The isolation, compound, and application of scale inhibition biological agents for treating recirculating cooling water system

The operation of circulating cooling water systems (CCWS) can lead to inorganic scale deposition, causing technical issues such as reduced heat transfer efficiency and pipe obstruction. In industry, chemicals are commonly used as scale inhibitors; however, many of these, such as phosphorus and nitrogen-containing compounds, can contribute to eutrophication. Growing environmental concerns and discharge regulations have shifted focus towards scale inhibitors that are biodegradable, non-toxic, and cost-effective. This study aimed to identify strains with scale inhibition capabilities to create a microbial agent for potential use for treating CCWS. Compound microorganism including three strains with scale inhibition activity was developed through isolation, screening and combination test. The 10 L and 100 L circulating water dynamic reaction device was used to optimize the best strain combination and formulation for CCWS treatment. The developed agent was applied in an actual CCWS at a power plant with a holding water volume of 2800 m 3 , and exhibited a more efficient and stable scale inhibition effect compared to chemical agents during practical application. This research contributes valuable insights for the adoption of biological treatment technologies in circulating cooling water systems. • Compound microorganism including three strains with scale inhibition activity was developed through isolation, screening and combination test. • An optimal additive amount of 0.02% was settle down through 100 L circulating water dynamic reaction device, which showed better scale inhibition efficacy and water purification ability. • The microbial agent was applied in an actual CCWS at a power plant with a holding water volume of 2800 m 3 , which exhibited a more efficiency and stable scale inhibition effect compared to chemical agents. • The developed compound microorganism showed potential for a ‘green’ ‘comprehensive’ circulating water treatment agent, with its water purification capacity, scale inhibition and corrosion resistance ability.