|Zhang, Ruihong - UC DAVIS|
|Mitloehner, Frank - UC DAVIS|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 3, 2006
Publication Date: N/A
Technical Abstract: This research is conducted to address the increasing public concerns over air emissions from dairy operations. The overall goal of this research is to develop effective mitigation technologies for reducing gaseous emissions from manure storages. Several treatment technologies (anaerobic lagoons, solid-liquid separation, anaerobic digestion, and aerobic treatment) are studied for their impact on the production and emission of gaseous pollutants as compared to the manure storage ponds. Research has been carried out to quantify the gaseous emission reductions in manure storages as a result of biological treatment of manure. We have completed laboratory experiments on evaluating the effect of treating manure via anaerobic digestion or aerobic treatment on the gaseous emissions from the storage. We are in the process of setting up experiments to study the effectiveness of surface aeration in lagoons on emission reduction. The results of our laboratory study are summarized as follows. Screen dairy manure of about 2% volatile solids (VS) was either anaerobic digested or aerobically treated prior to storage in an air-tight vessel. Anaerobic digestion was carried out by using a mesophilic anaerobic sequencing batch reactor of 20-day hydraulic retention time (HRT) and 1 g/L/day VS loading rate and aerobic treatment was done by using an aerobic reactor of 10-day HRT and 2 g/L/day VS loading rate. The treated manure was put into the storage on daily basis for a period of 180-days. All the gases produced during this period were captured and analyzed for VOCs, VFA and methane. The liquid samples were also taken from the storage vessels and analyzed for these compounds. The untreated manure was also stored and analyzed in the same way as the treated manure and used as the control for comparison. The six-month experimental results showed that both anaerobic digestion and aerobic treatment had significant effects on the reduction of VOCs, VFAs, CH4, CO2 and H2S in manure storages. Anaerobic process performed significantly or moderately better than aerobic process on the reduction of these gases in terms of mass of individual gas per mass of volatile solid fed. Detailed microbiological analyses were also performed to elucidate the effects of process conditions on the microbial community which are responsible for gas production.