THE INVESTIGATION ON PHOTOCATALYTIC TREATMENT OF WASTE WATER CONTAINING PHENOL OVER ZnO

This paper adopts a medium pressure mercury lamp as light source and ZnO powder as catalyst to investigate the effect of radioactive wave length, component of phenol ZnO suspension and stirring method on phenol decomposition rate. The optimized conditions for the phenol decomposition are: (1) Radioactive wave length: 360～420 nm; (2)Phenol concentration in the suspension is less than 200 mg/l; (3)ZnO concentration is 3～8 g/l; (4)pH value is 5～7; (5)Reaction temperature is 25℃～40℃; (6)Agitation at atmosphere. Phenol can decompose in two ways: (1)Reacting with photogenerated cavity; (2)Reacting with ·OH radical.

Intended process water management concept for the mechanical biological treatment of municipal solid waste

Accumulating operational experience in both aerobic and anaerobic mechanical biological waste treatment （MBT） makes it increasingly obvious that controlled water management would substantially reduce the cost of MBT and also enhance resource recovery of the organic and inorganic fraction. The MBT plant at Gescher, Germany, is used as an example in order to determine the quantity and composition of process water and leachates from intensive and subsequent rotting, pressing water from anaerobic digestion and scrubber water from acid exhaust air treatment, and hence prepare an MBT water balance. The potential of, requirements for and limits to internal process water reuse as well as the possibilities of resource recovery from scrubber water are also examined. Finally, an assimilated process water management concept with the purpose of an extensive reduction of wastewater quantity and freshwater demand is presented.

A Three-Stage, Completely Sustainable Process Addressing Industrial Water Waste Treatment Management: The Case of the Sorption of Methylene Blue in Column Experiments

A detailed study regarding the optimization of a complete system for the purification of water waste is presented.Three main concerns are addressed:the nature of the absorbing material,the efficiency dependence on scale and the management of the final waste of the assembly.These three points have to be optimized in the best acceptable way from an environmental point of view.Subsequently,the wet filling material,comprised of the absorbent and the absorbed dye,was buried in dry soil,promoting soil bacterial and fungal growth.The absorbance of CO2 was determined.The use of natural vegetative material as absorbents of chemical dyes in industrial water waste is an environmentally friendly solution.Combination with the utilization of the final solid waste as fertilizer is an optimum solution,promoting sustainability within an industrial ecology framework.The adsorption column scale-up studied herein,for the removal of basic dyes from wastewaters,using methylene blue as a representative adsorbate and barley straw as a representative waste biomass adsorbent,was successful,as regards consistency and reliability(judged by low absolute and relative standard deviation)of results.

STUDY AND SIMULATION OF AN ACTIVATED SLUDGE TREATMENT FOR METHYL VIOLET WASTE WATER

This paper researched a promising biological treatment of methyl violet waste water by methods of activated sludge.Effects of temperature and pH were studied on this process.Kinetic equation of the substrate biodegradation was investigated in the experimental range.It was studied and simulated that flow within the bubble region of this bioreactor according to the κ ε two fluid equation.Simulation results agree well with experimental data.

Impact of <i>Moringa oleifera</i>Cake Residue Application on Waste Water Treatment: A Case Study

Most of water treatments require higher expenditure. Chemical coagulant requires higher cost and has some drawback after treatment such as pH changes. Moringa oleifera cake residue (MOCR) is one of the alternatives to replace chemical coagulant. A jar test apparatus was used to monitor water treatment. Water quality of Gebeng River (GR) and waste water (WW) was examined before and after treatment. Different parameters using (MOCR) was investigated. Preliminary laboratory results showed the great potential of the (MOCR) to be used in water treatment. MOCR shows an excellent reduction in turbidity (97 % was removed). The bacteria were reduced from 1.7 × 105 to 8 × 103 CFU/ml. Dissolved oxygen (DO) was improved that elevated from 1.06 ± 0.04 to 5.09 ± 0.03 mg/L. However, chemical oxygen demand (COD) and biological oxygen demand (BOD) were increased from 520.5 ± 0.71 to 865.0 ± 2.12 mg/L and from 120.5 ± 2.12 to 270.5 ± 2.12 mg/L respectively. Nevertheless, there is no significant alteration of pH, conductivity, salinity and total dissolved solid (TDS) after treatment. The iron (Fe) was fully removed while copper (Cu) and cadmium (Cd) were successfully removed up to 98%. The reduction of lead (Pb) also achieved 82.17%. Also, (MOCR) can be stored for long time up to 6 months without affecting the biological properties of MO.

