JERRY McBRIDE/Durango Herald
MANCOS – In 1894, town founders used a huge septic tank to do the job. Now, Mancos is on the cutting edge of innovative technology with an internationally developed wastewater system that is taking over the job this month.
The new system, created in the late 1980s in the Soviet Union, doesn’t use chlorine gas and doesn’t require four huge lagoons, making it friendlier to the environment and taking up much less space. It also has greater capacity.
It’s a municipal first in the state, town administrator Tom Yennerell said Wednesday during a tour of the facility.
The state’s only other application of the technology is at Two Rivers Village, a privately developed community of manufactured houses in unincorporated Eagle County.
Yennerell said the new system is called a multistage advanced biological process. It replaces the former system– four aerated lagoons that used a biological process to produce clear water that was chlorinated before being pumped into the Mancos River.
“Chlorine gas is dangerous,” Yennerell said. ”The new process doesn’t use chlorine.”
The lagoon system could process up to 80,000 gallons of effluent a day. The new system has an upper limit of 200,000 gallons a day that will serve the town for 20 years, Yennerell said.
As sewage enters the headworks of the plant, solids that shouldn’t be flushed down a toilet are removed. A 50-gallon can of such items is sent to the landfill about once a week.
The first phase of waste treatment consists of a concrete tank with 24 cells, 12 on either side of a bioreactor. In each cell, 19 feet deep, bacteria-impregnated sheets of a striated synthetic material hang like curtains 2 inches apart.
As effluent flows from cell to cell, increasingly aggressive bacteria consume waste. At the end of the process, the effluent is treated with ultraviolet light, which kills the last of the the bad stuff.
“It’s as clear as tap water by then,” Yennerell said. “Then everything goes into the Mancos River.”
Public Works Director Robin Schmittel said the end product exceeds Environmental Protection Agency and state water-quality standards. He said the water could be used for irrigation.
The Soviet technology was applied in Israel in the mid-1990s and reached the United States in 2008. Today, there are about 30 such systems around the world, including Wisconsin and Indiana. Systems are under design or construction in Idaho and Georgia.
Mancos got word from the Colorado Department of Public Health and Environment in 2007 that the town’s aerated lagoons were aging and performing near capacity.
It began planning for a new system with greater capacity to meet the town’s increasing needs.
Sounder, Miller & Associates of Cortez, with consultant Aqua Engineering of Salt Lake City, designed the new system. Southwest Contracting of Cortez started construction in April 2011, and the facility began operating on a limited basis beginning in May.
By the beginning of June the system was servicing over 50 percent of the town’s wastewater, and that’s now 100 percent, Yennerell said Wednesday.
The project cost $3 million, paid for by a $1.5 million grant from the Colorado Department of Local Affairs and a no-interest loan for the same amount from the state.
Operation costs for the new plant are expected to be lower, with a savings as high as $75,000 per year from reduced energy and labor expenses, Yennerell said.
The lagoon system will remain in place, although not in operation, for two years until it’s certain the new system is doing its jobs, Yennerell said. The lagoons are now being evaporated.