Amount Of Wastewater Discharge Research Articles

Design of a Conduction-Cooled Open Gradient Superconducting Magnetic Separation Magnet

Magnetic separation of wastewater is required to solve the problem of water pollution caused by a large amount of wastewater discharge in urbanization and industrialization. Superconducting magnets reduce energy consumption, increase the magnetic field strength, and improve the magnetic separation effect compared to traditional magnetic separation using permanent magnets and electromagnets. In this paper, an open gradient superconducting magnetic separation magnet conduction-cooled by a two-stage GM cryocooler was designed and developed. The open gradient superconducting magnetic separation magnet comprised four saddle-shaped coils and an optimized iron yoke. The radial magnetic flux density was 1 T at a distance of 20 mm from the surface of the coil at an operating current of 120 A, resulting in a magnetic force density of 3.5*10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> N/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , with a peak field in the coil of 4.82 T. Additionally, this paper proposed a superconducting coil structure and winding method with an end positioning groove. The design and manufacture of the end former, as well as the magnet structure, was completed. Finally, this paper designed a compact cryostat with a two-stage GM cryocooler.

A hierarchical intelligent control strategy for greenhouse gas reduction in wastewater treatment process of paper mill

Due to the huge amounts of wastewater discharge and the high pollution loads in papermaking industry, many greenhouse gases (GHG) are emitted in the papermaking wastewater treatment process. The wastewater dissolved oxygen (DO) control has been considered as the most cost-effective control solution for GHG reduction in wastewater treatment plants (WWTP). However, the competition between contaminant removal efficiency and GHG reduction hinders the drastic reduction of GHG emissions from WWTP. In this study, based on the established integrated GHG emission model, explicitly considering the total GHG reduction targets on the premise of effluent compliance, an intelligent control scheme has been developed for an activated sludge process in a paper mill. Regarding DO as the controlled variable, the proposed hierarchical optimal proportional-integral (HOPI) control scheme was established consisting of three layers: 1) Layer 1 for the effluent quality estimation, 2) Layer 2 for the optimal DO set point determined by genetic algorithm with the influent variations to obey discharging norms and reduce GHG emissions, 3) Layer 3 for the DO tracking proportional integral (PI) control with the controller parameters adjusted by the back propagation neural network to track the dynamically optimized DO set points. The simulation results showed that, compared with the open-loop (OL) operation (averaged aeration, 10/h), the proposed HOPI control (averaged aeration, 7.9/h) reduced the GHG emissions by 12.54% under the premise of discharging norms, which was mainly attributed to the reduction of the aeration electricity consumption. In contrast, the PI control (averaged aeration, 12.9/h) increased the GHG emissions by 7.48% compared with the OL operation. Thus, the proposed HOPI control strategy has demonstrated potential for the application of GHG reduction in industrial WWTPs.

Water pollutant discharge permit allocation based on DEA and non-cooperative game theory

Against the background of the ecological civilization system reform in the new era, the appropriate allocation of water pollutant discharge permits is an important policy for controlling the amount of wastewater discharge. Traditional allocation methods have disadvantages, such as high additional costs, an unfair allocation scheme, and market distortion. In the present study, a fixed-cost allocation model based on data envelopment analysis (DEA) and the Nash non-cooperative game theory is employed to allocate water pollutant discharge permits of totally 31 provinces in China from 2008 to 2017. The allocation scheme considers environmental efficiency. The results demonstrate regional differences in the allocation of water pollutant discharge permits. The eastern region has abundant allocations. The northeastern and central regions have insufficient allocations. Besides, the western region has a significant shortage of allocations. It indicates the higher the utilization efficiency of the water pollutant discharge permits, the higher the region's sustainable development is. Based on the analysis, we propose guidelines for industrial wastewater discharge reduction.

