A cross-sectional survey was conducted to establish the utilisation of non-conventional animal waste in multiple livestock species systems. Farmers (150) were selected from four out of ten districts of Central Uganda ...A cross-sectional survey was conducted to establish the utilisation of non-conventional animal waste in multiple livestock species systems. Farmers (150) were selected from four out of ten districts of Central Uganda in Lake Victoria Crescent. A structured questionnaire was used and descriptive analysis showed that over 80% are smallholder farmers on 3.0) years. Household husbands (80%) significantly (P 1.0) as they cause poor livestock health due to pathogens, parasites and toxins which are associated (OD > 1.0) with poor growth, mortality and condemnation of livestock products. The remedy to unsafe non-conventional feeds is to apply effective solar-heating (75%), chemical and ensiling treatment methods. The study showed that there are no significant (P < 0.001) public health risks associated with utilising treated non-conventional feeds instead it improves production and sustainability of multiple livestock species systems.展开更多
Modified aluminum slag (MAS) was applied as an adsorbent for Congo red (CR) prepared by the hydrothermal treatment of Ca(OH)<sub>2</sub>. At 25°C, with a MAS dosage of 0.3 g, initial CR concentration ...Modified aluminum slag (MAS) was applied as an adsorbent for Congo red (CR) prepared by the hydrothermal treatment of Ca(OH)<sub>2</sub>. At 25°C, with a MAS dosage of 0.3 g, initial CR concentration of 100 mg/L and initial pH = 5, and the adsorption time was 40 min, the CR removal efficiency was 98.41%. The adsorption trend of CR conformed to the second-order kinetics, and the adsorption isotherm follows the Freundlich isotherm model. Compared with RAS, MAS has a larger pore volume and specific surface area. The mechanism of action of MAS on CR was the interaction between membrane diffusion and internal diffusion, and the adsorption rate during the membrane diffusion was the fastest.展开更多
Excess amounts of livestock wastes are excreted in limited area and cause pollution problems in Japan.Comparative studies on livestock waste management among EU(European Union),US(the United States of America)and Asia...Excess amounts of livestock wastes are excreted in limited area and cause pollution problems in Japan.Comparative studies on livestock waste management among EU(European Union),US(the United States of America)and Asia including Japan are surveyed.In Japan,livestock wastes are mostly separated into solid and liquid matter.Solid matter is converted into organic fertilizer by means of composting.Composting should be developed into the technology that has low emission,high-quality and low cost.Various odorous compounds are emitted from the process of livestock waste management.Odor emission from livestock farms should be mitigated to protect the local community.High-quality compost can be widely distributed to cropland to decrease expenditure of chemical fertilizer.Although liquid matter,namely wastewater or slurry,could be applied to cropland of livestock farms such as EU countries,most of Japanese farms do not have enough cropland to use liquid matter.Particularly pig farms have no area to spread wastewater,which should be purified to clean water in accordance with the criteria of water quality and could be discharged into public water area.The most desirable management of livestock wastes should involve sustainable recycling as compost and environmentally friendly control of odors and wastewater.展开更多
Pyrolysis has the potential of transforming waste into valuable recyclable products. Pyrolytic char(PC) is one of the most important products from the pyrolysis of used tires. One of the most significant applications ...Pyrolysis has the potential of transforming waste into valuable recyclable products. Pyrolytic char(PC) is one of the most important products from the pyrolysis of used tires. One of the most significant applications for pyrolytic char recovered is used for the removal of Cr(Ⅵ) in the wastewater effluent to control waste by waste. The surface chemistry properties of surface element distribution / concentration and chemical structure were examined for the pyrolytic char and the commercial activated carbon(CAC) respectively. The results showed that surfaces of PC possesses a large amount of ester and hydrocarbon graft, whereas there are mainly carbon functional components of C—OH, C O and COOH on the surface of CAC. Therefore the surface electronegativity of PC is lower than that of CAC in the water. The repulsive interactions between the surfaces of PC and the negatively charged Cr(Ⅵ) ion are weaker than that of CAC, which results in an intensification of the adsorption process by the utilization of PC. The adsorption isotherms of Cr(Ⅵ) ion on the two kinds of carbons were determined experimentally. The larger adsorption amount on the PC in the case of Cr(Ⅵ) may be attributed mainly to its special surface micro-chemical environment. The mechanism of the removal Cr(Ⅵ) from aqueous solution was assumed to be the integration of adsorption and redox reaction. The adsorption was the rate-controlled step for Cr(Ⅵ) removal. The adsorption of Cr(Ⅵ) was identified as pseudo-second-order kinetics. The rate constants of adsorption were evaluated.展开更多
