Simultaneous synthesis of heat-integrated water networks by a nonlinear program:Considering the wastewater regeneration reuse

Heat-integrated water network synthesis(HIWNS)has received considerable attention for the advantages of reducing water and energy consumptions.HIWNS is effective in water and energy sustainability.Mixed integer non-linear programming(MINLP)is usually applied in HIWNS.In this work,a novel nonlinear programming(NLP)was proposed for HIWNS by considering wastewater reuse and wastewater regeneration reuse.Integer variables are changed to non-linear equation by the methods for identifying stream roles and denoting the existence of process matches.The model is tested by examples with single and multiple regeneration unit problems.The testing results showed that the NLP is an alternative method for HIWNS with wastewater reuse and regeneration reuse.

Ammonium removal by modified zeolite from municipal wastewater

Ammonium removal by modified zeolite, H-form and Na-form zeolite, were examined by batch-type methods. The adsorption of ammonium on modified zeolite was exothermic process. The saturation adsorption capacity of ammonium on H-form and Na-form zeolite were 21.23 and 41.15 mg/g, respectively. After ten times adsorption-desorption-readsorption cycles the standard deviations of H-form and Na-form zeolite were 6.34% and 6.59%. The zeolite adsorption process has proved cost effective and practical in reducing ammonium by H-form and Na-form zeolite in municipal wastewater from concentration 27.68 mg/L to 2.80 mg/L and 5.91 mg/L.

Knitted Microporous Polymers as Efficient Adsorbents for Wastewater Treatment: Effects of Skeleton Structure and Pore Distribution

Hyper-cross-linked microporous organic polymers(MOP) with controlled skeleton structure and pore distribution were prepared by Friedel-Crafts alkylation reaction. The hyper-cross-linked polymers(HCPs) produced by knitting aromatic functional groups posses the typical micro-and meso-porous composite structure and specific surface areas of up to 957 m^2·g^(-1). The obtained materials were evaluated as adsorbents for methylene blue(MB) and subjected to several batch adsorption tests to investigate the effects of adsorbent dosage, concentration of MB, temperature, and pH on MB removal. The maximum adsorbed capacity(q_m) of KAPs-Ph(381 mg·g^(-1), knitted using benzene) exceeded those of less mesoporous KAPs-PhPh_3(310 mg·g^(-1) knitted using 1,3,5-triphenylbenzene) and chloromethyl polystyrene resin(58 mg·g^(-1)). Moreover, KAPs-Ph could be regenerated by Soxhlet extraction with ethanol and reused for up to 15 times with minimal loss of adsorption capacity. The results illustrate that adsorption performance can be improved by controlling the pore structure of the adsorbing materials, and KAPs-Ph has a potential application values for the industrial removal of organic dyes from wastewater.

Minimization of the Flowrate of Fresh Water and Corresponding Regenerated Water in Water-using System with Regeneration Reuse

A sequential three-step programming method is proposed for determining the minimum flowrate of fresh water and corresponding regenerated water in water-using system of single contaminant with regeneration reuse. In step 1, a programming with the objective of min fws is used to determine the minimum flowrate of fresh water, in which the mathematical representation is a mixed integer nonlinear programming (MINLP1). Then under the same constraints with step 1, a programming with the objective of min freg in step 2 and a programming with the objective of min Cr in step 3 are subsequently used to determine the minimum flowrate of regenerated water and the minimum inlet concentration to regeneration process corresponding to the minimum flowrate of fresh water based on step 1. The method is easy to apply because we only need to change the objective function but keep the constraints constant to go along the following steps after step 1. In addition, the relationship between the fresh water flowrate required, fws and inlet concentration to regeneration process, Cr, is investigated. It is found that there exist three relationships between fws and Cr, which indicate three possibilities for C\>: below the pinch, above the pinch or at the pinch. Therefore, a new conclusion is drawn, which differs from that 'regeneration of water at pinch minimizes fresh water flowrate' derived in literature and indicates that in some cases, regeneration at other point also minimizes fresh water flowrate.

A heuristic design method for batch water-using networks of multiple contaminants with regeneration unit

This work develops a heuristic method for the design of batch water-using networks of multiple contaminants with regeneration unit based on the concepts of concentration potential. A water-using network involving regeneration unit can be formed by adding the regenerated stream(s) into the network involving reuse only. In the design procedure of the network operated in a single batch mode, time is take n as the primary factor a nd con centration potentials as the secondary one. For the networks operated in a repeated mode, the design procedure is similar to that for continuous processes, besides designing the storage tanks with the rules proposed. Continuous regeneration unit is selected in this work. With the proposed method, the network structure corresponding to the minimum freshwater consumption can be obtained. It is shown that the method proposed in this article is simple, effective and has clear engineering meaning.

