An Iowa Farming Community Shapes Its Decentralized Wastewater Future

A complex mix of individual and cluster systems helps Rowan, Iowa, clean up the environment and serve the treatment needs of homes and businesses for generations to come.

An Iowa Farming Community Shapes Its Decentralized Wastewater Future

Many homes in Rowan, Iowa, were converted from a community collections system to individual gravity-flow tanks feeding a drainfield on the property. Wieser Precast Steps tanks were used, as well as Orenco Systems risers and Orenco Systems and Polylok lids.

Rowan, Iowa, is a small community of just over 150 people, but a few years ago it confronted a big change. The state required the upgrade of all the wastewater systems serving the city because effluent was flowing into a field tile that emptied into a creek about a quarter mile from its borders.

Mort’s Water Co., a five-generation firm based in nearby Latimer, received the contract for the yearlong project. The company knew the project was coming. During the city’s three-year planning process, Mort’s had been asked to provide expert advice. As the winning bidder for the job, the company put its expertise to the test.

Systems

The mix of lot sizes and available areas for absorption fields resulted in a mix of solutions.

There are:

  • 50 conventional gravity septic tanks feeding individual drainfields that use Infiltrator Water Technologies Quick4 Plus chambers.
  • 16 septic-tank-effluent-pump tanks feeding individual drainfields with Infiltrator Water Technologies chambers.
  • 18 STEP tanks feeding pressure mains that lead to two drainfields for a cluster of homes.
  • Three Orenco Systems AdvanTex pods feeding individual drainfields.

For the conventional and STEP systems, Mort’s used two-compartment tanks from Wieser Precast Steps in Stewartville, Minnesota. The AdvanTex AX20 systems were offset on top of the Wieser Precast Step tanks. STEP systems used pumps and pump vaults from Clarus Environmental. All tanks use Orenco Systems risers. Half the tanks are topped with Orenco Systems lids and half with Polylok lids.

The project also required making 91 sewer hookups, laying 20,400 linear feet of Infiltrator Water Technologies chambers and boring 6,000 linear feet of 1 1/2-inch force main.

About 16 wells, hand-pumped and used mainly to water gardens, had to be capped and abandoned because they were too close to a treatment system.

To do the work, Mort’s used a:

  • 2017 Case CX80C excavator.
  • 2017 Case TR340 compact track loader. This was acquired for this project and was very useful because it could be driven across drainfields as soon as they were backfilled.
  • 2005 Sterling Acterra tractor with a Knapheide service body.
  • 2009 Sterling Acterra dump truck with a box from Godwin Mfg. Co.
  • 2019 M2 106 Freightliner with a 3,650-gallon stainless steel tank and National Vacuum Equipment 4310 blower from Advance Pump & Equipment. This truck pumped out old tanks before they were abandoned.
  • MX7 Harley Power Rake by Paladin Attachments for grading.
  • 2010 Case 36B mini-excavator.
  • 2010 Astec boring machine.
  • 2014 Case 590N backhoe.

Starting easy

When the work started in the fall of 2017, installations began with the gravity systems on lots with the most space because those were similar to typical residential installations performed by the company, says Brandon Morton, the project manager for Mort’s.

“We wanted to get a good start on the job because we were not sure how long the work would take, and we didn’t want to run over our time. As work progressed, the city gave us needed extensions for subcontractor work because they wanted the job done right,” Morton says.

Every one to two weeks, the Mort’s crew would look over the jobs ahead and pick five or six properties to work on. They would examine the engineering drawings and in some cases suggest changes so drainfields better fit the space. They would have all the utilities located at once, then pick one to two properties for each day. Tanks were delivered on each working day, and the Infiltrator Water Technologies chambers were installed after. For most gravity systems, Morton and his partner Travis Hunter put in two tanks per day.

After the simplest installations, work shifted to the lots with tighter space. Then the crew tackled the STEP systems feeding a drainfield on the property. Last they worked on the AdvanTex systems and the STEP systems feeding the cluster drainfields.

Plans originally called for eight AdvanTex units, but once the crew was on site, they saw ways to lay out drainfields so gravity or STEP systems were possible. As a result, only three AdvanTex units were used for the project.

On a few lots, the crew found steel tanks that had disintegrated. “They were all dirt. The liquid was running over the top from the inlet to the outlet. It was working, but it wasn’t doing any treatment at all,” Morton says. It was easiest to pull those tanks out.

Most of the existing concrete tanks were not up to code and were abandoned in place. On a few properties, owners had installed newer tanks that could be reused for the new systems.

Drainfields for the cluster systems were installed in the fall 2017 so soil could settle during the winter. Distribution boxes and incoming pressure lines were laid at the same time.

Morton and Hunter did about 90 percent of the work on their own. Directional boring for lines was done by the company’s specialized three-person crew, and wells were abandoned by the company’s licensed pump installers.

Service to homes was interrupted for two to three hours at most. The hard part of that was estimating what time tanks had to be delivered based on how much space there was and how deep it had to be placed. New tanks were connected on the same day they were installed, but drainfield lines didn’t have to be connected immediately because tanks would not be filled for a couple of weeks, Morton says.

The old wastewater system was abandoned in part or in total depending on each house, Morton says. For homes with perimeter tiles and floor drains, the crew plumbed from the old tank’s inlet to outlet to preserve the floor drain. In homes without floor drains, technicians abandoned the old tanks in place by plugging outlets.

Necessary plumbing

Inside plumbing was done by Morton, Hunter and another crew on rainy days and during winter. Under Iowa code, anything that touches a human body or is from a human body must go to a wastewater system, Morton says. But in one home, for example, they found a clothes washer discharging into a floor drain. “We had to re-plumb that washing machine so water flowed by gravity into the system. If we can keep everything gravity, it’s better for us and better for the customers because then there are no mechanicals to deal with.”

In some cases, they could raise the height of the wastewater outflow. In other cases, homeowners opted to abandon a basement shower to avoid the need for a pump to lift the wastewater. “These are older houses with 7- to 8-foot basement ceilings,” Morton says. About a fourth of the properties needed to have wastewater discharges raised to maintain gravity flow.

Some discharge pipes from homes were about a foot below grade to maintain a gravity system. As long as there is snow on the ground, those pipes will be insulated against winter freezes, Morton says. Because driveways are cleaned of snow in winter, pipes running beneath them were insulated with pink sheet insulation cut into 2-inch-by-8-foot sections to fit in the pipe ditch.

The company’s licensed plumber changed the path of backwash water from the iron filter for the city domestic water system. Wash water was flowing into a floor drain that eventually emptied into the same creek taking the rest of the city effluent, but the Iowa Department of Natural Resources didn’t want this because of the iron sediments in the wash water. So Mort’s plumbed the flow into four 3,000-gallon holding tanks that are pumped as needed.

The Rowan job was a great learning experience for the company, Morton says. Rethinking drainfields for tight spaces in the city has helped installers more efficiently arrange drainfields for rural systems the company has done since.

There is still a little finish work left in Rowan, primarily seeding after the thaw in the spring of 2019.

Mort’s has been in operation for decades and has always done septic, pump and well work, and water conditioning but this was its first community project, Morton says. It may not be the last. More communities in this area of north-central Iowa (about 87 miles north of Des Moines) have received warning letters from the state about the need for wastewater upgrades, and some of those communities are within easy working distance of Mort’s base in Latimer. With one project under its belt, Mort’s is ready to help other Iowa communities improve their wastewater systems and protect the rural environment.



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