Salem plans to test treated water for chlorine by-products
SALEM – The Salem Utilities Commission took another step to reduce the amount of chlorine by-products in the city’s drinking water by finding a way to test the levels at the plant and make adjustments during treatment.
The commission voted Tuesday to purchase a Parker THM Analyzer for an estimated cost of $32,500 plus an additional $3,000 for chemicals and miscellaneous items required for operation.
Utilities Superintendent Don Weingart recommended the purchase based on an investigation by Salem Water Treatment Plant Manager Larry Sebrell, who was asked to find a way to test the treated water for the disinfectant by-products so adjustments could be made chemically.
Officials in Akron and Alliance told him sample testing results by the analyzer came within a close margin of certified laboratory results of samples, which normally require a two to three-week turnaround. The rapid test results at the plant will allow for adjustments to reduce the disinfectant by-products in an effort to stay in compliance with state rules.
Sebrell said it’s a good tool and other communities appear happy with the results.
Weingart said they have no way of knowing the level of naturally-occurring organics coming into the water supply, which then react with the chlorine used as a disinfectant to control contaminants in the water, forming the chlorine by-products known as Total Trihalomethanes. He said they’re more of a problem during warm weather.
In talking about the TTHMs the past year and the need to reduce them due to new regulations by the Ohio Environmental Protection Agency, Weingart stressed that the city’s water is safe to drink.
The regulation took effect last year, limiting the maximum allowable level at 80 parts per billion or 0.080 micrograms per liter. The city received a letter in October noting that the TTHM in the water system exceeded the limit during the April through June 2013 quarterly monitoring period. Leetonia and Washingtonville, which purchase their water supply from the city, recently discussed problems with TTHM.
As a way to reduce the formation of the chlorine by-products, the commission agreed in October to have Burgess & Niple design plans to improve the flow and circulation of potable water into the Stewart Road Reservoir, with part of the plan to have all the drinking water flow through that facility. The project was estimated to cost $104,000 and will be completed this year.
The age of the water also contributes to the problem and Weingart said the analyzer will allow the city to know the water age, too.
“This will help us with our compliance and what we’re doing at Stewart Road,” commission Chairman Bob Hodgson said.
In another matter related to the amount of water on hand, which can contribute to the age of the water, Burgess & Niple project manager Zach Held reported on an evaluation of the Highland water tank. The commission has been trying to determine whether to spend the money for needed maintenance on the tank or just eliminate the tank’s usage.
Held explained that using a computer model, different scenarios were plugged into the system with and without the Highland water tank, considering what would happen if there was a fire, what happened during peak demand or how the supply would be affected during a power outage.
Part of the discussion dealt with water pressure and some with fire flows, which he defined as the flow available for fire fighting and the ability to still sustain a minimum pressure of 20 pounds per square inch in the system.
He told the commission he would prefer to look at a calibrated model first before making a final recommendation. He said they would look at the actual flow and pressure at hydrants throughout the system with the intent of obtaining a representative sample to input into the hydraulic water model, which would give them more accurate information.
The commission agreed to do the calibrated testing at a cost of $12,500.
The commission also awarded the contracts for annual supplies based on bids opened last month for chemicals, ductile iron pipe and gate valves. Bonded Chemical received the award for hydrofloursilicic acid, liquid ferric chloride and potassium permanganate, while Univar received the award for chlorine and liquid aluminum sulfate.
Pipeline Inc. received the award for ductile iron pipe, but Weingart said they may try PVC on an upcoming project due to high cost increases for ductile iron pipe.
He recommended not awarding a contract for water valves since only one company submitted a bid. He said they’ll buy them on the open market if needed. He also recommended holding off on the contract for hydrate lime until the lime from the low bidder can be tested.
Most of the costs for the chemicals went down this year, but the cost for ductile iron pipe increased by nearly 20 percent.
The next commission meeting will be held March 11, with the time to be announced.