Falls Lake pollution could require new treatment plant
Posted January 5, 2010
Raleigh, N.C. — Raleigh could be forced to spend more than $250 million on a new water treatment plant because increasing pollution is overwhelming the current plant, according to city officials.
Falls Lake provides drinking water for more than 450,000 Wake County residents, but runoff from farm fields and storm drains in Durham and Granville counties, near the lake's headwaters, has led to excessive algae growth and sediment.
In a Dec. 28 report to City Manager Russell Allen, the city's Public Utilities Department said the E. M. Johnson Water Treatment Plant cannot handle the growing amount of carbon in the lake that is being produced by runoff from developed areas and the algae and bacteria in the lake that thrive on other nutrients in the runoff.
"The consequence of declining water quality in Falls Lake will invariably lead to greater operational and capital expenditures to ensure compliance with Safe Drinking Water Act regulations," officials said in the report. "Additional (organic carbon) removal would require the
construction of one or more 'advanced' treatment processes."
Algal blooms also have the potential to clog the filters at the treatment plant's intake pipe in the lake, diminishing its water treatment capacity, officials said.
Expanding the plant to handle 100 million gallons a day, from the current capacity of 86 million gallons a day, and upgrading it with various options to treat the pollution could cost the city from $265 million to $341 million, according to the report.
The state Environmental Management Commission and the state Department of Environment and Natural Resources have set a January 2011 deadline for putting a plan in place to clean up the lake. Raleigh officials have said they would like all pollution cleared from the lake by 2016.