Microplastics on beaches and mangrove sediments along the coast of South China

Accumulation of microplastics (MPs) data on a global scale is key to supporting plastic waste management for protecting ecosystems. To respond this call, a sampling campaign was conducted in the summer and winter seasons of 2018 to collect beach and mangrove sediment samples from 32 sites along the coastline of South China. The MPs concentrations in the intertidal zone along the coast of South China were comparable to those in other regions around the world. Polystyrene foams and fibers were the most abundant debris in the 0.2–5 mm and 0.02–2 mm MPs, respectively. Principal component and correlation analyses indicated that the abundances of MPs were related to wind direction, wastewater discharge amount, and tourist and fishing activities. Risk assessments suggested that potential ecological risks induced by MPs on beaches and mangrove forest along the coast of South China should not be overlooked.

Effects of saturated hot air pretreatment compared to traditional blanching on the physicochemical properties of Apricot (Prunus armeniaca L.) kernels and its skin during removing skin

In this paper, the experiments were conducted to investigate the effects of saturated hot air (SHA) pretreatment on the components in apricot kernels and skins compared with the traditional blanching (TB) method, so as to evaluate the feasibility of SHA for removing the skins. Furthermore, the heatmap was employed to correlate the phenolic components and the color values. The results indicate that the SHA temperature and time had a definite influence on some of the components including phenols, amygdalin, proteins and reducing sugars. Compared with the TB, not only the loss of amygdalin, proteins and reducing sugars in apricot kernels used in SHA pretreatment greatly decreased, but also the loss of the phenols, flavonoids, protocatechin, catechin, vanillic acid and chlorogenic acid in the skins decreased by 42.3%, 50.5%, 57.8%, 63.3%, 94.5% and 42.5%, respectively. The SHA pretreatment for removing skins could decrease the amount of wastewater discharge, and lower the loss of active substances in apricot kernels and its skins. In conclusion, the SHA might be as a novel green and efficient method for removing the apricot kernel skins.

Simulation and Application Research on the River System Connectivity, Considering the Flood Control and Agricultural Water Objectives

With the rapid development in social economy, the waste water discharge amount in many cities of China is on the rise continuously. This has resulted in excess pollutants in rivers and lakes, deteriorating hydro-ecology environmental issues and so on. The problems have a serious impact on the social and economic development. Focusing on the demonstration site of Zhong Shun Da Wei, this paper started to approach how the connectivity of river-lake water system influenced the two objectives of the great water-retaining structure, which were flood control and agricultural water storage. It deeply probed into the basic theory and key scheduling technology of water system connection throughout the river networks in Zhong Shun Da Wei. The results are indicating as follows. 1). Under present condition, the demands on river system connection at the demonstration site of Zhong Shun Da Wei are mainly represented by two aspects, namely flood control and agricultural water divergence; 2). For Zhong Shun Da Wei, if it is primarily used to control floods, Scheme One is the optimal solution; 3). If it is mainly applied to agricultural water, Scheme Three is the optimal solution. The research findings can provide important technical support and theoretical basis for comprehensive dredging, renovation, hydro-ecological protection and other projects in Zhong Shun Da Wei.

Removal of direct red dye using polysulfone-chitosan ultrafiltration membrane

Textile industries are one of the largest pollution contributor to the environment through high amount of wastewater discharge that contain high concentration dyes. The present state of application of using membrane technology in the removal of dyes from textile wastewater has shown positive pathway for this research. Chitosan are biopolymer that are naturally occurring. It is used as a hydrophilic additive in the fabrication of polysulfone (PSF) and chitosan (CS) membrane. Different loadings of CS at 0.1, 0.3, 0.5, 0.7 and 1.0wt% were used. The fabricated PSF-CS membrane by phase inversion method were characterized using SEM for its morphology, FTIR for its functional group and contact angle for membrane hydrophilicity. As the addition of CS increase the hydrophilicity of the PSF-CS membrane, excessive CS precipitation was observed at chitosan loading at 1.0wt% creating a large macro void causing lower permeation performance. It is found that PSF-CS membrane with 0.7wt% has the best contact angle and dye rejection performance of 65.49º and 99.78%.

