To address the public’s concern, the Electrical and Mechanical Services Department (EMSD) has been regulating water quality of Freshwater Cooling Towers (FWCT) under the Public Health and Municipal Services Ordinance, Cap 132 (PHMSO) since 2011.
According to the scheme, cooling tower water sample require monitoring for below test parameters monthly and quarterly. The monthly test parameters include pH, conductivity, total hardness, total alkalinity, total dissolved solids, chloride, sulfate, nitrate, and nitrite. Quarterly tests include Legionella bacteria, total coliform bacteria, and heterotrophic bacteria. The samples are taken from various points in the FWCT system, including the tower basin, makeup water, and cooling water circulation system.
EMSD also requires that all FWCT systems have a water treatment program in place to prevent scaling, corrosion, and biological growth, which can negatively impact water quality. The program must include regular monitoring and testing of the water quality, as well as appropriate treatment methods such as filtration, chemical treatment, and disinfection. Additionally, all FWCT systems must have a management plan that outlines procedures for safe operation, maintenance, and cleaning.
In summary, the EMSD has implemented strict regulations to ensure the safety and quality of cooling tower water. With regular monitoring, testing, and treatment, FWCT systems can provide efficient and effective cooling without compromising public health. It is important for building owners and operators to comply with these regulations and always prioritize the safety of their occupants.
Test parameters for cooling tower water quality criteria:
| Monthly Sampling | Quarterly Sampling |
| Parameters : Criteria Water Temperature : Optimal temperature for the system design and current operating conditions Heterotrophic Colony count : < 100,000 cfu/mL Conductivity : < 1,500 μS/cm Total Dissolved Solids : < 1,000 ppm Suspend Solids : < 150 ppm Calcium Hardness : < 500 ppm pH : 7 – 10 | Parameters : Criteria Total Legionella count : < 10 cfu/mL Chloride (Cl) (mg/L) : < 200 mg/L Sulphate (SO4) (mg/L) : < 200 mg/L Total Iron (Fe) (mg/L) : < 1.0 mg/L Total Alkalinity : 80-500ppm |
