Answers to the vexing issues of discolored water are coming into focus for staff with the city of Port St. Joe.
City commissioners will soon be asked to weigh-in on a path forward.
A meeting this week with David Kozan from CDM Smith, the contractor which designed the city’s $21 million surface water treatment plant, continued to hone the dialogue on potential solutions for discolored water which have plagued the city since its new water plant came online more than three year ago.
A foundation of consensus is built upon the belief that the ongoing replacement of aging pipes in the distribution system, particularly the cast iron pipes, will eliminate an estimated 90 percent of the iron present in the system by the end of this year or early 2015.
Iron, or ferric (iron-containing compounds), has been identified as the likely source of “red water” complaints in the city.
However, iron is not the sole issue, as was discovered during a pilot water study conducted by CDM, in partnership with Virginia Tech University.
As Kozan noted, nearly half of complaints about the city’s water has described “dirty”, “ice tea” or “black” water conditions. The likely source of that, the pilot study found, was manganese.
The CDM study, which is being finalized with city staff comments incorporated in the final draft, identifies several potential solutions and recommends changing the corrosion control chemical used in the treatment while also increasing the strength of the solution.
The corrosion control chemical’s impact on aging cast iron pipes has long been identified as the primary culprit for red water.
“This is a small problem that we think will solve itself over time as the pipes are replaced,” said city manager Jim Anderson. “But we know the problem is there.”
Lowering the levels of manganese could be addressed through options both early and late in the treatment of the water, to both segregate it within the system and by increasing the purity of a specific treatment chemical.
A tricky part to manganese treatment, Kozan noted, is the chemical tends to accumulate in stagnant areas of the line, increasing the likelihood of water discoloration.
The city’s flushing program, which commissioners implemented year round last year, is a significant factor in alleviating the problem.
“A regular high-velocity flush will also regulate the levels and the accumulation,” Kozan said.
Recommendations are not just coming from CDM, Anderson said.
“We have to keep everything on the table,” Anderson said. “We have gone out for a lot of input.”
Staff from the water plant in Bay County – which also uses a surface water source – has been in the Port St. Joe plant performing some jar testing and staff from Port St. Joe has been to Bay County to examine the system and treatment protocol.
The identified culprit, Anderson said, was ferric and in Bay County the process includes pre-treatment with lime in amounts Anderson and Port St. Joe plant manager Larry McClamma said were less than expected.
“We have looked at their process and that is our feeling, that the ferric is the 500-pound gorilla in the room,” Anderson said.
At two previous City Commission meetings McClamma has raised pretreatment with lime as a viable option, both in terms of costs and finished water results.
The trick is that the treatment protocol used in the Port St. Joe plant is designed specific to the Siemens-manufactured microfiltration system.
The concern is that lime can cause buildup – less of the lime than the impurities in slaked lime – on those filters.
McClamma enlisted the Florida Rural Water Association – which has been working for several years with the city on addressing water issues – to perform a study relative to issues and costs associated with lime pretreatment.
Pretreatment with lime would also mean the city would not have to examine any treatment option that would include the use chloramines as a disinfecting agent as chloramines have been linked to health issues and thus far ruled out for use at the plant by city commissioners.
The city would have to secure an okay, in writing, from U.S. Filter, which manufactures the filters, and/or Siemens to pretreat with lime, Anderson said.
Anderson said he would like to bring to the Commission in the next few weeks recommendations for moving forward on the pretreatment option; addressing manganese with a more pure treatment solution; and a change in the makeup of a front-end treatment chemical to address iron.