Electrochemical Oxidation of Chlorimuron-ethyl on Ti/SnO_2-Sb_2O_5/PbO_2 Anode for Waste Water Treatment

The electrochemical oxidation of chlorimuron-ethyl on metry. The electrochemical behaviour of the electrode in a sodium Ti/SnO2-Sb2O5/PbO2 electrode was studied by cyclic voltamsulfate solution and in the mixture solution of sodium sulfate and chlorimuron-ethyl was studied. The experimental results of cyclic voltammetry show that the acidic medium was suitable for the efficient electrochemical oxidation of chlorimuron-ethyl. Some electro-generated reagent was formed in the electrolysis process and chlorimuron-ethyl could be oxidized by the electro-generated reagent. A Ti/SnO2-Sb2O5/PbO2 electrode was used as the anode and the electrolysis experiment was carried out under the optimized conditions. The electrolysis process was monitored by UV-Vis spectrometry and high performance liquid chromatography（HPLC）, and the chemical oxygen demand（COD） was determined by the potassium dichromate method. The mechanism of chlorimuron-ethyl to be oxided was studied primarily by the cyclic voltammetry and UV-Vis spectrometry. The results of electrolysis experiment demonstrate the possibility of the electrode to be used as an anode for the electrochemical treatment of chlorimuron-ethyl contained in waste water.

A Case Study on the Utilization of Wind Energy Potential on Remote and Isolated Small Wastewater Plants

Small WWTP （wastewater treatment plants） are frequently located, by necessity, in remote and isolated sites, which increases the difficulty of its energy supply. This paper describes a case study which is a step by step procedure concerning the evaluation of the wind potential of sites that are dependent of in-situ energy generation, as well as, on the utilization of the potential wind energy in Magoito WWTP. The adopted methodology comprised the collection of one year of in-situ wind data and its validation by comparison with historical data of more than 10 years of a nearby anemometric station. The data provided by the two anemometric stations was statistically treated and allowed the analysis of the results from the two stations. These results are promising in terms of wind availability and velocity. Finally, the study comprised the simulation of the local wind conditions for a considerable larger area in order to find the best site for locating a wind turbine.

Performance Simulation of H-TDS Unit of Fajr Industrial Wastewater Treatment Plant Using a Combination of Neural Network and Principal Component Analysis

Nowadays, with regard to environmental issues, proper operation of wastewater treatment plants is of particular importance that in the case of inappropriate utilization, they will cause serious problems. Processes that exist in environmental systems and environmental engineers are dealing with them mostly have two major characteristics: they are dependent on many variables;and there are complex relationships between its components which make them very difficult to analyze. Being familiar with characteristics of industrial town effluents from various wastewater treatment units, which have high qualitative and quantitative variations and more uncertainties compared to urban wastewaters, plays very effective role in governing them. In order to achieve a better and efficient control over the operation of an industrial wastewater treatment plant, powerful mathematical tool can be used that is based on recorded data from some basic parameters of wastewater during a period of treatment plant operation. In this study, the multilayer perceptron (MLP) feed forward neural network with a hidden layer and stop training method was used to predict quality parameters of the industrial effluent. Data of this study are related to the Fajr Industrial Wastewater Treatment Plant located in Mahshahr—Iran that qualitative and quantitative characteristics of its units were used for training, calibration and evaluation of the neural model. Also, Principal Component Analysis technique was applied to modify and improve performance of generated models of neural networks. The results of this model showed good accuracy of the model in estimating qualitative pro- file of wastewater. This model facilitates evaluating the performance of each treatment plant units through comparing the results of prediction model with the standard amount of output.

Troubleshooting and Optimization of High-Strength Inhibitory Chemical Wastewater Treatment Process

Wastewaters from the chemical industry are usually of high-strength and may contain minor inhibitory and recalcitrant organics that are at times not readily identifiable. This paper describes the experience of a biological waste water treatment plant （WWTP） processing a COD concentration of 43000 mg·L^-1 wastewater from an oxochemical manufacturing plant. Stage improvements of the plant process by dilution of the inhibitory influent using other chemical wastewater streams resulting in a synergistic process effect, and removal of inhibitory organics by phase separation via acidification, effectively achieved process optimization producing a high quality effluent. In particular, the COD removal efficiency of granular sludge based anaerobic reactors increased from 56% to 90%. The final effluent COD decreased from 250mg·L^-1 to 50mg·L^-1, consistently meeting the COD concentration of 100 mg·L^-1 regulatory discharge limit. The success of the process enhancements supports the hypothesis that long-chain quaternary carboxylic acids act as substrate inhibitors in the biological process.