Prediction of Major Pollutants Discharge from Wastewater in 31 Cities of China

A large amount of wastewater discharge has seriously damaged China's water environment, so it is very significant to accurately predict the future trend of wastewater discharge and pollutants discharge in wastewater. In this paper, the grey prediction model with fractional order accumulation is adopted to predict the discharge of wastewater, chemical oxygen demand and ammonia nitrogen from wastewater in 31 cities of China from 2020 to 2030. The predictive results indicate that the discharge of industrial wastewater, chemical oxygen demand and ammonia nitrogen will decrease in more than 50% of the cities. However, domestic sewage discharge in more than 50% of the cities will show an upward trend. According to the predictive results, reasonable suggestions can be put forward for the effective control of wastewater discharge in China.

Spatio-Temporal Comprehensive Measurements of Chinese Citizens' Health Levels and Associated Influencing Factors.

Health is the basis of a good life and a guarantee of a high quality of life. Furthermore, it is a symbol of social development and progress. How to further improve the health levels of citizens and reduce regional differences in citizens’ health status has become a research topic of great interest that is attracting attention globally. This study takes 31 provinces (municipalities and autonomous regions) of China as the research object. Through using GIS (Geographic Information System) technology, the entropy method, spatial autocorrelation, stepwise regression, and other quantitative analysis methods, measurement models and index systems are developed in order to perform an analysis of the spatio-temporal comprehensive measurements of Chinese citizens’ health levels. Furthermore, the associated influencing factors are analyzed. It has important theoretical and practical significance. The conclusions are as follows: (1) Between 2002 and 2018, the overall health levels of Chinese citizens have generally exhibited an upward trend. Moreover, for most provinces, the health levels of their citizens have improved dramatically, although some provinces, such as Tianjin and Henan, showed a fluctuating downward trend, suggesting that the health levels of citizens in these regions displayed a tendency to deteriorate. (2) The health levels of citizens from China’s various provinces showed clear spatial distribution characteristics of clustering, as well as an obvious spatial dependence and spatial heterogeneity. As time goes by, the degree of spatial clustering with regard to citizens’ health levels tends to weaken. The health levels of Chinese citizens have developed a certain temporal stability, the overall health status of Chinese citizens shows a spatial differentiation of a northeast–southwest distribution pattern. (3) The average years of education and urbanization rate have a significant positive effect on the improvement of citizens’ health levels. The increase of average years of education and urbanization rate can promote the per capita income, which certainly could help improve citizens’ health status. The Engel coefficient, urban–rural income ratio, and amount of wastewater discharge all pose a significant negative effect on the improvement of citizens’ health levels, these three factors have played important roles in hindering the improvements of citizen health.

Water quality simulation of sewer plant discharge considering long-term and short-term conditions

The development of economy and society in China leads to a huge amount of wastewater discharge, which becomes a serious problem in most of Chinese cities. Therefore, the construction of sewer plant is more popular than before in lots of these cities. The wastewater discharge from the plant is then considered as a point source in most of the important rivers and channels. In this study, a typical wastewater treatment plant is introduced, a monitoring experiment is designed and executed to observe current river status. Additionally, a two-dimensional model is established to predict the water quality downstream of the plant. It is confirmed that the water quality will not significantly deteriorate, however, systematic control of wastewater discharge and protect of current river environment is still encouraged.

