Design Challenge
A chemical manufacturing company, located in the Gulf region of the southern U.S., needed additional process water to meet expanding production needs. The company owns and operates a clarification system treating river water for general plant use and had outsourced, under a temporary water treatment services solution with Evoqua, a mobile/temporary water treatment system to further polish the water to produce high-purity water for process and boiler feed use. As the water treatment system and service provider, Evoqua successfully operated the temporary system for a few years, providing the customer with hands-off, reliable operation. The system included media filtration, a softening process to remove excess hardness, a reverse osmosis (RO) process to remove the bulk of dissolved ions and final off-site regenerable ion exchange service equipment.
The customer’s production needs were expanding from 1,200 to 1,450 gal/min. However, the clarification system was undersized and could not produce adequate service water to meet the plant’s increasing needs. Additionally, the process and boiler feedwater system required upgrades to produce more water.
Economic Challenge
The cost and logistics to expand or replace the existing clarification system were daunting. The customer was under pressure to reduce capital expenditures while recognizing that they needed a long-term solution. Furthermore, any expansion would require civil work to build a suitable concrete pad and pavilion structure to set and protect the upgraded system while the existing permanent and temporary equipment remained in operation.
Solution and Results
The bottleneck in the process was the limitation of the existing clarification system. If additional clarified water could not be economically produced, how could the polishing system produce more water?
Evoqua’s design philosophy is based on a holistic approach, considering customer needs and desires, space limitations and life-cycle costs. Evoqua engineered the new polishing system with wastewater recovery as a priority, allowing for treatment and reuse of a portion of the waste to supplement the feedwater flowrate. To accomplish this, Evoqua added a brine recovery reverse osmosis (BRRO) system to treat the waste stream of the primary RO system. By processing the primary RO waste through a BRRO, Evoqua was able to recover up to 65% of the waste stream, which represents ~61.5M gallons per year of wastewater reduction. This beneficial process resulted in reduced wastewater treatment costs prior to disposal. A further benefit of the process was that the product water from the BRRO was of higher quality than the clarified water stream. By reintroducing this water to the front of the system, the feedwater to the primary RO improved, improving overall operation and reducing final ion exchange (IX) requirements. Design value benefits to the customer is defined below.
Operational Benefits:
- Allows staff to focus on core competencies.
- Quality and quantity guarantee over length of contract.
- Make-right protection.
- Partnering. Evoqua has the "skin in the game" to operate efficiently.
- Minimized downtime.
The customer financial structure and policies presented additional challenges. While their production was expanding, they were under pressure to preserve capital. To meet these needs, Evoqua proposed a financial solution based upon the Build-Own-Operate (BOO) model. In a BOO, Evoqua designs, manufactures, installs, commissions and operates the upgraded polishing equipment for an extended term. All chemicals, equipment maintenance and consumables are included in a monthly fixed price. Chemicals are priced based on a variable billing, such that the customer chemical spend is dictated by produced volume and remains fixed on a volume basis (typically $ per 1,000 gallons produced). Economic benefits to the customer is defined below.
Financial Benefits:
- Capital conservation. No up-front capital expenditure.
- Desire an operating lease. This requires that assets be skid mounted and reusable.
- Long-term steady spend stream. Predictable. No surprises.
- Ability to exit contract at any point, subject to a cancellation charge to cover Evoqua's sunk cost.
Ability to purchase teh system at any point, based on fair-market value at time of buyout. - Design/build financial risks eliminated.
- Minimized downtime.
To meet all requirements, Evoqua performs periodic business reviews with the customer to review safety, system data, confirm long-term goals are “on-track”, schedule maintenance activities and maintain the business partnership.