Treatment of phosphate-containing oily wastewater by coagulation and microfiltration

The oily wastewater generated from pretreatment unit of electrocoating industry contains oils, phosphate, organic solvents, and surfactants. In order to improve the removal efficiencies of phosphate and oils, to mitigate the membrane fouling, coagulation for ceramic membrane microfiltration of oily wastewater was performed. The results of filtration tests show that the membrane fouling decreased and the permeate flux and quality increased with coagulation as pretreatment. At the coagulant Ca （OH）2 dosage of 900 mg/L, the removal efficiency of phosphate was increased from 46.4% without coagulation to 99.6%; the removal of COD and oils were 97.0% and 99.8%, respectively. And the permeate flux was about 70% greater than that when Ca（OH）2 was not used. The permeate obtained from coagulation and microfiltration can be reused as make-up water, and the recommended operation conditions for pilot and industrial application are transmembrane pressure of 0.10 MPa and cross-flow velocity of 5 m/s. The comparison results show that 0.2 μm ZrO2 microfilter with coagulation could be used to perform the filtration rather than conventional ultrafilter, with very substantial gain in flux and removal efficiency of phosphate.

Preparation and Application of Polymer Silicate Phosphate Ferric Sulfate Used in High-Viscosity Oil Refining Wastewater Treatment

A new kind of flocculants, named Polymer Silicate Phosphate Ferric Sulfate(PSPFS), was synthesized by ferrous sulfate used as the main material and activated silicic acid as additive. In this paper, High-Viscosity Oil Refining wastewater from Liaohe Petrochemical Corporation was the treatment object. Overall, the in-fluencing factors and synthesis technology conditions of PSPFS were determined by experiments. First of all, the conditions of influencing factors were showed as follows: the mass percent concentration of ferrous sulfate 55%,concentration of sodium silicate 15% , the molar ratio of ferrous sulfate and hydrogen peroxide 1.2:1, oxidation temperature 40 degree Celsius, oxidation time 4 hours, polymerization temperature 60 de-gree Celsius and polymerization time 2 hours. Secondly, the optimal ratios of components were determined by uniform design method. The molar ratio of Fe/Si is 5.0:1, Fe/H2SO4 is 3.2:1, and Fe/P is 18.0:1. At last, the optimal experimental condition was determined as follows: the dosing quantity 200mg/L, pH value 5.5~9, temperature 25~45℃, stirring time 2 min, and standing time 3 min, according to the result of floc-culation experiments with PSPFS. Besides, the result of the comparative experiments showed that the effi-ciency of PSPFS was much better than the reference flocculants.

Kinetic and Thermodynamic Study of the Dephosphation of Wastewater by Clay Materials from Côte d’Ivoire

Phosphorus is introduced into the aquatic environment from different point sources, mainly by domestic and industrial wastewater;contributing to the eutrophication of water bodies. The most common way for wastewater dephosphation is the injection of expensive chemicals into these bodies of water. Thus, the main objective of this work was to find an alternative to chemicals by using clay materials from Côte d’Ivoire to adsorb phosphate ions from aqueous solutions. The clay samples, taken from various regions were characterized by X-ray diffraction. They have a different mineralogical composition. The influence of various parameters such as the pH of the medium, contact time, the ion force, temperature, etc. on the adsorption was studied. Adsorption is influenced by the temperature, the pH of the medium, valence of the saturated cation and the clay composition. It is described by a kinetic model of the pseudo-second order. The salt of the medium has no significant effect on the process. The thermodynamic study revealed that adsorption is spontaneous, endothermic and that it is done by electrostatic means of physical nature.

Mechanism of high concentration phosphorus wastewater treated by municipal solid waste incineration fly ash

The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier transform infrared spectroscopy),BET(specific surface area),and BJH(pore size distribution).The results indicate that the removal rate of phosphate(100 mg/L)in 50 mL phosphorus wastewater reaches at 99.9% as the dosage of MSWI fly ash being 0.9000 g under room temperature.The specific surface area of MSWI fly ash is less than 6.1 m2/g and the total pore volume is below 0.021 cm3/g,suggesting that the absorption capacity of calcite is too weak to play an important role in phosphate removal.SEM images show that drastic changes had taken place on its specific surface shape after reaction,and EDS tests indicate that some phosphate precipitates are formed and attached onto MSWI fly ash particles.Chemical precipitation is the main manner of phosphate removal and the main reaction is: 3Ca2++2 PO4 3-+xH2O→Ca3(PO4)2↓·xH2O.Besides,XRD tests show that the composition of MSWI fly ash is complex,but CaSO4 is likely to be the main source of Ca2+.The soluble heavy metals in MSWI fly ash are stabilized by phosphate.

