脱硫灰改善污泥脱水性能的机理及用于水泥掺料的研究

发布时间：2017-12-30 18:22

本文关键词：脱硫灰改善污泥脱水性能的机理及用于水泥掺料的研究　出处：《北京科技大学》2017年博士论文　论文类型：学位论文

【摘要】：城市污水处理副产物——污泥,含有大量水分,如何经济、高效的实现泥水分离,是降低污水处理成本的瓶颈,也是实现污泥减量化和资源化的关键。半干法烟气脱硫副产物——脱硫灰,对工业生产和环境安全日益构成威胁,如何有效的处理和处置,已成为现实难题。本研究从"以废治废"的理念出发,将脱硫灰的利用与污泥脱水性能的改善紧密结合起来,以脱硫灰调理污泥的机理研究为基础,优化调理方案。试图用脱硫灰代替常规污泥调理剂,降低污泥脱水成本,提高污泥脱水性能。将调理后的脱水污泥掺入水泥生料,开拓脱硫灰和污泥的资源化利用途径。通过混凝脱水试验,以污泥沉降高度、滤饼含水率(Wc)、污泥比阻(SRF)和毛细吸水时间(CST)为评价指标,比较了脱硫灰、FeCl_3、O_3和电解单独及联合调理对污泥脱水性能的影响;通过测定污泥各层胞外聚合物(EPS)含量、溶解性化学需氧量(SCOD)、Zeta电位变化和傅里叶变换红外光谱分析(FTIR),提出了脱硫灰调理污泥的机理;通过水泥生料易烧性试验,水泥胶砂强度试验,氯离子含量测试,浸出毒性试验等,获得了调理脱水污泥在水泥中的掺入量及其影响。主要结论如下:研究改善污泥的脱水性能,应从提高污泥脱水速度和脱水程度两个方面着手。脱硫灰的架桥作用为自由水的滤出提供通道,其吸附性能使进入污泥上清液的部分EPS又返回固相表面,减少溶解性有机物,有利于提高脱水速度;脱硫灰、O_3或电解都能剥离污泥中紧密粘附性EPS、破坏细胞和絮体结构,使之部分被转化为溶解性EPS和松散粘附性EPS,并使其中一部分EPS进一步水解成羧酸、羧酸盐等小分子有机物,释放其中的表面吸附水和内部结合水,有利于提高脱水程度;脱硫灰中CaO的电性中和作用,能改变污泥颗粒表面特性,压缩双电层,增强絮体的凝聚,提高污泥的颗粒密度,释放颗粒表面的吸附水,既有利于提高脱水速度,又有利于提高脱水程度;紧密粘附性EPS是影响污泥脱水性能的主要因素。脱硫灰调理污泥对改善污泥的脱水性能有重要作用。脱硫灰调理污泥的最佳混凝搅拌条件为:先以350r/min的速度混合搅拌30s,再以50r/min的速度絮凝搅拌15 min;投加425 mg/g脱硫灰,可使Wc降至79.34%,SRF、CST和Wc分别降低76.43%、60.5%和14.65%。投加脱硫灰不超过干基污泥质量的50%,能使难脱水污泥(SRF=1012～1013cm/g)转变为中等难脱水污泥(SRF=(0.5～0.9)× 1 012 cm/g);脱硫灰与FeCl_3、O_3或电解联合调理污泥,好于脱硫灰单独调理的效果。投加300 mg/g脱硫灰和60 mg/g FeCl_3,使Wc降至72.68%,CST和Wc分别降低 97.7%和 13.16%;通入 O_3 85.72 mg/g,投加 400 mg/g 脱硫灰和 60 mg/g FeCl_3,使Wc降至 70.70%,CST和Wc分别降低 83.5%和 15.41%;采用 Ti/RuO_2电极、4cm极间距、20V电压、0.100mol/L NaCl浓度、电解40min,投加300 mg/g脱硫灰和60 mg/g FeCl_3,使Wc降至70.50%,CST和Wc分别降低91.4%和 15.76%。将调理脱水污泥用于水泥掺料具有可行性,试验获得调理脱水污泥的最佳掺入量为7.5%。验证了在此掺量下,熟料试样中硅酸三钙的结晶度显著提高,并出现大量的中间相,水泥熟料的煅烧性能得到提高;污泥对水泥强度无明显影响,水化物中出现了更多的钙矾石晶体,能得到正常的水化产物;熟料中的氯离子和重金属元素含量均远低于国家标准的限定值。本研究为脱硫灰和污泥的减量化、稳定化、无害化和资源化探索了一条途径。为利用脱硫灰改善污泥脱水性能提供理论依据,为污水处理厂降低污泥脱水成本提供有益借鉴。
[Abstract]:City sewage treatment byproduct sludge contains large amounts of water, how to achieve economic, efficient separation of the mud, the bottleneck is to reduce the cost of sewage treatment, it is also the key to sludge reduction and recycling. Semi dry flue gas desulfurization by-product of desulfurization ash, increasing threat to industrial production and environmental safety, handling and disposal effectively, has become a real problem. This research is from "bywaste" concept, will use the desulfurization ash and the sludge dewatering performance improvement of the combination mechanism of desulfurization ash sludge conditioning research based optimization scheme. Try to use conditioning desulphurization ash instead of conventional sludge conditioner, reduce sludge dewatering cost, improve sludge dewatering performance. After conditioning the sludge from the cement raw material, resource utilization and development of desulfurization ash sludge. Through flocculation dewatering experiments with high sludge sedimentation Degree of moisture content of filter cake (Wc), sludge specific resistance (SRF) and capillary suction time (CST) as the evaluation index, the desulfurization ash, FeCl_3, O_3 and electrolysis alone and in combination with conditioning effect on sludge dewatering performance of sludge; through the determination of each layer of extracellular polymeric substances (EPS) content, soluble chemical oxygen demand (SCOD), Zeta analysis of potential changes and Fu Liye transform infrared spectroscopy (FTIR), the mechanism of desulfurization ash sludge conditioning is put forward; the burnability of cement raw materials test, cement mortar strength test, the test content of chlorine ion, leaching toxicity test, the incorporation of dewatered sludge in cement and its influence the main conclusions are as