Technical feasibility study of a low-cost hybrid PAC-UF system for wastewater reclamation and reuse: a focus on feedwater production for low-pressure boilers

This study has applied the concept of the hybrid PAC-UF process in the treatment of the final effluent of the palm oil industry for reuse as feedwater for low-pressure boilers. In a bench-scale set-up, a low-cost empty fruit bunch-based powdered activated carbon (PAC) was employed for upstream adsorption of biotreated palm oil mill effluent (BPOME) with the process conditions: 60 g/L dose of PAC, 68 min of mixing time and 200 rpm of mixing speed, to reduce the feedwater strength, alleviate probable fouling of the membranes and thus improve the process flux (productivity). Three polyethersulfone ultrafiltration membranes of molecular weight cut-off (MWCO) of 1, 5 and 10 kDa were investigated in a cross-flow filtration mode, and under constant transmembrane pressures of 40, 80, and 120 kPa. The permeate qualities of the hybrid processes were evaluated, and it was found that the integrated process with the 1 kDa MWCO UF membrane yielded the best water quality that falls within the US EPA reuse standard for boiler-feed and cooling water. It was also observed that the permeate quality is fit for extended reuse as process water in the cement, petroleum and coal industries. In addition, the hybrid system’s operation consumed 37.13 Wh m⁻³ of energy at the highest applied pressure of 120 kPa, which is far lesser than the typical energy requirement range (0.8–1.0 kWh m⁻³) for such wastewater reclamation.

     

污水排放的远程监视监测系统

本文介绍了由环保部门通过电脑远程监视、监测所属企业污水排放的情况 ,并在电脑上自动记录各项监测的数据 ,当有某项数据超标时能即时声音报警的污水排放远程监视监测系统的设计方案     

嵌入式污水COD在线监测仪的研制与应用

分析化学需氧量的监测原理,提出研制一种基于重铬酸钾氧化-分光光度法的COD在线监测仪,并对仪器预处理、计量、消解和光电比色等主要单元进行研究和设计。通过正交实验的直观分析法和方差分析法,确定仪器的最佳工作条件为：消解温度170 ℃,消解时间20 min,催化剂用量为进液至低液位4 次。通过对催化剂进行研究及实验,表明MnSO4可代替Ag2SO4进行生活污水COD的测量,且仪器示值误差≤±5.0%,重复性≤3.0%。仪器准确度和精密度接近国外先进水平,且价格低,可大大降低监测成本。     

城市污水处理厂的自动控制设计要点

通过一个城市污水处理厂自动控制系统的选取与设汁过程作为实例,说明了可编程逻辑控制器(PLC)自动控制方案是当今城市污水处理厂的最佳选择。论文对PLC自动控制方案的设计过程提出了详细的指导,将基于PLC的生产过程自动化与办公自动化进行了有机结合,为大型污水处理厂自动化控制设计提供了极重要的借鉴。     

小型磷化废水处理成套设备的开发与设计

考虑到机械行业磷化废水的特点 ,利用混凝沉淀与结晶除磷的原理 ,设计成 2t h的磷化废水处理成套设备     

Bioindicators for toxicity assesment of effluents from a wastewater treatment plant

The discharge of effluents and toxic compounds into aquatic systems represents a growing environmental problem involving an impact on water ecology and potential effect on human health. Most municipal wastewaters are complex mixtures; their complexity led as to carry out a hazard assessment using chemical analyses and biological tests.This study investigates biochemical alteratiobns in two sentinel organisms, the Anodonta cygnea mussel and the Xenopus laevis frog exposed for different lengths of time to various concentrartion of wastewater of the S. Antonino Ticino treatment plant. The results point out the long-life of toxic compounds.     

Design and startup of a membrane-biological-reactor system at a Ford-engine plant for treating oily wastewater.

