电镀污水处理的pH＼ORP自动控制系统

为了保证电镀污水处理效果,采用pH/ORP自动控制系统,该系统主要部分组成: ①监测、控制和记录仪表; ②pH/ORP探头(电极)和支架; ③污水反应池; ④计量加药泵和化学药剂溶液贮槽; ⑤混合(搅拌)机械。 待处理的污水流入反应池,池中在出流处安装pH/ORP电极探头,探头把污水的pH值或ORP(氧化还原电位)值讯号传送到控制器,     

ORP检测在水处理中的应用

介绍了氧化还原电位ORP检测在国内、外对饮用水、泳池水和温泉消毒以及污水生物处理等方面的研究及应用现状，分析了应用中存在的问题，并提出了ORP检测在我国水处理工业中的研究和发展方向。     

二次启动法培养无凝结核的硫酸盐还原颗粒污泥

采用自制EGSB反应器,通过二次启动法培养无凝结核的硫酸盐还原颗粒污泥。第一阶段为非硫酸盐还原培养阶段,在进水有机负荷为10.20kgCOD/(m3.d)、碱度为3000mg/L、回流比为3.6∶1时,可初步培养出厌氧颗粒污泥,其以黑色为主,直径为1～2mm,此时对COD的去除率可达90%以上,出水pH值稳定在6.5～7.5之间,ORP值为-250mV左右;第二阶段为硫酸盐还原阶段,在保持其他条件不变的情况下添加1000mg/L的硫酸盐,成功培养出硫酸盐还原颗粒污泥,EGSB反应器对COD和硫酸盐的去除率均稳定在70%左右,出水中的硫化物含量为25mg/L、pH值为6.8～7.5、ORP值为-300～-350mV。硫酸盐还原颗粒污泥呈深黑色、椭球状,无凝结核,生长有大量微生物,以杆菌及弧菌为主,粒径主要分布在2～3mm的范围内。     

ORP用于优化改良型Carrousel氧化沟脱氮的研究

在水处理系统中,氧化还原电位(ORP)是一个反映系统氧化还原能力的状态参数,能够指示对污染物的去除过程。分析了改良型Carrousel氧化沟内ORP值的变化情况,以及与DO、NO3--N、NH3-N浓度的相关性,考察了ORP对于脱氮的指导作用,并在不同HRT、水温下进行了验证。在较为稳定的系统中,ORP与DO和NO3--N浓度分别呈对数和指数关系(R2>0.90),且主要受DO浓度的影响。在水温为18～20℃时,控制曝气后的ORP为40～50 mV、总体ORP在-30～50 mV内可取得较好的脱氮效果,SND效率达到最优,ORP显示出良好的脱氮指示作用,但在不稳定期ORP对脱氮缺乏指导意义。最后论证了改良型氧化沟系统在生产中建立基于ORP和DO联合脱氮控制模式的可行性。     

产酸脱硫反应器中COD/SO42-比对硫酸盐去除率的影响研究

采用两相厌氧生物处理工艺的产酸相作为硫酸盐还原单元,以食用红糖为碳源,通过连续流实验,重点研究了产酸相中COD/SO42-值(C/S)对SO42-去除率的影响.在34±1 ℃、进水碱度(ALK)300～500mg/L、pH 6.0～6.2、氧化还原电位(ORP)-250～-350mV等条件下,当进水C/S＜2.0时,SO42-去除率小于81%;当进水C/S值为2.5～2.0时,SO42-去除率为90～81%;当进水C/S值为大于2.5时,SO42-去除率为90%以上.随着C/S值的降低,SO42-的去除效果会将有所降低.     

