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Byline: Yin Ling Tan, Z.A. Manan This paper presents a new systematic technique for the retrofit of existing water network based on pinch analysis. This technique, which was applied on a paper mill, consists of three main steps: Network Diagnosis, Network Retrofit and Network Evolution. Network diagnosis step provides a good understanding of the existing water network through the use of a new tool called the Concentration Block Diagram (CBD). Next, modifications based on a set of pinch rules were performed on the existing water network to achieve the preliminary retrofit design. Finally, the preliminary retrofit design will go through an evolution to generate the final retrofit scheme. A paper making process case study was utilised to demonstrate the applicability of this new methodology. The results show that 55.5% of fresh water consumption and 65.7% of wastewater generation have been reduced, respectively, for the paper mill case study.

Byline: Zainuddin Abdul Manan, Yin Ling Tan, Dominic Chwan Yee Foo, Swee Yin Tea The Water Cascade Analysis (WCA) technique was used to identify opportunities for reduction in freshwater usage as well as wastewater generation and to assist in the retrofit of an existing paper mill water distribution network. This procedure involves three key steps; i.e., a global analysis of the present water distribution and consumption, setting the baseline minimum water targets using WCA technique and retrofit of water network to achieve the minimum water targets. Notwithstanding the extensive water recycling currently employed in the paper mill, this study identified a potential scope of reducing 13.3% freshwater and 13.3% wastewater. Water reduction represents a total potential annual savings of RM 595,232, taking into account the raw water and wastewater treatment costs, pumping and chemical costs.