What can a jar test determine in water treatment?

A jar test is a laboratory procedure used to determine the appropriate coagulation and flocculation parameters for water treatment processes. By simulating the conditions of a full-scale treatment system on a smaller scale, the jar test allows operators to assess how different coagulants will behave in terms of their ability to remove particulates and impurities from water.

The most economical coagulation doses can be determined through this test since it helps identify the minimum amount of coagulant needed to achieve the desired level of turbidity reduction and particulate removal. This enables water treatment facilities to optimize their chemical usage, ensuring effective treatment while minimizing costs associated with coagulation agents.

While the other options pertain to important aspects of water treatment, they are not directly assessed through a jar test. For instance, the optimal filtration method would require additional testing related to the specific filter media and design, the presence of heavy metals needs specific analytical techniques such as spectrophotometry or chromatography, and the effectiveness of disinfection typically involves different methods like chlorination tests or coliform testing. Thus, the jar test's primary purpose aligns closely with determining the most economical coagulation doses.