地下水生物除锰效果及其影响因素

通过小试研究了DO、pH值和滤柱关闭等因素对地下水生物除锰的影响,探讨了氧化还原电位(ORP)与生物除锰的关系。结果表明,当出水DO从0.9mg/L增加到5.7mg/L,生物滤柱出水含锰量均小于0.05mg/L,且没有明显变化;当出水pH值为5～8.5时,出水含锰量<0.1mg/L,但当pH<5时,出水含锰量随进水pH值的降低而急剧增加;当ORP为430～720mV时,生物滤池具有良好的除锰效果;滤柱关闭28d对生物除锰效果的影响短暂、轻微。     

淡化海水并网供水的管网铁释放控制技术研究

淡化海水由于具有较强的侵蚀性,并网供水后会对既有供水管网造成严重的铁释放现象和黄水问题。为了有效地控制管网铁释放,利用管段模拟反应器,定量研究了调节pH值、碱度、硬度和投加缓蚀剂对管网铁释放的控制效果。研究发现,提高pH值、增加碱度和硬度、投加磷酸盐缓蚀剂均可使淡化海水并网供水后造成的管网铁释放量明显降低。由此初步确定了控制淡化海水进入供水管网造成铁过量释放所需满足的水质条件为:管网水的pH值在7.70以上,碱度>80 mg/L,硬度>80 mg/L;必要时可选择投加0.25～0.50 mg/L的聚磷酸盐缓蚀剂。     

好氧/缺氧循环SBR工艺的脱氮研究

当原水碱度不足时，针对SBR工艺，采用好氧／缺氧循环的运行方式进行脱氮性能及其过程控制的研究。结果表明，通过在线监测pH值的变化可以判断硝化反应过程中碱度是否充足、氨氮是否全部被氧化，相应的控制策略为：如果好氧／缺氧的循环次数超过2次，那么第一次硝化反应以pH值下降0．4～0．5来控制好氧时间，中间的每一次硝化反应以pH值下降0．8～1．0来控制好氧时间，最后一次硝化过程根据DO与pH值变化曲线上的跃升点控制反应时间；每次的缺氧反硝化都根据ORP与pH值曲线上拐点的出现来控制缺氧时间。与传统运行方式相比，采用好氧／缺氧循环运行方式及上述控制策略可使脱氮效率得到明显提高。     

无外加碳源SBBR脱氮工艺及其控制方法研究

为提高脱氮效果并实现利用内碳源进行反硝化,开展了SBBR（以好氧-缺氧方式运行）处理生活污水的脱氮研究.在好氧阶段,SBBR中的生物膜能创造缺氧微环境并吸收、储存碳,实现了同步硝化反硝化,降低了硝态氮的浓度;在缺氧阶段,可利用内碳源实现剩余硝态氮的反硝化.溶解氧浓度的大小对好氧时间、好氧剩余硝态氮浓度和缺氧反应时间有较大影响,因而可以利用在线检测的DO作为曝气量控制参数.DO、pH和ORP值的变化具有规律性,反映了生物脱氮过程中耗氧和供氧、产酸和产碱、氧化和还原过程的变化.为准确判断好氧和缺氧反应过程的终点,并减少控制的滞后时间,建议以pH值的＂氨谷＂和ORP的＂硝酸盐膝＂作为主控制特征点分别指示硝化和反硝化的终点,而以ORP的＂氨肘＂和pH值的＂硝酸盐峰＂作为参考或辅助控制特征点.     

应用DO、pH和ORP在线控制A/O硝化过程

开展了应用DO、pH和ORP传感器在线控制A/O工艺硝化过程的试验研究,结果表明,好氧区第1格室的DO浓度可以指示进水氨氮浓度高低;好氧区首、末端pH差值与进水氨氮浓度具有较好的相关性;好氧区pH曲线可以指示系统硝化进行的程度及曝气量和碱度是否充足;好氧区末端ORP值与出水氨氮、硝酸氮浓度具有很好的相关性;好氧区最后格室的DO浓度和ORP值呈对数相关性。基于上述在线信息建立的A/O工艺硝化过程控制策略,不但能提高出水水质,而且降低了运行能耗。     

饮用水钙硬度去除中C/Ca值对CaCO3结晶的影响

饮用水中钙硬度去除效能主要受CaCO3结晶过程影响。通过改变C/Ca值模拟饮用水钙硬度去除,考察不同C/Ca值条件下,溶液体系pH值和Ca^2+浓度变化、上清液浊度变化以及结晶产物颗粒粒径分布、晶型和形态,以阐明钙硬度去除过程中CaCO3结晶行为。结果表明:试验条件下结晶产物均为方解石;溶液体系中加入的CO3^2-首先发生质子化,提高体系pH值,然后与Ca^2+结晶反应降低体系pH值;C/Ca值的增大提高了pH值,有助于Ca^2+的去除,但同时也会提高结晶产物颗粒数量、密度和减小结晶产物颗粒粒径,导致上清液浊度增大。饮用水钙硬度去除中要综合考虑残余Ca^2+浓度、出水pH值和浊度以及混凝剂用量等来优化确定C/Ca值。     

