Effect of turbidity on water disinfection by chlorination with the emphasis on humic acids and chalk

) was identified as a critical threshold, which when exceeded was found to have a negative impact on chlorine disinfection. Chalk, on the other hand, had no measurable impact up to 5 NTU. The observation applied to both bacterial species with identical conclusions from the two diagnostic methods. Results corroborate that different turbidity causing substances affect chlorination efficiency to very different extents with chlorine demand by organic material probably being the most important determinant. In the case of turbidities >1 NTU, turbidity measurement benefits from the consideration of the organic content as mere NTU values do not allow predicting an impact on chlorination efficiency.