A binder-free electrode for efficient H_(2)O_(2) formation and Fe2+ regeneration and its application to an electro-Fenton process for removing organics in iron-laden acid wastewater

The electro-Fenton process,with its capacity for in-situ H_(2)O_(2)formation and Fe^(2+)regeneration,is a strik-ing alternative to the traditional chemical-Fenton process.However,the frequent requirement of extra binders for electrode fabrication leads to low catalyst utilization,a complex fabrication process,and weak conductivity.Herein,a three-dimensional(3D)porous electrode was fabricated in-situ on a Ni foam(NF)substrate integrated with nitrogen-doped carbon nanotubes(N@C)derived from carbonization of zeolitic imidazolate framework-8(ZIF-8)without any binder.The resulting 900/N@C-NF cathode(synthesized at 900℃)was high in surface area,N content,and degree of graphitization,achieved high performance of H_(2)O_(2)production(2.58 mg L^(−1)h^(−1)H_(2)O_(2)/mg catalyst)at-0.7 V(vs.SCE),and enabled prompt regeneration of Fe^(2+).The electro-Fenton system equipped with the 900/N@C-NF cathode was effective in removing a diverse range of organic pollutants,including rhodamine B(Rh B),phenol,bisphenol A(BPA),nitroben-zene(NB),and Cu-ethylenediaminetetraacetic acid(EDTA),and significantly attenuating the concentration of chemical oxygen demand(COD)in the real acid wastewater,exhibiting superior activity and stability.This binder-free and self-supporting electro-Fenton cathode was thus shown to be an attractive candidate for application to wastewater treatment,particularly those rich in organics,acids,and Fe^(3+)/Fe^(2+).

脱氮人工湿地深度处理分散养猪废水性能分析

为适应国家对地表水环境日益严格的要求,需要构建强化硝化区人工湿地对分散养猪废水进行强化脱氮处理。以砾石、砖渣、沸石和石灰石混合物、细砂为基质制作人工湿地反应器(2 m×1 m×0.75 m)。在进水COD、氨氮(NH_(3)-N)和总磷(TP)质量浓度分别为150、110和25 mg/L条件下,考察了反应器启动阶段性能;在启动完成后将进水COD质量浓度提高到200 mg/L,考察COD负荷的影响;将NH_(3)-N质量浓度提高到200 mg/L,考察NH_(3)-N负荷的影响;分析反应器中氮的去除途径。结果表明:接种挂膜阶段,沸石可以达到吸附-再生平衡,反应器运行性能稳定,启动末期反应器吸附NH3-N的质量浓度约为45 mg/L,产生的硝酸盐氮(NO_(3)-N)质量浓度约为60 mg/L;提高进水COD质量浓度,COD去除率保持在77.50%左右,提高进水NH_(3)-N质量浓度,NH3-N质量浓度未出现明显升高,稳定在30 mg/L左右。研究显示,构建的人工湿地运行稳定,深度脱氮效果良好,可用于实际推广运用。

改性天然沸石对煤化工废水中高浓度NH_(4)^(+)的吸附和再生研究

针对目前常用的蒸氨法和吹脱法去除煤化工废水中高浓度氨氮带来的能耗高、处理成本高、操作复杂等实际问题,对天然沸石进行改性,探究改性沸石对煤化工废水中高浓度氨氮的吸附性能和化学再生性能。结果表明,相较于未改性天然沸石,经300℃热处理与1.5 mol/L NaCl溶液协同改性后,沸石的比表面积由18.541 m^(2)/g增加至32.198 m^(2)/g,吸附容量提升了74%,NH_(4)^(+)去除率达88.94%。吸附动力学和等温线分析表明,改性沸石对煤化工废水中高浓度NH_(4)^(+)的吸附过程符合化学多层吸附过程。0.100 mol/L NaClO溶液对改性沸石再生效果最好,再生率高达94.5%,且可将再生NH_(4)^(+)转化为无毒、无害的N_(2),实现了沸石的高效、可持续再生,且无二次污染。

