Why Test Ammonia levels can reach several mg/L in groundwater systems, especially those located in agricultural areas. The ammonia levels can change seasonally and need to be monitored. The ammonia will react with chlorine to form chloramines creating an uncontrolled chloraminated water. The chloramines can cause taste and odor issues and possible nitrification problems in the distribution system. The standard salicylate method for ammonia can be used to determine ammonia levels in the unchlorinated water.
Why Test Ammonia in groundwater can be destroyed by taking the water through breakpoint chlorination. Free chlorine is added to the water to convert all the ammonia into chloramines. The further addition of free chlorine converts or "breaks" the chloramines down into nitrogen gas and other volatiles species leaving only free chlorine as the residual disinfectant. DPD Free Chlorine can be used to determine when the desired free chlorine residual is reached. Free chlorine also causes iron and manganese to form insoluble precipitates, which can be removed by filtration. Use the Indophenol Method for Free Chlorine to measure free chlorine when iron or manganese is present.
Why Test Iron is present in most ground waters. The level of natural iron in a groundwater remains nearly constant and is usually present as ferrous iron (soluble iron). When the ferrous iron reaches the surface it is oxidized by air to the ferric iron form giving the characteristic red water color and precipitating to give the red rust-colored stains on equipment and plumbing fixtures. Iron can also occur as the result of corrosion of well pipes or as the result of iron-reducing bacteria. Any sudden change in the iron concentration may indicate pipe or equipment corrosion, the presence of iron reducing bacteria or changes to the aquifer itself from seismic events, well infiltration or new drilling or fracturing activities in close proximity of the groundwater source. Use FerroVer Iron method for the routine checking for the presence of iron. The TPTZ method may be used for low level iron testing.
Why Test Manganese is present in most ground waters especially when iron is present. At concentration levels above 0.05 mg/L, it causes black stains on plumbing fixtures, laundry and other items in contact with the water. Use the extremely sensitive PAN method to determine manganese levels.
Why Test The pH of groundwater varies widely throughout the various regions of the world. Monitor the pH of the groundwater to determine the pH adjustments that are required to give the optimum pH range for chlorine disinfection. While the pH of groundwater remains essentially constant, monitoring of the pH is also a surrogate method to quickly detect any intentional or unintentional events that have occurred to the groundwater source.
Why Test Toxic hydrogen sulfide is produced by the anaerobic decomposition of organic material and sulfate reducing bacteria. It is characterized by a very noticeable rotten-egg odor. It is mainly found in groundwater supplies. It contributes to the chlorine demand of a raw water source and is easily removed by aeration or by the addition of chlorine.
Why Test Chlorine demand is a measure of the amount of chlorine consumed by a source water after a fixed time at a fixed pH and temperature. Organic materials, ferrous iron, reduced manganese, sulfide and ammonia are examples of species that consume chlorine during the disinfection process. A high chlorine demand suggests that disinfection by-products may form if the demand is due to organics. Chloramines may be formed when ammonia is present and sulfides may be produced when sulfate reducing bacteria are present. The chlorine demand test can be modified to use the specific conditions of your source water or to investigate the demand from alternative groundwater sources.