PREPARATION AND APPLICATION OF COPOLYMERS OF 2-ACRYLAMIDO-2-METHYL PROPANE SULFO ACID AS WASTE WATER TREATMENT AGENTS

In this paper, the preparation and application of copolymers of 2-acrylamido-2-methyl propane sulfo acid (AMPS) were discussed. The results showed that the copolymers with molecular weight 18.10 million can be prepared. In treating waste water from deinked pulp, the dosage of copolymers was 0.75ppm, the optimum dosage of PAC was 100ppm; dosage of the amphoteric polyacylamide (AmPAM) with molecular weight 11.34 million was 0.75ppm, the optimum dosage of PAC was 75ppm. The removed rate of CODcr was above 70%.

Recycling water glass from wet reclamation sewage of waste sodium silicate-bonded sand

Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.

Test of membrane bioreactor for waste water treatment of a petrochemical complex

Membrane bioreactor (MBR) used in water and waste water treatment is a developing technique for water pollution control and water reuse. This paper described a membrane bioreactor for treatment of waste water in a petrochemical complex. The experimental MBR was a lab scale one composed of an activated sludge bioreactor unit and an ultrafiltration membrane unit. The relationship of COD removal with MLSS and HRT in this MBR was studied. The effects of crossflow velocity, backwash interval and volume of flush liquid on the flux were discussed. The results showed that average removal of COD, oil, SS and turbidity in petrochemical waste water by the MBR was 91%, 86%, 92% and 99%, respectively. The average removal of NH 3 N and total phosphorous was 85% and 82% respectively. A coefficient of COD removal, k , was 0017—0080 L/(mg.d). The membrane flux maintained higher than 60 L/hm 2 bar for 34 days without chemical cleaning when the velocity of crossflow was 35—39 m/s and the backwash interval was 30 minutes and backwash duration at 20 seconds. The results indicated that it is feasible for MBR technology to be used in petrochemical waste water treatment. The treated water could be considered as a source of to make up water for industrial cooling system or to be reused for other purposes.

Swedish Experience and Excellence in Wastewater Treatment Demonstrated Especially in Phosphorus Removal

Water quality protection in Sweden has a more than 80-year history. The needed knowledge has by large been imported. Now, to some extent the development of phosphorus removal technology may be Swedish contribution to advanced knowledge. This paper presents the development in Sweden, mainly a close to 50-year period. Starting in the late 1960s, a standard of <0.5 mg P/l was the normally raised effluent criteria, regardless of the magnitude of the discharge flow. The successive sharpening of the discharge levels has today resulted in a level of 0.2 to 0.3 mg P/l typically. As a matter of fact, even levels of 0.1 to 0.15 mg P/l have been discussed. The period should a large extent demonstrated both improved technologies and a far better efficiency with respect to the use of chemicals and energy. Some important points in this development may be the understanding of the Oxygen Consumption Potential, as well as the identified needs for an improved nitrogen removal. Lately the problems of complex pollution agents and predominantly the remains of pharmaceutical agents have been identified. To illustrate the development during the 50-year period, two examples are presented from the Swedish context. The main conclusion in this paper is that the Swedish history on phosphorus removal illustrates how empirical science in practice sometimes works, including a never-ending need for an open mind and a readiness to take revised and improved knowledge on board.

Pytoremediation of fluoroquinolone group of antibiotics from waste water

The study involved selection of wetland plant species hyper efficient in removing fluoroquinolone group of antibiotics so that they can be used in a constructed wetland system patented by NEERI, India (European Patent Office (EPO) Pub. No.: WO2004087584) or any other constructed wetland. Phyto removal of these antibiotics at such high concentrations without any toxic effect on the plant species is very useful as incomplete removal of certain antibiotics such as Ciprofloxacin, and Ofloxacin from waste waters is of concern due to their health effects if they do persist in finished waters even at ng/l levels. Five different wetland plant species which were also tested for their efficiency to treat municipal wastewater were used to test their efficiency to scavenge commonly used fluoroquinolone antibiotics (which are not degraded easily) namely Ciprofloxacin, Gemifloxacin mesylate, Ofloxacin and Gatifloxacin from aqueous medium (Hoagland-Arnon solution). EC double beam UV-VIS spectrophotometer was used to obtain lambda max of Ciprofloxacin, Gemifloxacin mesylate, Ofloxacin and Gatifloxacin in Hoagland-Arnon solution. The most efficient plant species for each antibiotic were selected and tested again for confirmation of antibiotic removal efficiency at a high concentration of 50 mg/l of each antibiotic. Taxodium distichum was found to be the most suitable for the removal of Ofloxacin, Gatifloxacin and Ciprofloxacin showing maximum removal of 32 mg/l (on 6th day), 21 mg/l (on 8th day), 32 mg/l (on 9th day), respectively and Canna indica was found to be the most suitable for removal of Gemifloxacin mesylate showing maximum removal of 38 mg/l (on 8th day).

