厌氧处理之五：造纸工业

厌氧技术的工业应用实例Application Examples of anaerobic technologyin Full Scale,Xian Jiaotong University西安交通大学He Yanling贺延龄,厌氧技术在造纸工业废水处理中的应用Application of anaerobic technology in pulp and paper wastewater treatment,1.INTRODUCTION 简介1.1 The application history of anaerobic treatment in pulp and paper 历史的回顾,工业废水的特点复杂，性质多样，一厂一个样；工艺原料产品。成分复杂：POPs、毒性物质、难降解物；3. 波动的水质、极端的水质： pH范围大、可能波动；温度；营养物：N、P,1.INTRODUCTION 简介1.1 The application history of anaerobic treatment in pulp and paper 历史的回顾,l In the early 80s, the paper industry started to apply anaerobic effluent treatment. as an additional pre-treatment, because of problems with activated sludge plant. 80年代初开始应用于造纸废水，作为好氧处理之前的单元操作。以便解决好氧处理的问题： -动力消耗过大，成本高； -污泥膨胀等问题。,As an pre-treatment stage, it has been proved to have important advantages: 应用实践已证明：-an effective way to multiply the capacity by a factor of four to five; -增加原有处理设施的能力甚至3-4倍。-The extra space required was only a small fraction (20 %) of what was required for a conventional expansion. -增加的占地面积仅为约20%；-Mills decreased operational cost and -运行成本大幅度降低；-got rid of typical activated sludge plant problems like foaming and sludge bulking.克服传统的活性污泥方法存在的问题，例如泡沫和污泥膨胀等。,1.INTRODUCTION简介 1.2.Anaerobic treatment of industrial waste water in China and in the foreign countries 中外造纸工业废水厌氧应用情况的比较,N=372，Paques & Biothane possess63% of the worlds total excluding China， 国外,N=219，至2001年，中国,2 . Overview of applied anaerobic systems 厌氧系统应用情况 2.1 The first two types of anaerobic systems in paper industry in early 1980s 造纸工业最早使用的两种厌氧系统,- CSTR (continuous stirred tank) reactors in Scandinavia 厌氧接触工艺（北欧）- UASB reactors, in the Netherlands. 上流式厌氧污泥床工艺（荷兰）Both applied to paper industry in early 1980s 都开始于80年代早期,2.1 The first two anaerobic systems in paper industry造纸工业最早使用的两种厌氧系统,（1）The CSTR system -The loading rates are relatively low (2-5 kg/m.d) 负荷2-5-The reactor volumes are quite huge.反应器体积巨大-Poor contact and thus poor mass transfer. 污泥废水间接触不良、传质效果差,2.1 The first two anaerobic systems in paper industry造纸工业最早使用的两种厌氧系统,（2）UASB reactor 上流式厌氧污泥床反应器-overcame the mixing problem, by leading the influent water and gas produced through a layer of anaerobic sludge bed. -改善了污泥和废水的混和-Sludge grows in the form of excellent settling spherical particles of 1 to 3 mm. -污泥形成1-3mm的颗粒，具有非常好的沉淀性能。 high sludge concentrtion can be achieved. -可以得到很高的污泥浓度。-Reactor could be loaded from 8 to 15kgCOD/m.d. 反应器负荷8-15kg/m.d。,2.1 The first two anaerobic systems in paper industry,Therefore, the UASB reactor became by far the most popular anaerobic system, as can be seen in Figure 1. 由于UASB反应器的突出优点，至今它仍然是应用最广泛的厌氧反应器（如图2）Inventor: Prof. G.Lettinga , The Netherlands 发明人：荷兰，Lettinga 教授,Fig.1. Anaerobic systems in the pulp and paper industry ( N = 139, China not involved) 图2、制浆造纸工业废水处理系统的厌氧反应器 （总数139，不包括中国，2000年）,2.2 b high tower reactors,-FB (Fluidised Bed), 流化床 -EGSB (Expanded Granular Sludge Bed) 膨胀颗粒污泥床 -IC (Internal Circulation) reactors. 内循环反应器 EGSB reactor has gained an important market share of almost 20% as can be seen in Figure 1. 