Designing for the Future: Optimum Resource Recovery Process Design and Long Term Value Analyses of Recovered Commodities
Palmer, S. and Ajay Nair MWH (UK) Ltd
(free)
The water industry faces four decades to 2050 in which its main operating costs will increase, increasing costs for customers and suppliers of non-privatised wastewater treatment and reducing revenue and margin for privatised wastewater treatment.
As these are global trends, it will be impractical to financially hedge against them once the market begins to understand the risk, but other mitigation of these cost risks is possible. Proper investment, beginning now, in resource recovery, can provide the water industry with a wastewater treatment asset base that can supply an operational mitigation of these cost risks by reducing energy costs and providing revenue streams for the water company, from materials recovered from sewage.
This paper presents an optimal resource recovery flowsheet, integrated to provide both maximum energy recovery and material resource recovery. The implications of maximising resource recovery on process technology selection and the synergies that can be obtained between the most appropriate technologies are presented and described. This paper also describes the first commodities that can be recovered now with existing technologies; assesses their value and provides a long term projection of their potential value up to 2050.
Keywords
Resource recovery design, upgrading assets, reducing carbon footprint, reducing operating costs, strategic resources, climate change and economics.
Introduction
The water industry is characterised by a fixed capital asset base with substantial civil elements in the infrastructure. This gives a long asset life for any design produced at a given time, nominally 40 years on average (as described by OFWAT). Consequently when 15 to 25 year asset-life mechanical and electrical equipment is provided by and in a treatment plant design, then replaced after that period, the overall wastewater or sludge treatment facility often has significant remaining capital value and significant residual, viable asset life which results in old civil assets being reconfigured to meet new demands. This is a capital ‘inertia’ that places restrictions on the next stage of asset development. For good financial reasons, premature asset write should be avoided, justified on a simple value for money basis.
