,比混凝沉淀法提高了 2 6 .8%。     

Fenton/絮凝工艺深度处理制浆造纸废水的工程应用分析

以某制浆造纸厂生化出水Fenton/絮凝深度处理工艺长期运行数据为依据,系统分析了H2O2、废酸液（FeSO4含量约8%）、硫酸铝、PAM及氧化钙等处理药剂用量与水量、进水负荷和COD去除量之间的关系。结果表明,H2O2、废酸液、硫酸铝、PAM及氧化钙的单位水量平均投加量分别为0.05、2.18、0.07、0.0075和0.27 kg/m3,而去除单位COD的药剂平均消耗量分别为0.20、8.48、0.27、0.029和1.06 kg/（kg COD）;H2O2、废酸液、硫酸铝和氧化钙的用量随进水负荷的增大而增加,而PAM随进水负荷的变化较小。H2O2和FeSO4的投加摩尔比（MH2O2/Fe2＋）主要集中在1.0-2.0之间,其中在1.0-1.6之间的累积频率达到93%。该工艺的出水COD和SS分别为65-100 mg/L和20-30 mg/L,达到《制浆造纸工业水污染物排放标准》（GB 3544-2008）排放要求。废水深度处理成本约为1.01元/m3,其中药剂费用约0.58元/m3,占56.98%。     

Dioxin formation in pulp and paper mills of India

Samples of effluents, sludge, pulp, final products (paper) and soil were collected from the identified pulp and paper mills in India. The samples were analysed for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD) and other dioxin congeners and precursors. Pulp and paper mills using chlorine for the bleaching process showed the presence of 2,3,7,8-TCDD in effluent samples. In the effluent and pulp samples from mills where chlorine dioxide was used as a bleaching agent, the 2,3,7,8-TCDD congener ranged from below the detection limit 0.05 to 0.12 ngL⁻¹/ngg⁻¹. The relative standard deviation of reproducibility and the percent recovery of 2,3,7,8-TCDD were 2.07 and 82.4% in pulp and 2.8 and 92% in effluent, respectively. The 1,3,6,8-TCDD was the only other major dioxin congener found in the treated and untreated effluent and sludge samples. However, dichlorobenzene, trichlorophenyl, and hexachlorobiphenyl were detected in all samples. The formation of dioxins can be minimised by replacing chlorine with chlorine dioxide in bleaching processes in pulp and paper mills.     

Removal of methanol from pulp and paper mills using combined activated carbon adsorption and photocatalytic regeneration

Methanol is one of the major hazardous air pollutants emitted from chemical pulp mills. Its collection and treatment is required by the Maximum Achievable Control Technology portion of the 1998 Cluster Rule. The objective of this study is to investigate the technical feasibility of combined adsorption and photocatalytic regeneration for the removal and destruction of methanol. To facilitate the regeneration, activated carbon (AC) was coated with commercially available photocatalyst by a spray desiccation method. Laboratory-scale experiments were conducted in a fixed-bed reactor equipped with an 8 W black light UV lamp (peak wavelength at 365 nm) at the center. The photocatalyst loaded onto AC had no significant impact on the adsorption capacity of the carbon. High humidity was found to greatly reduce the material's capacity in the adsorption and simultaneous adsorption and photocatalytic oxidation of methanol. The photocatalytic regeneration process is limited by the desorption of the adsorbate. Increasing desorption rate by using purge air greatly increased the regeneration capacity. When the desorption rate was greater than the photocatalytic oxidation rate, however, part of the methanol was directly desorbed without degradation.     

Sulfur dioxide and nitrogen oxides emissions from U.S. pulp and paper mills, 1980-2005

Comprehensive surveys conducted at 5-yr intervals were used to estimate sulfur dioxide (SO,) and nitrogen oxides (NO.) emissions from U.S. pulp and paper mills for 1980, 1985, 1990, 1995, 2000, and 2005. Over the 25-yr period, paper production increased by 50%, whereas total SO, emissions declined by 60% to 340,000 short tons (t) and total NO, emissions decreased approximately 15% to 230,000 t. The downward emission trends resulted from a combination of factors, including reductions in oil and coal use, steadily declining fuel sulfur content, lower pulp and paper production in recent years, increased use of flue gas desulfurization systems on boilers, growing use of combustion modifications and add-on control systems to reduce boiler and gas turbine NO, emissions, and improvements in kraft recovery furnace operations.     

