A holistic framework for design of cost-effective minimum water utilization network
ABSTRACT Water pinch analysis (WPA) is a well-established tool for the design of a maximum water recovery (MWR) network. MWR, which is primarily concerned with water recovery and regeneration, only partly addresses water minimization problem. Strictly speaking, WPA can only lead to maximum water recovery targets as opposed to the minimum water targets as widely claimed by researchers over the years. The minimum water targets can be achieved when all water minimization options including elimination, reduction, reuse/recycling, outsourcing and regeneration have been holistically applied. Even though WPA has been well established for synthesis of MWR network, research towards holistic water minimization has lagged behind. This paper describes a new holistic framework for designing a cost-effective minimum water network (CEMWN) for industry and urban systems. The framework consists of five key steps, i.e. (1) Specify the limiting water data, (2) Determine MWR targets, (3) Screen process changes using water management hierarchy (WMH), (4) Apply Systematic Hierarchical Approach for Resilient Process Screening (SHARPS) strategy, and (5) Design water network. Three key contributions have emerged from this work. First is a hierarchical approach for systematic screening of process changes guided by the WMH. Second is a set of four new heuristics for implementing process changes that considers the interactions among process changes options as well as among equipment and the implications of applying each process change on utility targets. Third is the SHARPS cost-screening technique to customize process changes and ultimately generate a minimum water utilization network that is cost-effective and affordable. The CEMWN holistic framework has been successfully implemented on semiconductor and mosque case studies and yielded results within the designer payback period criterion.
SourceAvailable from: Walter DenResources Conservation and Recycling 01/2015; 94:35-42. DOI:10.1016/j.resconrec.2014.11.007 · 2.69 Impact Factor
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ABSTRACT: Mathematical programming techniques have been widely used to solve water minimisation problems. Yet, to date, there is lack of research on water minimisation for fixed schedule and cyclic operation batch processes that also targets the minimum storage capacity as well as inter-connections, and considers mass-transfer based (MTB) and non-mass transfer-based (NMTB) operations, for problems with multiple contaminants. In this study, a four-stage mathematical model is formulated to address the aforementioned problem, by considering water minimisation options within a Water Management Hierarchy (WMH). The developed model was employed on an urban and an industrial facility to demonstrate the effectiveness of proposed model to solve the minimum water network with minimum storage tank capacity and network inter-connections. For the urban facility case study involving a mosque, the maximum potential freshwater and wastewater reductions are 99.89% and 65.7%. Setting the minimum number of inter-connections (MNI) as the objective function has further reduced the MNI by 13%. For the industrial case study, the maximum potential freshwater and wastewater reductions are 59.53% and 16.43%. Imposing the MNI constraint as the objective function further reduced the number of inter-connections by 20.83%.Journal of Cleaner Production 08/2014; 77:65–78. DOI:10.1016/j.jclepro.2013.11.061 · 3.59 Impact Factor
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ABSTRACT: Rising demand for paper has resulted in increased number of trees being chopped around the world. The loss of forest lands due to rampant tree cutting has caused a steady increase in the earth's temperature, changed the weather pattern and ultimately threatened the world's ecosystems. One way to mitigate these problems is through efficient paper recycling. To ensure that maximum recycling is achieved, proper mixing of different types of paper of different fiber contents should be considered. This work presents a new generic graphical method for simultaneous targeting and designing of a maximum paper recycling network. The first step is to establish the maximum paper recycling target using a graphical approach called the source–sink composite curves. Next, source–sink allocation curve and network allocation diagram are constructed to design the maximum paper recovery network. The graphical tool allows a designer to graphically visualize, explore, evolve and systematically select the best paper recycling network. Application of the method in Universiti Teknologi Malaysia campus yields a new fresh fiber target of 1464 tons/year. This is a potential reduction in 43.7% fresh fiber and translates into an annual reduction in 38 622 chopped trees and a potential savings of up to 4.5 GWh of electricity and 30.1 × 103 m3 of water. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.Asia-Pacific Journal of Chemical Engineering 09/2011; 6(5). DOI:10.1002/apj.546 · 0.62 Impact Factor