Turnkey Solution to Meet Zero Liquid Discharge Goals

Challenge

A Gulf Coast chemical plant was faced with an unreliable demineralizer system to meet a proposed expansion of boiler feedwater requirements. In addition, the plant had a wastewater goal of zero liquid discharge.

High total dissolved solids (TDS) in a proposed new well-water source threatened to increase demineralizer regeneration frequency, greatly increasing acid and caustic usage. Increasing regenerations also meant more wastewater to treat, a condition that ran counter to a zero discharge system.

Solution

The chemical plant selected an outsourcing alternative and opted to shutdown its old demineralizer. A consulting engineering team from Evoqua Water Technologies designed and installed a system to expand capacity and reduce wastewater discharge. The turnkey solution consisted of an expandable 300-gpm reverse osmosis (RO) system with mobile cation softening to pretreat the RO.

Evoqua drilled a 1,200-foot well, poured the concrete pad, constructed a building and installed the system as part of its build/own/operate service. Under this program, Evoqua owns and operates the system to supply water for a fixed price and at an agreed upon quantity and quality of water for the length of the contract.

All pretreatment chemicals were eliminated due to the use of mobile softening and off-site regeneration. To conserve plant water and minimize waste, the RO concentrate stream is used for cooling tower makeup. ​A remote monitoring system supplements the regular maintenance and operational service from Evoqua.

Results

• Reduced wastewater by 22 million gallons annually
• Eliminated $300,000 emergency mobile demineralizer expense
• Ensured predictable boiler feedwater costs
• Advanced zero discharge goal by mobile softening and reuse of 2.2 million gallons per month of RO concentrate
• Eliminated hazardous chemical storage providing a safer workplace and environment
• Redirected plant capital and labor to core business
• No unexpected costs from operational upsets
• No unscheduled downtime due to purified water shortages