废弃马铃薯渣改性制备瓦楞纸板粘合剂研究

研究了胶体磨湿法超微粉碎及高压蒸气处理对废弃污染物——马铃薯渣粒径分布及颗粒破坏程度的影响,调节胶体磨齿间隙为12μm处理30 min,并结合高压蒸气121℃处理20 min的条件下,通过显微镜观察和激光粒度分析证明马铃薯渣颗粒粒径明显减小且分布更加均匀,细胞壁和纤维素被破坏,体现出胶粘剂的性质。进而通过氧化变性处理改善其流动性,并添加一系列的助剂,制得了一种瓦楞纸板用粘合剂,其主要性能均接近于目前广泛使用的淀粉基瓦楞纸板粘合剂。     

造纸污泥的电渗透脱水效果

采用电渗透脱水技术对经过带式压滤后的制浆造纸混合污泥进行深度脱水,考察了机械压力、电压梯度和污泥厚度对污泥电渗透脱水效果与能耗的影响。结果表明,机械压力从25 kPa升至76 kPa时,脱水效果也会随之提高,但是继续增大机械压力对脱水效果的提高作用就会变得不明显;随着电压梯度的增加,脱水效果会有明显的升高,但是能耗也会相应地增加;电压梯度恒定为30 V/cm且污泥厚度从0.35 cm增加到1.40 cm时,脱水效果和能耗都会相应地增加。对于所有的电脱水实验,当污泥的含水率从74.85%降至60%时所需要的能耗均在0.14～0.28 kWh/kg去除水之间。综合考虑脱水效果和能耗,可认为最优脱水条件是：机械压力为76 kPa,电压梯度为30 V/cm,污泥厚度为0.7 cm。     

Characterisation of non-condensable sulphur containing gases from Kraft pulp mills

This paper describes work performed on the sampling and analysis of non-condensable gases (NCG) emitted from diffuse sources of a Portuguese Kraft pulp mill, which is the background information for a NCG collection, treatment and disposal system. The variability found in the composition of the gaseous compounds showed the existence of gaseous streams other than typical total reduced sulphur (TRS) compounds as usually described. From the measured TRS concentrations and the gas flow rate from each source it was possible to calculate the emission flow rate, E, of each source. These emission flow rates were then divided into three categories which are quite useful to identify significant sources and to choose abatement techniques. The methodology presented allows for a precise quantification of sources so that similar emissions can be grouped for treatment purposes. Sources with an emission flow rate bigger than 1 kg/h have a marked effect on the overall TRS emissions of the mill, as they are major contributors. It was also found that a new analytical procedure using Restek columns is more easy to use and overcomes operational problems noticed previously, namely a run time of 20-25 min instead of 50-60 min.     

Determination of dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) in paper pulp mill defoamer additives and in paper pulp samples

An analytical procedure has been developed for quantitatively measuring dibenzo-p-dioxin (DBD) and dibenzofuran (DBF) present at part-per-billion levels in paper mill defoamers and paper pulp using gas chromatography coupled with either low resolution mass spectrometry (GC-LRMS) or high resolution mass spectrometry (GC-HRMS).     

Modelling the absorption and desorption of cadmium on paper pulp using kinetic approaches

The presence of toxic metals on paper pulp and the migration of these metals to food from the food package is receiving significant attention. The final exposure levels for consumers depend on two main processes. First the potential of metals to bind paper pulp during manufacture. Second, the metal potential to migrate from paper to food during storage and use. Binding and unbinding processes are modelled for cadmium kinetics through kinetic approaches. The cadmium concentration in paper pulp is estimated from the cadmium concentration in the water-pulp liquor during manufacture, the temperature, and contact time. Two food simulants have been employed for desorption studies, water and acetic solution (3%, w/w). As expected, under acidic conditions desorption is total and rapid (close to 100% desorption reached in a few minutes). However, the desorption of cadmium into the neutral food simulant depends on the initial cadmium concentration in the paper pulp, temperature and contact time. Surface response curves for each combination are presented. Temperature did not affect cadmium binding, but played a significant role for the desorption processes into the neutral food simulant. The proposed equations offer a good fitting of the experimental values, with p < 0.001 and residuals within a factor of 3 for over 99% of the measured data. These models allow estimations of the expected exposure levels in consumers, on the basis of manufacture and use conditions. Linking the expected exposure with toxicity thresholds, such as the admissible daily intake (ADI), would allow a scientific assessment of the maximum acceptable cadmium levels in water-pulp liquors during manufacture and in the final paper pulp on the basic of the use patterns of each food packaging material.     

Atmospheric methanethiol emitted from a pulp and paper plant on the shore of Lake Baikal

On-site measurement of methanethiol (CH₃SH) was performed for three years on ships and cars near a pulp and paper plant standing on the shore of Lake Baikal in Siberia, Russia, to investigate the behavior and impact of atmospheric CH₃SH emitted from a point source. Despite its strong odor, there are few reports on atmospheric CH₃SH, while many investigations have been carried out on dimethyl sulfide (DMS). In this work, CH₃SH and DMS were measured every 15 min by a recently developed automated instrument based on single column trapping/separation and chemiluminescence measurement. Hydrogen sulfide, sulfur dioxide and ozone were also measured simultaneously by individual instruments. Of these sulfur compounds, CH₃SH was dominant and its concentration sometimes reached several tens of ppbv. The concentration of CH₃SH was high at night, because of the lack of photodecomposition and local winds from the mountain to the lake. Such time variation was marked in the summer. The CH₃SH level decreased significantly downwind, while decreases in concentrations of other compounds such as DMS and SO₂ were relatively small. From these temporal and spatial variations, the behavior of CH₃SH is described in this paper. The impact of CH₃SH near the Siberian big sources is discussed with the presented data.