电絮凝处理海水中污染物的研究

采用铁电极和铝电极对电絮凝处理受污染海水过程中浊度和化学需氧量(COD)去除效率进行了研究,试验结果表明:电絮凝处理海水工艺对浊度具有一定的去除效果,其去除率可达85%以上,铝电极的处理效果要好于铁电极。对电絮凝处理海水过程中COD的去除效率进行了试验研究,试验中发现电絮凝处理海水过程中剩余COD值与电流密度呈二级反应关系,并拟合出相应的动力学方程。     

电絮凝法深度除磷的试验研究

用电絮凝法深度处理污水二级处理厂出水,解决了前面工艺除磷效果不太理想的问题.取二级污水处理厂出水,测定了电流密度、电极间距、原水pH以及电解时间等因素对电絮凝法深度除磷效果的影响.试验表明:电絮凝法深度除磷的效果明显;在电解密度为7.82 A/m2,电极间距为15mm,水样pH保持在中性或弱碱性条件下,电解时间为15～...     

利用电絮凝法深度处理二级处理生活污水出水的研究

采用双铝极板,利用电絮凝法对城市生活污水二级处理出水进行处理,以氨氮、总磷和COD的去除率等为指标,通过探索电解时间、极板间距、电流密度、pH值等参数的单因素影响分析,研究各参数对处理效果的影响,确定最佳条件。实验表明,采用双铝极板电絮凝法深度处理城市生活污水二级处理出水可有效的去除氨氮、总磷和COD。     

交变脉冲电源下的电絮凝研究

以铁电极作为电极阳极,研究了在交变脉冲电源条件下,不同溶液电导率条件下的电絮凝表现.实验表明,控制电源脉冲频率30Hz的条件下,连续过流时铁溶出量符合法拉第定律.但随着溶液电导率增加,溶出铁量逐步增加,电流效率也逐步增加.在每一个溶液电导率条件下,电极间距的设计都有相关的优化条件.电极倒极操作虽然有助于系统电极溶出改善...     

铁空气电池产电同步絮凝除磷性能及影响因素研究

利用碳基空气阴极构建铁-空气电池絮凝反应器,考察电池外阻、溶液电导率、初始pH值对铁空气电池絮凝除磷及电池产电的影响。结果表明,在10Ω外阻,NaCl浓度10 mmol/L,磷酸盐浓度5 mg/L条件下,絮凝时间40 min,不同初始pH条件下,磷酸盐去除率可达到98%以上,电池平均电流密度达到0.22 mA/cm²。对实际生活污水的絮凝实验表明,磷酸盐浓度5 mg/L时,絮凝40 min,磷酸盐浓度降低至0.5 mg/L以下,满足一级A排放标准要求。     

铁空气电池产电同步絮凝除磷性能及影响因素研究

利用碳基空气阴极构建铁-空气电池絮凝反应器,考察电池外阻、溶液电导率、初始pH值对铁空气电池絮凝除磷及电池产电的影响。结果表明,在10Ω外阻,NaCl浓度10 mmol/L,磷酸盐浓度5 mg/L条件下,絮凝时间40 min,不同初始pH条件下,磷酸盐去除率可达到98%以上,电池平均电流密度达到0.22 mA/cm~2。对实际生活污水的絮凝实验表明,磷酸盐浓度5 mg/L时,絮凝40 min,磷酸盐浓度降低至0.5 mg/L以下,满足一级A排放标准要求。     

电絮凝法在水处理过程中影响因素研究现状

电絮凝过程是一种物理化学反应过程,能够有效去除水中的悬浮物、胶体、可溶物等各类形态污染物,具有去除率高、对环境影响小、污泥产率低、操作简单、化学药品投加量小等优势。介绍了电絮凝的主要作用机理,综述了电絮凝反应过程中影响处理效率的各类重要因素,如电源、电极材料、极板间距、p H、共存离子等,并提出目前电絮凝技术的局限性和未来发展趋势。     

