A sequential three-step programming method is proposed for determining the minimum flowrate of fresh water and corresponding regenerated water in water-using system of single contaminant with regeneration reuse. In st...A sequential three-step programming method is proposed for determining the minimum flowrate of fresh water and corresponding regenerated water in water-using system of single contaminant with regeneration reuse. In step 1, a programming with the objective of min fws is used to determine the minimum flowrate of fresh water, in which the mathematical representation is a mixed integer nonlinear programming (MINLP1). Then under the same constraints with step 1, a programming with the objective of min freg in step 2 and a programming with the objective of min Cr in step 3 are subsequently used to determine the minimum flowrate of regenerated water and the minimum inlet concentration to regeneration process corresponding to the minimum flowrate of fresh water based on step 1. The method is easy to apply because we only need to change the objective function but keep the constraints constant to go along the following steps after step 1. In addition, the relationship between the fresh water flowrate required, fws and inlet concentration to regeneration process, Cr, is investigated. It is found that there exist three relationships between fws and Cr, which indicate three possibilities for C\>: below the pinch, above the pinch or at the pinch. Therefore, a new conclusion is drawn, which differs from that 'regeneration of water at pinch minimizes fresh water flowrate' derived in literature and indicates that in some cases, regeneration at other point also minimizes fresh water flowrate.展开更多
Systematic studies on the treatment and reuse of the acid industrial wastewatercontaining Sodium 2-Naphthylsulfonate (β-salt) from 2--Naphthanol of production processby ND--910 resin (made by self)is reported in this...Systematic studies on the treatment and reuse of the acid industrial wastewatercontaining Sodium 2-Naphthylsulfonate (β-salt) from 2--Naphthanol of production processby ND--910 resin (made by self)is reported in this paper.Under the operation conditionsof initial β-salt concentration of 10000-25000mg/L and initial CODcr of 2000040000mg/L, the removal rates of Sodium 2-Naphthylsulfonate and CODcr are over 95%and over 89%, respectively. The effluent can be discharged directly after biologicaldegradation. The working sorption capacity of ND-910 Resin for β-salt is over 230g/Kg.An alkali-water wash procedure is utilized to regenerate resin and the reclaiming rate ofβ-salt is over 98%.展开更多
A waste water reuse engineering was designed and then operated in Hongshan, a small town in ZhejiangProvince, China, in order to solve pollution and shortage of water resources due to the development of ruralenterpris...A waste water reuse engineering was designed and then operated in Hongshan, a small town in ZhejiangProvince, China, in order to solve pollution and shortage of water resources due to the development of ruralenterprises. The results showed that series-structure design and cycling model were two effective modes ofsaving water and decreasing pollutants into environment, and wetland strategy should be a component partof the integrated planning for waste water reuse of rural enterprises. This case study could provide a basisfor the optimum utilization and pollution avoidance of water resources.展开更多
In order to find new approaches to alleviating the water crisis in Beijing which is caused by among others dwindling precipitation and rapid growth of population and manifests in a rapidly declining groundwater table ...In order to find new approaches to alleviating the water crisis in Beijing which is caused by among others dwindling precipitation and rapid growth of population and manifests in a rapidly declining groundwater table this study explores decentralized stormwater harvesting and greywater reuse at household level as a means to reduce groundwater abstraction and water transfer from other regions.Based on a desktop case study two concepts for combined harvesting and reusing of storm-and greywater are presented.With rough pre-assumptions calculations show that a saving of 67.8%of tap water consumption can be achieved with the upgrading concept compared with 5.9% with the simple downgrading concept.The saving with the upgrading concept equals 0.545 ×109 m3 annual water volume if 20 million Beijing people apply this approach.Despite numerous prerequisites such as water treatment technology space demand energy and cost and public acceptance this paper advocates combining stormwater harvesting and greywater reuse in households with other measures for Beijing’s sustainable water management.展开更多
In order to take full advantage of regeneration process to reduce fresh water consumption and avoid the accumulation of trace contaminants, regeneration reuse and regeneration recycle should be distinctive. A stepwise...In order to take full advantage of regeneration process to reduce fresh water consumption and avoid the accumulation of trace contaminants, regeneration reuse and regeneration recycle should be distinctive. A stepwise optimal design for water network is developed to simplify solution procedures for the formulated MINLP problem. In this paper, a feasible water reuse network framework is generated. Some heuristic rules from water reuse network are used to guide the placement of regeneration process. Then the outlet stream of regeneration process is considered as new water source. Regeneration reuse network structure is obtained through an iterative optimal procedure by taking the insights from reuse water network structure. Furthermore, regeneration recycle is only utilized to eliminate fresh water usage for processes in which regeneration reuse is impossible. Compared with the results obtained by relevant researches for the same example, the present method not only provides an appropriate regeneration reuse water network with minimum fresh water and regenerated water flow rate but also suggests a water network involving regeneration recycle with minimum recycle water flow rate. The design can utilize reuse, regeneration reuse and regeneration recycle step by step with minor water network structure change to achieve better flexibility. It can satisfy different demands for new plants and modernization of existing plants.展开更多
基金Supported by the National Fundamental Research Development Program of China(No.2000026308).