A wastewater-treatment facility at Ford (Dearborn, Michigan) was recently upgraded from chemical de-emulsification to ultrafiltration (UF) followed by a membrane-biological reactor (MBR). This paper describes the design, startup, and initial operational performance of the facility. Primary findings are as follows: (1) the MBR proved resilient; (2) the MBR removed approximately 90% of chemical-oxygen demand (COD) after primary UF; (3) the removal of total Kjeldahl nitrogen by MBR appeared to be more sensitive to operating conditions than COD removal; (4) nitrification and denitrification were established in one month; (5) the MBR removed oil and grease and phenolics to below detection levels consistently, in contrast to widely fluctuating concentrations in the past; (6) permeate fluxes of the primary and MBR UF were adversely affected by inadvertent use of a silicone-based defoamer; and (7) zinc concentrations in the effluent increased, which might have been a result of ethylenediaminetetraacetic acid used in membrane washing solutions and/or might have been within typical concentration ranges.     

生活污水的臭氧深度处理及其急性毒性

以生活污水处理厂二级生物处理出水为研究对象,利用固相萃取、吸附树脂层析等手段,研究了臭氧氧化过程中进出水及不同分级组分的发光细菌急性毒性的变化,揭示了无机离子浓度对臭氧氧化出水急性毒性的影响,并采用三维荧光光谱对急性毒性相关的物质组分进行了解析。结果表明,在反应时间为15 min,臭氧投加速率为2.1 mg·（L·min）-1,臭氧氧化出水的急性毒性明显下降,出水的急性毒性仅为进水的24.7%。水样不同分级组分的生物毒性测试结果显示,生物处理出水中的亲水性物质和疏水中性物质分别贡献了44.6%和27.8%的毒性当量。当生物处理出水的氯离子含量为75~400 mg·L-1时,经臭氧氧化后,出水的急性生物毒性与氯离子浓度成正相关关系,当生物处理出水的硫酸根离子和硝酸根离子含量分别在150~300 mg·L-1和20~110 mg·L-1变化时,经臭氧氧化后,出水的急性生物毒性变化不大,结合三维荧光光谱的分析结果,臭氧氧化出水中急性毒性物质可能主要存在于芳香族蛋白质类似物（Ⅱ区）和类腐殖酸类物质（Ⅴ区）中。     

污水处理厂除臭工艺选择及工程设计

随着无锡市城北污水处理厂二期工程的扩建,污水处理厂除臭问题日益突出.针对目前常用的化学、活性炭吸附、氧离子基团、燃烧、纯天然植物提取液喷洒和生物等6种除臭方法,重点说明了除臭工艺的选择及除臭系统的工程设计,最后结合运行情况总结了除臭系统的设计特点.     

A feasibility study on the predictive emission monitoring system applied to the Hsinta power plant of Taiwan Power Company

The continuous emission monitoring system (CEMS) can monitor flue gas emissions continuously and instantaneously. However, it has the disadvantages of enormous cost, easily producing errors in sampling periods of bad weather, lagging response in variable ambient environments, and missing data in daily zero and span tests and maintenance. The concept of a predictive emission monitoring system (PEMS) is to use the operating parameters of combustion equipment through thermodynamic or statistical methods to construct a mathematic model that can predict emissions by a computer program. The goal of this study is to set up a PEMS in a gas-fired combined cycle power generation unit at the Hsinta station of Taiwan Power Co. The emissions to be monitored include nitrogen oxides (NOx) and oxygen (O2) in flue gas. The major variables of the predictive model were determined based on the combustion theory. The data of these variables then were analyzed to establish a regression model. From the regression results, the influences of these variables are discussed and the predicted values are compared with the CEMS data for accuracy. In addition, according to the cost information, the capital and operation and maintenance costs for a PEMS can be much lower than those for a CEMS.     

Development of a gravity-independent wastewater bioprocessor for advanced life support in space.