An Ecological Compensation Model for Liuxi River Basin Based on Emission Rights

Researches on standards of ecological compensation will raise awareness of protecting the ecological environment in the basin and maintain the economy&amp;rsquo;s and society&amp;rsquo;s sustainable development. This paper constructed an ecological compensation model on the Liuxi River Basin in Guangzhou, China. Data and statistics were acquired from the statistical yearbook in Guangzhou Statistical Information Network, including the total GDP, total wastewater discharge amount and total population of Guangzhou for 13 years (1995, 2000, 2005&amp;ndash;2015). Then, SPSS was used to fit the scatter plot of volume of wastewater discharged per capita and GDP per capita, and the most accurate regression equation was selected. Most importantly, an ecological compensation model was constructed based on emission rights and it was then used to calculate the annual eco-compensation fee for Conghua, where the river&amp;rsquo;s upper part is located. The results showed that the amount of ecological compensation in 2017 was 33.821 billion Chinese Yuan, which should be used to compensate Conghua for the emission rights it had given up for protecting water quality of the Liuxi River. This study provided an effective reference to the government&amp;rsquo;s decision on continuous improvement of the &amp;ldquo;Guangzhou Ecological Compensation Plan for Liuxi River Basin&amp;rdquo;.

Dynamic wastewater-induced research based on input-output analysis for Guangdong Province, China

Large amounts of wastewater discharge have emerged as a burden in the process of industrialization and urbanization. In this study, a dynamic wastewater-induced input-output model is developed to systematically analyze the related situation. The developed model is applied to Guangdong Province, China to analyze its prominent characteristics from 2002 to 2015. Combining input-output analysis, ecological network analysis and structural decomposition analysis, the developed model reveals issues of direct and indirect discharges, relationships among various discharges, and driving forces of wastewater discharges. It is uncovered that Primary Manufacturing and Advanced Manufacturing dominate the system because of significant temporal and spatial variations in wastewater discharge. In addition, Manufacturing of paper, computer and machinery and Services are the key industries responsible for large amounts of wastewater discharge and unhealthy source-discharge relationships. The largest wastewater discharge occurred in 2005 and indirect wastewater discharge is the main form. Furthermore, final demand is found to be the biggest driving force of wastewater discharge. Finally, a three-phase policy implementation system implemented in stages proposes solutions to wastewater problems.

Spatial-temporal pattern evolution of wastewater discharge in Yangtze River Economic Zone from 2002 to 2015

This study uses Exploratory Spatial Data Analysis (ESDA) method and Logarithmic Mean Divisia Index (LMDI) model to analyze and discuss the Spatial-temporal pattern as well as the dominant driving factors of wastewater discharge in Yangtze River Economic Zone from 2002 to 2015. The paper indicates that: (1) In terms of the spatial-temporal pattern, the amount of wastewater discharge in Yangtze River Economic Zone shows an increase trend from 2002 to 2005, and then put up a decline trend between 2005 and 2015. Referring to the spatial characteristics, firstly, the amount of wastewater discharge increases from upstream to downstream. There are few high discharge cities whereas more low and middle discharge cities. Secondly, a certain amount of wastewater discharge transfers from the downstream to the midstream and upstream, and the wastewater discharge in mountainous area is lower than other regions. (2) In terms of the change of spatial relationship among cities in the research area, the wastewater discharge shows a significant spatial agglomeration. High discharge cities are concentrated in the Yangtze river delta and low discharge cities are distributed in underdeveloped areas in the western part of China, especially the tourism-oriented cities. (3) In terms of the driving factors, the technical improvement effect did a negative contribution and controlled the amount of wastewater discharge, whereas the industrial structure effect did a positive or a negative contribution depend on the policy and market. The economy development effect, which was one of the dominant factors, did a positive contribution to the amount of wastewater discharge. Moreover, the population scale effect did a positive contribution to the wastewater discharge, but the impact is not significant.

Water environmental stress, rebound effect, and economic growth of China's textile industry.

