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Study on Sewage Purification Effect in Surface Flow Constructed Wetland
2020
Xiuli Li
The status quo that the shortage of water resources in North China and the arbitrary discharge of sewage in rural areas have led to the deterioration of water environment, which not only aggravates the contradiction between supply and demand of regional water resources but also brings harm to people’s life and health. How to properly discharge sewage according to the actual situation in rural areas is a question that needs to be answered urgently. The method adopted in this paper is to build a constructed wetland with low cost and simple operation and maintenance in the study area, and purify the water quality through parallel + multi-stage cascade surface flow constructed wetland system. The results show that the purification effect of the wetland system is acceptable, and the removal rate of each index shows a decreasing trend with time. The larger the area is, and the more plant species there are, the better the removal effect will be. The trend of concentration change along the water flow path of each index is also gradually decreasing, and the decline in the early stage is larger. The method of standard index evaluation is adopted to evaluate water quality purification effect of the wetland system, and all indexes reach the standard. In accordance with the Surface Water Environment Quality Standard (GB3838-2002), after wetland purification, the water quality indexes of COD, TP, NH3-N and DO all reach Class IV water quality standard, and BOD5 reaches Class II water quality standard. The wetland system effectively reduces the impact of arbitrary sewage discharge on the water environment in rural areas and achieved water quality purification and ecological restoration. The quality of the living environment of local residents is improved. The beautiful environment also promotes people’s awareness of protecting wetland ecological environment.
Show more [+] Less [-]Evaluation of the Effect of Sewage Irrigation on Groundwater
2020
Xiuli Li and Xiaoyu Li
In areas with water resources shortage, sewage irrigation can alleviate the contradiction between supply and demand for water. However, long-term use of sewage irrigation will affect soil, crops and groundwater. In this paper, irrigation water and groundwater in different irrigation source areas were sampled and analysed respectively to study the effect of sewage irrigation on groundwater. The irrigation water was evaluated for Cl-, Cd, Pb, Cr6+, As, Cu, F-, TP, Hg and Zn as standards for irrigation water quality which along with Nemerow index method were used for comprehensive evaluation. The result of the evaluation is that the water quality of the reclaimed water, domestic sewage and mixed sewage meet the requirements of the agricultural irrigation, and the industrial sewage pollution index is relatively high and less suitable for agricultural irrigation. The fuzzy comprehensive evaluation method was adopted to evaluate groundwater quality, using Quality Standard for Ground Water (GBT14848- 2017) as evaluation factor standard and ammonia nitrogen (NH3-N), chloride (Cl-), nitrate (NO3-N) and nitrite (NO2-N) as evaluation indicators. The results of the evaluation showed that the water quality of 2 monitor wells among the 11 monitor wells was within Category II, 6 within Category III, and 3 within Category IV. With regards to the influence of different irrigation sources on groundwater, the comprehensive evaluation results are reasonable as well. According to the comprehensive membership grades, it can be concluded that the influence of different water sources on groundwater quality, in turn, is reclaimed water < domestic sewage < mixed sewage < industrial sewage. The evaluation results are in line with the actual situation in the study area.
Show more [+] Less [-]Hydrochemical Characteristics and Water Quality Assessment of Surface Water and Groundwater in Agriculture Demonstration Base, Jiagou District, Northern Anhui Province, China
2020
Jie Ma, Linhua Sun, Song Chen, Zhichun Li, Ting Gao, Hongbao Dai and Haitao Zhang
Jiagou district, located in Northern Anhui Province, China, has been taken as an agriculture demonstration base for several decades, but limited hydrochemical work has been conducted on the water resources. The objective of this research was to understand the controlling processes of hydrochemical evolution and the water quality for drinking and irrigation. Twenty-seven samples of surface water and groundwater have been collected and analysed for major ions. Although the values physicochemical parameters are subjected of spatial fluctuation in different water resources, calcium and bicarbonate is still the dominant ion in the cations and anions, respectively. The values of all the parameters are within the WHO maximum permissible limit for inhabitant drinking. The predominant water type is Ca-Mg-HCO3 and Ca-HCO3. The hydrochemical methods (Gibbs diagram, Mg/Na and HCO3/Na versus Ca/Na diagram and ion ratios) suggest that rock-water interactions furnish the dominant major ion sources of the samples. Carbonate dissolution, silicate weathering and ion exchange have the predominant contribution to the origin of chemical solutes, as well as a slight function of halite dissolution. The USSL and Wilcox diagram reveal that all the samples have low salinity and low sodium water. It is of good quality suitable for irrigation, and it can be used for irrigation of most crops on most soils with less negative impacts.
