Chemical precipitation of phosphate and ammonia from swine wastewater

• Published in: Biomass & bioenergy Vol. 4; no. 5; pp. 365 - 371
• Main Authors: Liao, P.H., Gao, Y., Lo, K.V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1993
• Subjects: chemical precipitation; nitrogen and phosphate removal; Swine waste; Swine waste; chemical precipitation; nitrogen and phosphate removal
• ISSN: 0961-9534; 1873-2909
• DOI: 10.1016/0961-9534(93)90053-7

A study was undertaken to investigate magnesium sulfate as a precipitation reagent for the treatment of highly concentrated swine wastewaters. The effects of pH and of the dosage of magnesium sulfate on the removal efficiencies of ammonia and phosphate were studied. The pH is a factor in the removal efficiency of phosphate and ammonia. In this study, the highest phosphate removal was achieved at pH 9, while the highest ammonia removal occurred at pH 11. Results show that magnesium sulfate could be used on its own to remove phosphate and ammonia. However, due to low efficiencies of magnesium sulfate in the removal of concentrated solids, a polymer (PERCOL 728) was also tested as a co-precipitation reagent. The results indicated that a combination of magnesium sulfate and PERCOL 728 could be used to reduce phosphate, ammonia and solids concentrations. A dosage of 50 mg 1 −1 of PERCOL 728 and 1000 mg 1 −1 of MgSO 4 reduced phosphate levels from 479 to 6 mg 1 −1, and suspended solids from 1.8% to 0.2%.