Temperature Effects On Pig Manure Under Low Level Batch Aeration

This project investigated the temperature effect on some chemical and biological characteristics of liquid swine manure under low level batch aeration conditions. An airflow rate of 0.129 L/min/L manure was used to aerate manure contained in reactors made of plexiglas tubes. Five temperatures, i.e. 5°C, 10°C, 15°C, 20°C, and 25°C, were examined. Data showed that manure pH would decrease with an increase in temperature. When temperature increased from 5°C to 25°C, the average oxidation-reduction potential decreased from +40 mV to m 60mV, resulting in a decrease in aerobic counts from 5.5 2 10 6 to 2.2 2 10 6 . This was accompanied by an increase in anaerobic bacterial counts (from 3.8 2 10 6 to 5.1 2 10 6 ). The increased anaerobic population produced more volatile fatty acids, leading to the decrease in pH. An inversely linear correlation was observed between pH and volatile fatty acids with a correlation coefficient of 0.8742. To prevent aerobic bacteria from decreasing and anaerobic bacteria from increasing, manure temperature should be kept under 15°C during aeration. To reduce odor generation potential (based on reduced VFA production), the oxidation-reduction potential should be maintained at +35 mV or higher.

Keywords:

• Temperature
• Aeration
• Swine Manure
• Aerobes
• Anaerobes