Burgess, A., Smyth, M., Forgacs, G. and Elliott, C., Aqua Enviro, UK(free)
To realise OPEX savings and maximise energy generation it is being increasingly recognised that a
detailed understanding of wastewater, feedstock and sludge characteristics is required. The data
generated is of most use when inputted in to predictive, calibrated models that allow the user to simulate
changes to the configuration of a plant, which alter the characteristics and subsequent running costs
and revenues. Once verified the data gathered can be used to drive investment decisions and/or
process operational strategies.
In this paper, we outline the standard and specialised test methods for waste and wastewater
characterisation that can be used to populate & verify models such as BioWin. These include
FRACTIONATION of: 1) Solids, 2) COD, 3) nitrogen and 4) phosphorus, as well as, 5) methods for
evaluating total and available energy potential and, 6) the quantification of inhibitory compounds.
Sankey diagrams have been used to demonstrate the potential impact upon energy consumption and
generation for a theoretical wastewater treatment works with a PE of 230,000 and taking sludge imports
of 15 tonnes of dry solids.
This paper aims to review standard and bespoke test methods utilized for waste and wastewater
characterisation to produce data for the population of BioWin models and Sankey diagrams. Such
software applications and visual tools can then be used inform process operational strategies to reduce
operating costs and maximise energy generation.
Current drivers for optimisation of municipal WwTW assets originate from Ofwat’s reform on the
expenditure model for investment, moving from a capital investment bias (CAPEX) to Total costs
(TOTEX) model. The TOTEX expenditure model considers energy usage, operation and maintenance
costs, encouraging a review and optimisation of current assets prior to capital investment.
Drivers for optimisation in the food waste and agricultural anaerobic digestion (AD) sector have been
caused by uncertainty over incentives and feedstock competition. These changes have, on occasion,
caused operators to switch from processing high volumes of feedstock to obtain a maximum gate fee,
to a focus on achieving maximum energy generation for the feedstock available, by more efficient
operation of the AD process
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