Composting
Composting Process Control
C:N Ratio * Organic mixture will have to provide the microbes with the correct balance of carbon and nitrogen. The ideal ratio for a composting mixture is accepted to be C:N 30. * C:N ratios within the range of 25:1 to 40:1 result in an efficient process. * High C:N ratio - without adequate nitrogen, microbes lack the tools required to break down carbon sources. The process will proceed very slowly. * Low C:N ratio - nitrogen in excess of what the microbes need to break down the available carbon can easily be lost to the atmosphere as ammonia gas. * C:N ratio for EFB is 60, other materials such as manure (normally 20% of EFB) and POME must be added to achieve C:N of 30 for optimum composting process.
Particle size * 0.5 – 2 inches – best balance of moisture retention and oxygen diffusion. * Too large * Good aeration but will dry out quickly. * Low surface area – low microbial activities. * Too small * Good moisture retention * Easily become anaerobic because air can’t infiltrate easily.
Control of Moisture * 45 – 60% of Moisture content. * Low biological reaction if too dry * Anaerobic conditions will dominate the composting process if too wet. * Slowing decomposition * Generating foul odor
Control of Aeration * Air requirement is determined by the nature of the composting materials and the stage of the composting process. * > 5% of oxygen content * Aeration also provides a means of cooling down the composting material when overheated. * Air requirements can roughly be assessed by observing the color and smell of the compost. * Under the following conditions, more air is needed: * There is an objectionable odor from the windrow. * Color is lighter in the inner section of the windrow. * The composted materials are too wet
Temperature
* > 65oC indicates active process of microbes. * 3 stages * Initial
C:N Ratio * Organic mixture will have to provide the microbes with the correct balance of carbon and nitrogen. The ideal ratio for a composting mixture is accepted to be C:N 30. * C:N ratios within the range of 25:1 to 40:1 result in an efficient process. * High C:N ratio - without adequate nitrogen, microbes lack the tools required to break down carbon sources. The process will proceed very slowly. * Low C:N ratio - nitrogen in excess of what the microbes need to break down the available carbon can easily be lost to the atmosphere as ammonia gas. * C:N ratio for EFB is 60, other materials such as manure (normally 20% of EFB) and POME must be added to achieve C:N of 30 for optimum composting process.
Particle size * 0.5 – 2 inches – best balance of moisture retention and oxygen diffusion. * Too large * Good aeration but will dry out quickly. * Low surface area – low microbial activities. * Too small * Good moisture retention * Easily become anaerobic because air can’t infiltrate easily.
Control of Moisture * 45 – 60% of Moisture content. * Low biological reaction if too dry * Anaerobic conditions will dominate the composting process if too wet. * Slowing decomposition * Generating foul odor
Control of Aeration * Air requirement is determined by the nature of the composting materials and the stage of the composting process. * > 5% of oxygen content * Aeration also provides a means of cooling down the composting material when overheated. * Air requirements can roughly be assessed by observing the color and smell of the compost. * Under the following conditions, more air is needed: * There is an objectionable odor from the windrow. * Color is lighter in the inner section of the windrow. * The composted materials are too wet
Temperature
* > 65oC indicates active process of microbes. * 3 stages * Initial