Wastewater, which involves easy-soluble reactive dyes, especially non-degradable dyes, is very difficult to decolor efficiently by normal processes such as coagulation process and biological treatment. The high chroma...Wastewater, which involves easy-soluble reactive dyes, especially non-degradable dyes, is very difficult to decolor efficiently by normal processes such as coagulation process and biological treatment. The high chromaticity se- riously hinders the reuse of reactive dye waste water. In this paper, a new method by bentonite adsorption and coagulation (PAC) is employed for removing color from synthetic dye waste water which contains reactive red K-2G, K-RN blue, K-GR blue, X-3B red, K-GN orange, KB-3G yellow, K-2BP red, K-RN yellow and K-6G yellow. Bentonite pre- treated by 4% CTMAB and milled to 160 order screen is proven to the best decoloring agent. For a 100 mL reactive red K-2G sample (CODcr 400 mg/L, 25 000 chromaticity color), 0.5 g bentonite pretreated and 2.5 mL PAC is enough to decolor wastewater up to 99.92% and the sediment time is short. Non-degradable dyes such as active red X-3B and K-GN orange are declored completely as well. Raw sewage (low chromaticity color) is decolored completely at a ben-tonite dosage of 0.001g. More researches prove the high practical value of this process.展开更多
The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier tra...The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier transform infrared spectroscopy),BET(specific surface area),and BJH(pore size distribution).The results indicate that the removal rate of phosphate(100 mg/L)in 50 mL phosphorus wastewater reaches at 99.9% as the dosage of MSWI fly ash being 0.9000 g under room temperature.The specific surface area of MSWI fly ash is less than 6.1 m2/g and the total pore volume is below 0.021 cm3/g,suggesting that the absorption capacity of calcite is too weak to play an important role in phosphate removal.SEM images show that drastic changes had taken place on its specific surface shape after reaction,and EDS tests indicate that some phosphate precipitates are formed and attached onto MSWI fly ash particles.Chemical precipitation is the main manner of phosphate removal and the main reaction is: 3Ca2++2 PO4 3-+xH2O→Ca3(PO4)2↓·xH2O.Besides,XRD tests show that the composition of MSWI fly ash is complex,but CaSO4 is likely to be the main source of Ca2+.The soluble heavy metals in MSWI fly ash are stabilized by phosphate.展开更多
This study is aimed at evaluating alternative designs of waste stabilization ponds (WSPs) and constructed wetlands (CWs) for Kaputiei Housing Estate consisting of 2000 low cost housing units in Kenya. The entire analy...This study is aimed at evaluating alternative designs of waste stabilization ponds (WSPs) and constructed wetlands (CWs) for Kaputiei Housing Estate consisting of 2000 low cost housing units in Kenya. The entire analysis was carried out by simulating the effectiveness and purification efficiencies of WSPs and CWs in terms of Biological Oxygen Demand (BOD) reduction and faecal coliform (FC) removal under different scenarios of water treatment systems that included Re-sizing of the initial sewage treatment system, optimizing the design of the initial system and design of hybrid system for the estate. The graphic comparison of the simulated parameters under different scenarios showed that a hybrid design that combines both the WSPs and CWS provides an effluent BOD of 20 mg/l and 195 FC per 100 ml that meets the standard effluent discharge that is acceptable for unrestricted crop irrigation and thus will be reused in the housing estate for kitchen gardening and agroforestry.展开更多
The catalytic combustion technology for treating waste gases exiting from wastewater treatment system and oil separators in petrochemical enterprises was introduced in this article. Commercial application of this tech...The catalytic combustion technology for treating waste gases exiting from wastewater treatment system and oil separators in petrochemical enterprises was introduced in this article. Commercial application of this technology showed that the process "desulfurization and total hydrocarbon concentration homogenizationcatalytic combustion" and the associated WSH-1 combustion catalyst were suitable for treating volatile organic gases emitted from the oil separators, floatation tanks, inlet water-collecting well, waste oil tanks, etc. The commercial unit was equipped with an advanced auto-control system, featuring a simple operation and low energy consumption with good treatment effect. The purified gases could meet the national emission standard.展开更多
The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on bios...The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on biosorption of cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae and precipitation process of waste saccharomyces cerevisiae after adsorbing cadmium were studied. The results show that removal rate of cadmium is over 88% after 30 min adsorbing under the condition of cadmium concentration 26 mg/L, the dosage of waste saccharomyces cerevisiae 16.25 g/L, temperature 18 ℃, pH 6.0 and precipitation time 4 h. Biosorption-precipitation method is effective to remove cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae. The SEM, infrared spectroscopy and Zeta-potential of the cells show that chemical chelating is the main adsorption form; electrostatic attraction, hydrogen bonding and van der Waals force all function in adsorption process; and ―NH2―,―C=O―,―C=O―NH―,―CH3, ―OH are the main adsorption groups.展开更多
