ASABE Technical Library - Abstract

Click on “Download PDF” for the PDF version or on the title for the HTML version.
If you are not an ASABE member or if your employer has not arranged for access to the full-text, view access and subscription options

Phosphorus Removal from Dairy Lagoon Wastewater by On-Site Alum Injection

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Pp. 179-179 in Total Maximum Daily Load (TMDL) Environmental Regulations: Proceedings of the March 11-13, 2002 Conference, (Fort Worth, Texas, USA)  701P0102.(doi:10.13031/2013.7548)
Authors:   R.M. Jones, R.W. McNew, and S.P. Brown

Regulatory limits for soil P, significant P concentration in wastewater, lack of nearby pasture or cropland, and uneconomical transport costs have created a wastewater disposal dilemma for many dairies. A simple on-site alum injection system was used to determine the alum requirement to reduce soluble reactive P (SRP) to 1.0, 0.5, or 0.25 mg P L -1 . Alum solution was injected at target rates of 15, 37, 73, and 110 mg Al L -1 wastewater during transfer by centrifugal pump to a cone tank which provided for solids separation and sample collection. SRP was reduced from 11.3 (untreated) to 1.0 mg P L -1 in the supernatant by treatment with 0.47 ml liquid alum L -1 lagoon water (27.6 mg Al L -1 ; 95% CL=0.38 - 0.58 ml L -1 (22 - 33.8 mg Al L -1 )). Solution of the inverse quadratic equation SRP= 1/0.435 + 0.964x + 2.65x 2 (r 2 = 0.96) for SRP = 0.5 and 0.25 resulted in the alum requirement of 0.72 and 1.07 ml L -1 . Supernatant chemical oxygen demand, pH, total P, total N, total solids, total suspended solids, and turbidity decreased steadily (p< 0.0004) with increasing alum rate. Initial electrical conductivity (0.359 S m -1 ) was greater than that of quality irrigation water and linearly increased (p=0.0093) with increasing alum. Estimated increase in soil aluminum content in the surface 15 cm during 20 yr of supernatant application at 39 600 L/day to 8.1 ha is only 0.33%. Estimated chemical cost for reduction of SRP to 1.0 mg P L -1 was $US 11.10/cow/yr or $US 8.04/kg P removed. Results indicate potential for economic and effective reduction of SRP with collateral improvement of other water quality factors.

(Download PDF)    (Export to EndNotes)