Thermal-chemical sludge conditioning, co-digestion, and gas to grid at the Capital Region Water AWTF: PAPER & PRESENTATION
Auerbach, E.,1, Vergara Romero, L.1, Rosentel, J.2, 1Arcadis Consulting, UK, 2Capital Region Water, USA
(free)
Abstract
From 2018 to present, Capital Region Water (CRW) has been developing a programme to enhance energy recovery from its biosolids. CRW engaged with Arcadis to facilitate this programme which started with a holistic planning study, then design, and is currently in procurement and construction.
The key tool used to evaluate biosolids and energy processes and their interacting effects was the Arcadis solids and energy flow model. With this tool, any potential combination of processes or loading rates was quantitatively analysed for annualized cost, greenhouse gas (GHG) reductions, net power generation, and capital spend. The identified project included conversion of gravity co-thickening of sludge to the mechanical thickening of Surplus Activated Sludge (SAS), thermal-alkaline hydrolysis of Surplus Activated Sludge (SAS), acceptance of local organic high strength waste (HSW), and upgrading biogas to renewable natural gas (RNG) for injection to grid in an adjacent natural gas facility.
By partnering with local food producers and natural gas utility, this project serves as model for how cooperation and regionalization can significantly raise energy recovery potential and value from biosolids. This programme also demonstrates the benefits of effective planning as CRW staff were able to confidently move forward with implementation and pursue long term operational improvements such as thickening in combination with financially lucrative aspects such as RNG.