T.S.Eliot's works have the didactic purpose of turning his readers away from what he considered the selfindulgence of the Romantics and toward the sterner splendors of Elizabethan drama and the 17th-century metaph...T.S.Eliot's works have the didactic purpose of turning his readers away from what he considered the selfindulgence of the Romantics and toward the sterner splendors of Elizabethan drama and the 17th-century metaphysical poetry.Associated with the rise of literary modernism,he was established as the voice of a disillusioned generation by The Waste Land(1922).Especially,Eliot's description of the discourse of animality received highly artistic effect on the aspect of expressing his "impersonal theory".The discourse of animality in The Waste Land in plenty,thus,it made the author's expressive force more vivid.Furthermore,various imagos of different animals drew a mythical picture of modern waste land.So that,Eliot's The Waste Land also has the epic signification.展开更多
The feasibility of sewage treatment via combined chemical-biological techniques has been investigated. Two-stages pilot plant were designed for this purpose. The first stage was direct chemicalcoagulation-sedimentatio...The feasibility of sewage treatment via combined chemical-biological techniques has been investigated. Two-stages pilot plant were designed for this purpose. The first stage was direct chemicalcoagulation-sedimentation using ferric chloride in-combination with lime to reduce the organic load and to remove the colloidal and suspended solids. A comparison of two separtion techniques namely chemical coagulation conventional sedimention and chemical coagulation tube settler sedimention were investigated. The second stage was either high rate oxidation pond or biological sand-bed to oxidize ammonia to nitrate. The results obtained showed that the effluent produced from the first stage is amaenable for restricted irrigation purposes. The HIROP proved to be satisfactory second treatment method for removal of pollutant. In addition high algal biomass was obtained. However, the use of sand-bed for nitrification proved to be more efficient, complete removal of ammonia was acheived.Average residual COD and BOD values were 66 and 38 mg O2/L, respectively. Fish toxicity was completely eleminated after the nitrification processes展开更多
With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environmen...With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.展开更多
Leather industry is an important light industry in China.Leather making requires a series of chemical treatment.Degreasing,unhairing and chrome tanning wastewaters are the main portions of tannery wastewater.Reclaimin...Leather industry is an important light industry in China.Leather making requires a series of chemical treatment.Degreasing,unhairing and chrome tanning wastewaters are the main portions of tannery wastewater.Reclaiming and reusing these wastewaters can eliminate 80% of COD,75% of BOD,95% of chromium and 93% of sulfuret,furthermore reduce environment impact,decrease treatment costs,save chemicals and water.Some application methods of wastewater reclamation and reuse for different operations were reported.The suitable reclamation and reuse technologies can enable leather making processes more rational,and realize the recovery and recycle of several chemicals in the tannery.Resourceful utilization of tannery wastewater should mate with renovating production technology,updating equipment,and must be guaranteed sufficiently by environmental protection measures.展开更多
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 biolo...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.展开更多
The mining industry has contributed tremendously to the global economy.However,waste generated by this activity poses many challenges.Current low-cost technologies for the removal of heavy metals from mining wastewate...The mining industry has contributed tremendously to the global economy.However,waste generated by this activity poses many challenges.Current low-cost technologies for the removal of heavy metals from mining wastewater include biosorption,adsorption,CWs(Constructed Wetlands)and waste stabilization ponds.This chapter focuses on sustainable mining wastewater treatment technologies with emphasis on gold mining wastewater.It discusses the technical and environmental challenges associated with mining effluent treatment,process conditions for optimum plant performance,efficiency,limitations and the economics of treating mining wastewater.The overall treatment cost of metal contaminated wastewater depends on the process employed and the local conditions.In general,technical applicability,cost-effectiveness and plant simplicity are the key factors in selecting the most suitable treatment method.Proper management of the spent biosorbent and solid wastes generated is also discussed.展开更多
