Water Treatment Questions

Chiller Inspection

2012-02-11T01:59:00.001-08:00

When is the best time of year for selling cooling tower water treatment? It is during the winter months. During the cooler season many clients will begin to do their preventative maintenance on Chillers, Cooling Towers, and Heat Exchangers. It is during this maintenance period that the effects of water treatment will become apparent. When a chiller is opened up for an inspection you want to be there to give your professional opinion. Having a boroscope, digital camera, and a flashlight will assit you in making a quality inspection.

Dirty Tower Sump

2011-01-09T19:22:00.000-08:00

This 1,000 ton tower was drained at the end of the cooling season. There was a considerable amount of mud and debris left behind. While in operation this mud/debris created an environment favorable for microbiological growth and accelerated under deposit corrosion. Biocide feed rates had to be increased (raising treatment cost) to keep micro biological dip slide counts at an acceptable number.

Cooling towers need to be cleaned regularly to achieve lower operating costs, maintain efficiency, and to lengthen equipment life.

Broken Cooling Tower Fan Blades

2010-09-17T19:10:00.000-07:00

When a cooling tower fan blade breaks it can create significant damage and/or injury. When one blade breaks it puts the fan out of balance. The combination of high speed and lack of balance can cause other blades to break, the shaft to bend, and/or gear box damage. The broken blades in the picture came out of a 500 ton tower installed at grade level. Both blades broke and shot out through the side of the fan shroud. Fortunately, there were no personnel in the area at the time of the failure.

Griswold SBC Non Chemical Water Treatment Device

2010-06-18T09:52:00.000-07:00

Here is a picture of an installed Griswold SBC Non Chemical Device (NCD) for water treatment. It is claimed to prevent scale and eliminate biofilm in cooling towers and closed loops. Traditional water treatment chemistry is still being utilized to treat the system. The system volume is 65,000 gallons with a constant 42 gpm make up rate.

The unit claims to treat the water through "electronic resonance". The advertising brochure claims that the treatment chamber "uses less energy that a standard 100 W light bulb". Who in the scientific community can explain how there is enough energy to perform the tasks this unit claims it can do? If you choose to defend the unit please list your credentials.

Wasted Resources

2010-04-17T21:33:00.000-07:00

During a recent central plant survey I came across these boiler blowdown controllers. Both were controlling on line boilers with similar run time, load, and make up water characteristics. The controller on the right is in alarm due to low conductivity. Unfortunately, the plant operator hadn't noticed the alarm. No corrective action was taken. Running the boiler in this condition is costly. It wastes water, chemical, and electricity. The water treatment cost associated with running a poorly controlled boiler can easily be double the cost of running a similar program with good controls. If you find that your water, chemical, and electrical costs have suddenly increased it may be time to revisit the control parameters of your water treatment program.

Chemical Induced Corrosion

2010-01-29T23:35:00.000-08:00

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

2009-12-21T19:54:00.000-08:00

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

2009-12-08T16:38:00.000-08:00

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

2009-12-03T11:09:00.000-08:00

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

2009-11-23T23:00:00.000-08:00

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...

2009-10-25T00:42:00.000-07:00

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

2009-10-22T13:05:00.000-07:00

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?

Training

2009-10-21T23:48:00.000-07:00

What is the best source for learning about the best practices for cooling tower and boiler water treatment?