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.

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.

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.

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.

Overview coking plant & Lurgi gasifier plant waste water treatment

The paper described the coking plant and Lurgi gasifier plant waste water types and characteristics , comparing the COD and ammonia-N level in different source of waste water in the plant.The currently maturity coking plant waste water treatment method was statement in the paper and analyzed the pros and cons of each method.The primary cost analysis of each type of waste water treatment was also completed in the paper.According to these analyses , recommendation was prepared for coking plant and Lurgi gasifier plant waste water treatment.

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 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.

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.

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.

Performance of Wuxi WWTP in China

In Wuxi Wastewater Treatment Plant, the Anaerobic, anoxic and oxic (A2/O) process was employed to remove the nitrogen and phosphorus, which exhibited the positive results of the high removal efficiency for phosphorus with a range of 67.7% to 89.9% and an average value of 78.0. The effluent of phosphorus met the national discharge standard. The removal of TN was effected by both BOD variation of influent and wastewater temperature. TN removal was in the range of 28.5% to 55.8% with an average value of 39.4%. The energy cost was 0.15 kWh(m3d)-1 or 1.35 kWh(kgBOD@d)-1. The annual average sludge production was 46.3 m3d-1, the annual average dosage for the dewatering was 40 kg d-1 .

Approximate Analytical Expressions for the Concentrations of Acetate and Methane in the Microbial Electrochemical Cell

Mathematical modeling of microbial electrochemical cells (MXCs) for both microbial fuel cell and microbial electrolysis cell is discussed. The model is based on the system of reaction diffusion of reaction-diffusion equation containing a non-linear term related to substrate consumption rates by electrogeneic and methanogenic microorganism in the bioflim. This paper presents the approximate analytical method to solve the non-linear differential equation that describes the diffusion coupled with acetate (substrate) consumption rates. Simple analytical expressions for the concentrations of acetate and methane have been derived for all experimental values of bulk concentration, distributions of microbial volume fraction, local potential in the biofilm and biofilm thickness. In addition, sensitivity of the parameters on concentrations is also discussed. Our analytical results are also validated with the numerical results and limiting cases results. Further, a graphical procedure for estimating the kinetic parameters is also suggested.

Algal massive growth in relation to water quality and salinity at Damietta,north of Egypt

Objective:To relate the proliferation and dominance of certain algal species at the Damietta and its relation to water quality.Methods:Water and algal biomass were bimonthly sampled from five selected sites at Damietta Province,Egypt during 2012.Algae were identified and quantified.Waters,algae and sediment were analyzed.Results:The physicochemical properties of water showed limited seasonal but substantial local variation.The high levels of nitrogen and phosphorus and turbidity of water pointed to marked eutrophication,which could enhance massive algal growth.The temporal fluctuation in temperature,exposure to industrial and domestic sewage and salinity results in succession between blooming algal species.Spirulina platensis and Chlorella vulgaris alternated in a moderately saline water and Oscillatoria agardhii and Mougeotia scalaris in a fresh water body during summer and winter respectively.Likewise,Microcystis aureginosa and Ulva lactuca alternated in a moderately saline site during autumn and summer respectively.Cladophora albida dominated a fish pond of brackish water and Dunaliella salina dominated the most saline water over the whole period of study.Conclusions:Growth of the predominant algal species is correlated to water quality.These species are of considerable nutritive value,with moderate contents of protein,carbohydrate,macronutrients and micronutrients,which evaluates them for usage as food(green and macroalgae),fodder or bio-fertilizer(cyanophytes).

Water Quality Management of Beijing in China

At present, Beijing's water resources are insufficient and will become the limiting factor for sustainable development for the city in the near future. Although efforts have been made to control pollution, water quality degradation has occurred in some of the important surface water supplies, aggravating the water resource shortage. At present, approximately three quarters of the city's wastewater is discharged untreated into the urban river system, resulting in serious pollution and negatively influencing the urban landscape and quality of daily life. To counteract these measures, the city has implemented a comprehensive “Water Quality Management Plan” for the region, encompassing water pollution control, prevention of water body degradation, and improved water quality. The construction of municipal wastewater treatment plants is recognised as fundamental to controlling water pollution, and full secondary treatment is planned to be in place by the year 2015. Significant work is also required to expand the service area of the municipal sewage system and to upgrade and renovate the older sewer systems. The limitation on available water resources has also seen the emphasis shift to low water using industries and improved water conservation. Whilst industrial output has increased steadily over the past 1015 years at around 10% per annum, industrial water usage has remained relatively constant. Part of the city's water quality management plan has been to introduce a strict discharge permit system, encouraging many industries to install on site treatment facilities.

Quantifying and managing regional greenhouse gas emissions: Waste sector of Daejeon, Korea

A credible accounting of national and regional inventories for the greenhouse gas （GHG） reduction has emerged as one of the most significant current discussions. This article assessed the regional GHG emissions by three categories of the waste sector in Daejeon Metropolitan City （DMC）, Korea, examined the potential for DMC to reduce GHG emission, and discussed the methodology modified from Intergovernmental Panel on Climate Change and Korea national guidelines. During the last five years, DMC＇s overall GHG emissions were 239 thousand tons C02 eq./year from eleven public environmental infrastructure facilities, with a population of 1.52 million. Of the three categories, solid waste treatment/disposal contributes 68%, whilst wastewater treatment and others contribute 22% and 10% respectively. Among GHG unit emissions per ton of waste treatment, the biggest contributor was waste incineration of 694 kg CO2 eq./ton, followed by waste disposal of 483 kg CO2 eq./ton, biological treatment of solid waste of 209 kg CO2 eq./ton, wastewater treatment of 0.241 kg CO2 eq./m3, and public water supplies of 0.067 kg CO2 eq./m3. Furthermore, it is suggested that the potential in reducing GHG emissions from landfill process can be as high as 47.5% by increasing landfill gas recovery up to 50%. Therefore, it is apparent that reduction strategies for the main contributors of GHG emissions should take precedence over minor contributors and lead to the best practice for managing GHGs abatement.

Catalytic activities of ultra-small β-FeOOH nanorods in ozonation of 4-chlorophenol

We report the catalytic properties of ultra-small β-FeOOH nanorods in ozonation of4-chlorophenol（4-CP）. XRD, TEM, EDS, SAED, FTIR and BET were used to characterize the prepared material. Interaction between O3 and β-FeOOH was evident from the FTIR spectra.The removal efficiency of 4-CP was significantly enhanced in the presence of β-FeOOH compared to ozone alone. Removal efficiency of 99% and 67% was achieved after 40 min in the presence of combined ozone and catalyst and ozone only, respectively. Increasing catalyst load increased COD removal efficiency. Maximum COD removal of 97% was achieved using a catalyst load of 0.1 g/100 m L of 4-CP solution. Initial 4-CP concentration was not found to be rate limiting below 2 × 10^-3mol/L. The catalytic properties of the material during ozonation process were found to be pronounced at lower initial p H of 3.5.Two stage first order kinetics was applied to describe the kinetic behavior of the nanorods at low p H. The first stage of catalytic ozonation was attributed to the heterogeneous surface breakdown of O3 by β-FeOOH, while the second stage was attributed to homogeneous catalysis initiated by reductive dissolution of β-FeOOH at low p H.