2002 Annual Report
Research
Swine Manure Nutrient Removal by Microbial Additives Assisted by Aeration
Jun Zhu, Assistant Professor, Southern
Research and Outreach Center, Waseca, MN
Zhijian Zhang, Post-Doctoral Associate, South Research and Outreach Center,
Waseca, MN
Curtis Miller, Assistant Scientist, Southern Research and Outreach Center,
Waseca, MN
Funding Source
University of Minnesota Agricultural Experiment Station
Objective
The objective of the project is to investigate the effect of a microbial
additive (Sporzyme) and the activated sludge on nutrient removal in swine
manure (total Kjeldhal nitrogen and total phosphorus) under low aeration
conditions. The effect of anaerobic preconditioning was also investigated.
Project Description
Plastic columns were used as bioreactors in this study. A total of five
treatments were employed to evaluate a microbial additive and the activated
sludge as seed in removing swine manure nutrient under low aeration conditions.
The five treatments included control, aeration without additive, aeration
with microbial additive, aeration with sludge added immediately before
aeration started, and aeration with sludge added 3 days before aeration
started. The sludge was obtained from an activated pond in the municipal
wastewater treatment plant at Waseca. The measurements included oxidation-reduction
potential, pH, aerobic and anaerobic counts, biochemical oxygen demand,
volatile fatty acids, organic carbon, soluble and insoluble phosphorus,
ammonium, and total Kjeldahl nitrogen.
Results
The results indicated that both TKN and ammonium nitrogen were greatly reduced by the treatment from 6 g/L to 3.5 g/L and 3.2 g/L to 1.3 g/L, respectively. After one day aeration, a drastic decrease was observed in total soluble P from 378.8 mg/L to 69.9 mg/L and 27.4 mg/L for aeration alone and aeration plus additive, respectively. Accompanied by these reductions is the increase in manure pH from 7.5 to about 8.8 during the aeration process that could contribute to the phosphorus precipitation and ammonia volatilization. According to the data, it was found that average reductions of total soluble P in manure from day 2 to day 15 were 81.5% for aeration only and 92.8% for aeration with the addition of Sporzyme.