follows: improve the sludge dewatering performance of two aspects, should improve the dewatering velocity and degree of hands. Bridging desulfurization ash free water filter provides a channel, the adsorption performance of the EPS into the sludge supernatant Returned to the solid surface, reducing the dissolved organic matter, is conducive to improve the speed of dehydration; desulfurization ash, O_3 or electrolysis can peel sludge close adhesion EPS, damage cells and floc structure, which was partially transformed into soluble EPS and loosely adherent EPS, and made a part of the EPS further hydrolysis a carboxylic acid, carboxylic acid salt and other small organic molecules adsorbed on the surface of the water and the internal release of bound water, is conducive to improve the degree of dehydration; desulphurization ash CaO electrical neutralization, can change the surface properties of granular sludge, the compression of electric double layer, enhance the floc, improve the particle density of sludge, adsorption and release the water surface of the particle, which is conducive to the improvement of dehydration speed, and improve the degree of dehydration; close adhesion of EPS are the main factors that influence the performance of sludge dewatering. The desulfurization ash sludge conditioning plays an important role in improving the dewatering performance of sludge ash desulfurization. Sludge conditioning the best mixing condition of coagulation are as follows: first, with the speed of 350r/min mixing with 30s, 50r/min 15 min speed flocculation stirring; adding 425 mg/g desulfurization ash, can make the Wc to 79.34%, SRF, CST and Wc were decreased by 76.43%, 60.5% and 14.65%. adding desulfurization ash not more than dry sludge quality 50%, can lead to dehydration of sludge (SRF=1012 ~ 1013cm/g) into medium hard sludge (SRF= (0.5 ~ 0.9) * 1012 cm/g); desulfurization ash and FeCl_3, O_3 or electrolytic sludge conditioning, to separate desulfurization ash conditioning effect. The dosage of 300 mg/g and 60 mg/g FeCl_3 desulfurization ash, the Wc to 72.68%, CST and Wc were decreased by 97.7% and 13.16%; in O_3 85.72 mg/g, adding 400 mg/g and 60 mg/g FeCl_3 desulfurization ash, the Wc fell to 70.70%, CST and Wc were decreased by 83.5% and 15.41%; the Ti/RuO_2 electrode, 4cm electrode spacing, 20V voltage, 0.100mol/L concentration of NaCl, electrolysis 40min , the dosage of 300 mg/g and 60 mg/g FeCl_3 desulfurization ash, the Wc fell to 70.50%, CST and Wc were decreased by 91.4% and 15.76%. will be used for cement admixture sludge conditioning and dewatering test is feasible, the best mixed sludge conditioning with 7.5%. verified this dosage, crystallization in samples of calcium silicate clinker three degrees increased significantly, and the emergence of a large number of intermediate phase, the burning performance of cement clinker is improved; sludge has no obvious effect on the strength of cement, the ettringite crystal more hydration, hydration products can be normal; chloride and heavy metals content in clinker are far below the national standard limit value in this research. For the desulfurization ash and sludge reduction, stabilization, harmless and resources to explore a way to provide a theoretical basis for utilization of desulfurization ash to improve sludge dewatering performance, to reduce cost of sewage treatment plant sludge dewatering Provide useful reference.

【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X703

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