污泥性质和废水处理的影响外文翻译.doc

絮凝：污泥性质和废水处理的影响 摘要 进行研究，以确定在激活的絮凝作用污泥单元过程。实验室和完整的大型研究显示，絮凝最重要的，在于确定沉淀，脱水，污水和消化污泥特性（活性污泥属性），并可能涉及到的所有进程的功能是至关重要的。在这些研究中，结果表明，二价阳离子，如钙和镁改善活性污泥的性质，而单价阳离子如如钠，钾和铵离子，不利于这些属性。 “二价阳离子通过衔接机制，促进负责絮凝带负电荷的生物大分子（主要是蛋白质和多糖）。结果发现，氧化铁起着重大作用，在活性污泥的絮凝和决心通过铁和生物大分子之间的表面相互作用的性质。氧化铁有效地消除从凝固的胶体溶液聚合物和空调的研究。这项研究包括钾的实验评估影响沉降和脱水性能和铵离子，镁的影响沉降性能;影响钠，钾，钙和镁的废水质量;固体停留时间，对出水水质的影响;絮状物评估在有氧和高温消化的属性。一个絮状物模型中提出钙，镁，铁絮凝的功能是很重要曝气池，沉淀池，脱水设备和好氧或厌氧沼气池。 结果表明，活性污泥絮状物性能的影响废水处理效率。关键词：阳离子，活性污泥，沉淀，脱水，镁，铵。前言 活性污泥是由微生物财团和胞外聚合物和二价阳离子（手冢，1969年形成了矩阵一起举行的有机和无机粒子;诺瓦克和豪根，1981年埃里克森和alm，1991; bruus等，1992;希金斯和诺瓦克，1997年，b）。 bruus等人。 （1992年）和希金斯和诺瓦克（1997年b）表明，多余的单价阳离子可引起中絮状物的恶化结构和沉降性能。观察与二价阳离子的增加沉降性能的改善。 许多工业系统需要高纯度的进水。因此，除了规定的化学品在工业过程和废水预处理的废水进入激活污泥盆地的阳离子组成。这些废水通常会在一些阳离子缺陷，将包含他人的过多。单价离子的增加导致活性污泥脱水性能的恶化，而二价离子的增加已被证明可以改善活性污泥脱水性能希金斯和诺瓦克，1997，（二）已被观察到。这些意见进行了实验室和工业系统中活性污泥絮体。希金斯和诺瓦克（1997年b）评估从七个工业设施的阳离子和发现，时的上chargeequivalent的基础上的单价超过二价阳离子比（m / d）2，在脱水性能（具体到过滤阻力）发生恶化。最经常发现添加烧碱的ph值控制在行业的高m/ d比值的相关问题。因此，钠离子是游离在这些系统中的单价离子输入。本研究的目的是评估nonfilamentous沉降和脱水的问题进行鉴定的潜力，通过筛选阳离子，到达实验室或田间试验的策略，找出并解决相关的问题（s）。工业体系研究含有高浓度的钠离子（平均为2000毫克/升）加入氢氧化钠预处理步骤，以防止醋酸的挥发。废物流中的主要成分是醋酸。进水cod为10000毫克/升的顺序。活性污泥的ph值8.8。工业废水处理系统被发现有极端贫困的沉降和脱水性能由于高浓度的钠离子。最初进行化验，以评估为二价阳离子的可能的应用领域，以实现较低的m / d比值，其次是活性污泥性质的每周监测的田间试验的战略。提出了短期和长期的解决方案。结论1离子是直接关系到沉降和脱水性能的变化。该实验室的研究是一个有效的田间试验的序幕。实验室可处理的研究表明钙此外田间试验的不适应。进一步的实验室研究表明，镁会是一个合适的二价阳离子替代。田间试验表明，在絮状密度增加镁离子的改善。前一个时间差可以预计实现沉降性能的改进。虽然阳离子交换可能发生，可能需要更换的污泥絮体的完整的二价金属离子被完全纳入到污泥絮。镁离子提高脱水性能的实验研究，在更大程度上比在实地试验，可能是由于在实验室研究中使用的二价离子浓度较高的表现。田间试验与增长中的可溶性铵离子的脱水性能。看来，铵离子活性污泥絮体在类似的方式，以钠离子相互作用，导致可溶性蛋白的释放和脱水性能恶化。复杂的变化，同时在几个阳离子可使其具有挑战性的隔离沉降和脱水性能变化的原因。考虑对他们的影响力，解决anddewatering属性时，需要考虑不同的阳离子和絮状物（成絮状物的掺入阳离子）之间的互动和彼此之间（阳离子交换）。硫酸镁除了被证明是非常有益的沉降性能改善。如果需要进一步改善，长期战略是必不可少的。 对于工业设施，它可能是有用的，以探索其他替代品的ph值控制。在曝气池硝化的成就可能会进一步改善活性污泥絮体的属性。硝化活性污泥性能的影响，需要进一步探索。结论2实验室和现场进行了研究，评估调节选项atad污泥脱水。本研究的目的是探讨机会，以减少化学空调费用。研究，进行阳离子聚合物和无机调理组合（三氯化铁或明矾）阳离子聚合物。这项研究表明，如氯化铁和明矾等无机空调非常有效地降低空调的化学要求，从而减少经营成本，为atads。无机空调消除阴离子biocolloids有效。之前实现电荷中去除的阴离子biocolloids的发生。去除这些阴离子biocolloids的可能是通过铁羟基矿物相关降水量为混凝研究中观察到。与阳离子聚合物的调理机制是通过电荷中和。前凝血与无机调理污泥将减少溶液中的负电荷，从而消除了一些阳离子聚合物的需求。不同的机制导致不同的空调需求。氯化铁和明矾是更有效地消除较大规模的蛋白质和多糖分子（大于30k）。无机混凝剂，也更有效的生物聚合物和化学需氧量释放更大。应考虑使用无机化学混凝剂，在消化过程中释放大量的蛋白质，多糖和cod时发生。其次是用明矾和阳离子高分子絮凝剂大大降低空调化学学院站成本的空调温曝气相结合。成本相近或低于，需要温厌氧消化。 滤液回收化学需氧量明显减少，厂内发泡大学是很大程度上消除了采用组合的中温曝气和利用明矾。bioflocculation: implications for activated sludge properties and wastewater treatment abstract studies were conducted to determine the role of bioflocculation in the activated.sludge unit processes. laboratory and full-scale studies revealed that bioflocculation is important in determining settling, dewatering, effluent and digested sludge properties(activated sludge properties) and may be vital to the function of all processes related to the above properties. in these studies, it was shown that divalent cations such as calcium and magnesium improved activated sludge properties, whereas monovalent cations such as sodium, potassium and ammonium ions were detrimental to these properties. the divalent cations promoted bioflocculation through charge bridging mechanisms with negatively charged biopolymers (mainly protein and polysaccharide). it was found that oxidized iron plays a major role in bioflocculation and determination of activated sludge properties through surface interactions