占领了20%的市场,Some common advantages of these high-tower reactors高塔型反应器的共同优点,- higher sludge concentration.-高污泥浓度 - better mass transfer because of intensive turbulence they offer better circumstances for better contact 。 -强烈的湍流状态引起的高传质速率 -Thus result in higher VLR, compact reactor -所以反应器负荷高、体积小 回忆：VLR = f A Cs f-factor for the turbulence degree; A-methanogenic activity; Cs-sludge concentration in reactors,3. Analysis on the application of anaerobic technology in Paper industry 厌氧处理在造纸的应用现状的分析3.1. Distribution in continents 在各大洲的分布情况 图4、 造纸工业厌氧技术在各大洲使用的情况,4. Anaerobic treatment for different products 不同浆纸产品的厌氧处理 4.1. Pulp and paper 浆和纸,One can not define the effluents exactly between pulping and papermaing. 制浆和造纸往往难以明确区分，大多数工厂既制浆也造纸 Because most of them are pulp and paper integrated mills. It is more important to know where and how effluents come from, say:了解废水如何产生更重要，例如： -final product and raw materials; -原料和产品的种类； -pulping process, chemicals used, pulp yield etc. -制浆工艺、使用的化学药品、纸浆得率等； -Internal treatment system like Alkaline recovery, acid recovery and fibre recovery. -内部处理系统例如碱回收、酸回收、白水回收等 Most of pollutant comes from pulping Therefore pulp effluent is more complicated and more important. 绝大多数 污染物来自制浆，制浆废水也更复杂、更重要,4. Anaerobic treatment for different products 不同浆纸产品的厌氧处理 4.1. Pulp and paper 浆和纸,图6、制浆造纸工业的厌氧废水处理,4.2 Anaerobic systems related to pulp 图7、厌氧处理在制浆废水中的应用情况,4.2 Anaerobic systems related to pulp 厌氧处理在制浆废水中的应用情况,Effluent with good anaerobic treatability:应当首选厌氧-好氧处理工艺的废水APMP (Alkaline peroxide mechanical pulping)废纸制浆 (recycled paper pulping )、机械浆 (Mechanical puling )、TMP （Thermomechanical pulping )蒸发冷凝水 Condensate,5. Energy requirement and sludge production 能源消耗和剩余污泥,It can be interesting to compare the role of anaerobic treatment with the total energy requirement for a paper mill.从能源角度看厌氧处理的作用可以发现一些重要的东西。The example is based on a recycled paper mill using 100% OCC. (old corrugated container)以使用OCC为原料的造纸厂为例。,5.3. Power consumption and sludge production in an activated sludge plant 好氧活性污泥工艺处理废水时的能耗和剩余污泥量,- 25 kWh/ton paper(or 90 MJ/ton) for aeration曝气消耗的动力：25kWh/吨纸 （90MJ/吨）（1kWh =3.6MJ)The sludge production:9 kg/ton of paper (dry solids ). -剩余污泥9kg/吨纸,5.4. Power consumption and sludge production in an anaerobic /aerobic plant厌氧+好氧工艺处理废水时的能耗和剩余污泥量,BOD removal in the anaerobic stage: 80-85%. 厌氧阶段除去80-85%BOD。The residual energy requirement is reduced from 90 to 18 MJ/ton paper . 能耗由90MJ降低到18kWh/吨纸。Sludge production is reduced from 9 to 1.8 kg/ton. 污泥量由9降到1.8kg/吨纸Methane production:每去除1kgCOD可产生0.35Nm3甲烷气； -0.35 Nm methane gas/kg COD removed. -8 m methane gas/ton paper or 280MJ/ton for this case. -5 MJ/ton can be reduced from this figure for pumping energy, so that the residual yield is 275 MJ/ton. 相当于每吨纸产生8m3甲烷或280MJ能源；如果减去泵消耗的能量，每吨纸仍可产生275MJ的能。,5.5 Some other advantages in an anaerobic /aerobic plant厌氧-好氧的其他优势,The filamentous bacteria that are responsible for foaming and bulking in the activated plant, are almost always absent.