基于PLC的滤站自动控制系统设计

针对滤站的污水处理流程,设计基于可编程逻辑控制器(Programmable Logic Controller,PLC)的滤站自动控制系统,并详细阐述该系统的硬件设计、软件设计。通过应用自动控制系统,滤站能够自动完成污水处理流程,缩短人工时间,提高工作效率。

反洗系统投用对芳烃联合装置的影响

某石化公司芳烃联合装置采用吸附分离工艺生产对二甲苯(PX)。自2014年吸附塔换剂投用至2020年期间,在带来巨大经济效益的同时,伴随着吸附剂寿命老化,性能下降等问题,导致PX纯度持续恶化,PX收率持续降低。为改善PX纯度,提高PX收率,经公司研究决定,投用吸附塔反洗系统。自反洗系统投用后PX纯度由99.72%上升至99.78%,PX收率由93.5%上升至97.6%,经核算反洗系统投用后年增效约4399万元。

Backwash Effects of Language Testing in EFL Classrooms

The article presents some major researches concerning the concept of backwash effect of language testing; analyses both the positive and negative effects and their implications in EFL classrooms; then provides some suggested ways to be followed when creating positive backwash effects on teaching and learning.

一种新的地下室疏排水减压系统

提出一种新的地下室疏排水减压系统,该疏排水减压系统由截水系统和疏排水系统组成,其中截水系统以基坑止水帷幕和肥槽回填粘性土为主;疏排水减压系统由排水系统、集水系统、监测预警预报与应急系统和反冲洗系统组成。四大系统组成的疏排水减压系统有效保证了地下室抗浮效果,有效克服了传统抗浮系统的工期长和造价贵等问题,同时解决了传统排水减压法的通病问题,实现了工程技术难题的一大突破。

A Study on the Backwash Effect of the Reform of TEM-8 on Advanced English Course

TEM-8,which aims at testing students’integrated abilities of English,is more and more highly valued.Advanced Eng-lish,with its core teaching aim of cultivating this ability,should have high-quality teaching and optimized test as its objectives.Thus the test and the course can bring out the best in each other.

二十辊轧机轧制油净化系统反冲洗排气口优化改造

叙述了轧制油系统在不锈钢二十辊轧机系统构成中的重要作用。通过结合生产实践,详细介绍了轧制油主净化过滤系统的作用、流程、控制方法及生产过程中存在的不足,针对反吹排气存在的问题,通过对净化系统排气口的改造优化,解决了设计不足造成的油雾污染和损耗,实现了过滤罐反冲洗时排气口的油雾吸收和净化功能,有效降低了反吹气流的压力,消除了油气对过滤罐周围的污染,降低了轧制油损耗和劳动清扫强度。

Effect of powdered activated carbon on Chinese traditional medicine wastewater treatment in submerged membrane bioreactor with electronic control backwashing

Chinese traditional medicine wastewater, rich in macromolecule and easy to foam in aerobic biodegradation such as Glycosides, was treated by two identical bench-scale aerobic submerged membrane bioreactors （SMBRs） operated in parallel under the same feed, equipped with the same electronic control backwashing device. One was used as the control SMBR （CSMBR） while the other was dosed with powdered activated carbon （PAC） （PAC-amended SMBR, PSMBR）. The backwashing interval was 5 min. One suction period was about 90 min by adjusting preestablished backwashing vacuum and pump frequency. The average flux of CSMBR during a steady periodic state of 24 d （576 h） was 5.87 L/h with average hydraulic residence time （HRT） of 5.97 h and that of PSMBR during a steady periodic state of 30 d （720 h） was 5.85 L/h with average HRT of 5.99 h. The average total chemical oxygen demand （COD） removal efficiency of CSMBR was 89.29% with average organic loading rate （OLR） at 4.16 kg COD/（m^3.d） while that of PSMBR was 89.79% with average OLR at 5.50 kg COD/（m^3.d）. COD concentration in the effluent of both SMBRs achieved the second level of the general wastewater effluent standard GB8978-1996 for the raw medicine material industry （300 mg/L）. Hence, SMBR with electronic control backwashing was a viable process for medium-strength Chinese traditional medicine wastewater treatment. Moreover, the increasing rates of preestablished backwashing vacuum, pump frequency, and vacuum and flux loss caused by mixed liquor in PSMBR all lagged compared to those in CSMBR; thus the actual operating time of the PSMBR system without membrane cleaning was extended by up to 1.25 times in contrast with the CSMBR system, and the average total COD removal efficiency of PSMBR was enhanced with higher average OLR.

