SPRING 2002 11
Environmental Quality Projects
Recycling Finished and Waste Water Bioproducts to Improve Environmental Quality
Ken Barbarick and Jim Ippolito
Water-treatment residuals (WTR), often called alum, are a waste product of treating municipal water supplies. This material can adsorb large quantities of phosphorus (P) may lessen P input into fresh-water systems from over application of sewage biosolids or from runoff from large feedlots. Barbarick's studies suggest solid octacalcium phosphate formation absorbs P from solution and is stable in WTR. Surface P chemisorption as an amorphous surface mineral phase also might occur to stabilize P.
Land application of biosolids provides a less expensive
means of biosolids recycling for cities. Barbarick shows that long-term
recycling of biosolids on dryland wheat and wildfire-burn areas is socially,
environmentally and economically sustainable. To determine effects on
the agronomic rate of long-term, continuous application of biosolids over
seven years, biosolids and nitrogen (N) fertilizer were applied to dryland
wheat on Weld loam soils.
In summer 1999, incorporation of biosolids on no till crop rotations of
wheat-fallow, wheat-corn-fallow and wheat-wheat-corn-sunflower-fallow
began on Littleton and Englewood land near Byers, CO. In 1997, research
in the Buffalo-Creek wildfire burn area in Jefferson County, CO Barbarick
applied and incorporated composted biosolids followed from Denver Metro
by seeding with an US Forest Service approved mixture. Biosolids significantly
increased biomass production and plant canopy cover; however, production
levels were smaller then the first year following initial addition due
to another unusually dry growing season.
Studying the Release of Mn and Trace Metals from Acid Mine Drainage in Soils Under Reducing Conditions
Dean HeilIrrigated soils in the Alamosa River Basin, Colorado are impacted by water from acid mine runoff which results in acidification and metal accumulation. The current research objective is to determine if trace metals associated with these Mn oxide minerals are released after soils are saturated (soil reduction) from irrigation. Identification of the processes responsible for manganese (Mn) and trace metal solubilization will provide information to develop agricultural management practices for these soils, which will help protect water resources in this region. Results indicated that copper, palladium, nickel, and zinc (Zn) solubilities were greatly increased following reduction. The soluble concentration of Zn was significantly correlated with Mn in all four of the soils studied.
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