活性污泥工艺的泡沫和污泥膨胀问题基本消失Due to this change of bacteria population, by which the sludge flocs become less slimy, polymer and defoamer cost are drastically reduced or eliminated completely. 由于菌群的变化，污泥粘性降低，消泡剂和其他聚合物用量减少或不用。,Table. A comparison of energy consumption between activated sludge and An/A.表、两种工艺的能耗比较,5.6 Comparison of sludge treatment and disposal 污泥处理 和处置(1) the disposal cost for landfill 填埋的成本,5.6 Comparison of sludge treatment and disposal (2) some other comparison,Aerobic needs dewatering polymer and the dewatering operation cost (belt press or centrifuge) -好氧污泥脱水成本高Anaerobic system produces granular sludge: 0.5 kg/ton paper- with a positive value 0.2 Euro/t paperas innoculum. about 2.5 RMB/t paper (0.3 USD) in China. -厌氧产生的颗粒污泥已经成为商品。 污泥量约0.5kg/吨纸，合约2.5元/吨纸（？）,6.Closed circuit reuse of effluent 封闭循环和水的循环回,For the reuse of treated effluent a number of advantages are quite clear, namely: 水回用的好处：- reduction of fresh water consumption.用水量减少- reduction of effluent charges. 废水排放减少 - energy recovery. 节能 lower investment and operation cost for WW treatment. 废水处理的成本减少,6. Closed circuitreuse of effluent6.1 Energy recovery and closed circuit 封闭循环和能源回收,Effluent discharge causes energy loss -if fresh water has a temperature of 10C and the discharge is at 35C, the loss of energy is 104.5 MJ/m. 排水引起能的损失。例如，通常每立方可损失大约104MJ。 -Closed circuit causes an increased temperature of process water to 35-55 C . 封闭循环后，温度可以上升为35-550C. -Productivity is increased by 4% for every 10C of temperature increase，because of the lower water viscosity. 温度每升高10度，车速可提高4%，因为水的粘度降低、脱水速率增加.,6.2 废水循环利用需要解决的问题,高度的封闭循环，需要循环水的处理，否则污染物的积累引起以下问题：（1） 微生物在循环水中大量生长： 足够的营养物、合适的温度、中性的pH条件 -由此引起： 腐浆（纸断头、压花、纸质量问题、） 气味（产品和环境）-厌氧环境产生硫化氢、挥发酸,6.2. 废水循环利用需要解决的问题,（2）盐的积累和腐蚀问题 碳酸 钙-来自废纸原料和造纸过程的填料；硫酸铝-来自造纸的施胶过程。 盐积累引起：-泡沫。碳酸 钙和挥发酸反应产生CO2, 造纸过程匀度问题、断头、孔洞-设备结垢（网和毛布）。与松香酸、树脂及硫酸盐反应；-H2S产生；-腐蚀,6.2. 废水循环利用需要解决的问题,（3）二次胶粘物（Secondary Stickies）影响造纸过程中的胶粘性物质，它们是分散在液体中的憎水性胶体，造纸中沉积。来自于：印刷油墨，造纸中添加的胶料；纸表面的涂料 问题:-堵塞通网和毛布孔。-粘烘缸。,6.2. 废水循环利用需要解决的问题,(4) 阴离子垃圾（ Anionic trash）,亲水的溶解性的阴离子或阴离子胶体的积累 来自于： -造纸添加剂，例如CMC(羧甲基纤维素)、淀粉。等 -油墨中的某些组分。 问题： -增加造纸过程中助剂用量的增加（例如施胶矾土、助滤剂等） -造纸过程滤水速率下降，车速降低（5）臭味和有毒气体，来自硫酸盐和挥发酸,6.3 废水零排放完全的封闭循环,西安交大天津零排放工程,paper180TPD,Waste paper210TPD,UASB,好氧反应器,鉴于以上原因，在废水回用前应当经过适当的处理。处理的目的: -循环水系统的水质量满足造纸所需的质量要求。 -25年前已有的化学、物理的零排放已有报道，证明是不成功的。因此， 1）零排放的前提：必须寻求合适的循环水处理方法。 2）真正的零排放必须是可持续进行的。,6.4 生物处理技术是实现零排放的关键,早期的经验证明：物理的、化学的方法不能够实现真正的零排放。因为：前述的有机的污染物主要以溶解状态存在。生物处理是溶解性有机物消减的唯一可行的方法；早期的纸厂又先后放弃零排放 4，5。问题是：水质变臭、黏度增大、结垢严重、细菌滋生；当真正封闭循环时，有害的物质逐渐积累，达到很高的浓度，远远高于未封闭时的排水浓度。厌氧和好氧是去除有机污染物的最为经济的方法。厌氧和好氧生物软化除盐是当前唯一经济地软化废水的方法。,表2. 德国Zlpich纸厂在零排放前的工艺水水质,生物处理技术是实现零排放的关键采用气浮水处理，废水排放量2m3/吨纸时，有机物积累的程度如表2所示：,7.零排放工程水处理运行实例 7.1. COD的去除情况,（40天平均）1/10-8/11）根据操作记录，计算得出的平均值,7.2. BOD的去除情况,BOD去除情况（p18表6）计算的平均值 表6测定相当准确。 单位%,7.3. VFA和硬度的去除情况,挥发性脂肪酸几乎完全去除（大于99.7%)，其中厌氧去除大约88%；水的硬度的累积得到遏制，逐渐降低保持在较低水平(小于5mmol)，平均可去除23% 。,-在车速130m/min的情况下（设计车速75 m/min) ，用水量2.5m3/t, 以下，废水实现零排放。（不包括锅炉用水）,在其他工业方面的应用,果汁废水节能低成本处理,果汁废水来源,洗果水：泥沙、果肉、溶解性有机物；设备清洗水：浓度大、强酸碱、消毒剂；罐底物与超滤浊汁；地面清洗生活废水烂果、过滤果渣,果汁废水特征,高浓度废水，生化可降解性高