Operation of aerobic biological reactors in space is controlled by a number of challenging constraints, mainly stemming from mass transfer limitations and phase separation. Immobilized-cell packed-bed bioreactors, specially designed to function in the absence of gravity, offer a viable solution for the treatment of gray water generated in space stations and spacecrafts. A novel gravity-independent wastewater biological processor, capable of carbon oxidation and nitrification of high-strength aqueous waste streams, is presented. The system, consisting of a fully saturated pressurized packed bed and a membrane oxygenation module attached to an external recirculation loop, operated continuously for over one year. The system attained high carbon oxidation efficiencies often exceeding 90% and ammonia oxidation reaching approximately 60%. The oxygen supply module relies on hydrophobic, nonporous, oxygen selective membranes, in a shell and tube configuration, for transferring oxygen to the packed bed, while keeping the gaseous and liquid phases separated. This reactor configuration and operating mode render the system gravity-independent and suitable for space applications.     

Application of a constructed wetland for industrial wastewater treatment: a pilot-scale study

The main objective of this study was to examine the efficacy and capacity of using constructed wetlands on industrial pollutant removal. Four parallel pilot-scale modified free water surface (FWS) constructed wetland systems [dimension for each system: 4-m (L)x1-m (W)x1-m (D)] were installed inside an industrial park for conducting the proposed treatability study. The averaged influent contains approximately 170 mg l(-1) chemical oxygen demand (COD), 80 mg l(-1) biochemical oxygen demand (BOD), 90 mg l(-1) suspend solid (SS), and 32 mg l(-1) NH(3)-N. In the plant-selection study, four different wetland plant species including floating plants [Pistia stratiotes L. (P. stratiotes) and Ipomoea aquatica (I. aquatica)] and emergent plants [Phragmites communis L. (P. communis) and Typha orientalis Presl. (T. orientalis)] were evaluated. Results show that only the emergent plant (P. communis) could survive and reproduce with a continuous feed of 0.4m(3)d(-1) of the raw wastewater. Thus, P. communis was used in the subsequent treatment study. Two different control parameters including hydraulic retention time (HRT) (3, 5, and 7d) and media [vesicles ceramic bioballs and small gravels, 1cm in diameter] were examined in the treatment study. Results indicate that the system with a 5-d HRT (feed rate of 0.4m(3)d(-1)) and vesicles ceramic bioballs as the media had the acceptable and optimal pollutant removal efficiency. If operated under conditions of the above parameters, the pilot-plant wetland system can achieve removal of 61% COD, 89% BOD, 81% SS, 35% TP, and 56% NH(3)-N. The treated wastewater meets the current industrial wastewater discharge standards in Taiwan.     

Performance of a constructed wetland-pond system for treatment and reuse of wastewater from campus buildings.

A constructed wetland-pond system consisting of two free-water-surface-flow (FWS) wetland cells, a scenic pond, and a slag filter in series was used for reclamation of septic tank effluent from a campus building. The results show that FWS wetlands effectively removed major pollutants under a hydraulic loading rate between 2.1 and 4.2 cm/d, with average efficiencies ranging from 74 to 78% for total suspended solids, 73 to 88% for 5-day biochemical oxygen demand, 42 to 49% for total nitrogen, 34 to 70% for total phosphorous, 64 to 79% for total coliforms, and 90 to 99.9% for Escherichia coli. After passing through the scenic pond and slag filter, the reclaimed water was used for landscape irrigation. There were a variety of ornamental plants and aquatic animals established in the second FWS cell and scenic pond with good water quality, thus enhancing landscape and ecology amenity in campuses.     

厌氧反应器废水资源化过程在线监测系统

为克服现行厌氧反应器状态离线分析的滞后性,充分利用资源,改进废水排放状态,研究了基于荧光光谱的废水资源化处理过程在线监测系统。系统以厌氧反应器中的关键产物色氨酸、核黄素及辅酶为主要检测组分,自动定位滤波轮并控制脉冲氙灯的闪烁次数,使用光电倍增管采集荧光信号。针对反应产物的混合体系,提出了将三维数据二维化的准三维荧光谱概念,优化获得了的3×3荧光强度矩阵,采用偏最小二乘法并优化其模型参数,实现了反应器中3种关键过程产物的实时在线检测、统计与分析,使其回收率范围达到85%至112%。     

均匀设计法处理含硫废水的研究

对钠盐型和铵盐型含硫工业废水进行脱硫处理,采用均匀设计法设计试验,得到定量描述试验内在规律的多元非线性回归方程.用该回归方程计算的预测值与试验结果一致.对影响脱硫效果和脱硫效率的影响因素--絮凝剂投加量、pH以及废水含硫量进行了考察.利用回归方程,对反应体系进行了模拟优化处理.研究表明,在试验条件下,用聚合氯化铝作为絮凝剂、pH=7的条件下,采用两段工艺,可以使脱硫后废水含硫量降至40 mg/L以下,满足下游污水处理装置对含硫量的要求.     

