King County produces a lot of crap. After passage and break down through sewer treatment plants in Seattle some of the remaining dry solids are shipped across the mountains to Douglas County dryland farms on the Waterville Plateau.
The nearly black biosolids stand in sharp contrast to the light brown native glacial soils.
Dryland farms in Douglas County have been receiving biosolids from King County for over 20 years.
The product is regulated by both Washington State and the EPA with metals being one of the primary concerns. The King County product is very low in metals, and adds nutrients and structure to the soil.
The Boulder Park Project on numerous dryland wheat farms in Douglas County receives about 60% of the biosolids from King County or 68,000 tons. The name Boulder Park is derived from the many large boulders on the glacial drift plains of the Waterville Plateau.
King County crap may be low in metals, but what concerns me are the hormones and pharmaceuticals that remain in the sludge and get into the environment, including into the stuff the farmers grow and then we eat. Yuck.
ReplyDeleteValid concerns that are actively being studied. It's a bit outside my area, but it appears that how the municipal biosolids are treated prior to application makes a big difference regarding estrogen content - anaerobic vs. aerobic treatment. Animal manure actually can be worse for some hormones. Run off into aquatic environments has been demonstrated, and hence, the advantage of application to dry land sites with low run off potential. The above said, I know very little about possible plant uptake. If you know of any studies it would be great to hear about them.
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