Analysis of the Factors Influencing the Solid-liquid Separation Experiment of Guar Gum Waste Liquid

Based on the water quality detection and analysis of guar gum waste liquid,as well as the data of experiments on the treatment of waste liquid under different viscosity and pH conditions,the influencing factors of solid-liquid separation under conventional"coagulation+filtration"treatment process are studied.Under the conventional"coagulation+filtration"treatment process,the viscosity of guar gum waste liquid is lower than 3 mPa·s;the pH is 6-7.5;the filtration accuracy is not lower than 20μm,which can meet better treatment conditions.This experimental study provides an experimental basis for the optimal design of the treatment process of guar gum waste liquid.

Microplastics and Wastewater Treatment Plants—A Review

The emission of microplastics into nature poses a threat to aquatic and terrestrial ecosystems. Their penetration of the food chain presents a danger to human health as well. Wastewater treatment plants can be seen as the last barrier between microplastics and the environment. This review focuses on the impact of waste treatment plants in retaining microplastics. Studies show that no wastewater treatment method leads to a complete retention of microplastics, and so wastewater treatment plants themselves are viewed as point sources for the discharge of microplastics into the aquatic environment. Problems associated with the utilization of microplastic loaded sewage sludge are also discussed in the review.

Simulation-Guided Design of Bamboo Leaf-Derived Carbon-Based High-Efficiency Evaporator for Solar-Driven Interface Water Evaporation

Solar interface water evaporation has been demonstrated to be an advanced method for freshwater production with high solar energy utilization.The development of evaporators with lower cost and higher efficiency is a key challenge in the manufacture of practical solar interface water evaporation devices.Herein,a bamboo leaf-derived carbon-based evaporator is designed based on the light trace simulation.And then,it is manufactured by vertical arrangement and carbonization of bamboo leaves and subsequent polyacrylamide modification.The vertically arranged carbon structure can extend the light path and increase the light-absorbing area,thus achieving excellent light absorption.Furthermore,the continuous distribution of polyacrylamide hydrogel between these vertical carbons can support high-speed water delivery and shorten the evaporation path.Therefore,this evaporator exhibits an ultrahigh average light absorption rate of~96.1%,a good water evaporation rate of 1.75 kg m^(-2) h^(-1),and an excellent solar-to-vapor efficiency of 91.9%under one sun irradiation.Furthermore,the device based on this evaporator can effectively achieve seawater desalination,heavy metal ion removal,and dye separation while completing water evaporation.And this device is highly available for actual outdoor applications and repeated recycling.

没食子酸强化Fenton体系对水中DEET降解的研究

针对Fenton反应过程中生成的Fe^(3+)的还原速率相对于Fe^(2+)和H_(2)O_(2)的反应速率较慢限制了其降解效率的问题,以N,N-二乙基-间甲苯酰胺(DEET)为目标污染物,比较了3种络合剂对Fenton反应的促进效应。结果表明,在DEET浓度为200μmol/L、H_(2)O_(2)/Fe^(2+)摩尔比为20∶1、初始Fe^(2+)浓度为50μmol/L、没食子酸(GA)/Fe^(2+)摩尔比为1∶1以及pH=7.0的条件下,DEET的去除效率在20 min内达到75.3%。与传统的Fenton体系相比,DEET的降解效率提高了63.8%。HO·是加速DEET降解和矿化的主要活性氧物质。GA促进了Fe^(3+)的还原和H_(2)O_(2)的分解,从而促进了额外自由基的生成,加速了Fe^(2+)/H_(2)O_(2)体系对DEET的降解。

Industrial Wastewater Treatment by Using MBR (Membrane Bioreactor) Review Study

This study demonstrated the importance, process, activation and applications of Membrane in bioreactor to treat the waste water. Membrane Bioreactor (MBR) process consists of a biological reactor integrated with membranes that combine clarification and filtration of an activated sludge process into a simplified, single step process. Operating as an MBR allows conventional activated sludge plants to become single step processes, which produce high quality effluent potentially suitable for reuse. Application of MBR technology for industrial wastewater treatment has also gained attention because of the robustness of the process. Theoretically, maintenance of long SRT in MBR is in favor of the retention and development of special microorganisms, which may lead to better removal of refractory organic matter and make the system more robust to load variations and toxic shocks. Literature suggested the conceptual expectation of enhanced biodegradation of hardly biodegradable compounds in MBR does not often come true. Improved biodegradation to certain extent has been reported in a few studies;however the underlying factors leading to such improvement still remains to be elucidated. This is comprehensive review of the studies dealing with recalcitrant industrial wastewater treatment by MBR, and casts light on the strategies to achieve enhanced biodegradation of hardly biodegradable industrial pollutants in MBR.