Electrochemical denitrificaton of simulated ground water

Electrochemical denitrification of ground water was studied with an objective to maximize nitrate transformation to nitrogen gas. Aluminum, graphite, iron and titanium were selected as electrode materials. While aluminum, iron and titanium electrodes showed 70-97% nitrate reduction, with graphite electrode the removal was only 8%. Nitrate was transformed to ammonia with iron and aluminum electrodes but with titanium electrodes nitrogen was apparently the major end product. Iron electrodes exhibited the maximum reducing condition (ORP=-463mV) and titanium showed the minimum (ORP=-206mV). Nitrate reduction with titanium electrodes was retarded in the presence of chloride ions possibly due to formation of hypochlorite ions. The first-order nitrate transformation rate constant with respect to time decreased with decrease in current density. However, when the rate constant was expressed with respect to charge passed (Coulomb/l) it was nearly same under different experimental conditions (current density and pH). The study indicates that the process might be suitable for denitrification of drinking water.     

Ozonation kinetics of winery wastewater in a pilot-scale bubble column reactor

The degradation of organic substances present in winery wastewater was studied in a pilot-scale, bubble column ozonation reactor. A steady reduction of chemical oxygen demand (COD) was observed under the action of ozone at the natural pH of the wastewater (pH 4). At alkaline and neutral pH the degradation rate was accelerated by the formation of radical species from the decomposition of ozone. Furthermore, the reaction of hydrogen peroxide (formed from natural organic matter in the wastewater) and ozone enhances the oxidation capacity of the ozonation process. The monitoring of pH, redox potential (ORP), UV absorbance (254 nm), polyphenol content and ozone consumption was correlated with the oxidation of the organic species in the water. The ozonation of winery wastewater in the bubble column was analysed in terms of a mole balance coupled with ozonation kinetics modeled by the two-film theory of mass transfer and chemical reaction. It was determined that the ozonation reaction can develop both in and across different kinetic regimes: fast, moderate and slow, depending on the experimental conditions. The dynamic change of the rate coefficient estimated by the model was correlated with changes in the water composition and oxidant species.     

pH值对高铁酸盐复合药剂强化除藻的影响

探讨了ＰＨ值对高铁酸盐复合药剂强化混凝除藻效果的影响规律,分别考察了原水ＰＨ为５．０、７．０和１０．０条件下高铁酸盐复合药剂预氧化对除藻效率的影响规律。试验结果表明,对于微酸性原水（ＰＨ＝５．０）,高铁酸盐复合药剂强化混张除灌效果最好;随着提高,高铁酸盐复合药剂强化混凝除藻效果逐渐降低,但即使在高校ＰＨ值条件下（ＰＨ＝１０．０）仍然可取得明显的强化除藻效果。     

臭氧/高锰酸盐预氧化助凝及影响因素

提出了高锰酸盐强化臭氧氧化助凝技术,并分析了复合氧化助凝效果的各种影响因素。试验结果表明,复合氧化比单独臭氧氧化更有利于对浊度的去除。复合氧化的投加顺序是先投加高锰酸盐后投加臭氧,较佳的剂量配比是高锰酸盐0.4mg/L与臭氧1.0mg/L。复合氧化除浊的效果受诸多因素影响,复合氧化可适应更大的G值变化范围;助凝效果受原水水质的影响,原水硬度为160mgCaCO3/L时助凝效果最佳,原水TOC浓度为3mg/L时对混凝的影响最小;低温有助于复合氧化助凝;复合氧化受pH值影响较小,可以适应较大范围的pH值变化。与臭氧氧化相比,复合氧化更能适应水力和水质条件的变化。     

Electrochemical treatment of human urine for its storage and reuse as flush water

