Since 2004, when a Missouri Department of Natural Resources (DNR) review of Brookfield's drinking water tests found the City in violation of standards for the amount of acceptable chlorination/disinfection by-products (DBPs) in that water, substantial steps have been taken to bring the City into compliance.
Al Schneider, who has been the Brookfield Water Plant Chief Operator since October of 2005, explains, "In 2003 with the old [purification] system, we were barely meeting the state's standard for DBPs or not meeting it at all. Good TOC (total organic carbon) removal is an indication your [chlorination] by-product levels are being reduced."
Schneider adds, "Now, we're removing 60 to 70 percent of TOCs in the water before we begin disinfecting with chlorine."
TOCs represent the amount of carbon bound in an organic compound and since the 1970s, TOC levels have been measured in water treatment plants to determine drinking water quality during the purification process.
As TOCs come from naturally decaying organic matter (i.e., leaves, insects) and synthetic sources such as fertilizer runoff, one way to reduce them is by covering outdoor basins at water plants.
Basin covers allow less organic material to have the opportunity to interact with chlorine to form chlorination by-products (DBPs).
Schneider says the secondary basin at the Brookfield water plant is now equipped with a cover, and a cover will be installed on the primary basin once the rake drive in it is repaired.
A rake drive is a stirring mechanism that recirculates water and keeps sediment in the water from settling to the bottom of the basin.
"We have to have that rake drive working properly to avoid having a sludge build-up at the bottom of the tank," explains the Chief Plant Operator.
As there are organic compounds so minute that a cover won't bar them from making their way into the plant's raw water, two other methods have been employed to neutralize them before they have a chance to interact with chlorine.
Now at the front end of the water purification process, Schneider and his crew are adding sodium permanganate and carbon to the water.
Rather than using chlorine to oxidize or destroy the organic coverings on particles in raw water, sodium permanganate is being used, thereby reducing the possibility of DBPs forming.
Carbon is also now being added to raw water at the Brookfield Water Plant, and that carbon absorbs organic compounds before they have a chance to interact with chlorine and form the chlorination by-products (DBPs) trihalomethanes and haloacetic acids.
Schneider says, "In 2004 when we were found by DNR to be in violation of the chlorination by-product levels, we were only removing 25 to 35 percent of the TOCs. Now, and since the new system went on-line last year, we're removing 60 to 70 percent of those TOCs."
The question remains whether the new methods being used to remove or neutralize TOCs in the raw water are sufficiently reducing levels of the chlorination by-products (i.e., haloacetic acids and trihalomethanes).
The DNR's cutoff for acceptable levels of these chlorination by-products (DBPs) is 80 parts per billion for trihalomethanes and 60 parts per billion for haloacetic acids.
The quarterly readings at the plant for these two DBPs in March, the most recent readings available, were 17.1 parts per billion (ppb) for trihalomethanes and 11.5 parts per billion for haloacetic acids, which are well below EPA (Environmental Protection Agency) and DNR standards.
In 2007, when the new purification system was still being fine-tuned, the Brookfield Water Plant was still in violation of DNR/EPA standards for DBPs, but if the trend as indicated in the March readings continues for the remainder of the current year, the City of Brookfield will be in compliance with those standards.
Among the "kinks" that have had to be resolved since the new purification methods were instituted last year were the chemical feed system at the City Lake pumphouse.
"Those pumps and piping had to be re-engineered so the chemical feed system would work more efficiently," explains Schneider.
Other parts of the drinking water distribution system also contain compounds that will make readings for the two DBPs higher than what they are at the water plant.
At City Hall in March, for instance, the trihalomethane levels were at 19.1 ppb and the haloacetic acids were at 13.9 ppb.
At Breaktime, those readings were 21.3 ppb and 13.1 ppb, respectively.
At Rose Hill Cemetery, those readings were 7.2 ppb and 11.0 ppb, respectively.
This variation indicates some parts of the drinking water distribution system are aging and will eventually need to be replaced.
The flushing of different parts of the distribution system at different points in time will also cause this variation.