The rapid development of China’s textile industry (TI) has led to severe water environmental stress. Water environmental stress of China’s TI mainly comes from large quantities of discharged wastewater and chemical oxygen demand (COD). The sustainable development of the TI is realized to achieve the decoupling between economic growth and water environmental stress. This study analyzes the decoupling elasticity results from wastewater discharge and COD discharge, respectively. Decoupling results show that TI’s wastewater has strong decoupling from economic growth for three years (2002, 2013–2014) while COD has strong decoupling for six years (2002–2003, 2008, 2010, 2013–2014). The paper further calculates the decoupling elasticity results of the TI’s three sub-sectors (manufacture of textile sector, manufacture of textile wearing and apparel sector, and manufacture of chemical fibers (MCF) sector), and calculates the factors that affect wastewater discharge. The decrement and rebound effects of wastewater discharge are analyzed based on calculated results. Decomposition results show that the scale factor is the most significant contributor to wastewater discharge, the intensity factor inhibits wastewater discharge, and the effect of the structure factor is not evident. The decrement effect of TI increases yearly, but the rebound effect shows that the absolute amount of wastewater discharge also increases. The rebound effect has declined since 2012. In the three sub-sectors, MCF’s decrement effect is the strongest, and its rebound effect is the weakest, which indicate that MCF is the biggest contributor to the discharge reduction of China’s TI.

Geologic factors controlling groundwater chemistry in the coastal aquifer system of Douala/Cameroon: implication for groundwater system functioning

Douala city, located in the littoral province of Cameroon, receives abundant rainfall quantities due to its geographical position in the Gulf of Guinea and bears considerable surface water and groundwater resources. Due to socioeconomic development and rapid demographic growth in the city and its consequences of unplanned urbanization and improper sanitation system, these water resources are poorly protected and managed. Streams in the Wouri watershed receive large amounts of wastewater discharge, and hundreds of boreholes have been drilled into the aquifer system without any management plan. A detailed hydrodynamic and hydrogeochemistry study in Douala town and its environs was conducted to get a better insight into the groundwater system functioning in order to provide information for the sustainable management and protection of the groundwater resource. Two field campaigns were carried out with 187 samples collected and analyzed for major ions, stable isotopes (18O, 2H), and tritium 3H. The results of the sampling have shown that the weathering of silicate minerals is the dominant geochemical process affecting groundwater chemistry in this system. However, acid rainfall in the humid climate has also caused carbonate mineral dissolution, amorphous silica deposition, and ion exchange reactions to occur in aquifers in the region. The various water types identified were categorized into four major clusters C1 to C4, based on the major ion composition and the local hydrogeological conditions. Environmental isotope data reveal that modern-to-submodern waters occur in the phreatic Quaternary/Mio-Pliocene and Oligocene/Upper Eocene aquifers, respectively. These results corroborate with the conceptual model built where modern groundwater types indicated silicate mineral weathering and calcite dissolution (C1 and C2), whereas submodern groundwater mostly showed silica deposition, ion exchange, and, to a lesser extent, carbonate mineral dissolution (C3 and C4). This improved understanding of the aquifer system functioning is essential to provide a reasonable basis for effective control measures and sustainable water management.

REMOVAL OF HEAVY METAL IONS IN WATER USING MODIFIED POLYAMIDE THIN FILM COMPOSITE MEMBRANES

Heavy metals in the wastewater can pollute the water resources because they are durable, have a high toxicity in the environment and body tissues. Thus, the treatment of wastewaters containing heavy metal ions has attracted much attention, because they can economically provide water for industrial production, decrease the wastewater discharge amount, and minimize the effluent pollutant concentration. In some methods for treatment of heavy metal ions, membrane separation is considered as a great promise technique, because of their high efficiency, easy operation, and space saving. The commercial thin film composite polyamide (TFC-PA) membranes are used for the wastewater treatments, due to a high permeate flux, as well as a great rejection for relatively wide operation of temperature and pH range. However, TFC-PA membranes are sensitive to fouling. The improvement of the fouling resistance of TFCPA membrane can be achieved through the surface modification techniques. In this work, the surface of TFC-PA membrane has been successfully modified by the UV-photo-induced grafting of poly(ethylene glycol) (PEG) and acrylic acid (AA). The separation performance of the modified membranes has been investigated, through the possibility for removal of heavy metals such as Ni (II), Cu (II), Fe (III) and Cr (III) in water, and in electroplating wastewater. The experimental results indicated that the separation performance of the PEG-grafted and AAgrafted membranes is significantly improved, with an increased membrane flux at a great retention. The antifouling property of the modified membrane is also improved, with a higher maintained flux ratio, and a lower irreversible fouling factor in comparison with those of the unmodified one. Article DOI: https://dx.doi.org/10.20319/mijst.2017.31.91103 This work is licensed under the Creative Commons Attribution-Non-commercial 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.