With the high-quality development of modern agriculture and animal husbandry in the plateau,the waste resources produced by agriculture and animal husbandry show a trend of diversification.How to effectively carry out...With the high-quality development of modern agriculture and animal husbandry in the plateau,the waste resources produced by agriculture and animal husbandry show a trend of diversification.How to effectively carry out the key work based on the optimal combination and utilization of waste resources of agriculture and animal husbandry in Tibet is imminent.To realize efficient recycling of waste resources of agriculture and animal husbandry,innovative mode is explored.On the theoretical basis,it can effectively alleviate the resource crisis,control the pollution sources,effectively utilize the resources and construct the recycling mode,which plays an important role in promoting,integrating and coordinating the high-quality development of modern agriculture and animal husbandry in the plateau.In this paper,optimal combination and utilization manner of waste resources of agriculture and animal husbandry under the circular development concept is comprehensively analyzed and summarized,to continuously improve reasonable and effective utilization level and efficiency of agricultural waste resources.It could not only inhibit waste pollution but also promote rational and effective utilization of resources,thereby laying theoretical basis for sustainable and efficient development of agriculture and animal husbandry in Tibet,promoting the improvement of agricultural and rural ecological environment,and providing the thinking for exploring model of ecological recycling in plateau.展开更多
Sludge dewatering and treatment may cost as much as the wastewater treatment.Usually large proportion of the pollutants in wastewater is organic.They are attacked by saprophytic microorganisms,i.e.organisms that feed ...Sludge dewatering and treatment may cost as much as the wastewater treatment.Usually large proportion of the pollutants in wastewater is organic.They are attacked by saprophytic microorganisms,i.e.organisms that feed upon dead organic matter.Activity of organisms causes decomposition of organic matter and destroys them,where the bacteria convert the organic matter or other constituents in the wastewater to new cells,water,gases and other products.Demolition activities,including renovation/remodeling works and complete or selective removal/demolishing of existing structures either by man-made processes or by natural disasters,create an extensive amount of wastes.These demolition wastes are characterized as heterogeneous mixtures of building materials that are usually contaminated with chemicals and dirt.In developing countries, it is estimated that demolition wastes comprise 20%to 30%of the total annual solid wastes.In Egypt,the daily quantity of construction and demolition(C&D) waste has been estimated as 10 000 tones.That is equivalent to one third of the total daily municipal solid wastes generated per day in Egypt.The zabbaliin have since expanded their activities and now take the waste they collect back to their garbage villages where it is sorted into recyclable components:paper,plastics, rags,glass,metal and food.The food waste is fed to pigs and the other items are sold to recycling centers.This paper summarizes the wastewater and solid wastes management in Egypt now and future.展开更多
Organic solid and liquid wastes contain large amounts of energy, nutrients, and water, and should not be perceived as merely waste. Recycling, composting, and combustion of non-recyclables have been practiced for deca...Organic solid and liquid wastes contain large amounts of energy, nutrients, and water, and should not be perceived as merely waste. Recycling, composting, and combustion of non-recyclables have been practiced for decades to capture the energy and values from municipal solid wastes. Treatment and disposal have been the primary management strategy for wastewater. As new technologies are emerging, alternative options for the utilization of both solid wastes and wastewater have become available. Considering the complexity of the chemical, physical, and biological properties of these wastes, multiple technologies may be required to maximize the energy and value recovery from the wastes. For this purpose, biorefin- ing tends to be an appropriate approach to completely utilize the energy and value available in wastes. Research has demonstrated that non-recyclable waste materials and bio-solids can be converted into usable heat, electricity, fuel, and chemicals through a variety of processes, and the liquid waste streams have the potential to support crop and algae growth and provide other energy recovery and food production options. In this paper, we propose new biorefining schemes aimed at organic solid and liquid wastes from municipal sources, food and biological processing plants, and animal production facilities. Four new breakthrough technologies-namely, vacuum-assisted thermophilic anaerobic digestion, extended aquaponics, oily wastes to biodiesel via glycerolysis, and microwave-assisted thermochemical conversion-can be incorporated into the biorefining schemes, thereby enabling the complete utilization of those wastes for the production of chemicals, fertilizer, energy (biogas, syngas, biodiesel, and bio-oil), foods, and feeds, and resulting in clean water and a significant reduction in pollutant emissions.展开更多