文摘A sequential three-step programming method is proposed for determining the minimum flowrate of fresh water and corresponding regenerated water in water-using system of single contaminant with regeneration reuse. In step 1, a programming with the objective of min fws is used to determine the minimum flowrate of fresh water, in which the mathematical representation is a mixed integer nonlinear programming (MINLP1). Then under the same constraints with step 1, a programming with the objective of min freg in step 2 and a programming with the objective of min Cr in step 3 are subsequently used to determine the minimum flowrate of regenerated water and the minimum inlet concentration to regeneration process corresponding to the minimum flowrate of fresh water based on step 1. The method is easy to apply because we only need to change the objective function but keep the constraints constant to go along the following steps after step 1. In addition, the relationship between the fresh water flowrate required, fws and inlet concentration to regeneration process, Cr, is investigated. It is found that there exist three relationships between fws and Cr, which indicate three possibilities for C\>: below the pinch, above the pinch or at the pinch. Therefore, a new conclusion is drawn, which differs from that 'regeneration of water at pinch minimizes fresh water flowrate' derived in literature and indicates that in some cases, regeneration at other point also minimizes fresh water flowrate.
文摘Systematic studies on the treatment and reuse of the acid industrial wastewatercontaining Sodium 2-Naphthylsulfonate (β-salt) from 2--Naphthanol of production processby ND--910 resin (made by self)is reported in this paper.Under the operation conditionsof initial β-salt concentration of 10000-25000mg/L and initial CODcr of 2000040000mg/L, the removal rates of Sodium 2-Naphthylsulfonate and CODcr are over 95%and over 89%, respectively. The effluent can be discharged directly after biologicaldegradation. The working sorption capacity of ND-910 Resin for β-salt is over 230g/Kg.An alkali-water wash procedure is utilized to regenerate resin and the reclaiming rate ofβ-salt is over 98%.
文摘A waste water reuse engineering was designed and then operated in Hongshan, a small town in ZhejiangProvince, China, in order to solve pollution and shortage of water resources due to the development of ruralenterprises. The results showed that series-structure design and cycling model were two effective modes ofsaving water and decreasing pollutants into environment, and wetland strategy should be a component partof the integrated planning for waste water reuse of rural enterprises. This case study could provide a basisfor the optimum utilization and pollution avoidance of water resources.
文摘In order to find new approaches to alleviating the water crisis in Beijing which is caused by among others dwindling precipitation and rapid growth of population and manifests in a rapidly declining groundwater table this study explores decentralized stormwater harvesting and greywater reuse at household level as a means to reduce groundwater abstraction and water transfer from other regions.Based on a desktop case study two concepts for combined harvesting and reusing of storm-and greywater are presented.With rough pre-assumptions calculations show that a saving of 67.8%of tap water consumption can be achieved with the upgrading concept compared with 5.9% with the simple downgrading concept.The saving with the upgrading concept equals 0.545 ×109 m3 annual water volume if 20 million Beijing people apply this approach.Despite numerous prerequisites such as water treatment technology space demand energy and cost and public acceptance this paper advocates combining stormwater harvesting and greywater reuse in households with other measures for Beijing’s sustainable water management.
基金Supported by the National Natural Science Foundation of China(20906007)
文摘In order to take full advantage of regeneration process to reduce fresh water consumption and avoid the accumulation of trace contaminants, regeneration reuse and regeneration recycle should be distinctive. A stepwise optimal design for water network is developed to simplify solution procedures for the formulated MINLP problem. In this paper, a feasible water reuse network framework is generated. Some heuristic rules from water reuse network are used to guide the placement of regeneration process. Then the outlet stream of regeneration process is considered as new water source. Regeneration reuse network structure is obtained through an iterative optimal procedure by taking the insights from reuse water network structure. Furthermore, regeneration recycle is only utilized to eliminate fresh water usage for processes in which regeneration reuse is impossible. Compared with the results obtained by relevant researches for the same example, the present method not only provides an appropriate regeneration reuse water network with minimum fresh water and regenerated water flow rate but also suggests a water network involving regeneration recycle with minimum recycle water flow rate. The design can utilize reuse, regeneration reuse and regeneration recycle step by step with minor water network structure change to achieve better flexibility. It can satisfy different demands for new plants and modernization of existing plants.