Physico-Chemical Waste Water Treatment Technologies: An Overview

Waste-water treatment is becoming even more important in the light of diminishing water resources, increasing industrial, domestic and agriculture water usage and consequently waste-water disposal and its costs along with stricter discharge regulations that have lowered permissible contaminant levels in waste streams. The treatment of waste-water for reuse and disposal is particularly important for water scarce states like Rajasthan, Maharashtra, and other states in India where water availability is highly critical. The municipal sector consumes significant volumes of water, and consequently generates considerable amounts of waste-water discharge. Municipal waste-water is a combination of water and water-carried wastes originating from homes, commercial and industrial facilities, and institutions. The present paper comprises of the various Physico-Chemical methods and technologies currently used in waste-water treatment, with emphasis on municipal waste-water.

Design of regeneration recycling water networks by means of concentration potentials and a linear programming method

Regeneration reuse/recycling of industrial wastewater can effectively reduce freshwater consumption and wastewater discharge amount. A new method is presented in this article to design regeneration recycling water networks with multiple contaminants. The concentration potentials and linear programming approach are combined for solving the problem of minimization of freshwater and regenerated stream flow rates. The values of concentration potential of demands are utilized to identify the precedence order of water-using processes. The allocations of sources to demands are formulated as linear programming models. To reduce the consumption amounts of high quality source streams, each source stream is assigned a weighting factor based on the quality of the sources. Two examples are solved to illustrate the effectiveness of the proposed approach. The consumptions of freshwater and regenerated stream obtained by using the proposed method are comparable with those obtained in the literature. The method has the characteristics of converging easily and needing no initial values.

Empirical Study on the Relationship between Economic Growth and Environmental Pollution Level in Jilin Province

Based on the Environmental Kuznets Curve hypothesis (EKC), the measurement models of various environmental pollution indicators with economic growth indicators were obtained by using the regression simulation of PASW Statistics 18.0 statistical software based on the data of environmental indicators and economic growth indicators in Jilin Province, and analyzed the characteristics of EKC. The result indicated that the EKC of environmental indicators did not completely accord with the “U” shape. The EKC of industrial wastewater discharge amount showed the “U + inverted U” shape, the inflection point appeared in 2009; The EKC of industrial waste gas emissions was in continuous growth without an inflection point; The EKC of industrial solid waste output showed the left half part of the “U” shape, the inflection point will appear in 2014. The EKC of industrial dust emissions was a shape of logarithmic function, being in a gradually decreasing trend without an inflection point; The EKC of industrial SO2 emissions showed the “U + inverted U” shape, the inflection point appeared in 2008; The EKC of COD discharge amount of industrial wastewater showed the unobvious “U + inverted U” shape, the inflection point appeared in 2009. The overall environmental pollution level in Jilin Province was in the stage of continuous improvement.

An Empirical Analysis on Regional Differences in Pollutants Discharge Reduction and Environmental Investment: Based on Data of Chinese Thirty Major Cities

In recent years, environment renovation has caused the extensive concern of the government and the public. All parts of the country have introduced corresponding policies and driving measures of environmental management, and a series of relevant work has been carried out environmental protection investment and pollution treatment. Our concern is the effect of the work. The article chose data of environmental management investment and exhaust gas and waste water discharge amount of Chinese thirty major cities to analysis the regional differences in pollutants discharge reduction and environmental investment. Our results showed that analysis on no matter a national or a regional basis both indicated environmental investment had a positive impact on pollutants discharge reduction.