The waste of foodstuffs is increasing in the agri-food industries. This is reflected in the increasing volume of their waste. Food is thrown away on criteria that have nosthing to do with its nutritional quality. In m...The waste of foodstuffs is increasing in the agri-food industries. This is reflected in the increasing volume of their waste. Food is thrown away on criteria that have nosthing to do with its nutritional quality. In most cases, the criteria are shape, color and stains. In order to reduce this waste, a way of valorization was investigated. This paper focuses on waste reduction through feeding the Abidjan zoo animals with the unsold products of three agro-industries. The unsold products collected by the zoo were characterized over an 8-year period (2011 to 2019). Deaths and births were recorded. The food needs met by the unsold products harvested were evaluated and the economic gains estimated. The results showed that the food recovered by the Abidjan Zoo at SOCOCE contained 34.94% fruit, 38.58% vegetable and 23.47% meat products. At SCB and Coquivoire the donations are estimated at 2 tons of bananas and 1.5 tons of chickens (smoked and cold chicken) respectively. These donations allowed the Zoo to save 25.94% of its budget allocated to animal feed. The diversity of the food collected has a positive impact on the quality of life of the animals at the Zoo. This is reflected in an increase in the number of births from 0 to 12 per year and a decrease in mortality of 90%.展开更多
文摘A cross-sectional survey was conducted to establish the utilisation of non-conventional animal waste in multiple livestock species systems. Farmers (150) were selected from four out of ten districts of Central Uganda in Lake Victoria Crescent. A structured questionnaire was used and descriptive analysis showed that over 80% are smallholder farmers on 3.0) years. Household husbands (80%) significantly (P 1.0) as they cause poor livestock health due to pathogens, parasites and toxins which are associated (OD > 1.0) with poor growth, mortality and condemnation of livestock products. The remedy to unsafe non-conventional feeds is to apply effective solar-heating (75%), chemical and ensiling treatment methods. The study showed that there are no significant (P < 0.001) public health risks associated with utilising treated non-conventional feeds instead it improves production and sustainability of multiple livestock species systems.
文摘Modified aluminum slag (MAS) was applied as an adsorbent for Congo red (CR) prepared by the hydrothermal treatment of Ca(OH)<sub>2</sub>. At 25°C, with a MAS dosage of 0.3 g, initial CR concentration of 100 mg/L and initial pH = 5, and the adsorption time was 40 min, the CR removal efficiency was 98.41%. The adsorption trend of CR conformed to the second-order kinetics, and the adsorption isotherm follows the Freundlich isotherm model. Compared with RAS, MAS has a larger pore volume and specific surface area. The mechanism of action of MAS on CR was the interaction between membrane diffusion and internal diffusion, and the adsorption rate during the membrane diffusion was the fastest.
文摘Excess amounts of livestock wastes are excreted in limited area and cause pollution problems in Japan.Comparative studies on livestock waste management among EU(European Union),US(the United States of America)and Asia including Japan are surveyed.In Japan,livestock wastes are mostly separated into solid and liquid matter.Solid matter is converted into organic fertilizer by means of composting.Composting should be developed into the technology that has low emission,high-quality and low cost.Various odorous compounds are emitted from the process of livestock waste management.Odor emission from livestock farms should be mitigated to protect the local community.High-quality compost can be widely distributed to cropland to decrease expenditure of chemical fertilizer.Although liquid matter,namely wastewater or slurry,could be applied to cropland of livestock farms such as EU countries,most of Japanese farms do not have enough cropland to use liquid matter.Particularly pig farms have no area to spread wastewater,which should be purified to clean water in accordance with the criteria of water quality and could be discharged into public water area.The most desirable management of livestock wastes should involve sustainable recycling as compost and environmentally friendly control of odors and wastewater.
文摘Pyrolysis has the potential of transforming waste into valuable recyclable products. Pyrolytic char(PC) is one of the most important products from the pyrolysis of used tires. One of the most significant applications for pyrolytic char recovered is used for the removal of Cr(Ⅵ) in the wastewater effluent to control waste by waste. The surface chemistry properties of surface element distribution / concentration and chemical structure were examined for the pyrolytic char and the commercial activated carbon(CAC) respectively. The results showed that surfaces of PC possesses a large amount of ester and hydrocarbon graft, whereas there are mainly carbon functional components of C—OH, C O and COOH on the surface of CAC. Therefore the surface electronegativity of PC is lower than that of CAC in the water. The repulsive interactions between the surfaces of PC and the negatively charged Cr(Ⅵ) ion are weaker than that of CAC, which results in an intensification of the adsorption process by the utilization of PC. The adsorption isotherms of Cr(Ⅵ) ion on the two kinds of carbons were determined experimentally. The larger adsorption amount on the PC in the case of Cr(Ⅵ) may be attributed mainly to its special surface micro-chemical environment. The mechanism of the removal Cr(Ⅵ) from aqueous solution was assumed to be the integration of adsorption and redox reaction. The adsorption was the rate-controlled step for Cr(Ⅵ) removal. The adsorption of Cr(Ⅵ) was identified as pseudo-second-order kinetics. The rate constants of adsorption were evaluated.
