NAMPA, Idaho — Amalgamated Sugar Co. may use much of the nutrient-rich wastewater from refining sugar at its Nampa plant to irrigate crops rather than continuing to have it all treated by the city.
Company officials said the move would allow them flexibility to adjust to future rate hikes by the Nampa wastewater treatment plant.
Amalgamated land applied its wastewater on farm fields located at the plant before reaching an agreement with the city in 1996. Nonetheless, the company maintained its reuse permit to irrigate crops with its wastewater and has applied with the Idaho Department of Environmental Quality to renew the permit for another five years.
DEQ will take public comment on the permit renewal through Dec. 26. Comments may be emailed to email@example.com. According to DEQ, Amalgamated will have to specify how it will address certain environmental concerns, including its methods to prevent contamination of surface and ground water. Furthermore, DEQ said the draft permit imposes buffer zones, loading rate limits and monitoring requirements.
Dean DeLorey, Amalgamated’s director of environmental affairs, said more than half of the plant’s wastewater would be land applied over farm land owned by Amalgamated and leased to growers for alfalfa. The water — distilled from juice when beets are dried for sugar — contains some ammonia and has fertilizer value. The deep roots of alfalfa plants help prevent any leaching into waterways, DeLorey said. The crops would still require supplemental irrigation water, he said.
DeLorey said the main challenge of land application is that Amalgamated processes beets from Oct. 1 through mid-February, when there’s no alfalfa growing to utilize the nutrients. Amalgamated may need to build a lined storage pond to hold the liquid until it can be used in the spring and summer.
“We’re still in the initial planning stages to try to make this all work to land apply the water,” DeLorey said.
Nampa public works officials said their treatment rates are increasing because of new Environmental Protection Agency requirements that they begin removing phosphorus from wastewater. The city will invest $28 million in new infrastructure in its first phase of upgrades to meet the new mandate.
Nampa officials said high-volume industrial customers, such as Amalgamated, pay individual rates based on the specific details of their waste streams.
DeLorey said if Amalgamated does nothing to reduce its treatment volume, its costs will double within the next five years.