Removal of Nitrogen and Phosphorus from Saline Wastewater Using Up-Flow Sludge Blanket Filtration Process

There is recent trend of providing additional treatment of wastewater beyond tertiary level. The purpose is to refine water to a quality that is safe for reuse for unrestricted irrigation and other non potable uses. For this purpose, Kuwait has built and operated an advanced wastewater treatment plant with capacity of 500,000 m3·dl. This plant providing treatment beyond tertiary utilizes the process of Ultra Filtration （UF） and Reverse Osmosis （RO）. The reject water of this unit contains high concentration of total nitrogen and total phosphate. Safe disposal of this water into the environment or possible reuse needs substantial reduction of these chemicals. In this study, a bench scale up-flow sludge blanket filtration system was investigated. The system operated with an average Hydraulic-Retention Time （HRT） of 19 h, whereas, sludge age varied within the range of 14 days to 16.5 days. The results show that the average removal efficiencies of the system for Biological Oxygen Demand （BOD）, Chemical Oxygen Demand （COD） were over 86% and 82% respectively. The phosphate and nitrogen＇s average removal were found to be 50% and 45% respectively.

Modification of Titanium Dioxide for Wastewater Treatment Application and Its Recovery for Reuse

Magnetic Fe3O4 nanomagnetic particles were synthesized by the titration co-precipitation method followed by coating by the sol-gel method with Titamiun dioxide. The photocalytic activities of different synthesized TiO2/Fe304 nanomagnetic particles with different molar ratios of TiO2 to Fe3O4 were investigated by the reduction of phosphate, nitrate and decolorizing of methyl blue solutions. X-ray diffraction was used to characterize the size, composition and morphology of the synthesized particles. The results obtained from these experiments indicate an increase in the photocatalytic activity as the amount of TiO2 coating increases. The results show a higher activity of the synthesized particles in the removal of phosphate, nitrate and methyl blue, which can be achieved at early reaction periods at about 70-80%. The activities were higher when the particles were incubated without UV illumination. This study shows that TiO2/Fe3O4 particles are effective in phosphate, nitrate and methyl blue removal in wastewater treatment.

Simultaneously energy production and dairy wastewater treatment using bioelectrochemical cells： In different environmental and hydrodynamic modes

A successful design, previously adapted for treatment of complex wastewaters in a microbial fuel cell （MFC）, was used to fabricate two MFCs, with a few changes for cost reduction and ease of construction. Performance and electrochemical characteristics of MFCs were evaluated in different environmental conditions （in complete darkness and presence of light）, and different flow patterns of batch and continuous in four hydraulic retention times from 8 to 30 h. Changes in chemical oxygen demand, and nitrate and phosphate concentrations were evaluated. In contrast to the microbial fuel cell operated in darkness （D-MFC） with a stable open circuit voltage of 700 mV, presence of light led to growth of other species, and consecutively low and unsteady open circuit voltage. Although the performance of the MFC subjected to light （L-MFC） was quite low and unsteady in dynamic state （internal resistance = 100 Ω, power density = 5.15 W.m-3）. it reached power density of 9.2 W.m-3 which was close to performance of D-MFC （internal resistance = 50 d, power density = 10.3 W.m-3）. Evaluated only for D-MFC, the coulombic efficiency observed in batch mode （30%） was quite higher than the maximum acquired in continuous mode （9.6%） even at the highest hydraulic retention time. In this study, changes in phosphate and different types of nitrogen existing in dairy wastewater were investigated for the first time. At hydraulic retention time of 8 h, the orthophosphate concentration in effluent was 84% higher compared to influent. Total nitrogen and total Kjeldahl nitrogen were reduced 70% and 99% respectively at hydraulic retention time of 30 h, while nitrate and nitrite concentrations increased. The microbial electrolysis cell （MEC）, revamped from D-MEC, showed the maximum gas production of 0.2 m3 H2·m-3·d-1 at 700 mV applied voltage.