文摘Wastewater, which involves easy-soluble reactive dyes, especially non-degradable dyes, is very difficult to decolor efficiently by normal processes such as coagulation process and biological treatment. The high chromaticity se- riously hinders the reuse of reactive dye waste water. In this paper, a new method by bentonite adsorption and coagulation (PAC) is employed for removing color from synthetic dye waste water which contains reactive red K-2G, K-RN blue, K-GR blue, X-3B red, K-GN orange, KB-3G yellow, K-2BP red, K-RN yellow and K-6G yellow. Bentonite pre- treated by 4% CTMAB and milled to 160 order screen is proven to the best decoloring agent. For a 100 mL reactive red K-2G sample (CODcr 400 mg/L, 25 000 chromaticity color), 0.5 g bentonite pretreated and 2.5 mL PAC is enough to decolor wastewater up to 99.92% and the sediment time is short. Non-degradable dyes such as active red X-3B and K-GN orange are declored completely as well. Raw sewage (low chromaticity color) is decolored completely at a ben-tonite dosage of 0.001g. More researches prove the high practical value of this process.
基金Projects(51108100,50808184)supported by the National Natural Science Foundation of ChinaProject(100Z007)supported by the Ministry of Education of China+1 种基金Project(200103YB020)supported by Foundation of Guangxi Educational Committee,ChinaProject supported by Guangxi Normal University Education Development Foundation for Young Scholars,China
文摘The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier transform infrared spectroscopy),BET(specific surface area),and BJH(pore size distribution).The results indicate that the removal rate of phosphate(100 mg/L)in 50 mL phosphorus wastewater reaches at 99.9% as the dosage of MSWI fly ash being 0.9000 g under room temperature.The specific surface area of MSWI fly ash is less than 6.1 m2/g and the total pore volume is below 0.021 cm3/g,suggesting that the absorption capacity of calcite is too weak to play an important role in phosphate removal.SEM images show that drastic changes had taken place on its specific surface shape after reaction,and EDS tests indicate that some phosphate precipitates are formed and attached onto MSWI fly ash particles.Chemical precipitation is the main manner of phosphate removal and the main reaction is: 3Ca2++2 PO4 3-+xH2O→Ca3(PO4)2↓·xH2O.Besides,XRD tests show that the composition of MSWI fly ash is complex,but CaSO4 is likely to be the main source of Ca2+.The soluble heavy metals in MSWI fly ash are stabilized by phosphate.
文摘This study is aimed at evaluating alternative designs of waste stabilization ponds (WSPs) and constructed wetlands (CWs) for Kaputiei Housing Estate consisting of 2000 low cost housing units in Kenya. The entire analysis was carried out by simulating the effectiveness and purification efficiencies of WSPs and CWs in terms of Biological Oxygen Demand (BOD) reduction and faecal coliform (FC) removal under different scenarios of water treatment systems that included Re-sizing of the initial sewage treatment system, optimizing the design of the initial system and design of hybrid system for the estate. The graphic comparison of the simulated parameters under different scenarios showed that a hybrid design that combines both the WSPs and CWS provides an effluent BOD of 20 mg/l and 195 FC per 100 ml that meets the standard effluent discharge that is acceptable for unrestricted crop irrigation and thus will be reused in the housing estate for kitchen gardening and agroforestry.
文摘The catalytic combustion technology for treating waste gases exiting from wastewater treatment system and oil separators in petrochemical enterprises was introduced in this article. Commercial application of this technology showed that the process "desulfurization and total hydrocarbon concentration homogenizationcatalytic combustion" and the associated WSH-1 combustion catalyst were suitable for treating volatile organic gases emitted from the oil separators, floatation tanks, inlet water-collecting well, waste oil tanks, etc. The commercial unit was equipped with an advanced auto-control system, featuring a simple operation and low energy consumption with good treatment effect. The purified gases could meet the national emission standard.
基金Project(50174014) supported by the National Natural Science Foundation of ChinaProject(20042021) supported by the Natural Science Foundation of Liaoning Province,ChinaProject(2006223002) supported by the High Science and Technology Plan of Liaoning Province,China
文摘The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on biosorption of cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae and precipitation process of waste saccharomyces cerevisiae after adsorbing cadmium were studied. The results show that removal rate of cadmium is over 88% after 30 min adsorbing under the condition of cadmium concentration 26 mg/L, the dosage of waste saccharomyces cerevisiae 16.25 g/L, temperature 18 ℃, pH 6.0 and precipitation time 4 h. Biosorption-precipitation method is effective to remove cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae. The SEM, infrared spectroscopy and Zeta-potential of the cells show that chemical chelating is the main adsorption form; electrostatic attraction, hydrogen bonding and van der Waals force all function in adsorption process; and ―NH2―,―C=O―,―C=O―NH―,―CH3, ―OH are the main adsorption groups.
