Thursday, June 26, 2008

Water Neutralization Saves $23,000 Annually

Res-Kem has published another white paper on water treatment. This next one is entitled "Bucking the Industry Trend… Simple Change to Water System Saves New Jersey Manufacturer $23,000 Annually"by Kevin Preising.

This paper details how the addition of an acid water neutralizer (5.5-6 pH) as a pre-treatment step to the Reverse Osmosis system saved over $23,000/year in downstream operation expenses at a New Jersey manufacturing plant. The acid water neutralizer, with an investment of less than $7,000 and operational and labor costs of only $700/year, has a Return on Investment of less than three months. While not a solution for all systems with reverse osmosis and high acidity, discussing neutralization with a qualified vendor can save Electrodeionization and/or Service DI operational expenses.

What is really interesting about this paper is it shows how a simple acid water neutralizer, properly applied, can save a considerable amount of money on operating expenses.

Having been in the water treatment industry for two decades, I have seen the trend in the water treatment industry towards more and more complex water treatment technologies and discounting past knowledge as old-fashioned. Often lost is a true understanding of water chemistry by some current "industry experts" and the simple, economic solutions to water treatment problems.

Please take a look and tell us what you think!

Tuesday, June 03, 2008

Activated Carbon: Mesh Size

We are often questioned about the differences between 1240 (12 by 40) mesh activated carbon and 830 (8 by 30) mesh activated carbon. The 1240 mesh activated carbon is smaller than the 830 activated carbon.

The screens or the mesh sizes are different. The 12 mesh screen has 12 openings per square inch 12 across and 12 down. The 40 mesh screen has 40 openings per square inch, 40 across and 40 down. Obviously the "holes" of the 12 mesh screen are larger than the "holes" of the 40 mesh screen. It follows that the holes on an 8 mesh screen are larger than 12 and 30 mesh holes are larger than 40 mesh holes.

Activated Carbon Particle Size Table Courtesy of Calgon Carbon Corporation

If you would like a laminated card with this guide, contact Res-Kem.

As part of the manufacturing process the activated carbon companies pass the carbon through various screens to meet the specification.
Particle Screening System Courtesy of Calgon Carbon Corporation

So if you look at 1240 mesh activated carbon, it shouldn't have particles larger than 12 mesh or smaller than 40 mesh. The 830 mesh activated carbon shouldn't have particles larger than 8 mesh or smaller than 30 mesh.

What difference does this make to the user of the activated carbon? The most commonly used activated carbons for residential POE (point of entry) systems, commercial and industrial systems are 830 and 1240 mesh. We use 1240 mesh activated carbon because it has greater surface area and provides excellent chlorine and organics removal. Because the activated carbon filter acts as a mechanical filter in addition to removing chlorine and adsorbing organics, it will accumulate particles of dirt or crud at the top of the bed. An activated carbon filter is backwashed on a regular basis to remove this and prevent pressure loss across the bed.

In instances where the water contains more turbidity or crud, an 830 mesh activated carbon may be used. Having larger particle size than the 1240 activated carbon, the filter containing 830 mesh activated carbon won't need to be backwashed as often. However, as the particle size increases from a 1240 mesh activated carbon to an 830 mesh carbon, thereby decreasing the backwash flow rate, adsorption capacity will generally decrease.

When we specify an activated carbon it's important to know the water source. If it's city water or well water from a potable source, we can assume there is little if any turbidity and use of a 1240 mesh activated carbon will work well. If an industrial plant is taking water directly from a river or lake there may be disruptions to the clarification system that may cause excess crud or turbidity. In these cases we see the use of 830 mesh activated carbon.

Here is a full glossary of activated carbon definitions.