Application of a novel backwashing process in upflow biological aerated filter

To improve the efficiency of backwashing in upflow biological aerated filter （BAF）, a novel backwashing process named air-water siphon backwashing （AWSB） was proposed and applied on laboratory scale. The effects of backwashing on turbidity and suspended solid （SS） in backwashing efluent using this new backwashing process were compared with those of traditional backwashing process, namely air-water backwashing （AWB）. In AWB, the turbidity of backwashing efluent maintained 100 NUT when consumed 60 min and 10.5 L water. However, in AWSB, it declined to 44 NUT, consumed 40 min, and 7 L water. The COD removal of BAF after backwashing was also analyzed. The average removal rate of COD in the reactor backwashed by AWB and AWSB was 89.34% and 90.91%, respectively. Compared with AWB, the backwashing interval had been prolonged 35%. The volume of backwashing water in that AWSB was only 66.7% of that in AWB. The results demonstrated that AWSB required less water and took shorter backwashing timerelative to AWB to achieve the same turbidity of backwashing efluent, and AWSB was more effective in removing fouling than that of AWB. More significant advantage of AWSB was that the backwashing interval was effectively prolonged

Promoting Positive Backwash on Practical English Test for Colleges

Practical English Test for Colleges (PRETCO) is a large-scale national standardized EFL test for the students of higher vocational colleges,postsecondary specialized colleges,and colleges for adults.This thesis is for a preliminary research of PRETCO backwash based on previous studies from home and abroad,making use of their research methods and models.It attempts to explore the aspects of practical English learning of students from higher vocational colleges (HVC) influenced by PRETCO,and the nature of the backwash.Based on the results reported in the study,the writer analyzes the factors inducing negative backwash and puts forward some suggestions for promoting positive one.

Membrane Fouling Alleviation by Chemically Enhanced Backwashing in Treating Algae-Containing Surface Water: From Bench-Scale to Full-Scale Application

Ultrafiltration(UF)has been increasingly implemented in drinking water treatment plants;however,algae and their secretions can cause severe membrane fouling and pose great challenges to UF in practice.In this study,a simple and practical chemically enhanced backwashing(CEB)process was developed to address such issues using various cleaning reagents,including sodium hypochlorite(NaClO),sodium chloride(NaCl),sodium hydroxide(NaOH),sodium citrate,and their combinations.The results indicate that the type of chemical played a fundamental role in alleviating the hydraulically irreversible membrane fouling(HIMF),with NaClO as the best-performing reagent,followed by NaCl.Furthermore,a CEB process using a combination of NaClO with NaCl,NaOH,or sodium citrate delivered little improvement in the alleviation of membrane fouling compared with NaClO alone.The optimized dosage and dosing frequency of NaClO were 10 mg·L^(-1) two times per day.Long-term pilot-scale and full-scale experiments further verified the feasibility of the CEB process in relieving algae-derived membrane fouling.Compared with the conventional hydraulic backwashing without chemical involvement,the CEB process can effectively remove the organic foulants including biopolymers,humic substances,and proteinlike substances by means of oxidization,thereby weakening the cohesive forces between the organic foulants and the membrane surface.Therefore,the CEB process can efficiently alleviate the algae-related membrane fouling with lower chemical consumption,and is proposed as an alternative to control membrane fouling in treating the algae-containing surface water.

Recycling of Mud Derived from Backwash Wastewater Coagulation as Magnetic Sodalite Sphere for Zn^(2+) Adsorption

Herein,we reported a method to prepare magnetic sodalite sphere by using the mud from backwash wastewater after polyaluminum chloride(PAC)coagulation.The results showed that approximately 100%of Fe in the wastewater was precipitated as flocculent iron mud(FM)by adding PAC.FM was converted to spherical magnetic sodalite(FMP)with a diameter of 3μm via a facile alkali hydrothermal method without adding Al/Si resources or reductant.The product FMP had the saturated magnetization of 10.9 emu g^(-1) and high Zn^(2+)adsorption capacity of 50.6 mg g^(-1).Without coagulation with PAC,the removal rate of Fe from the wastewater was only 92.7%,and the precipitated mud(RM)was converted to irregular particles(RMP),which had weak magnetic response and low capacity of Zn^(2+)adsorption comparing with FMP.With the method,the Fe in backwash wastewater was effectively recycled,and the generated sludge was converted to well-formed sodalite sphere without generating any secondary waste.

Error Analysis of CET-4 Translation Produced by Vocational & Techni⁃ cal College Students and the Backwash Effect of English Teaching

CET-4 is a national standardized English proficiency test designed and developed by the National College English Ex⁃amination Committee.The purpose of the test is to accurately measure the comprehensive English application ability of college stu⁃dents in China.The more important the test,the more obvious its backwash effect.With the increase of the proportion of subjective questions in CET-4,teachers should pay more attention to the transfer of skills and correct English expression while teaching the basic knowledge of English.In particular,the students in vocational and technical colleges are weak in English abilities,and their errors in translation are even more numerous and varied.Therefore,this study will analyze the translation errors produced by 200 vocational and technical college students in CET-4 of June 2019.By interviewing and investigating the students’actual situation of English learning,tips and proposals on backwash effect on teaching can be achieved.