文摘T.S.Eliot's works have the didactic purpose of turning his readers away from what he considered the selfindulgence of the Romantics and toward the sterner splendors of Elizabethan drama and the 17th-century metaphysical poetry.Associated with the rise of literary modernism,he was established as the voice of a disillusioned generation by The Waste Land(1922).Especially,Eliot's description of the discourse of animality received highly artistic effect on the aspect of expressing his "impersonal theory".The discourse of animality in The Waste Land in plenty,thus,it made the author's expressive force more vivid.Furthermore,various imagos of different animals drew a mythical picture of modern waste land.So that,Eliot's The Waste Land also has the epic signification.
文摘The feasibility of sewage treatment via combined chemical-biological techniques has been investigated. Two-stages pilot plant were designed for this purpose. The first stage was direct chemicalcoagulation-sedimentation using ferric chloride in-combination with lime to reduce the organic load and to remove the colloidal and suspended solids. A comparison of two separtion techniques namely chemical coagulation conventional sedimention and chemical coagulation tube settler sedimention were investigated. The second stage was either high rate oxidation pond or biological sand-bed to oxidize ammonia to nitrate. The results obtained showed that the effluent produced from the first stage is amaenable for restricted irrigation purposes. The HIROP proved to be satisfactory second treatment method for removal of pollutant. In addition high algal biomass was obtained. However, the use of sand-bed for nitrification proved to be more efficient, complete removal of ammonia was acheived.Average residual COD and BOD values were 66 and 38 mg O2/L, respectively. Fish toxicity was completely eleminated after the nitrification processes
基金supported by the National Natural Science Foundation of China (No.52364022)the Natural Science Foundation of Guangxi Province,China (Nos.2023JJA160192 and 2021GXNSFAA220096)+1 种基金the Guangxi Science and Technology Major Project,China (No.AA23073018)the Guangxi Chongzuo Science and Technology Plan,China (No.2023ZY00503).
文摘With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.
文摘Leather industry is an important light industry in China.Leather making requires a series of chemical treatment.Degreasing,unhairing and chrome tanning wastewaters are the main portions of tannery wastewater.Reclaiming and reusing these wastewaters can eliminate 80% of COD,75% of BOD,95% of chromium and 93% of sulfuret,furthermore reduce environment impact,decrease treatment costs,save chemicals and water.Some application methods of wastewater reclamation and reuse for different operations were reported.The suitable reclamation and reuse technologies can enable leather making processes more rational,and realize the recovery and recycle of several chemicals in the tannery.Resourceful utilization of tannery wastewater should mate with renovating production technology,updating equipment,and must be guaranteed sufficiently by environmental protection measures.
文摘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.
文摘The mining industry has contributed tremendously to the global economy.However,waste generated by this activity poses many challenges.Current low-cost technologies for the removal of heavy metals from mining wastewater include biosorption,adsorption,CWs(Constructed Wetlands)and waste stabilization ponds.This chapter focuses on sustainable mining wastewater treatment technologies with emphasis on gold mining wastewater.It discusses the technical and environmental challenges associated with mining effluent treatment,process conditions for optimum plant performance,efficiency,limitations and the economics of treating mining wastewater.The overall treatment cost of metal contaminated wastewater depends on the process employed and the local conditions.In general,technical applicability,cost-effectiveness and plant simplicity are the key factors in selecting the most suitable treatment method.Proper management of the spent biosorbent and solid wastes generated is also discussed.
基金Supported by Open Fund Project of Key Laboratory for the Development and Utilization of Rural Renewable Energy of Ministry of Agriculture and Rural Areas(2017015)。
文摘With the high-quality development of modern agriculture and animal husbandry in the plateau,the waste resources produced by agriculture and animal husbandry show a trend of diversification.How to effectively carry out the key work based on the optimal combination and utilization of waste resources of agriculture and animal husbandry in Tibet is imminent.To realize efficient recycling of waste resources of agriculture and animal husbandry,innovative mode is explored.On the theoretical basis,it can effectively alleviate the resource crisis,control the pollution sources,effectively utilize the resources and construct the recycling mode,which plays an important role in promoting,integrating and coordinating the high-quality development of modern agriculture and animal husbandry in the plateau.In this paper,optimal combination and utilization manner of waste resources of agriculture and animal husbandry under the circular development concept is comprehensively analyzed and summarized,to continuously improve reasonable and effective utilization level and efficiency of agricultural waste resources.It could not only inhibit waste pollution but also promote rational and effective utilization of resources,thereby laying theoretical basis for sustainable and efficient development of agriculture and animal husbandry in Tibet,promoting the improvement of agricultural and rural ecological environment,and providing the thinking for exploring model of ecological recycling in plateau.
