Return to search

Phosphorus reduction in dairy effluent through flocculation and precipitation

Phosphorus (P) is a pollutant in freshwater systems because it promotes eutrophication. The dairies in the North Bosque and its water body segments import more P than they export. Dairies accumulate P-rich effluent in lagoons and use the wastewater for irrigation. As more P is applied as irrigation than is removed by crops, P accumulates in the soil. During intense rainfall events, P enters the river with stormwater runoff and can become bio-available. Reducing the P applied to the land would limit P build up in the soil and reduce the potential for P pollution. Since wastewater P is associated with suspended solids (SS), the flocculants, poly-DADMAC and PAM, were used to reduce SS. To precipitate soluble P from the effluent, NH4OH was added to raise the pH. Raw effluent was collected from a dairy in Comanche County, TX, and stored in 190-L barrels in a laboratory at Texas A&M University. Flocculant additions reduced effluent P content by as much as 66%. Addition of NH4OH to the flocculated effluent raised the pH from near 8 to near 9, inducing P precipitation, further reducing the P content. The total P reduction for the best combination of treatments was 97%, a decrease from 76 to 2 mg L-1. If this level of reduction were achieved in dairy operations, P pollution from effluent application would gradually disappear.

Identiferoai:union.ndltd.org:TEXASAandM/oai:repository.tamu.edu:1969.1/1646
Date17 February 2005
CreatorsBragg, Amanda Leann
ContributorsMcInnes, Kevin, McGuire, Jennifer, Feagley, Sam
PublisherTexas A&M University
Source SetsTexas A and M University
Languageen_US
Detected LanguageEnglish
TypeElectronic Thesis, text
Format644592 bytes, electronic, application/pdf, born digital

Page generated in 0.0019 seconds