美国某污水处理厂工艺设计及运行效果

介绍了美国某污水处理厂的处理工艺流程、主要构筑物构成及其设计参数,通过对该污水处理厂一年内运行效果的调研,分析评价了该污水厂的进出水水质指标;该水厂工艺流程对TSS、BOD5、COD、NH3-N、TP和浊度的年平均去除率分别可以达到97.7％、97.7％、93.5％、82.6％、95.2％和97.9％,各项出水水质均优于我国《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A标准,通过对该水厂工艺的介绍和分析,为我国污水厂的建设及改造升级提供了一定的参考依据.     

Development of a prefabricated treatment plant for diluted pig wastewater

In order to develop a prefabricated treatment and reuse plant for diluted pig wastewater, an entrapped-mixed-microbial-cell (EMMC) process was evaluated for its process performance and economic analysis. At the hydraulic retention time (HRT) of 30 hrs (loading rate of 1.0 g TCOD/L/d) and intermittent aeration of 1 hr of aeration and 1 hr of non-aeration, it was found that, by using the pretreatment of the ammonium crystallization, both the medium and large carriers were able to reduce TCOD, SCOD, and T-N by 83.51, 84.11, and 95.10%, respectively. The EMMC unit and lime post-treatment followed by ammonium crystallization can reduce BOD5, TCOD, SCOD, TSS, T-N, and T-P, respectively by 99.22, 93.85, 92.67, 97.73, 96.43, and 97.27%. The treated wastewater, after disinfection, is able to meet the requirements of the standards issued by the USEPA for reuse of food crops. The economic analysis indicates that based on the process performance of the EMMC unit, a prefabricated wastewater treatment plant for 2000 pigs has comparable net present worth (NPW) comparing intermittent aerated biological systems and less operation and maintenance and land requirement than conventional biological processes for removal carbon and nitrogen. A farm operation of more than 2000 pigs meets the unit cost of US$4.91/pig/yr. This will minimize the problems pertaining to technical factors or considerations that heavily influence planning, construction and operation of a pig wastewater treatment system.     

Development of a prefabricated treatment plant for diluted pig wastewater

Abstract

In order to develop a prefabricated treatment and reuse plant for diluted pig wastewater, an entrapped‐mixed‐microbial‐cell (EMMC) process was evaluated for its process performance and economic analysis. At the hydraulic retention time (HRT) of 30 hrs (loading rate of 1.0 g TCOD/L/d) and intermittent aeration of 1 hr of aeration and 1 hr of non‐aeration, it was found that, by using the pretreatment of the ammonium crystallization, both the medium and large carriers were able to reduce TCOD, SCOD, and T‐N by 83.51, 84.11, and 95.10%, respectively. The EMMC unit and lime post‐treatment followed by ammonium crystallization can reduce BOD₅, TCOD, SCOD, TSS, T‐N, and T‐P, respectively by 99.22, 93.85, 92.67, 97.73, 96.43, and 97.27%. The treated wastewater, after disinfection, is able to meet the requirements of the standards issued by the USEPA for reuse of food crops. The economic analysis indicates that based on the process performance of the EMMC unit, a prefabricated wastewater treatment plant for 2000 pigs has comparable net present worth (NPW) comparing intermittent aerated biological systems and less operation and maintenance and land requirement than conventional biological processes for removal carbon and nitrogen. A farm operation of more than 2000 pigs meets the unit cost of US$4.91/pig/yr. This will minimize the problems pertaining to technical factors or considerations that heavily influence planning, construction and operation of a pig wastewater treatment system.