Increasing significance of advanced physical/chemical Processes in the development and application of sustainable wastewater treatment systems
Scarcity of sufficient amounts of water of sufficient quality for potable drinking water supply and for industrial and agricultural use is currently one of the most serious worldwide problems.The awareness of this problem has strongly changed the approach how to deal with the treatment of wastewater.In the past the aim of a wastewater treatment process was primarily to produce an effluent that could be discharged on surface water.Traditional microbiological methods in combination with simple mechanical methods were able to produce the effluent quality required for the discharge on surface water.Currently there is an increasing need to achieve a higher quality of the effluent to make beneficial reuse of the treated wastewater possible but also for recovery of valuable products and euergy from the wastewater.Because microbiological treatment methods are only to a relatively small part able to satisfy all these needs,the role and significance of physical/chemical treatment steps in wastewater treatment is gaining more and more importance.In this paper first a short general overview is giyen of the most important physical,chemical and microbiological treatment steps.With respect to the specific role in the future of wastewater treatment the various physical/chemical treatment processes Can be categorized in five groups.The first group includes physical/chemical processes which are very helpful to improve the performance of existing aerobic and anaerobic treatment steps.The second group are processes which can be applied either as the main treatment process or as a final treatment step after a biological treatment in order to satisfy the high quality conditions required for reuse of the effluent or for discharge of the effluent on surface water.The third group are processes specificaJlv aimed at the recovery of valuable cornponents for beneficial reuse.The fourth group consists of processes focused on the removal or concentration of easily soluble minerals such as potassium,sodium and chloride from wastewater,brackish water and seawater.And finally there is a group of physical/chemical processes suitable to treat concentrated liquid,solid or semi-solid waste residues,produced in a wastewater treatment process.Development of more sustainable treatment processes or treatment chains for wastewater,in which physical/chemical processes play a crucial role,requires not only fundamental and practical knowledge about all separate treatment steps but also knowledge about process control and modeling of treatment processes and treatment chains.This is briefly shown by the elaboration of treatment scenarios for three specific wastewater problems.The problem of the scarcity of sufficient amounts of water of sufficient quality for potable drinking water supply and for industrial and agricultural use and also the problem of insufficient quality of the effluent for discharge on surface water only can be solved by strongly increasing the application of physical/chemical treatment processes and the application of chemical reaction engineering principles and approaches.Many innovative physical/chemical treatment methods are in the research or development stage or are in a phase of continuous improvement.From a sustainability point of view it can be expected that there will be an increasing focus on further developing membrane processes,on cheap and sinail scale desalination processes and on processes that are able to remove pollutants almost completely from the wastewater or at least to a level tllat allows beneficial reuse of the water.Also processes focused on recovery of valuable products such as heavy metals.phosphorous and nitrogen containing cornponents will get increasing attention.In the development of wastewater treatment scenarios the energy aspect minimization of energy use and maximization of the recovery of energY-is also a key aspect.Looking to all the potentials of physical/chemical treatment processes,the specific achievements that call be obtained,also in combination with biological treatment processes,it is evident that physical/chemical processes are moving to a very challenging future.
Wim RULKENS
Wageningen Uniersity,Sub-department of Environmental Technology,P.O. Box 8129,6700 EV Wageningen,The Netherlands
国际会议
西安
英文
29-43
2008-05-15（万方平台首次上网日期，不代表论文的发表时间）