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Co‐Application Effects of Water Treatment Residuals and Biosolids on Two Range Grasses
Author(s) -
Ippolito J. A.,
Barbarick K. A.,
Redente E. F.
Publication year - 1999
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1999.00472425002800050031x
Subject(s) - biosolids , bouteloua gracilis , water treatment , amendment , chemistry , sewage treatment , environmental science , flocculation , agronomy , environmental chemistry , adsorption , biomass (ecology) , zoology , environmental engineering , grazing , biology , organic chemistry , political science , law
Alum [Al 2 (SO 4 ) 3 14H 2 O] is commonly used in the municipal water treatment process to destabilize colloids for subsequent flocculation and water clarification. Water treatment residuals (WTR) can be classified as a waste material from these treatment plants. Concerns over land application of WTR are due to its postulated reduction of plant available P and potential plant Al toxicity with increasing WTR rates. Co‐application of WTR with biosolids may benefit municipalities with biosolids inherently high in P concentrations and in terms of a cost savings by landfill avoidance. In a greenhouse study, we investigated the efficacy of co‐application of WTR and biosolids to the native shortgrass prairie species blue grama ( Bouteloua gracilis H.B.K. Lag) and western wheatgrass [ Pascopyrum smithii (Rydb.) A. Love]. Our objectives were to quantify co‐application effects on plant P and Al concentrations and uptake, biomass production, and WTR P adsorbing capacity. With blue grama, we observed a positive linear relationship between increasing WTR rate and yield and a negative linear relationship with increasing WTR rate and shoot P and Al concentration ( P < 0.10). With western wheatgrass, increasing WTR rate produced a negative quadratic effect on shoot Al concentration ( P < 0.10). Some investigators have observed P deficiency symptoms associated with WTR application; however, we did not. Our adsorption study indicated that co‐mixing of the City of Fort Collins, CO, WTR and biosolids at ratios of 8:1 will adsorb all soluble biosolids P. Beyond this ratio the WTR could adsorb all biosolids available P and possibly some soil‐borne P.