In-House Plating: Rinse Water Treatment System Galvanizes Savings for Piping Manufacturer

Plating of metal piping is integral to producing components that withstand the rigorous processes of oil and gas extraction. Some manufacturers rely on an outside company to perform the plating, which can be time-consuming and expensive. Tube-Mac Piping Technologies (Hamilton, Ontario) overcame these challenges by adding a rinse water treatment system that enabled the manufacturer to move the plating process in-house.

The investment has paid off in spades. Turnaround time to produce and deliver finished piping components fell from two weeks to two days, and the manufacturer eliminated related shipping costs.

“The system enhances the experience our customers have with our products,” says Vice President of Operations Mike Hayes.

Eliminating Outsourcing Challenges

Tube-Mac makes non-welded piping and tube systems for applications where traditional welded piping isn’t suitable. The company’s non-welded piping is used in industries that have high quality requirements and for applications that demand leak-free performance. Customer in the marine, offshore, steel, automotive, aluminum, mining, and land-based oil industries rely on the company’s products for clean, reliable material transfer.

Providing them with a quick start-up is a key aspect of Tube-Mac’s value proposition, but part of the manufacturing process was creating delays. Just before shipping piping components or putting them into inventory, Tube-Mac had been outsourcing the zinc plating process. The logistics of sending the piping components to the plating company was cumbersome and expensive. Also, the finished products didn’t meet quality expectations; one month after plating, the components were developing white rust.

Taking a New Approach

To eliminate these headaches, Tube-Mac began an initiative to bring the process in-house in 2015. Completed over two years, the company’s new zinc/nickel plating line needed to complete plating quickly and cost-effectively, help meet product quality standards, and include a rinse water system that would meet the regulatory compliance requirements of the company’s publicly owned treatment works (POTW).

Tube-Mac partnered with PRAB Inc. (Kalamazoo, MI) to design and install a rinse water system that processes over 60,000 gallons per day and returns 70% of the treated water to the plating line for reuse. The system reduces Tube-Mac’s wastewater treatment costs through a fully automated multistep process.

Step 1: Metal Precipitation

Waste streams from the acid zinc/nickel plating line are collected in a sump (pH 3.5 to 4.0). The wastewater is transferred to a Stage 1 reaction tank, where pH is automatically adjusted to 9.0 to 9.4 to precipitate metals.

The tank overflows to a Stage 2 reaction tank, where a longer retention time can be used if needed. The pH is again monitored and maintained at 9.0 to 9.4 for metal precipitation. If required, coagulant can be added to help solids settle.

Step 2: Ultrafiltration

The treated Stage 2 fluid overflows to an ultrafiltration (UF) processing tank. Here the solids are concentrated. The UF system uses crossflow filtration to pump the slurry through UF membranes at high velocity. Up to 66,000 gallons per day is filtered.

The concentrate is returned to the UF tank for continual recirculation through the membranes. The clean effluent (permeate) passes through the membrane and is sent to the reverse osmosis (RO) feed tank.

Step 3: Reverse Osmosis

In the RO feed tank, the fluid goes to an activated carbon filter (ACF) to remove chlorine and other oxidizing compounds that can damage the RO membranes. The ACF is programmed to automatically back-flush during an “off” shift to remove contaminants. Fluid then goes to the RO system for further processing to remove minerals, salts, and total dissolved solids to allow for water reuse.

Step 4: Recycling and Discharge

The RO permeate is collected in a holding tank and reused in the rinse tanks on the plating line. The concentrate from the RO meets POTW discharge regulations and is discharged directly to the local sewer.

The Benefits of In-House Plating

In addition to improving customer service, the water-reclamation system benefits Tube-Mac in other ways.

It decreases the volume of sludge generated, keeps chemical costs low, and eliminates the need for clarifiers or lamella separators. Reclaiming and returning much of the wastewater to the plating line decreases water costs. The concentrate the system creates can be sent directly to the sewer, which lowers haul-away costs. Finally, the automated system lowers labor costs by reducing the need for operators to perform constant monitoring and manual cleaning.

“We set very high expectations and weren’t disappointed in the outcome,” says  CEO Gary Mackay.

PRAB Inc., 5801 E. N Ave., Kalamazoo, MI 49048, 269-382-8200, fax: 269-382-7770, www.prab.com.

Tube-Mac Piping Technologies, 853 Arvin Ave., Stoney Creek, ON L8E 5N8, Canada, 877-643-8823, [email protected], www.tube-mac.com.