Chemical Induced Corrosion

The nipple in this condenser water return line is experiencing severe corrosion. The cause of this corrosion is chemical. Rather then feed chemical through an injection quill an attempt was made to feed directly into an existing valve. Feeding chemical in this manner can be very harsh on the surrounding metallurgy. Although this was a quick and cheap install the long term reliability of the system has been compromised.

Non Chemical Water Treatment Device

I recently had the opportunity to see the conversion of a cooling tower from standard chemical water treatment to a new "Non Chemical Water Treatment Device". In this instance the unit installed was called a Fluidtron. These pictures were taken at about 90 days into the non chemical water treatment program. While the algae build up is troubling it is a minor problem compared to the aggressive corrosion cells that developed. The customer ended up re-coating the tower basin with an epoxy and installed brominators to add Bromine to control the algae.

A quick search of vendors selling this product uncovered some marketing literature. One brochure stated that the unit "eliminates the need for chemical treatment" and listed the benefit of "extended life of equipment" because "reduced corrosion rates extend equipment life". Certainly one case study does not reveal enough data to draw a conclusion, however, in my opinion the results achieved here border on negligence.

I am not implying that all non chemical water treatment devices do not work but the end user should to do their homework before making an investment in a "new" system that is designed to protect the heart of a buildings HVAC system.

Cooling Tower Frozen Over

A unexpected cold snap hit recently and created some problems for this cooling tower. It was was not drained and froze over. It is not apparent whether or not there was any damage to the tower or the fill. For towers that are operated in climates that may experience freezing temperatures be sure that the sumps are drained or that the sump heaters are on and operating correctly when the temperature begins to drop.

Non Oxidizing Microbiocide

Non Oxidizing Microbiocides (NOM) have a specific mode of operation. Some attack structural, or functional components of protoplasm such as enzymes, proteins, lipids, metals, or minerals. Some NOM poison or interfere with the normal metabolic process. Still others inhibit the permeability of the cell membrane. All of these modes contribute to the death of the cell body.

Regardless of the the mode, all NOM have the same general effects upon the system.

1. In the presence of a toxic substance mircorbiological organisms increase their rate of metabolism. This is part of their nartural survival response. This means that underfeeding a biocide will actually stimulate the microbiological growth in the system.

2. The microbiological population in a cooling tower can be drastically altered through the use of only one NOM. Species and strains of microbiological organisms least affected by the biocide will some become the dominant strain in the system.

3. NOM kill, but they do not consume the organic molecules that previously supported the life of microbes. The debris of the dead cells provides a significant source of food for new growth. This tends to cause a response of higher growth and reproduction rates. This is one of the main reasons an oxidizer is often used in conjunction with NOM. Oxidizers physically destroy the organics eliminating the food source.

4. Microbiological organisms rapidly adapt to a changing environment. The organisms will develop resistant strains.

Consulting Cost

In the cooling tower/boiler water treatment industry much of the cost associated with a vendor is directly related to the consulting time a representative dedicates to your facility. A good rule of thumb is that for every $300 spent on chemical a representative should dedicate an hour of consulting time to your facility. For example, if you spend $30,000 annually with your water treatment vendor you should expect to see a consultant dedicating 100 hours to your facility over this same time frame.

In these economic times many companies have resorted to reducing the total number of field consultants to help keep profit margins stable (less salary=more money on the bottom line). This means that the consultants are now being stretched thin. In addition to taking care of their own client base they now have to expand into the customer base left behind when another consultant in their territory was let go. This man power stretch results in many customers getting less direct consulting time then they are paying for. The company pitch often given is that modern technology allows the consultants to get the same results with less "time on the ground". Dont be fooled. Be sure you getting what you have paid for...

This is a good example of tower fill that has been heavily scaled and damaged by an earlier attempt at cleaning with a pressure washer. Once the fill has become fouled to this degree the tower suffers from a loss in efficiency. A sound water treatment program and operator involvement are the best ways to avoid this problem from occuring.

Microbiological Control in Wet/Dry areas

Some cooling tower designs have areas that frequently get wet and dry, or areas that recieve very little flow. These areas often become a source of microbiological growth. Frequent mechanical cleaning of the basin helps minimize this effect. What else can be done by an operator to help keep this area clean?