Show more [+] Less [-]Adsorption of Acid Orange 7 in Aqueous Solution by Biochar from Peanut Shell Supported with Clay Mineral Kaolinite
2020
Keyuan Huang, Wangying Li, Yue Wang, Bin Liu, Ruolin Xu, Jing Dai, Xitong Zheng, Ningcan Yang, Muqing Qiu and Li Han
Biochar was prepared from the peanut shell. Then, it was mixed with the clay mineral kaolinite and stirred under the magnetic stirrer. The biochar derived from peanut shell supported with clay mineral kaolinite (B@K) was obtained. Adsorption experiments of dye Acid Orange 7 by B@K were conducted. The characteristics of B@K were determined by the elemental analyzer, specific surface area meter, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer and the model axis-HS. The experimental results showed that a large number of oxygen-containing functional groups appear on the surface of B@K, which is beneficial for binding dye ions. The adsorption process fits well with the pseudo-second-order kinetic model. It indicated that the adsorption process was both physical adsorption and chemical adsorption. Chemical adsorption is the main adsorption process. Langmuir isotherm model can better describe the adsorption isothermal process of B@K on dye Acid Orange 7. The adsorption process is monolayer adsorption process.
Show more [+] Less [-]Real-time Detection of Cyanide in Surface Water and its Automated Data Acquisition and Dissemination System
2020
Alexander T. Demetillo, Rey Y. Capangpangan, Melbert C. Bonotan, Jeanne Phyre B. Lagare and Evelyn B. Taboada
Use of cyanide in developing countries is rampant, especially in gold mining areas. Though it could cause serious environmental problems, cyanide contamination is of less priority for government monitoring because of the limited resources. The current detection and monitoring schemes of cyanide are the conventional and expensive laboratory-based methods, which need technical capabilities to conduct the actual testing and preparing manual data recording, making it tedious and too laborious. More efforts were directed towards digitizing the data recording from manual laboratory analyses as the manual data recording usually cause problems like delayed information, lost data, and erroneous data entry. Hence, the goal of this study is to provide a cost-effective and zero manual-recording measurement method for cyanide in water samples. This work focuses on the design of electrochemical measuring devices with the same capability with the portable or benchtop-type of cyanide meter but with an automated and realtime data recording using global system for mobile communications (GSM) technology. Results of this study showed that with the existing GSM technology and infrastructure of the new monitoring system, the measurements are comparable to that of a commercial bench-type cyanide meter with an R-squared (R2) of 0.9907. It was also noted that data being recorded were intact during wireless transmission testing using the GSM Network. The results obtained suggest that wireless communication using GSM Technology could be applied to environmental monitoring. Importantly, the newly developed online system for cyanide monitoring offers significant advantages over the conventional techniques such as low-cost, easy deployment, and ease of use. It can increase spatiotemporal data for better analysis of the data. The automated data acquisition and display through cellular phones are also made readily-available.
Show more [+] Less [-]Experimental Evidence for Using Vegetated Ditches for Mitigation of Complex Contaminant Mixtures in Agricultural Runoff
2020
Moore, Matthew T. | Locke, Martin A.
Feeding a growing population requires striking a balance between increasing production and decreasing environmental impacts in agricultural settings. We established 12 experimental mesocosms with silt loam atop a base of sand and examined the ability of three emergent aquatic plants common to the USA to remediate pesticides and nutrients in agricultural runoff. Mesocosms were planted in monocultures of Myriophyllum aquaticum, Polygonum amphibium, and Typha latifolia, or left unvegetated to serve as controls. All mesocosms were amended with target concentrations of 10 mg L⁻¹ (each) nitrate, ammonium, and orthophosphate; 20 μg L⁻¹ (each) of the pesticides propanil and clomazone; and 10 μg L⁻¹ of the pesticide cyfluthrin. After a 6-h-simulated agricultural runoff with amended water, mesocosms sat idle for 48 h before flushing with unamended water for another 6 h. Outflow water samples were collected and analyzed for contaminant concentrations. Most significant differences between vegetated mesocosms and controls occurred when comparing mean contaminant transfer/transformation rates post-amendment. Differences among plant species occurred regarding retention of dissolved nutrients orthophosphate, ammonium, and nitrate. Similarly, all three plant species retained more propanil than controls during post-amendment (8–48 h), but individual plant differences occurred with regard to clomazone and cyfluthrin retention. While variation in mitigation of specific dissolved components of nutrients suggests different mechanisms involved in nutrient cycling within our mesocosms, consistent overall total nutrient and pesticide reduction during the post-amendment period indicate that holding runoff in vegetated ditches may reduce transport of agricultural contaminants to downstream aquatic ecosystems.
