Background

A former copper mine in the Salt Lake City is now in the process of cleaning groundwater affected by 140 years of mining operations. The main contamination issue with the groundwater is its high levels of total dissolved solids including sulfate levels above U.S. Environmental Protection Agency (EPA) requirements of 500 mg/L.

The remediation facility’s water treatment plant (WTP) uses reverse osmosis (RO) technology to bring sulfate levels down and ensure the water meets all EPA regulations for safe discharge. While the facility must meet all regulatory requirements and production goals, minimizing costs is also a key objective. To improve operating efficiency and reduce costs, staff sought maintenance reduction solutions that would extend RO membrane life and cleaning intervals while also minimizing downtime and the use of chemicals and labor for membrane cleaning.

The Role of Feed Channel Spacers in Spiral Wound Membranes

Figure 1. Example of Mesh feed spacer scaling

The WTP’s difficult feed water was causing rapid fouling and scaling, which required frequent cleaning by the operations and maintenance staff. Further, the plant experienced frequent upsets when profuse scaling would sharply reduce membrane permeability. At the time of this technology evaluation, the customer was cleaning their

Having learned about Aqua Membranes’ Printed Spacer Technology®, the customer suspected that the mesh feed spacers were a prime culprit of their scaling problem. They decided to evaluate a first-of-its-kind feed spacer innovation to determine if they could gain improvements in operational efficiency and membrane maintenance while achieving production and compliance mandates.

After searching for solutions to their problem, they selected Aqua Membranes’ Printed Spacer Technology® to replace their existing membranes, which used mesh spacers. The Aqua Membranes team performed modeling to determine that the best spacer pattern that would provide treatment levels to meet regulatory requirements was Aqua Membranes ECO (ECOBW505).

Advantages of Printed Spacer Technology®

Unlike traditional mesh spacers that haven’t changed in 60 years, Printed Spacer Technology® fundamentally solves mesh spacer problems by 3D printing spacers directly onto the membrane surface. This patented approach:

• Provides more efficient flow paths with optimal spacing
• Creates extremely low differential pressure and clear flow design
• Takes up less volume, providing more membrane surface area
• Delivers up to 30% energy savings and 20% more permeate production
• Maintains standard industry specifications for rapid retrofit

Results

The WTP has been using the new membranes for eight months with excellent outcomes, especially in the area of membrane fouling and scaling. A less frequent build-up of biological fouling and mineral scaling has resulted in much better cleaning efficiency and reduction of related costs.

The need to clean the Aqua Membranes ECO product first occurred on day 170, or about six months after installation. In the previous six months, the WTP had to clean the membranes six times, an average of once a month. This improvement represents an 83% reduction in the cleaning rate. Cost savings from this interval expansion are appearing in four areas. First, the customer saved money on cleaning chemicals, as they were able to cut back on their need for buying and storing those chemicals. Second, the need to take their system offline for cleaning has been reduced by 15 days per year, which translates into greater productivity. Third, membrane cleaning is a major contributor of membrane wear and tear, so by more than doubling the cleaning interval (from 1 to 6 months), membrane life is likewise expanded, reducing replacement costs.

In addition, with the new Aqua Membrane elements, the WTP is producing better water quality that consistently meets or exceeds EPA water quality standards.

The customer expects a significant return on investment using Aqua Membranes’ technology. When accounting only for the savings related to membrane cleaning, the facility expects an ROI of 16 months, a return that could be even shorter when factoring in the downtime avoided due to the decreased cleaning frequency. Cost savings over the lifetime of the elements are easily expected to amount to hundreds of thousands of dollars. By using Aqua Membranes’ Printed Spacer Technology®, the facility will reduce maintenance costs while optimizing operations and achieving environmental regulatory compliance.

Trustworthy Technology

During this project, Aqua Membranes earned its place as a trusted partner, with its Printed Spacer Technology® helping the customer exceed their goals to meet EPA regulations while also measurably cutting costs. Their confidence in the technology was cemented when they experienced a system upset on an older skid using mesh spacers. They were able to shift operations to the Aqua Membranes skid with Printed Spacer Technology® and maintain production.

Using Printed Spacer Technology®, the customer realized an optimized operation with lower maintenance costs and better water quality. With a 16-month ROI and a five-year membrane life industry average, the customer could save hundreds of thousands over the life of its system by using Printed Spacer Technology®.