高浊度原水絮凝过程的动力学和机理研究

选用无机低分子铝盐，铁盐和无机高分子聚合氯化铝以及无机与有机高分子聚丙烯酰胺复配等絮凝剂处理高浊度原水，测定了余浊，水体密度与静沉时间的变化曲线；采用多次多因素水平正交试验进行最佳水力条件选择，并结合矾花大小变化对絮凝过程动力学和机理进行深入研究，为管式絮凝器的研制提供理论为依据。     

电絮凝过程电流密度与槽电压关系研究

测定了不同材料电极的i-V关系曲线,研究了电解过程中溶液电导率、电极板间距以及电电极联结方式对i-V关系的影响。实验表明,在槽电压V相同时,铁电极的电流密度大于石墨电极,远大于铝电极。在相同电流密度i下,高浓度电导率对应的槽电压较低,而且随着i的增加,不同溶液电导率下的槽电压差别增大。在槽电压V相同时,随着电极板间距的增加,电流密度逐渐减小。不同电极板间距下铁电极的i-V曲线均呈现良好的线性关系。铁电极的电压梯度与电极板间距之间存在很在的线性关系。对应于相同的电流密度,单极式联结的槽电压远小于复式联结的槽电压。     

电化学法去除工业垃圾渗滤液中的总磷

采用电絮凝-电化学氧化组合工艺对工业垃圾渗滤液中的总磷(TP)进行去除。首先考察了电极材质、电极间距、电解电压、电解时间、曝气时长、反应体系pH等反应条件对电絮凝TP去除效果的影响,并综合经济性得到电絮凝除磷的最佳工艺条件为：铁、铝电极,脉冲电源,电极间距1.0 cm,铁电极电解电压2.0 V,电解20 s倒极,铝电极电解电压2.5 V,电解10 s倒极,反应体系pH 7～8,电解总时间15 min,电絮凝结束后无需采用曝气辅助除磷。在此最佳条件下,TP为11～15 mg/L的渗滤液样本经电絮凝处理后残余TP降至1.0～1.3 mg/L,TP去除率可达91.7%。将电絮凝工艺同Ti/Ru O₂-Ir O₂电极电化学氧化工艺组合,用于处理TP为14.7 mg/L的渗滤液,处理后渗滤液残余TP为0.2 mg/L,满足工业垃圾渗滤液TP≤0.3 mg/L的直接排放标准。同时,处理后渗滤液COD及氨氮也大幅下降,表明电絮凝-电化学氧化组合工艺对渗滤液样本中氨氮、COD也具有一定的处理能力。     

Effects of alternating and direct current in electrocoagulation process on the removal of fluoride from water

BACKGROUND: When direct current (DC) is used in electrocoagulation processes, an impermeable oxide layer may form on the cathode and corrosion of the anode may occur due to oxidation. This prevents effective current transfer between the anode and cathode, so the efficiency of the electrocoagulation process declines. These disadvantages of DC have been reduced by adopting alternating current (AC). The main objective of this study is to investigate the effects of AC and DC on the removal of fluoride from water using an aluminum alloy as anode and cathode. RESULTS: Results showed that removal efficiencies of 93 and 91.5% with energy consumption of 1.883 and 2.541 kWh kL^?1 was achieved at a current density of 1.0 A dm^?2 and pH 7.0 using an aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of fluoride fitted the Langmuir adsorption isotherm. The adsorption process follows second‐order kinetics and temperature studies showed that adsorption was exothermic and spontaneous in nature. CONCLUSIONS: The aluminum hydroxide generated in the cell removed the fluoride present in the water and reduced it to a permissible level thus making it drinkable. It is concluded that an alternating current prevents passivation of the aluminum anode during electrocoagulation and avoids the additional energy wasted due to the resistance of the aluminum oxide film formed on the anode surface. Copyright © 2010 Society of Chemical Industry     

氧化沟工艺生物除磷试验研究

以生活污水为研究对象,采用厌氧一缺氧一氧化沟工艺对氧化沟的除磷性能进行了研究,结果发现:(1)该工艺具有较好的除磷效率,稳定阶段TP去除率能够达到90%,出水TP平均为1.62ms/L.(2)序批式试验中前30min磷的释放速度很快,单位MLSS的释磷速率为10.75mg/(g·h),而在30～120min磷释放速率很低,为0.48mg/(g·h).(3)出水TP的浓度与出水NO3较好的相关关系.(4)该工艺进水COD为340.4mg/L时,出水COD为50.7mg/L,COD去除率为84.5%;大量COD在厌氧区转化为聚磷菌胞内聚合物而去除,这部分胞内聚合物能够在缺氧区充当电子受体被二次利用.     

