PROBLEM
In evaporative cooling tower systems, the make-up water can vary widely and is often “scaling” in nature. As the cycles used increase in these systems, the scaling problem is exaggerated and can lead to mineral scale and organic film formation throughout the system.
This scale buildup results in two confounding problems: First, the scale produces thermal barriers in the system, lowering the cooling tower’s overall performance. Over time, the scale can become so bad that portions of the system must be replaced. Secondly, the scale formation provides a breeding ground for bacterial growth, often harboring deadly Legionella which can lead to a host of health and safety issues. Also, organic films can significantly contribute to thermal conductivity loss.
SOLUTION
In conjunction with Puckorius and Associates, Inc. Blue Earth Labs has demonstrated that Clearitas has been effective at removing accumulated scale and preventing further scale buildup from cooling towers throughout the United States. Thus, Clearitas is a powerful cooling tower treatment for controlling bacterial growth.
Two systems were studied: an HVAC cooling tower in a Las Vegas casino was treated, as well as an evaporative condenser (that was scaled to the degree that it was decommissioned) at a food processing facility in Texas.
In both systems, Clearitas dosing was started at a level to aggressively descale the systems quickly (the dosing was adjusted for the first few days to maintain the oxidation-reduction potential (ORP) approximately 500mV above makeup water. Once significant descaling occurred, a maintenance dose was applied (approximately 100mV ORP above makeup water). In both cases, no intentional blow down was performed and all other chemicals were removed during the initial descaling period.
RESULTS
Overall, two very distinct systems were effectively descaled using a two-step Clearitas dosing. The initial high concentration dosing removed large amounts of scale very quickly. This was followed by a maintenance dose that continued to remove small amounts of scale and prevented further scale formation. Clearitas is effective at removing scale if the makeup water has some amount of organic material present, even at trace levels, including bacteria from cooling towers.