Processing Magazine

Iowa business plans year-round wastewater irrigation system

November 27, 2012

NORTH LIBERTY, Iowa — An Iowa-based company is working on an ambitious task but it is one that might lead to a huge step forward in sustainability. The business is planning to develop a system that will use wastewater for year-round irrigation of poplar trees, which could then be used in the wood processing industry, local newspaper the Gazette reports.

Ecolotree is a North Liberty-based business that specializes in phytoremediation, using plants to purify soil from waste products and contamination. It mainly works with poplar trees and is currently awaiting regulatory approval for its innovative system that would make use of wastewater. According to Ecolotree''s founder and president, Louis Licht, there is a huge amount of wastewater produced in the business hub at Port of Morrow on the Columbia River.

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Businesses there manufacture a range of products in different industries, including French fries for McDonald''s and the Blooming Onions served at Outback Steakhouse, and together they produce as much wastewater as a 40,000-population city.

Licht''s business needs significant amounts of water because poplar trees grow extremely fast and tall and need a constant supply of water. Similarly, other businesses at the port have also had to find ways to cope with the constant demand for water. Wastewater has been utilized during the summer but currently there are no conditions for its use to be extended to the rest of the year. Licht explained that a wastewater treatment plant would cost a total of $42 million plus about $1 million in operational costs per year. Another possible solution — building a wastewater lagoon — would cost about $14 million.

If Ecolotree''s idea gets the go-ahead from regulators, Licht estimates that it will pay for itself within a year in pulp wood production that can be put to a wide range of commercial uses. The main challenge is to convince environmental regulators that trees can effectively treat wastewater during the winter season after their leaves have dropped.

However, Licht claims that treatment could still go on over the winter, as most of the process takes place thanks to microbes that live in and around the roots and are not affected by the different seasons. In order to prove to regulators this is possible, Licht set up an improvised laboratory from insulated shipping boxes, supplied with a drain at the bottom. The boxes are filled with soil and then willow and poplar trees, fed with wastewater, are planted inside.

Two months later, the trees have developed a root system exactly the same as the one present in mature trees living in their usual habitat. Every drop of water that is placed in the box passes not more than one centimeter away from a root, Licht explains. Furthermore, soil samples from the boxes are taken and the amounts of nitrogen, ammonia and other waste products are compared to the amounts detected in the water draining out of the box.

The system might prove an efficient method for wastewater treatment for every small town in Iowa, as it can significantly reduce costs, Licht believes.