between iron and biopolymers. oxidized iron was effective in removing colloidal biopolymers from solution in coagulation and conditioning studies. the research included experiments evaluating effects of potassium and ammonium ions on settling and dewatering properties; effects of magnesium on settling properties; effects of sodium, potassium, calcium and magnesium on effluent quality; effect of solids retention time on effluent quality; and evaluation of floc properties during aerobic and thermophilic digestion. a floc model is proposed in which calcium, magnesium and iron are important to bioflocculation and the functionality of aeration tanks, settling tanks, dewatering equipment and aerobic or anaerobic digesters. it is shown that activated sludge floc properties affect wastewater treatment efficiency.keywords：cation, activated sludge, settling, dewatering, magnesium, ammonium.introduction activated sludge is comprised of microbial consortiums and organic and inorganic particles held together in a matrix formed by exocellular polymers and divalent cations (tezuka, 1969; novak and haugan, 1981; eriksson and alm, 1991; bruus et al., 1992; higgins and novak, 1997a, b). bruus et al. (1992) and higgins and novak(1997b) have shown that excess monovalent cations can cause a deterioration in flocstructure and settling properties. improvements in settling properties were observed with an increase in divalent cations. many industrial systems require influent water of high purity. therefore, the addition of chemicals during the industrial process and wastewater pretreatment dictate the cationic composition of the wastewater entering the activated sludge basins. often these wastewaters will be deficient in some cations and will contain an overabundance of others. an increase in monovalent ions has been observed to cause a deterioration in dewatering properties in activated sludge, whereas an increase in divalent ions has been shown to improve activated sludge dewatering properties (higgins and novak, 1997a, b). these observations were made for activated sludge flocs in laboratory and industrial systems. higgins and novak (1997b) evaluated the cations from seven industrial facilities and found that, when the monovalent to divalent cation ratio (m/d) on a chargeequivalent basis exceeded 2, deterioration in dewatering properties (specific resistance to filtration) occurred. the problems associated with a high m/d ratio were most often found in the industries that added caustic for ph control. therefore, sodium ions were the prevalent monovalent ion input in these systems.the purpose of this study was to evaluate the potential for identification of nonfilamentous settling and dewatering problems through screening of cations, to arrive at a strategy for laboratory or field trials, and to identify and address the associated problem(s).the industrial system studied contained a high concentration of sodium ions(average of 2,000 mg/l) added as sodium hydroxide in the pretreatment step to prevent volatilization of acetic acid. the major component in the waste stream was acetic acid. the influent cod was in the order of 10,000 mg/l. the activated sludge had a ph of 8.8. the industrial wastewater treatment system was found to have extremely poor settling