A Reuse Pilot Study at Southern Water Services, United Kingdom

A Reuse Pilot Study Southern Water Services, UK Shubha Oza, Brown and Caldwell Jonathan Greenwell, Stantec Varsha Wylie, Southern Water Services Katherine Bell, Brown and Caldwell March 7, 2024 Agenda  Drivers & Technology selection  Catchment Study  Pilot Study  Results & Discussions Drivers  Population growth  Climate change  Drought analysis Technology selection Desalination – no support from customers and stakeholders Full advanced treatment [(micro filtration (MF)→reverse osmosis (RO)→UV-advanced oxidation process (UV-AOP)]. CCRO Operating Parameters Parameters Unit Flow Data Target RO Permeate Flow rate m3/h 2,5 m3/h Targeted RO recovery rate % 75 % from 2.11.2020 – 11.12.2020 85 % from 11.12.2020 – 04.06.2021 82 % since 04.06.2021 Filtrate flow from the UF, as RO feed m3/h ~ 4,0 m³/h (range adapted to the required Recovery rate) Multiple clean-in-place (CIP) cycles: within a short period, potentially accelerating membrane deterioration. Operation Challenges HCl dosing out of specification: may have facilitated rapid fouling of the membranes. Potential contaminants: Peel Common WTW operation (both organic and inorganic). Pilot design: Planned to operate over a fixed period (2 months) Operated longer lacking redundancy and control. Membrane Autopsy Avista performed autopsy one element from the concentrate end one element from the feed end Results Fiberglass Casing Brine seal Permeate Water Tube Anti-Telescope Devices Membrane Autopsy Scroll ends pale brown-coloured foulant material some grey plastic swarf/detritus on the feed end Feed Concentrate Membrane Autopsy Foulant analysis summary Parameter Feed end element Concentrate end element Moisture content 89% Not tested Organic content 87% Not tested Inorganic content 13% Not tested Aerobic bacteria Yes Yes Fungal activity No No Bio slime and gram-negative bacteria Yes Yes Summary Organics and Calcium phosphate patches of calcium phosphate Key considerations validation of the design assumptions based on operational data update water safety plan to provide statistical representation of seasonal variability in water quality adopting a risk-based approach to identify a set of surrogate determinants to allow meaningful treatment performance monitoring Shubhashini Oza, PhD Principal, Environmental Engineer Brown and Caldwell E| soza@brwncald.com T| 704.373.7144.