We proposed the electrochemical treatment of human urine to enable its storage without the accompanying unpleasant odor. This urine can then be reused as flush water in toilets as a means to tackle water shortage problems. In laboratory-scale experiments, the time-dependent variation in the pH of human urine, after the addition of urease, could be suppressed by chlorine produced via the electrochemical treatment of diluted human urine. Ureolysis was quantified by pH increase within 100 h. This suppression occurred as a result of an irreversible change in the conformation of urease that resulted in its inactivation at an oxidation-reduction potential (ORP) of ca. 240 mV or above. Due to the electrochemical inactivation of urease during the entire storage period of urine, the hydrolysis of urea in urine, which results in the production of the unpleasant odor due to ammonia formation, can be avoided. Thus, the treatment enables the storage of urine for its reuse as flush water in toilets.     

Ozonation kinetics of cork-processing water in a bubble column reactor

The oxidative degradation of organic pollutants present in cork-processing water at natural pH (6.45) was studied in a bubble column ozonation reactor. A steady reduction in both chemical oxygen demand (COD) and total organic carbon (TOC) was observed under the action of ozone alone and the feasibility of deep mineralisation (organic matter removal more than 90% in 120 min under the following experimental conditions: liquid volume 9L; superficial gas velocity 6.8x10(-3) m s(-1); ozone partial pressure 1.31 kPa; initial COD 328 mg L(-1); initial TOC 127 mg L(-1)) was demonstrated. The monitoring of pH, redox potential (ORP) and the mean oxidation number of carbon (MOC) was correlated with the oxidation and mineralisation of the organic species in the water. The ozonation of cork-processing water in the bubble column was analysed in terms of a mole balance coupled with ozonation kinetics modelled by the two-film theory of mass transfer and chemical reaction. Under the experimental conditions used, and in contrast with the literature, it was determined that the reaction follows a fast kinetic regime at the beginning of the oxidation process, shifting to the moderate and the slow kinetic regimes at later stages of the oxidation reaction. The dynamic change of the rate coefficient estimated by the model was correlated to changes in the water composition.     

原水突发六价铬污染的应急处理技术

本文以南方某水源水库水为研究对象,探讨了采用硫酸亚铁还原、碱性条件下沉淀去除原水中高含量六价铬的可行性。研究结果表明,只要原水的酸碱性适宜、硫酸亚铁的投加量足够,混凝沉淀的pH值控制得当,对总铬的去除率可以达到接近100％,且出厂水中总铁和铝的浓度都能达到生活饮用水水质标准的要求。偏酸性的原水（pH3～5）有利于六价铬的去除,但对于试验的中性原水,不调节pH值出厂水中的总铬也能降低至0．05mg／L以下;硫酸亚铁的投加剂量以3倍最低化学反应剂量为宜,即硫酸亚铁剂量与六价铬浓度比为26;沉淀反应的pH值控制在8．5左右。     

Oxidation of microcystins by permanganate: reaction kinetics and implications for water treatment

A few genera of cyanobacteria produce toxins which contaminate drinking water resources. Microcystins (MC), widely reported cyanotoxins, cause acute and chronic toxicity effects in living beings including humans and warrant removal from drinking water. In the present study, unknown second-order rate constants for the reactions of microcystin-LR (MC-LR), -RR and -YR with potassium permanganate were determined at pH 6.2-8.2 and temperature 10-25 degrees C. The reaction of permanganate with MCs is second-order overall and first-order with respect to both permanganate and toxin. The second-order rate constant for the reaction of MC-LR with permanganate at pH 7 and 20 degrees C was 357.2+/-17.5M(-1)s(-1). The influence of pH on the oxidation process was not appreciable and the activation energy was 28.8 kJ mol(-1). Slightly higher reactivity with permanganate was found for MC-RR (418.0M(-1)s(-1)) and MC-YR (405.9M(-1)s(-1)). According to the results obtained, permanganate likely attacks the Adda moiety of the MC molecule. The oxidation of MCs in a natural surface water was also investigated. A permanganate dose of 1-1.25mgL(-1) was enough to reduce MCs concentration below the guideline value of 1microgL(-1). Permanganate oxidation is therefore a feasible option for microcystin removal during preoxidation processes. However, the oxidant dose must be carefully optimized in order to remove extracellular MCs without causing cell lysis (due to chemical stress) and further release of MCs.