AAO-RPIR工艺在高排放标准污水厂的应用及其工艺特点分析

深圳市某污水处理厂设计规模为24万m3/d,因片区污水处理需求增长迅速,污水厂长期超负荷运行。为缓解该厂污水处理压力,需利用厂区闲置绿地新增一套规模为6万m^(3)/d的污水处理设施。项目采用以AAO-快速生化污水处理(RPIR)为核心的污水处理工艺,生化池缺氧区混合液回流比为266%~400%,厌氧区混合液回流比为266%,斜管区平均时表面负荷为1.25 m^(2)/(m^(2)·h),单位用地指标为0.225 m^(2)/(m^(3)·d^(-1))。项目用时4个月即实现了单组构筑物通水调试,正式运行以来,出水主要水质指标达到《地表水环境质量标准》(GB 3838-2002)的Ⅳ类水标准(除TN外,TN≤15 mg/L),在未投加碳源的情况下生化池平均进水、出水TN分别为36.87、7.63 mg/L,TN去除效果好。结合近4年的运行实践详细分析了AAO-RPIR工艺的特点与不足,指出AAO-RPIR工艺处理效果好,适用于高排放标准污水处理厂,用地集约、工期短、布置灵活是其核心竞争优势。斜管藻类滋生和化学除磷效率较低等问题则应在设计阶段引起足够的重视,建议采用斜管加盖、设置自动反冲洗系统以及强化后置化学除磷等措施优化工艺设计。

聚结除油器改造及处理聚驱采出液效果研究

为解决聚结除油器处理高黏度聚驱采出液中存在聚结原件堵塞,破乳效果下降问题,通过优化聚结材料,设计合理反冲洗系统,开发新型聚结除油器,实现新型聚结材料再生,提高了油株聚并效果。运行结果表明,总来水平均含油365 mg/L,出水平均含油50 mg/L,去除率达到86%;来水平均含悬浮固体75 mg/L,出水平均含悬浮固体30 mg/L,去除率达到60%。

法国均质滤料滤池的设计特点

与国内通常的设计思路相比,法国得利满和OTV两大公司在均质滤料滤池的设计中有许多方面值得借鉴,笔者结合国内的设计方法,详述了法国公司在恒速过滤的控制、V形槽布水孔的位置、气路系统的设计、溢流系统的设置以及美观和人性化设计等方面的设计特点,为国内设计人员提供参考。

不锈钢冷轧机反冲洗过滤系统的设计及应用

针对宝钢1 450 mm钛镍不锈钢六辊轧机工艺润滑系统,设计一种反冲洗过滤系统,介绍该反冲洗过滤系统的工作原理以及系统自动控制原理的实现。该反冲洗过滤系统在六辊轧机上的应用表明,系统运行状况良好,工艺润滑机组稳定可靠,保证了轧机的稳定运行。

基于粒子系统的舰船尾流建模与仿真

在尾流自导鱼雷弹道设计与作战使用研究中,需要建立逼真的水面舰船尾流模型,用以进行鱼雷进出尾流的判断。舰船尾流是1种具有较好统计特征的随机物理场,与舰船速度、航向、位置等机动轨迹与海况存在内在的关联。而粒子系统正是解决这种随机物理场的最有效方法。根据舰船尾流的外在特征,采用粒子系统研究建立了舰船尾流模型,实现了舰船各种机动条件下尾流的模拟和鱼雷尾流探测的仿真,为尾流自导鱼雷的弹道研究提供了很好的技术支撑。

流体新技术在铜带轧机上的应用

针对铜带轧机大多采用的板式过滤机过滤精度低、易受污物堵塞等缺陷及传统的液压正负弯辊液压控制系统中正负弯辊切换时有时间差和过渡死区的问题，本文采用反冲洗滤系统，过滤流量大，过滤精度可以达到0．5～5um，过滤后固体渣含量≤10mg／L；采用的正负弯辊平滑过渡系统，通过电气操作杆实现弯辊力的快速、连续调节，消除了正负弯辊切换的时间差和过渡死区，且操作简便，可靠性高，提高了带材的表面质量，带材板形良好。

国外膜技术进展及其在水处理中的应用

简单介绍国外膜材料、膜工艺进展；评述国外有关膜技术在水处理中应用的进展情况，包括饮用水生产、超纯水制备、沙滤池反冲水回用及工业水软化．当前膜组合工艺备受重视，因其将 Ｍ Ｆ、 Ｕ Ｆ 去除颗粒物和螺旋卷绕式组件不易污损的优点同 Ｎ Ｆ、 Ｒ Ｏ 去除 Ｄ Ｂ Ｐ 前体、病毒、合成有机化合物的优点结合起来，并把膜技术与活性炭过滤、臭氧氧化、生物处理等高级水处理技术相结合。

普通快滤池配水及反冲洗系统的改造

针对普通快滤池存在的不足,禹城市自来水第一水厂将原有的大阻力配水、单水反冲洗的普通快滤池改造为小阻力配水、气水联合反冲洗滤池。改造后滤池出水浊度<0.2NTU,产水量大幅提高,过滤周期长,反冲洗水量减少。并增设膜处理车间,部分水经过反渗透设备深度处理,出水与原水混合后达到国家饮用水水质标准要求。