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 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 Siemens Water Technologies, formerly USFilter, 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.
Siemens 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, Siemens 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 Siemens.
Results
The following results were realized by the customer.
- Reduced wastewater by 22 million gallons annually
- Eliminated $300,000 emergency mobile demineralizer expense
- Assures predictable boiler feedwater costs
- Advances zero discharge goal by mobile softening and reuse of 2.2 million gallons per month of RO concentrate
- Eliminates hazardous chemical storage providing a safer workplace and environment
- Redirects plant capital and labor to core business
- No unexpected costs from operational upsets
- No unscheduled downtime due to purified water shortages