絮凝沉淀-SBR组合工艺处理屠宰加工废水工程应用

介绍了絮凝沉淀—SBR组合工艺在屠宰加工废水处理工程中的应用实例.经过3 个月的工程调试和2 年多的实际运行效果表明,当进水COD在1300~1800mg/L之间时,经该工艺处理,出水COO可达到GB8978-1996《污水综合排放标准》一级排放标准,总去除率在90%以上.实践证明,该工艺具有较好的经济效益和环境效益.     

粉煤灰改性处理啤酒废水的研究

以Na2CO3、CaO、HCI、H2SO4等多种试剂作改性剂对粉煤灰进行改性处理,得到改性粉煤灰,并以改性粉煤灰处理啤酒废水,研究了粉煤灰改性的最佳条件及改性粉煤灰处理啤酒废水的机理。结果表明:改性后粉煤灰的吸附混凝性能有显著的提高,啤酒废水中COD的去除率从50%增加到89%。实验确定Na2CO3为最佳改性剂,最佳改性条件为改性剂与粉煤灰的用量比为10mL:5g,室温下搅拌5min,静置30min。     

改良混凝反应器强化混凝效果的研究

通过设置水平隔板强化水力扩散作用,提高了普通混凝反应器的混凝效果;比较了改良与普通混凝反应器对某污水厂二级生化出水的处理效果:在相同的pH值、速度梯度、混合及絮凝时间、沉降时间以及相同的混凝剂种类及剂量下,改良混凝反应器对CODCr、总磷(TP)及浊度的去处效果都优于传统的混凝反应器;当达到相同的CODCr,TP和浊度的去除率时,聚合氯化铝(PAC)投加量分别可以降低25%～50%,20%～30%,20%左右,因此可以大大降低成本。可见改良后的反应器通过改善水力条件、增强传质作用,强化了原水和混凝药剂的混合作用,改善了混凝处理效果,提高了各污染物的去处率,给污水厂及再生水厂混凝沉淀工艺的改造提供了借鉴。     

Remediation of biodiesel wastewater by chemical- and electro-coagulation: a comparative study

The remediation of biodiesel wastewater was carried out using chemical and electrochemical techniques. Initially the fatty acid methyl esters (FAME or biodiesel) and free fatty acids (FFA) were chemically removed from the wastewater using three types of mineral acids, H(2)SO(4), HNO(3) and HCl, at different pH values within the range of 1.0-8.0. Optimally, approximately 24.3 ml/l of FAME/FFA were removed from the wastewater when using H(2)SO(4) to set a final pH of 2.5 for 7 min. All pollutant levels were markedly reduced during this step. That is, approximately 38.94%, 76.32% and 99.36% of COD, BOD5 and oil & grease were respectively removed. The acidic aqueous phase left after the removal of the FAME/FFA phase was then treated by chemical- and electro-coagulation processes. The results demonstrated that both investigated treatment processes were effective for treating wastewater from a biodiesel production plant. The chemical coagulation provided a lower operating cost (1.11 USD/m(3)) compared with the electro-coagulation process (1.78 USD/m(3)). However, the latter process provided a better quality of wastewater compared with the former process, with the exception of the BOD levels.     

Computer simulation of the coagulation of suspended solids — The applicability of the Müller–Smoluchowski theory

The results of studies carried out using a computer programme simulating the coagulation of suspensions containing spherical sol particles and spherical coagulant particles are reported.The influence of the degree of dispersion of the system on the coagulation reaction kinetics was investigated. The obtained results of kinetic studies were tested in the light of classical Müller–Smoluchowski equations. The influence of the physical properties of the coagulant,such as size, density and mass, on the coagulation rate was tested. It was found that within the range described in this paper, the rate of the simulated coagulation process fulfils both the kinetic equation of a first-order reaction, and the kinetic equation of a second-order reaction.Within the tested range, a significant influence of the mass and size of the coagulant on the coagulation rate was ascertained. The kinetic Müller–Smoluchowski dependence is fulfilled in a broader range of the degree of dispersion, when the coagulant particle mass and the sol particle mass are equal. When the particle mass increases with an increase in the particle radius, the coagulation rate increases faster that it would result from the Müller's dependence.     

