HILO — Recent tests of the sewer main along Alii Drive are showing highly elevated levels of chloride, indicating seawater is getting into the line.
HILO — Recent tests of the sewer main along Alii Drive are showing highly elevated levels of chloride, indicating seawater is getting into the line.
The new data is troubling to the county Department of Environmental Management for a number of reasons. Foremost is the worry about pollution leaking into the surrounding ground, and ultimately, into the ocean.
“Pukas let water go both ways,” Environmental Management Director Bill Kucharski said Wednesday. “When you get water flowing in, you’ve also got sewage flowing out.”
That’s a big concern for Environmental Management Commissioner Richard Bennett.
“It would be nice to know the extent to which fecal organisms are in that bay,” Bennett said, speaking of Kailua Bay. “A lot of people swim in that bay.”
Recent samples from the state Health Department’s Clean Water Branch show enterococci levels well within safe ranges, however, according to the department’s website.
Bennett and the department are also concerned about high salt levels in the wastewater headed to wastewater treatment plants. The goal is to treat that water to a standard acceptable for irrigating golf courses and parks. Too much salt will kill the plants, making it useless for irrigation.
The county is currently working on a $100 million-plus upgrade to the Kealakehe sewer plant that could help the environment while sending treated wastewater to thirsty North Kona landscapes. The Kealakehe plant currently treats water to the lower R-3 standard, then chlorinates the effluent to further sanitize it. The effluent pours into a sump, or pit, near the Kealakehe Police Station.
The plan is to take the water to the higher R-1 standard to use for irrigation.
The salty water has long been a concern to the county Environmental Management Commission. The commission wants the state Department of Health to be given funding to conduct tests of private sewer laterals for any suspected infiltration or the authority to compel private property owners to inspect their sewer lines.
First, though, the county needs to ensure it own pipes are leak-free.
Tests of the wastewater at four manholes along Alii Drive from Feb. 8-12 found chloride levels between 250 parts per million and 280 parts per million at the southern end of Alii Drive and 1,400-2,000 ppm at the northern end.
In comparison, typical potable water on the mainland contains 30-50 ppm chloride, Kucharski said.
One ppm corresponds to a single penny in $10,000 or about one minute in two years, according to the Department of Water Supply’s consumer information brochure.
The county has isolated a leak in the sewer main fronting Huggo’s Restaurant. The leak has nothing to do with the restaurant itself, but the business was used as a location aid for the commission on Wednesday.
Kurcharski said repairing the pipe is a priority. The good news, he said, is it can be repaired from the inside using a material that’s pumped in and forced against the interior wall of the pipe, where it hardens.
“The alternative is tearing up Alii Drive for a year or two,” Kucharski said to skeptical snorts from some of the commissioners.
Kucharski said after the meeting he doesn’t have the details of the cost and time frame of the planned repairs.
The region is also experiencing saltier than normal drinking water because four of the county’s mauka water wells are malfunctioning, forcing the Department of Water Supply to rely more on makai wells that have higher chloride levels. The department has asked for a 25 percent reduction of water use in North Kona.
“We like to rely on the high water wells,” Water Department Manager Keith Okamoto said.
Freshwater sits atop salt water in the aquifer. Pumping up too much of the freshwater can bring the saltwater up, too.
Potable water in the area is running 120-150 ppm of chloride, said Okamoto. For persons on a sodium-restricted diet, sodium concentrations greater than 120 ppm could be problematic, and people with health concerns should consult their physician, according to the department’s water quality brochure.