多段式接触氧化工艺除磷效果及污泥磷回收研究

利用多段式接触氧化法工艺的中试装置(有12级反应槽)处理北京某污水处理厂的污水,以污泥减量为目的研究不同水力停留时间和曝气量下装置的除磷效果及12格沿程的磷变化情况,探究污泥灰分磷回收。结果表明,水力停留时间24 h相对于12 h,装置抗冲击负荷能力较好,且磷去除率高达91. 92%,优于传统生物除磷工艺,腐殖污泥磷含量74. 5 mg P/g DS,其灰分磷含量高达167 mg P/g SA,相当于高品位磷矿,采用盐酸作为浸出剂时,可快速从腐殖污泥灰分中提取90%的磷。     

多段式接触氧化工艺除磷效果及污泥磷回收研究

利用多段式接触氧化法工艺的中试装置(有12级反应槽)处理北京某污水处理厂的污水,以污泥减量为目的研究不同水力停留时间和曝气量下装置的除磷效果及12格沿程的磷变化情况,探究污泥灰分磷回收。结果表明,水力停留时间24 h相对于12 h,装置抗冲击负荷能力较好,且磷去除率高达91. 92%,优于传统生物除磷工艺,腐殖污泥磷含量74. 5 mg P/g DS,其灰分磷含量高达167 mg P/g SA,相当于高品位磷矿,采用盐酸作为浸出剂时,可快速从腐殖污泥灰分中提取90%的磷。     

改良ORBAL氧化沟工艺除磷脱氮功效探讨

主要介绍了改良ORBAL氧化沟的工艺情况,探讨了其除磷脱氮功效。通过对溶解氧、泥龄、进水及回流方式的合理控制,可成功缓解除磷与脱氮之间的矛盾。试验表明：当系统泥龄控制在10-19d时．污水进水和污泥回流25％到缺氧沟,75％到厌氧沟,可获得良好的除磷脱氮效果(出水总磷质量浓度≤0．5mg／L,总氮≤15mg／L)。     

The effects of alternating current electrocoagulation on dye removal from aqueous solutions

The main goal of this study is to investigate the effects of alternating current (AC) on dye removal from aqueous solutions by electrocoagulation (EC). An EC system with parallel-connected aluminium electrodes was operated in batch mode. Two different aqueous dye solutions were used: one was obtained from Dianix Yellow CC (DY) and the other was obtained using Procion Yellow (PY). The experiments employing direct current (DC) were carried out using a DC power supply. The AC experiments were conducted using rectangular wave, which is produced with an adjustable time relay connected to the output of DC power supply. This current is called alternating pulse current (APC) in order to refer AC system in this study. Total organic carbon (TOC) and dye removal efficiencies were measured to assess treatment efficiency. Operating cost was calculated for both power supply systems and alternating pulse current was found superior to direct current for the treatment of reactive and disperse dyes used in this study.     

