【作者】 郑西强；

【导师】 蔡昌凤；

【作者基本信息】 安徽工程大学 ， 环境工程， 2010， 硕士

【摘要】 焦化行业是用水和环境污染最为严重的行业之一,长期以来对于焦化废水的治理只注重末端治理技术的开发,以焦化废水达标排放为目的。随着水环境容量的递减及对生态要求的日益严格,急需开发、研究和应用新型废水生物处理工艺和焦化废水的回用技术。本选题依据循环经济理念,利用煤焦化基地的产业链对水质的不同要求,提出大循环思路：洗煤因蒸发等原因产生的吨煤水耗为0.2m3／吨煤(以闭路循环为标准),为接纳焦化废水回用提供了有效空间。将焦化废水生化处理后作为洗煤补水,引入选煤厂洗水闭路循环系统,利用煤粉吸附处理和絮凝沉降处理焦化废水难生物降解的污染物,实现焦化废水大循环零排放新工艺。开发利用洗煤厂洗水闭路循环系统实现焦化废水大循环零排放新工艺,需考察焦化中水对浮选有无不良影响。通过对三家焦化废水二级出水中主要污染物分析与总结,利用两种煤粉对模拟焦化废水二级出水中主要污染物的吸附性能研究,对废水中主要微生物的疏水比率的测定,污染物吸附后对煤表面性质影响和煤的可浮性影响的研究,可以得出以下结论：(1)煤粉对模拟废水中有机物的吸附去除率焦煤略高于肥煤,煤粉(-0.5mm)吸附容量0.1094～0.1544 mg/g；焦煤吸附苯酚、肥煤吸附喹啉符合Freundlich吸附等温式、焦煤吸附喹啉则符合Langmuir等温式；不同煤种和不同粒度煤粉吸附有机物的反应动力学特性相似,均较好符合二级反应动力学模型,R2=0.990±0.008；吸附过程以液膜扩散为速率控制步骤；在不同温度下得到了焦煤吸附苯酚的速率常数方程lnk=188.54e-11.64/(RT),吸附活化能Ea=11.64kJ/mol.(2)生化法处理废水二沉池出水中微生物的疏水亲水性对中水深度处理和回用影响很大。通过对三种萃取剂的比较,选择最佳的菌液、萃取剂配比,确定分离条件,得出四氯化碳吸附微生物的能力较强,菌体在四氯化碳-水界面和四氯化碳层能维持长时间稳定；稀释控制待测菌液浓度；菌液、萃取剂配比为2.67(菌液：萃取剂=12ml：4.5m1)为最佳；采用低转速离心(1000r/min.10min)分离条件利用该方法对实际焦化废水中主要微生物进行疏水比率测定,并研究硝化细菌和反硝化细菌在不同的pH、温度、生长周期时的疏水性；通过试验发现,微生物的疏水比例随pH、温度、生长期、灭活与否变化,硝化细菌的疏水比例>60%,反硝化细菌的疏水比例<20%。(3)采用Zeta电位和油水润湿速度比(OHR)研究煤粉吸附焦化中水主要污染物氨氮、苯酚、喹啉和微生物后,表面电性、煤表面疏水性、可浮性变化趋势。分析煤吸附单一污染物后其表面特性的变化,试验结果表明：污染物吸附改变了煤浆的Zeta电位,变化显著：未吸附时Zeta为-17.27mv,吸附后依次为吸附硝化菌-21.88mv～-26.62mv、喹啉-25.21mv～-29.47mv、苯酚-27.39mv～-32.58 mv、氨氮-32.13mv～-38.53mv、反硝化菌-38.80mv～-43.40mv。煤泥悬浮液ξ电位研究表明微生物优先于矿物吸附煤表面,微生物对煤泥悬浮液有絮凝作用,有利于煤泥的沉降；煤吸附疏水性硝化菌及喹啉,煤表面疏水性提高。氨氮、苯酚在吸附量分别达到一定量后,对煤表面疏水性的负面影响显现；亲水性反硝化菌吸附使煤表面疏水性明显变差。红外光谱分析表明污染物对煤粉表面疏水性的影响主要是取决于吸附质本身所表现的亲、疏水性官能团。(4)采用单元浮选试验考察焦化中水中各主要污染物对煤可浮性的影响,结果发现：焦化中水中氨氮和苯酚对煤的浮选产生负影响,随着浓度增加,精煤产率和灰分也相应的提高,浮选完善指标也趋于下降,但在一定浮选药剂量下,氨氮、苯酚对精煤的产率和灰分影响较小,通过改变浮选药剂的投加量和配比,可以使焦化中水中氨氮对煤的可浮性影响忽略。喹啉对煤的浮选产生正向影响,在相同药剂量下,废水中喹啉浓度越高,浮选完善指标呈上升趋势,提高3-4个百分点；精煤灰分持平的情况下,精煤产率略有提高。证明了煤粉吸附喹啉能改善了煤的表面疏水性。煤粉吸附焦化中水中硝化菌和反硝化菌,其浮选精煤产率和灰分变化各不相同。原水中含有硝化菌时,精煤灰分要小于清水浮选灰分,且浮选完善指标也随菌液浓度的增加而提高；而反硝化菌却与之相反,反硝化菌使得精煤产率随菌液浓度增大而降低,精煤灰分却逐渐增大。说明硝化菌吸附有利于煤的浮选,反硝化菌则对煤的可浮性有不利影响。更多还原

【Abstract】 Coking industry is the most serious water and environmental pollution one of the industries, the treatment of coking wastewater treatment technology focus only on the development of end to coking wastewater discharge standards for the purpose for a long time. With the diminishing capacity of water environment and the ecological requirements of increasingly stringent, need development, research and application of new biological wastewater treatment process and coking wastewater reuse technology. The topics according to circular economy concept, using coal-based industrial chain of the different requirements on water quality, making a big circle idea:Coal washing and other reasons due to evaporation of water generated tons of coal consumption for the 0.2m3/t of coal (in closed loop as standard), to accept the coking wastewater reuse provides an effective space. The coking wastewater treatment supply water for washing, the introduction of coal preparation plant closed circulation system, use of coal adsorption treatment and flocculation treatment waste water biodegradable pollutants in coking wastewater to achieve zero discharge of a cycle of new technology. Closed water circulation system development and utilization of coal washing plant coking wastewater to achieve zero discharge of a cycle of new technology, need to examine