As a result of a planned plant expansion, GE Plastics was faced with a requirement to invest $15 million in doubling the capacity of the wastewater handling system of its Silicones Production Facilities in the Netherlands. Linnhoff March aimed to avoid this investment cost by reducing wastewater flow by 50%.

Water demands comprised process water (equivalent to city water), demineralized water and steam, the latter two being produced from process water. Effluent streams comprised wastewater, vapour (lost) and condensate.

Results

	An easy-win project was identified to re-use 10% of site water without changing the operating purities of any processes
	Relaxing inlet concentrations at the cooling tower and demineralisation plant within allowable limits saved an additional 12% of site water
	Removal of suspended solids from effluents of three specific compounding plants and of chloride from the resins plant effluent increased savings to 54%
	This reduction was achievable at a cost of only half that of increasing the capacity of the wastewater handling system

Benefits

	Re-use of effluent water from the compounding plants saves 20% of plant water
	The brine recovery project will save a further 34% of water and improve productivity
	150,000 tons of salt are now being re-used instead of being discharged into "open water" resulting in a significant environmental improvement
	Productivity gain from water re-use and product recovery worth $5 million per year at a cost of $12.5 million