重力驱动式动态膜生物反应器的膜清洗再生方式优化研究

构建了重力驱动式好氧动态膜生物反应器(DMBR)处理生活污水,比较不同物理清洗方法(空气反冲洗、表面刷洗和组合方式)对动态膜再生的影响,探究了动态膜的形成过程和过滤机理,解析DMBR的污染物去除性能。研究结果表明,动态膜的形成伴随着出水颗粒物粒径的不断减少,5 min后颗粒粒径分布基本稳定,动态膜形成阶段符合滤饼过滤模型,稳定运行阶段符合标准过滤模型。DMBR对浊度、NH_(4)^(+)-N、COD和SCOD的平均去除率分别为99.6%、94.0%、93.2%和82.8%。空气反冲洗辅助刷洗不仅可以去除微网表面的污染层,还可去除对DMBR长期运行有影响的污染物,五个过滤周期的初始通量恢复率均达到93.1%以上。

一锅法一次性合成片状羟基磷灰石及其对废水中铀的去除性能及机理研究

水体中存在的铀会损害人体健康,因此铀的去除是一个需要研究的课题。以低成本的CaCO_(3)和(NH_(4))_(2)HPO_(4)为原料,通过一锅法一次性合成羟基磷灰石(OP-HAP),并将其应用于去除溶液中的铀。通过单因素和正交试验探究了OP-HAP对铀的吸附性能,并利用SEM、EDS、XRD、FTIR及XPS对其进行表征。结果表明:最优条件下,OP-HAP对10 mg·L^(-1)铀的最大去除率为97%左右,拟合最大吸附量为1 584.79 mg·g^(-1);OP-HAP对铀的吸附过程符合Langmuir等温吸附模型和准二级动力学模型;热力学研究表明吸附过程是吸热且自发的;通过Zeta电位及对吸附铀前后的OP-HAP进行表征,发现吸附机理主要是静电吸附、离子交换、配合作用及溶解沉淀。OP-HAP对铀的吸附表现出较高的吸附量,是一种潜在的铀吸附材料。

沸石原位生物再生强化短程硝化处理高氨氮废水

为解决高浓度游离氨(FA)抑制氨氧化菌而造成高浓度氨氮废水无法进行生物处理的问题,采用添加天然沸石缓解FA的抑制影响。向SBR中添加天然斜发沸石并以短程硝化处理氨氮为2 210 mg/L的铜氨废水,在运行第86天时反应器在1.105 kg/(m^(3)·d)的氨氮负荷下达到98.5%的氨氮去除率。反应过程中原位生物再生保证了天然沸石的持续强化效果,沸石再生率为99.0%~106.3%。通过对污泥胞外聚合物(EPS)含量及成分分析发现进水氨氮的增加导致EPS含量升高,且在铜离子的胁迫下EPS中的蛋白质质量分数升高,促进了污泥颗粒化的形成。高通量测序结果显示亚硝化单胞菌属为主要氨氧化功能菌属,其相对丰度变化范围为10.3%~51.7%。丛毛单胞菌属(Comamonas)在高浓度氨氮环境下快速增长,其相对丰度从第22天的0.6%增长至第86天的29.9%。短程硝化在天然沸石的强化下实现了对铜氨废水的稳定高效处理。

造纸法烟草薄片废水处理运行分析及工艺探讨

某烟草薄片生产企业采用“物理除渣+A^(2)O生物处理+化学法深度处理”工艺进行废水处理,本研究统计该厂较有代表性的5个月运行数据,针对各月各工序处理能力、各污染物指标去除效率及含氮物质的转化进行了运行分析。运行数据表明,该厂厌氧进水pH值=7.5~7.8、悬浮物(SS)浓度平均值1 058 mg/L,两者存在偏高现象,同时存在厌氧污泥流失严重,A~2O工艺中总氮平均去除效率47.7%,需进一步改进优化。针对存在问题,结合造纸法烟草薄片废水水质特点和企业工艺运行参数探讨了问题产生的原因,提出了改进工艺措施的意见和建议,为行业废水处理工艺建设和改进提供参考意义。

碳基催化剂活化过硫酸盐降解煤化工高盐废水工艺及再生研究

采用碳基催化剂活化过硫酸盐的高级氧化技术处理煤化工高盐有机废水,考察碳基催化剂的吸附性能,研究了不同种类氧化剂、停留时间(HRT)、过一硫酸盐(PMS)投加量、进水pH和反应温度等工艺参数对有机物降解效果的影响。将失活后的碳基催化剂进行原位再生,考察不同工艺条件对再生后催化剂性能的影响。结果表明,碳基催化剂吸附能力较强;PMS相较于过二硫酸盐(PDS)对有机物去除率更高,停留时间越长、反应温度越高PMS催化氧化有机物去除率越高;TOC去除率随PMS投加量增加先上升后下降,最佳投加量为5 g/L,pH为酸性条件更有利于PMS催化氧化反应进行。微波辅助比热循环辅助的催化剂再生效果略强但损耗率高,热循环辅助再生效果和PMS浓度、反应温度和循环流量呈正相关关系,循环时间为1.5 h再生效果最佳,催化剂再生后催化性能提升35%左右,且再生后循环稳定性较好。

