If a coliform count fails to meet standards and the chlorine supply is not the problem, what could be an issue?

The correct answer highlights a critical aspect of disinfection processes in wastewater treatment. Short circuiting occurs when water moves through a treatment system too quickly, preventing adequate contact time with the disinfectant, in this case, chlorine. Effective disinfection relies on a sufficient duration for the disinfectant to interact with pathogens, such as coliform bacteria, to reduce their levels in the water to meet safety standards.

When there is short circuiting, the water does not get the necessary dwell time in the chlorination contact tank to achieve the desired reduction in coliform counts. This might occur due to improper design, turbulence, or sediment build-up in the treatment system, leading to inadequate mixing and resulting in areas of low disinfection.

Understanding this process is essential, as ensuring proper contact time can directly influence the effectiveness of chlorine disinfection. The other options, while they present valid concerns in disinfection processes, do not address this specific mechanism of failure in the context of insufficient disinfection leading to high coliform counts.