The Utah Division of Water Quality (DWQ) is requiring all communities to rush ahead with plans for sewage treatment plant (WWTP) projects to remove phosphorus and nitrogen (nutrients). The price tag: some $435 million to $1.2 billion — to be paid for by increases in our sewer bills. I maintain that at the locations of most Utah WWTPs, water quality problems associated with WWTP nutrients are negligible; thus, the universal treatment requirement is a gigantic waste of money and resources.
Nutrient problems, if they occur at all, are largely associated with aesthetic and recreational aspects of water and are not problems of disease and filth that existing facilities already handle very well. The real issue is a possibility of increased algae and other aquatic plant growth that sometimes results in less transparent water and additional stresses on existing biota. Significant changes are most likely in nutrient-poor waters usually found in alpine area headwaters or in areas with heavy rainfall and nutrient-poor rocks and soils, such as Lake Tahoe or generally in coastal northeastern and northwestern areas of the country.
In Utah, rocks and soils are generally nutrient-rich and most midrange and valley waters are naturally relatively high in nutrients, especially phosphorus. In these widespread nutrient-rich waters, fish production is great and aquatic wildlife abounds; Strawberry Reservoir could never be like Tahoe because it’s naturally nutrient-rich and wonderfully productive.
Since most of Utah’s waters are naturally nutrient-rich, particularly in basin-bottom areas where most of our people live, natural algae growth factors other than nutrients usually control the amount of algae and other aquatic plant growth. A prime example is Utah Lake. It’s naturally nutrient-rich (eutrophic), where inflowing nutrients are 10 to 15 times the amount needed to support its natural eutrophic state. Even if we removed all nutrients from WWTP discharges and all other human-caused additions, Utah Lake would still be eutrophic and remain as it is. (Incidentally, Utah Lake is a tremendous natural asset: a premium warm-water fishery and recreation area. Its water quality is good given its natural state. Its turbidity is caused by natural mineral precipitation and not pollution. Fortunately, its natural turbidity absorbs sunlight, causing light limitation to limit algae growth.) Regarding the Jordan River, marshes along the Great Salt Lake, etc., colleagues report that existing WWTP nutrient discharges seem to have little polluting impact on those waters.
We need to slam on the brakes now. To paraphrase a classic truism: It’s too often a human failing when we encounter something wrong first to abhor it, then tolerate it and finally embrace it. In my long experience, the people involved in water pollution control and management are dedicated and hardworking. Only a few years ago most of them solidly questioned the need for widespread nutrient removal in Utah. The notion that nutrients are inherently nasty and bad has worn down many. They are becoming resigned and are beginning to gear up to do their habitual good job in the nutrient removal arena as well.
I maintain that it would be far wiser to halt most, if not all, nutrient-related WWTP projects and first spend a fraction of this money and talent on enhanced monitoring and research to identify WWTP locations, if any, where nutrient removal would result in commensurate water quality improvements. This approach would ultimately address any significant nutrient problems — but at a far, far smaller overall price tag.
LaVere Merritt is a professor emeritus of civil and environmental engineering. His specialty areas include water quality evaluation and management. His past research includes multidisciplinary studies and evaluations of Utah streams and lakes.