A residential subdivision west of Rapid City is taking a proactive approach to protecting groundwater by installing a new type of septic system that claims to be cleaner and more efficient.

Schad Construction is building homes at Canyon Springs Preserve, a higher-end subdivision of more than 80 homes located about four miles west of Rapid City on Nemo Road.

Because the property is far from city services and is on top of a recharge area for the Madison Aquifer - the prime source of water for city wells - Schad needed an innovative solution to provide sewer service.

"One of the challenges was to come up with good ideas to preserve the water source in order to even get the project approved," Dusten Schad, vice president of Schad Construction, said.

The company's research pointed them to aerobic wastewater systems, a type of septic system used for more than 20 years in southern states but not in use in South Dakota. To use it here, Schad had to convince the state of the system's effectiveness.

In an aerobic system, an air compressor continuously pumps oxygen into the tank. The bacteria in aerobic systems work faster and more efficiently in breaking down sewage and contaminants than traditional septic tanks, which process waste in an oxygen-free environment.

"Aerobic bacteria is basically the magic of the whole system. It's 18 times more efficient at breaking down and digesting sewage contaminants," said Chris Calkins, operations manager of Crystal Mountain, the system distribution arm of Schad Construction.

The system must be tied into a power source to keep the air pump operating. Crystal Mountain's systems also are connected to an autodialer that will alert the company to power problems.

Aerobic systems are generally more expensive than a traditional septic tank - about $2,000 more, though the actual cost varies by site - and they must be inspected every six months. Although not ideal in every situation, they provide high-quality treatment. Calkins said effluent entering the drain field is 98.6 percent contaminant free.

"What you're putting back in the ground is a clear, odorless effluent, and you're doing it without adding any chemicals," he said. "They also get rid of about half of nitrates compared to standard septic systems, which does nothing for nitrate problems."

Dan Jennissen, Pennington County planning and zoning director, said he has been told aerobic septic systems clean wastewater to the point it could be consumed - but he said he isn't going to test the theory.

However, Jennissen said, it is definitely a cleaner system than standard septic tanks and agreed it would be beneficial in areas identified as being at higher risk for potential groundwater contamination.

According to Jennissen, the county commission has expressed interest in forming a committee to talk about ways to protect groundwater. Aerobic systems would be a good fit with that goal.

"Some people, when they realize they're in a vulnerable area, they have volunteered to put in this kind of system. It's fairly new, but it's been around for awhile," he said. "One of the more aggressive states is Minnesota. They've taken a proactive stand on how to treat wastewater because they have a much higher water table in certain areas."

Meade County has made aerobic treatment systems a requirement for multi-family units and some commercial properties, according to Bill Rich with the Meade County planning and zoning department.

"It's a change in the last 6 to 8 months. We'll probably - and it's just a guess - but we'll probably require it for all commercial buildings in the future," he said.

Rich said the biggest concern about traditional septic tanks is groundwater contamination caused by putting a large number in a small area. But the aerobic systems can alleviate that concern.

"It's a better treatment of waste. It's like a pre-treatment before it goes into the drain field. It cleans up the water," Rich said.

In a traditional septic system, effluent and pathogens are biologically broken down after leaving the tank and entering the drain field, he said. But the aerobic system breaks down most of the biomass before it gets to the drain field.

"It makes the impact to the environment a lot better, reduces the chance of groundwater contamination. It's definitely a lot better than traditional systems," Rich said. "I think it's good for the Black Hills, and I think we'll see a lot more of this type of technology used as time goes on."

Dusten Schad said aerobic septic tanks will be standard for all of the company's developments in the Hills and any custom home that can't be feasibly tied into a municipal sewage system. He said going "green" is becoming more of a trend in the home-building industry and is something customers appreciate.

"Most don't come to the table asking for it, but when they know you're working toward that, they appreciate it," he said. "We're not going overboard, trying to be hippies about it or anything. We just know that there is a concern about the water supply."

Contact Scott Aust at 394-8415 or scott.aust@rapidcityjournal.com