Show more [+] Less [-]Bioaccumulation of Vanadium in Selected Organs of the Freshwater Fish Heteropneustes fossilis (Bloch)
2020
Ambili Ravindran and M. V. Radhakrishnan
Extensive industrialization and urbanization have introduced domestic as well as industrial wastes into aquatic ecosystems.Dueto lack of proper treatment and improper mode of disposal, the water bodies have become more polluted with toxic substancesand their adverse effects including mortality to aquatic organisms, are becoming more prominent.In recent years, much attention has been paid to the possible danger of metal poisoning in humans as a result of consumption of contaminated fishes.Vanadium is a rare elementfound combined with certain minerals and mainly from the production of certain alloys used in jet engines. Humans may be exposed to excessive vanadium and may develop adverse vascular effects.In the present investigation, efforts have been made to investigate the effect of sublethal concentration of vanadium (6.5 ppm; 10% of 96h LC50) on the bioaccumulation in gill, liver and skin of the catfish Heteropneustes fossilis for 60 days. The pattern of bioaccumulation was in the order liver > gill > skin. Theresults suggest that the organ-specific variation is directly related to the structural and functional change, proximity to the toxicant and presence of ligands having high affinity to vanadium.
Show more [+] Less [-]Estimation of Environmental Damages of Cement Building and Environmental Benefits of Prefabricated Building: A Case Study Based on a Residential Project in Henan Province, China
2020
Chen Nan , Zhang Jie
Traditional cement building generates abundant construction wastes during construction and waste transportation. Thus, it incurs high building resource consumption, low building efficiency, and frequent occurrence of safety accidents, which result in relatively low utilization ratio of building resources and relatively serious environmental pollution pressure. A prefabricated building can save building materials and energies and decrease construction waste emission; it is also an essential choice when the construction industry develops to a high level in a country. A case study based on a residential project in Henan Province, China was carried out. Firstly, studies concerning the environmental benefits of prefabricated building in foreign developed countries were reviewed. Second, the types of environmental damage from cement building were summarized. Third, an evaluation index system of environmental benefits of the prefabricated building was established. Finally, environmental benefit scores in the case study were calculated using the fuzzy comprehensive evaluation method based on the analytic hierarchy process. Results demonstrated that prefabricated building is extensively applied in Europe. Traditional cement buildings bring various types of environmental pollution, including water, solid waste, and dust pollutions and vegetation damage. In a case study, the environmental benefits of the prefabricated building are assessed at a good level close to excellent. Environmental benefits of the prefabricated building can be improved by encouraging real estate developers to adopt prefabricated building. In this manner, the installation efficiency of mechanical devices and construction efficiency can be increased, and the construction safety of projects can be improved. Research conclusions can provide references not only for the government to formulate policies in favour of prefabricated building development and measures for reducing environmental pollutions but also for the construction industry to enrich benefit evaluation systems for prefabricated building projects. This study is highly important in the realization of green sustainable development in the construction industry.
Show more [+] Less [-]Analysis of the Spatial Patterns of Particulate Pollution in the Persistent Haze in Northeast China: A Case Study in Harbin City
2020
Lei Wang, Jiarong Deng, Lijin Yang, Yunlong Yao , Dawei Xu
With the help of PM2.5, PM10, and the Air Quality Index (AQI) and other air quality data, the posterior trajectory model of the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT-4) model, having researched fire points of the straw in Harbin City, spatial pattern characteristics and genesis of the persistent haze in Harbin City from 20th October 2016 to 11th November 2016 were analysed. During the study period, the highest value of PM2.5 reached 1880?g/m3, the PM10 reached 1411?g/m3, the daily average concentration was high, and the AQI concentration reached a maximum value on 28th October and 4th November, and the persistent haze phenomenon was the most significant. Besides, the study found that the haze incident and a large quantity of pollutants due to the concentration of burning straw around Harbin had a strong connection. The burning of particulate matter had a significant impact on the region’s pollution level. The results of this study contribute to the control of particulate pollution in winter cities of developing countries.
Show more [+] Less [-]Synthesis of Molecularly Imprinting Polymers for the Removal of Xylenol Orange from Water
2020
Showkat Ahmad Bhawani, Nur Anati Bazilah Daud, Salma Bakhtiar, Rachel Marcela Roland , Mohamad Nasir Mohamad Ibrahim
The molecularly imprinted polymers (MIPs) were prepared by using the non-covalent approach. In the polymerization process, xylenol orange was used as a template (T), acrylic acid as a functional monomer (M), divinylbenzene as a cross-linker (CL) and 2,2’-azobisisobutyronitrile (AIBN) as an initiator and microemulsion as a solvent. The synthesized polymers were characterized by using FTIR and SEM micrograph. The batch binding analysis was used to evaluate the rebinding efficiency of imprinted polymers. The highest rebinding efficiency was obtained from the MIP-R2 (0.1:0.6:2, T:M:CL). The selected MIP-R2 was used for the removal of xylenol orange from the water sample and have shown removal efficiency of about 80%.
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