磷酸铁废水零排放及资源化处理技术分析

目前,磷酸铁锂是锂电池的主要正极材料,而磷酸铁是制备磷酸铁锂的关键前驱体。磷酸铁生产过程产生大量废水,其酸性强、盐分高,处理难度大,现已成为制约磷酸铁生产企业发展的瓶颈。磷酸铁废水含有高浓度磷酸根、硫酸根、氨根及金属离子,废水经预处理+膜浓缩+蒸发结晶处理后可获得硫酸铵、磷酸二氢铵等副产品,处理后的废水可回用于生产环节,因而磷酸铁废水具有良好的资源化回收价值。本文综述磷酸铁废水处理技术现状,分析磷酸铁废水处理存在的问题,然后提出磷酸铁废水零排放处理技术思路,以实现磷酸铁废水的资源化利用,保护生态环境。

大肠杆菌高密度发酵制药废水处理工艺设计实例

大肠杆菌高密度发酵制药的废水包括发酵产生的工艺废水和清洗、冷却产生的低污染废水,前者水量小但污染物含量高,后者量大但污染物含量低。分析比较吹脱法、折点加氯法、生物法、离子交换法和化学沉淀法,确定对污染性强的工艺废水采用化学沉淀法、活性污泥法相结合的处理工艺,先MAP沉淀除氨脱磷,再用低污染废水10倍稀释后进行SBR生化处理,达标排放。MAP沉淀除氨脱磷药剂选用氯化镁和磷酸氢二钠,pH值9.5,投药比采用n(Mg^(2+))∶n(NH_(4)^(+))∶n(PO_(4)^(3-))=1.2∶1∶1,氨氮去除率达83%,COD Cr的去除率达19%,稀释10倍后氮磷含量符合SBR生化处理要求。该工艺污水综合处理成本约为51.8元/m^(3),但处理量小,污水处理总费用约为88元/d,综合费用低,且副产物MAP可用作肥料。

磷酸铁工业废水处理工艺研究进展

近年来锂离子电池正极材料磷酸铁锂广受关注,带动其前驱体磷酸铁相关研究及生产呈现爆发式增长。然而,主流工艺生产磷酸铁的过程中会产生大量废水,制约了磷酸铁行业绿色、健康发展。目前,已报道的磷酸铁工业废水处理方法有沉淀法、硫酸铵镁结晶法、微生物分解法、膜分离法等,但是沉淀法污泥难处理、难回收,磷酸铵镁法需额外加入药剂以满足沉淀配比,微生物法稳定性及灵活性较差,膜分离法需配合其他处理技术对膜进水预处理并对膜浓水处理回用,因此工业化应用中常将多种技术结合,形成综合处理方法,可对磷酸铁废水达到较好的处理效果。最后,从废水高效预处理及有价元素回收再利用方面入手,对未来磷酸铁行业的废水处理技术进行了展望。

高盐含酚工业废水的脱酚工艺研究与优化

研究了磷酸三丁酯(TBP)-煤油体系在对硝基苯酚(PNP)工业废水中的萃取工艺,TBP与PNP主要形成1∶1型的络合物,萃取过程的ΔH=-28.21 kJ/mol,废水中盐的存在对络合萃取有正向影响。采用单因素实验法考察了萃取剂浓度、搅拌转速、有机相/水相的体积比(O/A)对脱酚率以及化学需氧量(COD)去除率的影响。根据单因素实验结果,设计三因素三水平Box-Behnken模型进行响应面优化实验。实验结果表明,响应面优化后的最优工艺条件为:TBP浓度为28%,搅拌转速为187 r/min,相比为0.6,该条件下脱酚率为99.97%,单级萃取后萃余水相酚含量为0.12 mg/L。

磷酸铁废水资源回收工程实例

针对某新能源企业磷酸铁废水杂质离子多、氨氮和总磷浓度高等特点,设计采用氨水沉淀除杂-膜分离-MVR蒸发分盐结晶组合工艺进行资源化回收,回收回用水和废水中的硫酸铵及磷酸一铵。运行结果表明,预处理过程总铁去除率大于99.5%,Mn^(2+)去除率大于99%,膜浓水的硫酸铵质量浓度大于160000 mg/L,副产品硫酸铵质量符合GB/T 535—2020《肥料级硫酸铵》中Ⅰ型指标要求,磷酸一铵质量符合GB/T 10205—2009《磷酸一铵、磷酸二铵》中粉末磷酸一铵传统法一等品指标要求,每吨废水资源化回收处理净收益约为9.8元。