反硝化除磷+短程反硝化厌氧氨氧化工艺的深度脱氮除磷效能

为经济高效地去除城市生活污水和硝酸盐废水中的氮磷元素,本研究在厌氧折流板反应器（ABR）和连续搅拌反应器（CSTR）一体式反应器中分别建立了反硝化除磷（DPR）和短程反硝化厌氧氨氧化（PDA）工艺。结果表明,反应器运行185天,在缺氧/厌氧和外加COD/NO{}_{\mathrm{3}}^{-}-N比仅为0.7条件下,PO{}_{\mathrm{4}}^{\mathrm{3}-}-P和TN的去除率高达96.91%和97.75%,最终出水PO{}_{\mathrm{4}}^{\mathrm{3}-}-P和TN的浓度低至0.22mg/L和3.30mg/L,意味着该系统极佳的脱氮除磷效果不依赖氧气和有机碳源量。DPR对系统PO{}_{\mathrm{4}}^{\mathrm{3}-}-P和TN的去除均占主体部分（99.07%和60.23%）,而PDA对总氮（TN）的去除占比呈现逐渐上升的趋势（4.53%→37.52%）。批次实验表明：①COD（300mg/L）显著抑制DPR菌活性,PO{}_{\mathrm{4}}^{\mathrm{3}-}-P主要是在缺氧状态下以NO{}_{\mathrm{3}}^{-}-N为电子受体,有机物为电子供体通过DPR途径去除;②高效短程反硝化过程（亚硝酸转化率92.25%）稳定为厌氧氨氧化供给电子受体（NO{}_{\mathrm{2}}^{-}-N）,DPR系统剩余NH{}_{\mathrm{4}}^{+}-N主要被NO{}_{\mathrm{2}}^{-}-N氧化去除,因此DPR+PDA系统实现了高效同步脱氮除磷效果。高通量测序表明,Accumulibacter（7.41%）是DPR系统功能性除磷菌,Thauera（7.24%）和Candidatus Brocadia（3.12%）为PDA系统关键脱氮菌。     

Trivalent chromium removal by electrocoagulation and characterization of the process sludge

Removal of chromium compounds from wastewater is a known pollution control challenge for environmental engineers. In this present work Cr³⁺ was removed from wastewater by electrocoagulation (EC) using Al electrodes in a batch cell. Results indicate that EC with an Al electrode can reduce Cr³⁺ concentration below 2.0 mg L^?1, its discharge limit. At higher stirrer speed, Cr³⁺ removal increases owing to enhanced contact with the Al³⁺ species. Cell current density controls the rate of Al dissolution and solution pH that affects the Cr³⁺ removal significantly. pH elevation during EC is due to accumulation of OH^? ions forming a supersaturated solution of Al³⁺ species. Supersaturation with respect to Al(OH)₃(s) is attributed to incomplete precipitation of aluminum hydroxide in the dynamic (transient) state and subsequent precipitation when cell current is stopped. Sludge produced in the process can be classified as non‐hazardous according to the European Waste Catalogue. Disposal cost of this dried sludge is estimated to be $ 0.144 (INR 7.20) per m³ of tannery effluent treating an initial solution of 1000 mg L^?1 Cr³⁺ to about 2.0 mg L^?1 Cr³⁺. Batch gravity settling characteristics of the electrocoagulated metal hydroxide sludge (EMHS) at different initial sludge loadings (as generated at different current density) is also investigated. Batch sedimentation flux is reported from experimental settling velocity and concentration of sludge. Copyright © 2007 Society of Chemical Industry     

Evaluation of multiloop chemical dosage control strategies for total phosphorus removal of enhanced biological nutrient removal process

We developed several control algorithms and compare their control performances for controlling the total phosphorous (TP) concentration in wastewater treatment plant, which has strong influent disturbances and the disturbance effects should be removed while maintaining better effluent quality. An anaerobic - anoxic - oxic (AAO) process, which is a well-known advanced nutrient removal process, was selected as a case study, which is modeled with activated sludge model no. 2. Six control strategies for TP control with a polymer addition were implemented in AAO process and evaluated by the plant’s performance, where the costs of the dosed chemical were compared among the six controllers. The experimental work showed that the advanced control techniques with feedback, feedforward and feedratio controllers were able to control the TP concentration in the effluent, which must be less than 1.50 g P/m³ which is the legal limitation, while reducing the necessary chemical cost. The results showed that the best TP removal performance in the effluent TP removal could be achieved by advanced feedback controller with the tuned control parameters, which showed the best effluent quality and control performance index as well as the cheapest cost of chemical dosage among the six TP control strategies.