-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueAdvancing the Advanced Materials Discussion
Moore’s Law is no more, and the advanced material solutions to grapple with this reality are surprising, stunning, and perhaps a bit daunting. Buckle up for a dive into advanced materials and a glimpse into the next chapters of electronics manufacturing.
Inventing the Future With SEL
Two years after launching its state-of-the-art PCB facility, SEL shares lessons in vision, execution, and innovation, plus insights from industry icons and technology leaders shaping the future of PCB fabrication.
Sales: From Pitch to PO
From the first cold call to finally receiving that first purchase order, the July PCB007 Magazine breaks down some critical parts of the sales stack. To up your sales game, read on!
- Articles
- Columns
- Links
- Media kit
||| MENU - pcb007 Magazine
Pollution Prevention Techniques: Rinse Water Reduction
August 30, 2019 | Peter Moleux with contributions from Happy HoldenEstimated reading time: 3 minutes

The first step in any pollution prevention strategy is to minimize chemical wastes and their rinse waters. There are five general categories of common techniques for pollution prevention in a PCB fabrication facility: (1) new processes to replace sources of pollution; (2) extend the bath’s life; (3) rinse water reduction; (4) dragout reduction; and (5) ventilation reduction.
While this list is not all-inclusive, it provides an overview of the types of technologies used around the world that are important to consider. In this article, we will examine rinse water reduction.
Rinse Water Reduction
Most of the waste generated in the manufacturing of PCBs is from cleaning, plating, stripping, and etching. This section describes some of the techniques available for reducing the volume of rinse water used.
While we stress the need to reduce individual rinse water flow rates when a conventional wastewater precipitation system is anticipated, there may be at least one possible exception. If in excess of 95% of all chemicals are recovered, the chemicals do not enter the rinse water collection system, and a central membrane filtration or deionization system is used to produce a zero-effluent system; then, the need to reduce rinse water flow is reduced. However, one must also consider the capital and operating costs for the central system.
One author wrote the following concerning rinse flow rates in the case of a zero-effluent system [1].
“It should also be noted that in a well-engineered zero liquid discharge environment, water conservation is unnecessary. Instead, the focus is total dissolved solids (TDS) budgeting throughout the plant, along with an analysis of specific critical contaminants. Water supply is only limited by the size of the pumps. For instance, to maximize absorption in the fume scrubber, 10 gallons/minute of DI water can be fed continuously into and out of the scrubber system reservoir… With a closed-loop system, there is no sacrificing of rinse quality to save water. Lift stations integrated with conductivity sensors can automatically identify an out-of-control waste stream as it happens, allowing for quick corrections by maintenance. Also, fresh rinse-water conductivity is always DI quality.”
Particulate Filtration on Deburr and Panel-scrubbing Operations
Deburrers are used to remove stubs of copper formed after the drilling of holes in double-sided and multilayer panels before they enter the copper deposition process. Scrubbers are used to remove oxides from printed circuit laminates, clean the surface prior to a surface coating to provide better adhesion and remove residuals after etching or stripping. In deburring and board scrubbing, particulate materials are added to the water and are removed by various methods based on size and the weight of the copper particle such that the wash water becomes suitable for up to 100% recycling. The types of filtration available for this operation are cloth, sand, centrifugation, and gravity settling with filtration.
Etcher and Conveyorized Equipment Design Modifications
Etching machines can be the single largest source of copper waste in the discharge from a PCB facility. The amount of copper discharged, and the rinse flow rate from that machine, is a function of the machine design.
An older etching machine will contain a single-stage etchant replenishing module positioned between the etching chamber and its continuously flowing single or multiple stage water rinse chamber. Fresh etchant is fed to the replenishing module to wash the panels, and that etchant (now containing copper washed from the freshly etched panels) then flows (in a direction opposite to the direction of the panel movement) into the etching chamber. The continuous water rinse can contain from 100 to 500 milligrams per liter (mg/l or ppm) of copper, depending on the configuration of the rinse module. Companies that use this type of equipment, with a single-station rinse module, normally have floor space restrictions in their production area. The etcher design affects the rate of etchant solution dragout as does the volume of panels being processed and the quality of the etchant solution control.
By way of comparison, adding a second stage replenisher station will reduce the range of copper dragout in the following rinse from 50 mg/l to 300 mg/l. We have observed more than one etching machine–using a four-stage replenisher module and a combination of water recirculating with a single-stage rinse module–produce a rinse effluent containing from less than 1.0 mg/l up to 2.0 mg/l of copper. That is the option that we recommend to clients when etchant recycle, and copper recovery are not practical or economical.
To read the full article, which appeared in the August 2019 issue of PCB007 Magazine, click here.
Testimonial
"Advertising in PCB007 Magazine has been a great way to showcase our bare board testers to the right audience. The I-Connect007 team makes the process smooth and professional. We’re proud to be featured in such a trusted publication."
Klaus Koziol - atgSuggested Items
Electrodeposited Copper Foils Market to Grow by $11.7 Billion Over 2025-2032
09/18/2025 | Globe NewswireThe global electrodeposited copper foils market is poised for dynamic growth, driven by the rising adoption in advanced electronics and renewable energy storage solutions.
MacDermid Alpha Showcases Advanced Interconnect Solutions at PCIM Asia 2025
09/18/2025 | MacDermid Alpha Electronics SolutionsMacDermid Alpha Electronic Solutions, a global leader in materials for power electronics and semiconductor assembly, will showcase its latest interconnect innovations in electronic interconnect materials at PCIM Asia 2025, held from September 24 to 26 at the Shanghai New International Expo Centre, Booth N5-E30
Trouble in Your Tank: Implementing Direct Metallization in Advanced Substrate Packaging
09/15/2025 | Michael Carano -- Column: Trouble in Your TankDirect metallization systems based on conductive graphite are gaining popularity throughout the world. The environmental and productivity gains achievable with this process are outstanding. Direct metallization reduces the costs of compliance, waste treatment, and legal issues related to chemical exposure. A graphite-based direct plate system has been devised to address these needs.
Closing the Loop on PCB Etching Waste
09/09/2025 | Shawn Stone, IECAs the PCB industry continues its push toward greener, more cost-efficient operations, Sigma Engineering’s Mecer System offers a comprehensive solution to two of the industry’s most persistent pain points: etchant consumption and rinse water waste. Designed as a modular, fully automated platform, the Mecer System regenerates spent copper etchants—both alkaline and acidic—and simultaneously recycles rinse water, transforming a traditionally linear chemical process into a closed-loop system.
Driving Innovation: Depth Routing Processes—Achieving Unparalleled Precision in Complex PCBs
09/08/2025 | Kurt Palmer -- Column: Driving InnovationIn PCB manufacturing, the demand for increasingly complex and miniaturized designs continually pushes the boundaries of traditional fabrication methods, including depth routing. Success in these applications demands not only on robust machinery but also sophisticated control functions. PCB manufacturers rely on advanced machine features and process methodologies to meet their precise depth routing goals. Here, I’ll explore some crucial functions that empower manufacturers to master complex depth routing challenges.