不同高级氧化工艺预处理磷化废水

对比研究了单独臭氧(O_(3))氧化、O_(3)/单过硫酸氢钾(PMS)氧化和O_(3)/过氧化氢(H_(2)O_(2))氧化3种工艺预处理磷化废水的效果。通过对不同工艺处理后出水COD、UV_(254)和三维荧光光谱分析,研究不同高级氧化工艺对磷化废水出水水质的影响及去除途径。研究表明,增加臭氧投加量和添加适量的PMS、H_(2)O_(2)都可以提高对磷化废水出水中有机污染物的去除效果。废水初始COD (130±20) mg/L、反应120 min、O_(3)投加量7.65 mg/min时,单独臭氧氧化工艺,COD的去除率仅为37%;O_(3)/PMS氧化工艺,PMS投加量2 g/L,COD的去除率为45.65%;O_(3)/H_(2)O_(2)氧化工艺,H_(2)O_(2)(质量分数30%)投加量为0.5 g/L,COD去除率达到58.3%。3种工艺中O_(3)/H_(2)O_(2)对磷化废水中COD去除效果最好,O_(3)和H_(2)O_(2)协同产生更多强氧化性自由基,提高了反应体系的氧化能力。3种工艺对废水中的芳香族化合物及荧光类物质均有明显的降解作用,单独O_(3)氧化和O_(3)/PMS氧化工艺主要是将废水中类蛋白等物质降解为类富里酸和类腐殖酸类物质,O_(3)/H_(2)O_(2)氧化工艺可以对类富里酸和类腐殖酸类物质进一步降解。

高比表面积羟基磷灰石的制备及其在磷酸铁废水除氟中的应用

为提高羟基磷灰石(Hydroxyapatite,HAP)对氟离子的吸附效率,采用化学沉淀法,通过优化反应温度、Ca/P摩尔比、陈化时间等合成条件制备高比表面积HAP,通过FTIR、XRD、XPS、SEM和BET等对合成的HAP进行表征,并评价HAP对模拟废水中氟离子的吸附性能。结果表明:HAP的最优制备条件为反应温度20℃、Ca/P摩尔比1.6、陈化时间24 h,所制备的HAP比表面积达108.0 m^(2)/g;HAP对氟离子的吸附为自发和吸热过程,符合Langmuir吸附模型,在303 K下氟离子的最大吸附容量为13.53 mg/g,吸附过程符合准二级反应动力学模型;在酸性条件下,HAP的除氟机理为离子交换。磷酸铁废水HAP吸附除氟实验表明,出水氟离子浓度可连续32 h低于1.0 mg/L,体现了较好的除氟效果。研究结果可为高效除氟吸附剂的制备以及磷酸铁废水深度除氟提供一定的指导。

江苏某高新区再生水厂工程实例

江苏某高新区再生水厂以各企业预处理排放尾水为原水,采用化学沉淀、生化处理和超滤及反渗透膜分离等组合工艺流程,将含磷废水与不含磷废水分质分段处理,系统设计合理,处理效果良好,直接运行成本为6.25元/m^(3),出水水质达到《地面水环境质量标准》GB 3838—2002中Ⅳ类标准要求,并提供给高新区相关企业回用。

磷酸铁生产废水回用及零排放的预处理研究

磷酸铁生产过程中产生的母液废水具有较高的硫酸根含量、总磷(TP)、铵根含量及总硬度,为防止废水回用处理时发生结垢,必须进行有效的预处理。采用化学沉淀法研究不同药剂对废水中易结垢的阴离子和阳离子的去除效果。结果表明:向废水中投加氢氧化钙量为22.5 g/L(pH=9.0)时,TP为0.14 mg/L、去除率达到99.97%、硫酸根质量浓度降至1 525 mg/L、去除率为97.07%;向废水中投加磷酸根并用氨水调节pH,当磷酸根投加量为2 500 mg/L(pH=8.5)时,总硬度为110 mg/L、总硬度去除率达到97.82%、TP约为20 mg/L、绝干污泥量为7.32 g/L。投加氢氧化钙药剂可降低磷酸根、硫酸根等结垢阴离子和总溶解性固体含量,投加磷酸根和氨水可降低废水总硬度,即降低阳离子量。以上两种加药方式实现了对磷酸铁废水的有效预处理,避免废水在膜浓缩和零排放过程中结垢,是一种可行的磷酸铁废水预处理方法,同时应用ASPEN PLUS软件模拟向废水中投加氢氧化钙反应生成硫酸钙的过程并分析硫酸钙的比热容。

