Investigating Process Water Recovery Within the Irish Dairy Industry

Abolition of EU milk quotas in April 2015 has provided a platform for milk production to grow significantly within the EU. This growth has been dramatic and instantaneous with a 33% increase in milk production recorded in 2016. Typically Irish dairy processors obtain this water from ground supply, river, lake or treated public supplies, however as milk production increases the hydraulic demand also increases therefore long term sustainability issues surrounding water supply required make it imperative that an intelligent manufacturing solution be found to this problem. This paper outlines experimental work using filtration based recovery technologies for material which is currently sent directly to processors' wastewater treatment plant. A fundamental requirement to facilitate potential reuse is that the filtered material meets EPA and EU drinking water standards and guidelines. This paper has established, through design of experiments, the optimal running parameters for Ultrafiltration (UF), Nanofiltration (NF) and Reverse Osmosis (RO) membranes when filtering samples of between 0 and 0.5% fat. For NF filters a speed of 35Hz and pressure of 135 PSI is optimal, for UF Filters a Speed of 35 Hz and a pressure of 400 PSI is recommended and for RO membrane a speed of 35 Hz and a PSI of 475 operates best. This paper further outlines the quality levels required by recovered filtered water to match current fresh water used on site. Only by achieving this level of quality, will filtration offer the opportunity to reduce fresh water requirements within the industry (estimated by at least 20%) which would also reduce the hydraulic load currently going to wastewater treatment plants, a limiting factor to expansion of the industry. (C) 2018 The Authors. Published by Elsevier B.V.