Why Test Iron is tested to insure that flushing procedures are sufficient to reduce the iron concentration to acceptable levels. Iron testing is also conducted at sites within the distribution system to investigate red water complaints from customers.
Why Test Increased water turbidity levels within the distribution system can be a indicator of nitrification or other deteriorating water quality conditions. Turbidity is also measured during flushing operations to insure that the turbidity has decreased to acceptable levels before putting the line back into service.
Coliforms & Heterotrophic Plate Count (HPC)
Why Test Monitor for bacteria and HPCs to insure that sufficient microbial protection has been achieved and cross-connection errors have not occurred after replacing distribution system mains and service lines.
|Microbiology - Standard Plate Count
||Lab - Agar
||Pour Plate Accessories
|Microbiology - Membrane Filtration
||Lab - Agar
||Membrane Filtration Accessories
Why Test A slight sudden drop in pH is indicative that nitrification may be active in the distribution system water. A sudden rise or drop in pH may indicate a distribution system failure or security issue.
Why Test Check for total chlorine residuals to meet compliance requirements. The maximum level allowed is 4.0 mg/L. Most primacy agencies require a minimum of 0.2 mg/L free chlorine or 0.5 mg/L chloramine throughout the distribution systems. Monitoring is also done at storage tanks and reservoirs to study mixing efficiencies, water age and temperature gradient issues. A sudden loss of residual at any point within the distribution system can indicate nitrification issues, water infiltration, line breaks, extended water age or possible security violation issues.
Why Test Some primacy agencies require a free chlorine value for systems using free chlorine disinfection. Use the indophenol method for waters that have manganese and chloramine interference. This method eliminates over-estimating free chlorine levels due to monochloramine and manganese. The method also eliminates the use of arsenite for manganese interference compensation.
Why Test This method tracks monochloramine concentration. Compare the determined value to the monochloramine value at the POE into the distribution system. A drop in the monochloramine concentration indicates that the residual monochloramine has reacted with organic material in the system. This also would be an indication that the free ammonia level has likely increased and the total compliance residual as measured by DPD Total Chlorine has decreased.
Why Test Free ammonia levels will increase as monochloramine reacts with organics in the distribution system water. High free ammonia levels indicate nitrification issues. A sudden drop in free ammonia suggests that nitrification is in process and nitrite is being formed. The free ammonia value is useful in determining the amount of free chlorine to add to increase the monochloramine residual at a booster station. The free ammonia level can also be reduced or totally removed by adding free chlorine in a ratio of 5:1 as Cl2: N to help reduce nitrification episodes.
Why Test Manganese will give false positive chlorine values in the DPD chlorine methods causing an over-estimation of the actual disinfectant residual present.