State wastewater regulators last week identified Don Abel Building Supplies as the source of sewage that was discovered last month flowing into the Mendenhall River.
"We don't know when it started," said Lori Sowa, environmental engineering associate in the Department of Environmental Conservation's Division of Water.
Overflow from Don Abel's septic system came just as city contractors were laying new sewer pipe to hook the Industrial Boulevard area into the city wastewater treatment system. It's an upgrade the area's businesses have waited 20 years for.
"We are really glad that the sewer project is progressing out to that area," Sowa said.
Juneau resident Peter Francillon, walking along Glacier Highway on Aug. 27, discovered and reported a smelly, dark-brown discharge he couldn't identify coming from a corrugated metal culvert into the river, near Brotherhood Bridge.
"That can't be good for the fishies," he said.
The state confirmed the building supply store was the source by adding a greenish-yellow dye to a toilet there, then seeing that color come out the pipe about five hours later.
DEC found in tests that the discharge was partially treated wastewater. It had fecal coliform bacteria at 28,100 colonies per 100 milliliters of water, a level far exceeding state standards of between 200 and 400 colonies.
Fecal coliforms are bacteria that live in human and animal intestinal tracts. They are not a health threat themselves but are used to indicate whether other potentially harmful bacteria may be present, according to the U.S. Environmental Protection Agency.
Sowa said she didn't know how much wastewater ended up in the river. She estimated the operation might produce less than 1,000 gallons of wastewater a day. A single-family home might produce about 500 gallons a day, including water from toilets, showers and sinks.
DEC sent a letter Thursday requiring the company to stop the flow. The company by then had already pumped its septic system and ordered portable toilets, according to company owner Bruce Abel.
"They have been very cooperative," Sowa said.
Usually, the state requires a responsible party to submit plans to fix whatever is broken. But in this case, Don Abel's city connection is nearly online.
"They're literally laying the pipe at the corner of my property now," Bruce Abel said.
Don Abel's old wastewater system was designed in the 1970s with help and approval from DEC. It's a large-capacity tank with a leach field, down from which wastewater percolates and filters to the groundwater table. Abel said the leach system in this case didn't percolate the way it ordinarily would because the groundwater is so high right now.
This was the first time the system overflowed, Abel said.
It is not the first time the Industrial Boulevard area has had wastewater troubles, though. In 2007, the sewage system overflowed from Pavitt Health and Fitness and the next-door U-Haul store into a nearby ditch. The companies fixed the problem by reducing their water usage and pumping their system.
Other businesses in the area have a sewer connection that leads to the river, but the permit to discharge there expired. They have to pump their tanks on a regular basis to avoid sending fluid into the river.
Contact reporter Kate Golden at 523-2276 or firstname.lastname@example.org.