磷酸锰铁锂工厂近零排放水处理系统工程实例

浙江省某新型动力电池正极材料磷酸锰铁锂生产企业水处理系统,采用生产用纯水制备与废水处理耦合的整体解决方案。废水处理部分采用二级物化混凝沉淀-砂滤-锰砂过滤-树脂吸附-反渗透-高压反渗透-MVR的组合工艺;纯水制备系统采用砂滤-碳滤-软化树脂-反渗透-浓水反渗透的组合工艺。系统内反渗透配置大流量内循环系统,以提高回收率与抗污染性能。废水处理系统所产生回用水全部回收至生产用纯水制备系统。其中废水主要包含高浓度废水、低浓度废水、一般清洗废水,废水总磷、硬度、锰、铁含量高。经过水处理系统后的生产用纯水电导率稳定小于15μS/cm,锰、铁、总磷均稳定小于0.1 mg/L。该项目与生产线联动运行以来,出水水质良好,做到该厂整体水处理系统的近零排放,具有良好的环境与经济效益。

钛白粉生产酸性废水对磷矿石反浮选实验研究

钛白粉生产过程中产生大量酸性废水(<5%),为解决中和处理造成大量钛石膏堆积问题,在分析磷矿石特性的基础上进行浮选实验研究。混合捕收剂浮选效果优于单一FQ捕收剂、油酸钠、十二胺,当FQ捕收剂用量为10 L/t,油酸钠为7.5 kg/t时,精矿品位为29.18%,分别比单一捕收剂高5.35和2.46个百分点,回收率比单一用油酸钠时高10.15个百分点。当5%酸用量为3.442 kg/t时,产率和回收率分别比用稀硫酸高5.79和2.37个百分点。本研究提供了一条钛白粉酸性废水利用新途径。

磷酸钾改性秸秆生物炭高效去除酸性矿山废水中的镉

目的:磷酸盐改性被认为是提高秸秆生物炭(RBC)去除酸性矿山废水中Cd(Ⅱ)性能的潜在策略,本研究采用磷酸钾对水稻秸秆生物炭(KRBC)进行改性,以提高其对酸性矿山废水中Cd(Ⅱ)的吸附性能。方法:采用批量吸附试验探究溶液初始pH、共存离子、腐殖酸浓度、吸附时间及Cd(Ⅱ)初始浓度对吸附剂去除Cd(Ⅱ)影响,并调查改性生物炭对Cd(Ⅱ)去除的潜在机理。结果:吸附试验表明在溶液pH为5.0~7.0时,KRBC对水溶液中Cd(Ⅱ)具有较好去除性能。此外,共存离子K^(+)、Na^(+)、Ca^(2+)、Mg^(2+)、NO-3和SiO_(3)^(2-)对RBC和KRBC去除Cd(Ⅱ)没有影响,而PO_(4)^(3-)、CO_(3)^(2-)及腐殖酸对去除Cd(Ⅱ)具有促进作用。拟二阶动力学模型和Langmuir模型可以更好地描述Cd(Ⅱ)的吸附过程。RBC和KRBC对Cd(Ⅱ)的最大吸附能力分别为57.93 mg/g和159.46 mg/g。潜在的去除机理包括络合、静电作用、阳离子-π相互作用及共沉淀。在经过三次再生性试验后,RBC和KRBC对50 mg/L的Cd(Ⅱ)去除率分别为20.18%和86.75%。结论:以上结果表明磷酸钾改性生物炭在去除酸性矿山废水中的Cd(Ⅱ)具有更大的潜力。

氨法磷酸铁废水处理专利技术综述

本文主要分析了采用“硫酸亚铁+双氧水+磷酸+磷酸二氢铵”的氨法工艺合成磷酸铁生产过程中产生的高浓度废水;针对磷酸铁废水具有高氮、高磷、高硫酸根的特点,收集整理了近年来磷酸铁废水处理的专利;并将这些专利技术归纳分类成了零排放技术、回用与资源化技术、磷酸铵镁法、传统石灰法、硫酸钡沉淀法五大类;针对五类典型专利分别进行了简单的分析介绍;给出了技术对比;最后对磷酸铁废水处理专利技术进行了展望,磷酸铁废水零排放与资源化处理技术是最有前途的。