whether the coking of adverse effects of water on the flotation. Coking wastewater by two out of three major pollutants in water analysis and conclusion, using two kinds of coking coal on the simulated secondary effluent wastewater adsorption properties of the major pollutants of wastewater in the determination of rate of microbial hydrophobic pollutants adsorbed on the surface properties of coal and coal can affect the impact of floating, we can draw the following conclusions:(1) The adsorption removal rate of organic pollutants by coke is slightly higher than the fei coal’s, adsorption capacity of coal (-0.5mm) is between 0.1094～0.1544 mg/g. The adsorption of phenol with coke is consistent with the Freundlich adsorption isotherm, and the quinoline is fit with the Langmuir adsorption isotherm, but the adsorption of quinolineis more in line with the Freundlich isotherm on fei coal. Adsorption reaction of organic pollutants is well conformed to the characteristics of second-order reaction kinetics on different types and particle size of pulverized coal, R2=0.990±0.008.The adsorption process is controlled by liquid film diffusion. The rate constant equation In k=188.54e-11.64/(RT) and activation energy Ea=11.64kJ/mol may be obtained under different temperatures by the phenol has been adsorpted on coke.(2) In biochemical treatment of waste water, hydrophobicity and hydrophilicity of microorganisms, from a secondary sedimentation tank, has a significant effect on the deep treatment and recycle of reclaimed water. After compared three kinds of extracting agent, selected optimum bacilli and the best ratio of extracting agent, then the optimum separation conditions were determined. The results showed that capacities of carbon tetrachloride adsorbed micro-organisms were all strong, and micro-organisms could maintain stability in the interface of carbon tetrachloride-water and the carbon tetrachloride layer for a long time. Controlling the concentration of test micro-organisms were basically the same, the best ratio of bacilli and extractant was 2.67 (bacilli:extractant= 12ml:4.5ml). Using low-speed centrifugation (1000r/min、10min) as separation conditions. Main microbial hydrophobic in the actual coking wastewater had been determined, moreover the infrared spectra of microorganisms had been analyzed, proved this method is simple and feasible. It describes the study of hydrophobicity of nitrifying bacteria (NFB) and denitrifying bacteria (DFB) under different pH value, temperature and growth cycles using extraction-turbidimetry to determine hydrophobic percentage of microorganisms. Variation of Zeta potentials and sedimentation of coal particulates in coal suspension was investigated at various conditions of the coal particles absorbed with different hydrophobicity of the microorganisms. The study shows that the hydrophobic percentage of microorganisms varies with pH, temperature, growth cycle, and inactivation of the microorganisms. The NFB appear to be hydrophobic with hydrophobic percentage over 60% while the DFB are hydrophilic with hydrophobic percentage less than 20%.