The Establishment Of A Multilevel Reuse System With Source Separation Mode In Wastewater Reclamation In Printing And Dyeing Industrial Park

With the rapid development of economy and the growth of population in our country,the quantity of demand for the water resource is increasing.Therefore,relieving and solving the contradiction between the shortage of water resources and the demand of the society for water increase became the hot issue.As a typical product of economic growth,industrial demand and dependence for water resources are obvious.How to solve the problem of industrial water demand has become a part of the strategy of sustainable utilization of water resources in China.As a typical and main water consumer in industry,printing and dyeing industry has some problems such as large water consumption and pollutant discharge,low water reuse percentage.Therefore,it is of great research value to solve the problem of water resources.In C hina,printing and dyeing wastewater is a suitable water resource for reclamation.Considering the typicality and relative concentration of geographical position of printing and dyeing industry,the limitations and shortcomings of traditional printing and dyeing wastewater processes were analyzed at TuDian printing and dyeing industrial park.Through on-site investigation of the main links of yarn dyeing,warp knitted fabric dyeing,wool dyeing,alkali deweighting process and other process wastewater,the supply water quality requirements of each process was acquired,and the wastewater quality and quantity of each process were measured.According to water quality requirement of reclaimed water,evaluation methods of wastewater was established by matrix analysis method.Through the establishment of wastewater classification,the mode of source separated process in printing and dyeing wastewater treatment was built.According to the printing and dyeing wastewater emission standard and reuse standard of reclaimed water,the special,high and low contaminative wastewater was treated to different water quality by different treatment processes.Alkali deweighting and other special wastewater are treated to discharge standard directly by the advanced oxidation and biological treatment processes.The high contaminative wastewater of loose wool dyeing,desizing and other processes was also treated to discharge standard directly by pretreatment and biological treatment process.The low concentration and process wastewater with high water quantity,such as washing water of warp knitted fabric dyeing,was treated and reuse to some product processes by biological treatment and advanced treatment system.In the process of recycling,the mode of multilevel reused in sequence was established.For example,the high quality reclaimed water reused in sequence for first washing which has a high water quality requirement,second washing and last washing which has a low water quality requirement.By multilevel reuse,the fresh water consumption was minimized.To illustrate the efficiency of the proposed multilevel water reuses system with source separation mode,a case study in a new printing and dyeing enterprise in Zhejiang province was conducted.The wastewater reuse rate is as high as 62%which is much larger than the standard value 35%.In addition,it could reduce 600 thousand m~3/a surface water consumption,100 t/a COD emissions and 3 million Yuan per-year for the enterprise.Therefore,for printing and dyeing enterprise,source separated and cascading water reuse pattern can be considered in multilevel water reuses system design and management so as to maximize the reclaimed water utilization value and efficiency.