半导体行业废水处理与再生技术探讨

随着中国半导体行业的高速发展,该行业的生产过程中纯水使用量和废水排放量不断增加。本文对半导体行业废水的特性和主要废水类型进行了系统梳理,对各种废水处理方法及其优缺点进行了总结,并探讨了废水再生工艺和其中的膜污堵机制及解决措施。最后,本文展望了半导体行业废水处理和再生方面的未来发展。

螯合树脂塔再生废水回收工艺改进

优化了螯合树脂塔再生废水回收工艺:将酸性废水送至脱氯塔与淡盐水混合,淡盐水脱氯后,被送至盐水工序用于化盐;将碱性废水直接送至盐水工序用于化盐.工艺优化后,实现了酸性废水和碱性废水的高效回收利用.

二次盐水精制工序技术改造

对二次盐水精制工序螯合树脂塔再生过程中酸、碱加入量和加入方式以及再生废水的回收方式进行了改造,年增效190万元。

MVC浓水、软化再生废水及废热的资源化综合利用研究

针对新疆某油田特有的废热、废水条件,通过对蒸发结晶边界条件确定、二价盐除盐率影响因素及含盐水空气蒸发适应性等多个方面的技术研究,制定了“强制循环反应结晶+空气蒸发浓缩”的废水处理工艺技术方案。有效地利用废热对MVC浓水和软化再生废水的混合液进行蒸发,伴随整个蒸发过程对二价盐进行结晶处理,使这两股原本无法深度处理的污水得以再利用,且回收了部分热能。该工艺技术的应用,在完成水质除硬、除硅的同时,既生产出75%的冷凝水回用于锅炉,又产出氯化钠浓度为18%(质量分数)的盐溶液作为再生用盐供给软化器,解决了稠油开采水平衡的困难,实现资源回收利用,降低软化器的运行成本。其中,污水减排达99%,热能利用90%,热能回收10%。以研究单位现有外排水量及各类费用标准计,每年可产生经济效益约2300万元。

煤质与木质活性炭吸附处理焦化RO浓水及再生试验研究

以某钢铁厂焦化RO浓水为研究对象,采用煤质颗粒活性炭与木质颗粒活性炭进行吸附处理,考察了活性炭投加量、pH值、吸附时间对吸附效果的影响,同时进行2种活性炭的Freundlich吸附等温线研究,研究了再生温度、再生时间、再生次数对活性炭再生后吸附性能及再生损失的影响。结果表明,在最佳吸附条件下,煤质和木质活性炭对废水中COD的去除率分别为61.1%、56.3%。最佳再生温度为500℃,煤质和木质活性炭最佳再生时间分别为1.5 h和1.0 h。多次再生试验证明,煤质活性炭可进行大于6次的再生,使用寿命优于木质活性炭。

再生聚酯制备用滤芯清洗系统技术改造

在再生聚酯的制备过程中,需要对滤芯进行批量清洗,在滤芯清洗时带来废水、废气的排放,造成严重的污染。文章介绍了将清洗的废水进行在线回收循环再利用,以及增加废气吸附吸收环节等技术改造方案和措施,将清洗废水通过无纺布进行过滤,再通过多级沉淀池进行沉淀、过滤、净化,达到使用标准。对技术改造实施前后的数据进行评估对比,每清洗一批60根滤芯可节约用水量约60吨,污水减排约60吨,降本增效、节能减排效果显著,取得了较好的经济效益。

Fenton氧化与反渗透集成技术在再生铜冶炼废水深度处理中的应用研究

随着全球资源循环利用意识的提升与环保政策的日益严苛,再生铜冶炼产业在快速发展的同时所产生废水的处理问题也日益凸显。此类废水含有大量难降解有机物和重金属离子,若未经妥善处理就直接排放,不仅会对环境造成严重污染,更会威胁人类健康和社会的可持续发展。本文主要探讨了利用Fenton氧化技术和反渗透集成技术深度处理再生铜冶炼废水的原理、优势及潜在的应用价值,并深入剖析了Fenton氧化技术对有机物的高效降解机制及其与反渗透膜分离技术联用去除重金属离子和其他无机杂质的效果,以期为促进再生铜冶炼行业的绿色可持续发展提供科学依据和技术支持。