Preparing for the future – NI Water’s sludge strategy
Auty, D.1 and McArthur, J.2, 1PROjEN Ltd, UK, 2Northern Ireland Water
(free)
All the sewage sludge produced in Northern Ireland is currently disposed of by incineration under a
PPP scheme operated by Glen Water on behalf of NI Water. This PPP contract will end in 2032. To
prepare for this end date, NI Water recognised that it needed to start investigating options now so that
the preferred strategy could be planned for and installed in time for the end of the current contract.
NI Water began with Phase 1, which identified appropriate technologies that would meet its particular
requirements, arriving at a short list of; 4 standard dewatering technologies, Advanced Anaerobic
Digestion, Drying and Incineration. They also investigated the potential outlets for the products from
these technologies.
In Phase 2, NI Water employed a group of specialists to provide a detailed quantification of the pros
and cons of these technologies, in particular their deliverability, operability, reliability, capex and opex.
The results of these investigations were then used to provide the foundation data for a bespoke model
of the NI Water sludge operations. This model was developed to provide visibility to NI Water of the
realities of sludge operations and was further developed to calculate the optimum solution to NI
Water’s sludge strategy.
