Thursday, July 23, 2009

Fixed film systems are really just boxes full of something...

The question is: What is the "something"? You probably have a pretty good idea of what is available to fill the boxes; sand, gravel, textiles, peat, foam, sponges, plastic sheets, plastic beads and, of course, MetaRocks. Selecting the best treatment media can be confusing; too often, the manufacturer with the best marketing and sales pitch is disproportionately represented in the decentralized market, regardless of the quality of their treatment media.

As an aside, a boneheaded marketing guy once told me that my strategy for marketing my products was all wrong. You see , we dedicate quite a bit of effort and money to improving our products and developing better ways to accomplish our treatment goals. This "head-up-his -a*#, hand-in-my-wallet" marketing clown told me to stop trying to build a better mousetrap, and, instead, build a better brand. In other words, waste more money with him to develop a plan to dupe people into buying products. I could produce an inferior product as long as it had a really slick marketing plan. In fact, this particular marketing firm attempted to convince me that an ideal marketing campaign would include fear-mongering advertisements warning new parents that, without my advanced treatment system, they would be subjecting their children to heightened risk of "blue baby syndrome". That was pretty much the last straw for me. I fired that clown and kept improving the effectiveness, efficiency, reliability and value of our products. From the looks of things, however, it appears that many of my competitors embrace similar advice, and have profited not through the merits of their systems, but through their impressive marketing force and widespread distribution networks.
Now back to our regularly scheduled program...

So, what makes an effective treatment media?

Most people will say that surface area and porosity are the most important characteristics of packed bed reactor/biofilter media used in onsite systems. Using this logic, one might decide that a media offering a surface area of 45 m^2/gram and a porosity of 55% would provide superior wastewater treatment compared to media with 0.0005 m^2/gram and a porosity 40%. However this comparison is between Kaolinite clay and coarse sand. Clays have extremely high specific surface areas but are not at all suitable for use as a wastewater treatment medium. ( A cubic ft of Montmorillonite for example, has over 8000 Acres of surface area) Clearly, then, there are considerations other than maximizing the specific surface area of the media. Furthermore, the high porosity of clays and other types of media, when considered alone, really mean nothing. If the porosity is "dead-end" porosity or closed porosity, or if the pores are small enough to be bridged by microbial growth, then, as the media is put to use, there is a corresponding decrease in porosity over time. If, for instance, water can seal off pore spaces, then that porosity really is not available for treatment purposes. Enter the slick marketing clowns who will try to convince you that a treatment media is better simply because it boasts a lot of surface area.

Think of a kitchen sponge. It has internal porosity, and this porosity is effective porosity because the pores connect to one another. The sponge probably has a pretty high specific surface area, as well. Now, imagine the sponge being saturated. Even after gravity drainage, water is still being held in some of the pores. The water that is held creates a barrier to the transfer of air in and out of the pore spaces. Aerobic bacteria will be starved for O2 and die off. Is this what you want to happen in an aerobic bioreactor? NO!

Now think of all the different types of treatment media and evaluate whether or not the phenomenon I described can occur in each one. If it can, grab your rubber gloves, bleach, Hefty Steel Sacks, pressure washers and maybe even a Haz-Mat suit, because you will be washing, "fluffing", or replacing that media sooner than you think.

Next, I want to discuss how MetaRocks overcomes the limitations so apparent in other packing media.

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