基金Supported by a grant from Sanko Company for EM Production and its produetsa grant from JICA Agency.OIC.Okmawa.Japan
文摘Sludge dewatering and treatment may cost as much as the wastewater treatment.Usually large proportion of the pollutants in wastewater is organic.They are attacked by saprophytic microorganisms,i.e.organisms that feed upon dead organic matter.Activity of organisms causes decomposition of organic matter and destroys them,where the bacteria convert the organic matter or other constituents in the wastewater to new cells,water,gases and other products.Demolition activities,including renovation/remodeling works and complete or selective removal/demolishing of existing structures either by man-made processes or by natural disasters,create an extensive amount of wastes.These demolition wastes are characterized as heterogeneous mixtures of building materials that are usually contaminated with chemicals and dirt.In developing countries, it is estimated that demolition wastes comprise 20%to 30%of the total annual solid wastes.In Egypt,the daily quantity of construction and demolition(C&D) waste has been estimated as 10 000 tones.That is equivalent to one third of the total daily municipal solid wastes generated per day in Egypt.The zabbaliin have since expanded their activities and now take the waste they collect back to their garbage villages where it is sorted into recyclable components:paper,plastics, rags,glass,metal and food.The food waste is fed to pigs and the other items are sold to recycling centers.This paper summarizes the wastewater and solid wastes management in Egypt now and future.
基金Department of Transport/Sun GrantUS Department of Agriculture/ Department of Energy+4 种基金Minnesota Legislative-Citizen Commission on Minnesota ResourcesMetropolitan Council Environmental ServicesUniversity of Minnesota MNDrive programsUniversity of Minnesota Center for BiorefiningChina Scholarship Council (CSC) for their financial support for this work
文摘Organic solid and liquid wastes contain large amounts of energy, nutrients, and water, and should not be perceived as merely waste. Recycling, composting, and combustion of non-recyclables have been practiced for decades to capture the energy and values from municipal solid wastes. Treatment and disposal have been the primary management strategy for wastewater. As new technologies are emerging, alternative options for the utilization of both solid wastes and wastewater have become available. Considering the complexity of the chemical, physical, and biological properties of these wastes, multiple technologies may be required to maximize the energy and value recovery from the wastes. For this purpose, biorefin- ing tends to be an appropriate approach to completely utilize the energy and value available in wastes. Research has demonstrated that non-recyclable waste materials and bio-solids can be converted into usable heat, electricity, fuel, and chemicals through a variety of processes, and the liquid waste streams have the potential to support crop and algae growth and provide other energy recovery and food production options. In this paper, we propose new biorefining schemes aimed at organic solid and liquid wastes from municipal sources, food and biological processing plants, and animal production facilities. Four new breakthrough technologies-namely, vacuum-assisted thermophilic anaerobic digestion, extended aquaponics, oily wastes to biodiesel via glycerolysis, and microwave-assisted thermochemical conversion-can be incorporated into the biorefining schemes, thereby enabling the complete utilization of those wastes for the production of chemicals, fertilizer, energy (biogas, syngas, biodiesel, and bio-oil), foods, and feeds, and resulting in clean water and a significant reduction in pollutant emissions.
文摘The waste of foodstuffs is increasing in the agri-food industries. This is reflected in the increasing volume of their waste. Food is thrown away on criteria that have nosthing to do with its nutritional quality. In most cases, the criteria are shape, color and stains. In order to reduce this waste, a way of valorization was investigated. This paper focuses on waste reduction through feeding the Abidjan zoo animals with the unsold products of three agro-industries. The unsold products collected by the zoo were characterized over an 8-year period (2011 to 2019). Deaths and births were recorded. The food needs met by the unsold products harvested were evaluated and the economic gains estimated. The results showed that the food recovered by the Abidjan Zoo at SOCOCE contained 34.94% fruit, 38.58% vegetable and 23.47% meat products. At SCB and Coquivoire the donations are estimated at 2 tons of bananas and 1.5 tons of chickens (smoked and cold chicken) respectively. These donations allowed the Zoo to save 25.94% of its budget allocated to animal feed. The diversity of the food collected has a positive impact on the quality of life of the animals at the Zoo. This is reflected in an increase in the number of births from 0 to 12 per year and a decrease in mortality of 90%.