Arbortech Corporation | Products for a Better Environment

P2: Then and Now

After 20 years, recycling proponents still face the same confused preconceptions of what Pollution Prevention is all about.
By Raymond J. Graffia Jr. President Arbortech Corporation
his article's intent is to share recycling expertise so the reader can consider equipment to recover and reuse aqueous cleaners. We would all love to save the planet, keep it green, minimize waste and satisfy every other buzz phrase that is or ever was popular reflection of the sentiment toward reuse of vital resources. What if there actually is a way to reclaim all that wastewater generated from your washing operations? Pie-in-the-sky dream or reality?

The premise here is the latter. To begin, let us examine the concept, starting with an explanation of the heart of the technology used for equipment such as Washer Washer (small scale) and WWPro (larger scale) - membranes.

Membranes have been around for years in die casting plant applications. The two most common uses within the die casting industry are ultra-purification of incoming water and pre-treatment prior to sewer discharge. Focusing on the end-of-pipe scheme, the membrane selected often has pores that would be categorized as relatively "tight" - in hope of removing as much as can be achieved without severely curtailing the speed of processing. Materials of construction differ from vendor to vendor, but, in a majority of cases, consist of a polymer "skin" surface atop a fiberglass substrate. For limited pH range and ambient temperature projects, such as either of the above would typically be, these components serve well. However, when dealing with highly alkaline cleaners or very low pH combination phosphatizer/degreasers, especially at the elevated temperatures often seen in washing operations, they simply do not hold up. Additionally, the benefits of "tightness" prior to sewer discharge will now actually be detrimental to reuse because some of the "good stuff" may be removed during the processing.

Membranes intended for use in recycling are not so "tight," and are typically made to thrive under conditions where others might fail. Arbortech's equipment utilizes titanium dioxide membranes with a 316L stainless steel substructure. Hence, this module and others so designed can tackle applications where pH is anywhere from 0-14, at temperatures to 200° F - what it often takes to recycle water-based cleaners. The mechanism for removal and concentration of the "yuck" is cross-flow (not dead-end as in traditional bag or cartridge filters), pressure-driven (generated by a circulation pump) and multiple pass, with the long-term effect being that oils and soils are retained on one side of the membrane, while the water plus materials in true solution with water (like the cleaning product) pass through to the other side. With an in-line system set-up, permeate (that which passes through the membrane) is normally returned directly to the wash bath while the reject is slowly concentrated in a small (compared to the wash bath) process tank for later disposal. As a result, the wash bath stays perpetually near to freshly-made-up condition and the contamination concentrates in the recycling system's process tank instead of the wash bath, therefore no ( or at least greatly reduced) dump/recharge-just continual reuse. In one unusually successful case, a company that formerly dumped and recharged its 5000+ gallon bath quarterly before implementing a recycling system, only did so once in the next seven years... when they moved the operation out of one building and into another. While this performance is quite extraordinary, prolonging of bath life from 4-to-6 times is very common. Beyond extended bath life, what other direct or indirect contributions to the bottom line might be expected from installation of a good recycling system?

There are many factors to consider when purchasing a new washer water recycler such as part cleanliness, improved rinsing, increased production, less labor, cost efficiency and environmental benefits.

Improved parts' cleanliness - If the condition of the wash bath is consistently high quality, the washing process will be enhanced and parts cleaned will always be at maximum purity. You know how well your bath cleans just after a dump/recharge; why not just keep it that way?

Improved rinsing - Typical washing operations result in transfer by carry-over of a small portion of the wash bath to the subsequent rinse stage. Where this carry-over is highly contaminated, the negative consequences at the rinse stage can be dramatic. After installing adequate recycling, including counterflowing measures, rinse stages that formerly overflowed at high rates have been reduced, and, in some cases, even turned into standing rinses.

Improved subsequent steps - How difficult is it to paint or plate a part that has not been properly cleaned? By maintaining was bath cleanliness, those issues often disappear.

Increased production - Is your wash process a production bottleneck? If so, forget about ever-shortening cycles of dump and recharge, because recycling can keep high quality cleaning virtually perpetually available. Think about your reject rate on parts... how much might it be reduced if they come out consistently clean?

Save Labor - Do you dump and recharge on straight time or overtime? Many companies do such work after hours or on weekends, making the labor costs even greater. How about the dollars spent addressing all the paperwork required for proper handling/disposal of the wastewater?

Save power - Whether you heat by gas or electricity, as your wash bath deteriorates, one common performance booster is to turn up the heat and that can be expensive.

Save hauling costs - When was the last time that your cost per gallon to haul this "stuff" away was reduced? The right product can reduce volumes to be hauled (obvious benefit) but also reduce the cost per gallon for the much more highly concentrated wastewater achievable through recycling (not so obvious benefit).

Save water - In portions of the world where good quality water is a scarce and a precious commodity, (southwestern USA, for one example) keeping a 5000-gallon bath in use instead of recharging it 3-to-4 times per year would be substantial conservation. Further, if recycling can enable a rinse overflow to be reduced, say from 3 gpm to 2 or 1 gpm, or even eliminated, what a savings in water that would be... incredible!

Save chemistry - Savings in chemicals ranging from 50 percent to 80 percent have been reported. How much is your annual budget for cleaning chemicals? Think that might be worth a phone call or two to companies with a recycling focus? Think your chemical vendor should reconsider that purchase of a new luxury sedan?

Some final words to the wise... Pick your potential recycling partner carefully. Writing about the benefits of reclamation and "sales pitching" a product to accomplish this objective are both relatively easy. (Otherwise, the editors of this publication would never have given me this forum.) The willingness and ability to prove the application at your specific site, with your incoming water quality, your operating personnel, your chemicals and your contaminants are much better standards against which to measure credible vendors.
For more information, please contact Arbortech Corp. at
(815) 385-0001 or go to www.arbortech.com