(3) Hydrophobic variation tendency in the coal surface, surface potential and flotability were investigated to study by wetting speed of oil and water (OHR), Zeta potentialand after pulverized coal adsorbed main contamination such as ammonian, phenol, quinoline, and microbe in this paper.Analysis the change of coal surface properties after it adsorbed single pollutant revealing the mechanism of pollution:Zeta potential had a significant change of coal-water system after adsorption of pollutants, Zeta potential was-17.27mv without adsorption, after adsorption of pollutants and micro-organisms, Zeta potential were-21.88mv/-26.62mv (nitrobacteria),-25.21mv/-29.47mv (quinoline),-27.39mv/-32.58mv (phenol),-32.13mv/-38.53mv (ammonian) and -38.80mv/-43.40mv (denitrifying bacteria). The electro-dynamic study on Zeta potentials of coal particulates in coal suspension indicates the coal particles absorbed preferably by the microorganism instead of the other minerals. Absolute value of the Zeta potential of coal particles considerably increases when DFB absorb on their surfaces. The microorganisms are also functioning as a flocculant to flocculate coal particles in the coal suspension to promote sedimentation of the coal slime. The surface hydrophobicity of coal has been increased by adsorbing nitrifying bacteria and quinoline in surface. When coal adsorbed the amount of ammonian, phenol over a certain adsorption respectively, the negative impact of coal surface hydrophobicity was revealed relatively. While coal adsorbed denitrifying bacterium, its surface hydrophobicity deteriorated obviously. Infrared spectroscopy indicated characterization analyzed indicating that the effect of pollutants on the surface of hydrophobic mainly rested with the performance including hydrophilicity, hydrophobicity of the material itself.(4) Cell flotation tests showed the higher the concentration of phenol and ammonia in wastwater, coal and ash yield a corresponding increased in flotation perfect indicators also tended to decline, but to a certain drug dosage of flotation, ammonia, phenol, the yield of the coal and ash effects small, by changing the dosage of flotation reagent and the ratio of ammonia nitrogen could coking coal floatability of impact ignored. Quinoline on the positive effects of coal flotation in the same drug dose, the higher the concentration of quinoline wastewater, flotation perfect indicator was rising, increase 3-4 percentage points; coal ash balanced case, the fine coal production rate increased slightly. Showed that the flotation of coal quinoline positive effect that the foregoing results:coal adsorption quinoline can improve the surface hydrophobicity of coal. Coking coal in the water adsorption nitrifying bacteria and denitrifying bacteria, the flotation concentrate yield and ash change varies. Containing nitrifying bacteria in raw water, the coal ash, the ash is less than clear water flotation and flotation improve the indicators increased with the bacterial concentration increased; and denitrifying bacteria to the contrary, denitrifying bacteria contained in raw water, the concentrate yield decreased with the increase of bacteria concentration, coal ash has increased gradually. Description beneficial nitrifying bacteria adsorption of coal flotation, denitrifying bacteria are on the floatability of coal have an adverse effect.更多还原