Dip-Slide Technique to Monitor the Water Quality of Cooling Tower in Air Conditioning System to the Building

Abstract

Current population in Thailand and the tropical countries spend most of the time doing activities (e.g., work, study and even rest) in buildings with air conditioning. There are two main tools including a) Operation of Air Handling Unit and b) Cooling Tower each of equipment which has their own system but relates to cold water with the temperature in range of 8-15 Celcius. Consequently, the disease from cold water can be disseminated into the air-condition system. The large air-conditioning system of the Cooling Tower contains a bacterium called "Legionella" or "Legionare" which causes respiratory disease. If it is serious disease patient may be fatal. This research aimed to study the utilization of dip-slides technique applied for water quality analysis in cooling water system. The centralized air-conditioning system with case study comparing with laboratory techniques to represent the simply practice in controlling and the laboratory method could be same result; the controlled value. The relation of cold water system and the creation of Pneumonia as part of building syndrome were studied in this research. It is one of the tools to benefit of the management for building management to meet the requirements of the government. The objectives could be divided into 3 points including 1) to study how the Legionella can be existed in the cooling water system, 2) to take the sample by “dip-slides” Techniques as the simple method to compare with laboratory technique, and 3) to provide more factors related to the controlled value for cooling tower for preventing the Legionella exist. The population to study the sample source in cold water from the centralized air conditioning system, which is the variable are the amount of microorganisms contained. There are two types of testing tools including dip slides and laboratory tests. A simple principle to describe the dip-slides technique is to collect water samples from the test source rinse the water pass through and close immediately cylinder. Dip slides are recommended to monitor common bacterial activity. The test consists of sterile media on plastic containers dipped in liquid to be passed through the liquid. Most dip slides consist of 1 - 2 agars attached to a plastic sheet that resembles jelly. Dip slides are packed in a vacuum tube. Bacteria that are present in the liquid will grow and form a biofilm. The chart for the bacterial count is used to identify the number of bacteria in the test site, ranging from 1,000 to 100,000 CFU per milliliter. If the value exceeds 100,000 CFU to 1,000,000*, it is considered dangerous to respiratory system and forced to close the area and treat the water quickly with face mask working condition. In the same water to test hypothesis Microbial testing by Dipslides technique and by laboratory method. ISO11732 practice practice: 1998 to compare results.Bacteria and water quality control for central air conditioners. Public buildings can be operated. At present, facility management can use the dip-slides technique to monitor initial water quality and manage buildings using a combination of engineering, science and management that can be used as a baseline assessment and test results.