纳米TiO2-PAC复合絮凝剂的制备及絮凝效果研究

将溶胶-凝胶法制备的TiO2粉体与缓慢加碱法制得的PAC通过超声反应聚合制得纳米TiO2-PAC复合絮凝剂。通过絮凝实验表明：TiO2-PAC无论是在去除悬浮物,还是在降低CODG和色度方面,均优于普通PAC和AlCl30絮凝过程是纳米TiO2的强吸附作用和PAC的吸附电中和、吸附架桥和沉淀网捕作用共同作用的结果。     

Effects of alkalinity on interaction between EPS and hydroxy-aluminum with different speciation in wastewater sludge conditioning with aluminum based inorganic polymer flocculant

Extracellular polymeric substances (EPS) form a stable gel-like structure to combine with water molecules through steric hindrance, making the mechanical dewatering of wastewater sludge considerably difficult. Coagulation/flocculation has been widely applied in improving the sludge dewatering performance, while sludge properties (organic fraction and solution chemistry conditions) are highly changeable and have important effects on sludge flocculation process. In this work, the alkalinity effects on sludge conditioning with hydroxy-aluminum were comprehensively investigated, and the interaction mechanisms between EPS and hydroxy-aluminum with different speciation were unraveled. The results showed that the effectiveness of hydroxy-aluminum conditioning gradually deteriorated with increase in alkalinity. Meanwhile, the polymeric hydroxy-aluminum (Al₁₃) and highly polymerized hydroxy-aluminum (Al₃₀) were hydrolysed and converted into amorphous aluminum hydroxide (Al(OH)₃), which changed the flocculation mechanism from charge neutralization and complexing adsorption to hydrogen bond interaction. Additionally, both Al₁₃ and Al₃₀ showed higher binding capacity for proteins and polysaccharides in EPS than monomeric aluminum and Al(OH)₃. Al₁₃ and Al₃₀ coagulation changed the secondary structure of proteins in EPS, which caused a gelation reaction to increase molecular hydrophobicity of proteins and consequently sludge dewaterability. This study provided a guidance for optimizing the hydroxy-aluminum flocculation conditioning of sludge with high solution alkalinity.     

Removal of F− and organic matter from coking wastewater by coupling dosing FeCl3 and AlCl3

Coagulation and precipitation is a widely applied method to remove F^? from wastewater. In this work, the effect of coagulation on the removal of F^? and organic matter from coking wastewater was studied using AlCl₃ and FeCl₃ as compound coagulants. The removal rates of F^? and organic matter under different coagulant doses and pH conditions were investigated. The results show that the highest removal rates of F^? by AlCl₃ and FeCl₃ are 94.4% and 25.4%, respectively; when the dosage is 10 mmol/L, the TOC removal rates of FeCl₃ and AlCl₃ reach 20.4% and 34.7%, respectively. Therefore, the removal rate of F^? by AlCl₃ is higher than that of FeCl₃, but the removal rate of organic matter by FeCl₃ is relatively higher. The addition of Ca²⁺ can promote the removal of F^?, but the removal rate of organic matter decreases. In addition, by investigating the effects of different pH and Fe–Al ratio on the removal rate, the removal effect of adding FeCl₃ and AlCl₃ at the same time was discussed. The results show that the most suitable working condition for the removal of organic matter and F^? is that the pH is 6.5 and the molar ratio of Al/Fe is 8:2. Overall, the removal mechanism of F^? and organic matter in coking wastewater by FeCl₃ and AlCl₃ was explored in this study. The experimental results can provide reference for the advanced treatment of coking wastewater.     

漂染废水水解——生物接触氧化——混凝处理

采用水解--生物接触氧化--混凝沉淀工艺处理，漂染废水中的主要污染物CODcr、BOD5、色度、SS和PH值都能达到《纺织染整工业污染物排放标准》（GB-4278-92）中一级标准。     

某海洋油田采油废水混凝实验研究

无机铝盐混凝剂处理采油废水的实验表明,PAC在最佳投药量即750mg／L时,COD、BODs、KS和总P的去除率分别为64％、52．8％、91．5％和78．3％。Al2（SO4）3和PAM的投药量为750mg／L和1mg／L时,COD、BOD5、SS和总P的去除率分别为61．5％、40．9％、91．4％和75．3％。出水BODs／COD由0．32提高至0．42,可生化性明显提高。