and dewatering properties due to a high concentration of sodium ions. laboratory tests were initially conducted to evaluate a strategy for possible field application of divalent cations to achieve a lower m/d ratio, followed by field trials of weekly monitoring of activated sludge properties. short and long term solutions were proposed.conclusions1 cations were directly related to changes in settling and dewatering properties. the laboratory study was an effective prelude to field trials. the laboratory treatability study indicated the unsuitability of calcium addition for the field trial. the laboratory research further showed that magnesium would be a suitable divalent cation alternative. field trials demonstrated an improvement in floc density associated with an increase in magnesium ions. a time lag could be anticipated prior to achieving improvements in settling properties. although cation exchange may take place, a complete replacement of sludge flocs may be required for the divalent ions to be completely incorporated into the sludge floc. magnesium ions improved dewatering properties in the laboratory study to a greater extent than demonstrated in the field trials, probably due to the higher concentration of the divalent ion used in the laboratory study. the field trials linkeddewatering properties to an increase in the soluble ammonium ions. it appears that ammonium ions interact with activated sludge flocs in a manner similar to sodium ions, causing a release in soluble proteins and a deterioration in dewatering properties.complex variations in several cations simultaneously may make it challenging to isolate the cause for changes in settling and dewatering properties. interaction between different cations and the floc (cation incorporation into the floc) and amongst themselves (cation exchange) need to be taken into account when considering their influence on settling anddewatering properties. the addition of magnesium sulfate proved to be extremely beneficial in improving settling properties. if further improvements are required, long term strategies are essential. for the industrial facility, it may be useful to explore other alternatives for ph control. achievement of nitrification in the aeration basin may further ameliorate activated sludge floc properties. the effect of nitrification on activated sludge properties require further exploration.conclusions2laboratory and field studies were conducted to evaluate the conditioning optionsfor the dewatering of atad biosolids. the objective of this study was to investigate opportunities to reduce chemical conditioning costs. studies were conducted using cationic polymer and a combination of inorganic conditioners (ferric chloride or alum)and cationic polymer. this study indicated that inorganic conditioners such as ferric chloride and alumwere very effective in reducing conditioning chemical requirements, thereby reducingoperation costs, for atads. the inorganic conditioners were effective in removing anionic biocolloids. removal of the anionic biocolloids occurred prior to achieving charge neutralization. the removal of these anionic biocolloids may be through ferric-hydroxy mineral associated precipitation as observed in the coagulation study. the conditioning mechanisms as