Odor Control Efforts Proving Effective
Doug Emerson, Environmental Affairs Manager
You might have noticed as you traveled up the Valley lately or near the factories that the odors have not been as noticeable for the summer of 2015. How come? There are a number of influences that either prevent or reduce the odors near the plants. Below are a few examples of some of those influences.
Photo 1 shows a surface aerator within the South Mud Pond at Crookston. Our employees maintain these to get them up and running as soon as possible in the spring. Aeration plays a big role to keep the biological processes going in the ponds (i.e. treatment). Keeping the ponds “fresh” with air reduces the anaerobic (without air) activity that causes the odors and/or hydrogen sulfide (H2S). Back in 2008 the Company had no aerators in the ponds. Today there is a bit more than 3,355 horsepower-worth of aeration in the Valley.
Photo 2 shows one of our permeable covers located in Crookston’s North Mud Pond. In total, there are 8 covers on ponds or ditches at the Company. Some are permeable and some are gas collecting. The one pictured is permeable. The idea is that as anaerobic activity occurs under the cover to treat the high strength water, the odors and gas that are produced will travel through a biological layer that develops in the permeable layer of the cover and is treated. This one is huge at 24 acres.
Photo 3 shows another type of cover using straw. This is from one of Hillsboro’s mud ponds. Some would argue that these straw covers are just as effective as the synthetic ones. This is something new for Hillsboro as of last year.
Photo 4 is a shot of the East Grand Forks digester. This digester was full of calcium carbonate that deposited in the tank over time, and has recently been emptied. The volume taken up by those solids consumes treatment capacity. Cleaning out the digester will help East Grand Forks to keep up with treatment in the future, not allowing high strength wastewater to back up in the ponds. East Grand is also getting a new cover put on the tank.
In a recent visit to our East Grand Forks factory, Barrett Jesness (Environmental Compliance Supervisor – EGF) pointed out that a very import influence toward staying on top of the odors or H2S is the work of our people. Their work includes keeping sugar shots to the condenser ponds at bay, finding out ways to keep clean water clean and on the clean water side and dirty water on the dirty side, discovering how to reduce water volumes, and managing the polymer to keep the solids settling in the clarifiers. All of this deserves a big thank you to our dedicated employees inside the factory walls as well as those at the water treatment facilities.
Controlling odors requires a combined effort from everyone at American Crystal. It’s a responsibility we take very seriously.