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Dry Litter Technology System
is a waste management system that offers adaptable solutions for small-scale piggery operations. The Dry Litter Technology (DLT) focuses on beneficial uses of nutrient resources through natural composting processes. DLT incorporates the use of carbon materials, sloping pen floors, and requires no water for pen clean-up. The pig wastes are mixed into the carbon-rich materials and discharged out of the pens by the pigs. Through this process, odor is significantly reduced on the system. The carbon mix is then properly composted, resulting in a rich, organic soil amendment for crop production.
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Timeline of Outreach and Extension Conducted by Glen Fukumoto to Promote DLT System
1995-1996 – A US EPA 319 research project was completed by Glen Fukumoto from the University of Hawaii at Kealia Farms, Honaunau, Hawaii Island and at Masazo Hog Farm, Naalehu, Hawaii island.
1997 – The first outreach and introduction of the technology by Glen Fukumoto, University of Hawaii, to the Pacific island nations was through a presentation at the Pacific Island SARE Professional Development Program Training Session in Kolonia, Pohnpei. This workshop was sponsored by the Western Region Sustainable Agriculture Research and Education (SARE), Agricultural Development in the American Pacific (ADAP) Program, and the College of Micronesia-FSM.
1999 – National exposure and the results of the research work were published as a proceedings article.
2001 – American Samoa Community College workshop presented to farmers and government agency educators.
2001-2002 – USDA NRCS and American Samoa EQIP Jim Wimberly “Pigs in Paradise”.
2005 – American Samoa EPA Assessment. Pigs in Paradise II, AS EPA, ASCC Visit to Big Island.
2004, 2009 – Northern Marianas College workshops presented to farmers and government agency educators.
1997, 2004, 2005 – University of Guam, workshops presented to farmers and government agency educators.
1997 – College of Micronesia, Pohnpei workshop presented to farmers and government agency educators.
2010 – Piggery Assessment in the Republic of Palau.
2010 – Reconnaissance to American Samoa, compliance & DLT implementation.
February 2011 – the first Dry Litter Technology Summit in Pago Pago, American Samoa.
March 2011 – Palau National Water Summit, vision for DLT.
April 2011 – Piggery Assessment of Majuro, Republic of the Marshall Islands.
June 2011 – Piggery Assessment of Pohnpei, Federated States of Micronesia.
July 2011 – Tinian DLT Assessment, Saipan DLT double-wing.
August 2011 – GPS and Google Earth Mapping for Pohnpei EPA, Leptospirosis Study. Preliminary water testing conducted.
December 2011 – Federated States of Micronesia Piggery Advisory Council (PAC) formation.
January 2012 – Leptospirosis Study preliminary findings, S. Colt.
February 2012 – Federated States of Micronesia, PAC Strategic Planning.
February 2012 – Palau and Pohnpei Compost demonstration trials.
March 2012 – Pohnpei water testing project conduced with M. Hura.
1997 – The first outreach and introduction of the technology by Glen Fukumoto, University of Hawaii, to the Pacific island nations was through a presentation at the Pacific Island SARE Professional Development Program Training Session in Kolonia, Pohnpei. This workshop was sponsored by the Western Region Sustainable Agriculture Research and Education (SARE), Agricultural Development in the American Pacific (ADAP) Program, and the College of Micronesia-FSM.
1999 – National exposure and the results of the research work were published as a proceedings article.
2001 – American Samoa Community College workshop presented to farmers and government agency educators.
2001-2002 – USDA NRCS and American Samoa EQIP Jim Wimberly “Pigs in Paradise”.
2005 – American Samoa EPA Assessment. Pigs in Paradise II, AS EPA, ASCC Visit to Big Island.
2004, 2009 – Northern Marianas College workshops presented to farmers and government agency educators.
1997, 2004, 2005 – University of Guam, workshops presented to farmers and government agency educators.
1997 – College of Micronesia, Pohnpei workshop presented to farmers and government agency educators.
2010 – Piggery Assessment in the Republic of Palau.
2010 – Reconnaissance to American Samoa, compliance & DLT implementation.
February 2011 – the first Dry Litter Technology Summit in Pago Pago, American Samoa.
March 2011 – Palau National Water Summit, vision for DLT.
April 2011 – Piggery Assessment of Majuro, Republic of the Marshall Islands.
June 2011 – Piggery Assessment of Pohnpei, Federated States of Micronesia.
July 2011 – Tinian DLT Assessment, Saipan DLT double-wing.
August 2011 – GPS and Google Earth Mapping for Pohnpei EPA, Leptospirosis Study. Preliminary water testing conducted.
December 2011 – Federated States of Micronesia Piggery Advisory Council (PAC) formation.
January 2012 – Leptospirosis Study preliminary findings, S. Colt.
February 2012 – Federated States of Micronesia, PAC Strategic Planning.
February 2012 – Palau and Pohnpei Compost demonstration trials.
March 2012 – Pohnpei water testing project conduced with M. Hura.
Benefits
The positive impacts of the DLT system to our environment and natural resources, viewed from the larger perspective, are substantial. The waste system uses no water for pen clean up. The waste collection area is sealed to prevent seepage to ground or surface water resources. There is no over-flow potential (typically of waste lagoons) in a 25-year, 24 hour storm event since there are no water retention ponds. Furthermore, roof rainwater is diverted from the facility preventing polluted runoff from entering precious water resources. Nuisance threat of odor and vectors are minimized. Animal hoof action effectively reduces fly breeding sites. Heat of composting reduces parasite and other vector buildup. Odor is minimized through the carbon interaction with nitrogen in the co-composting process. And, recycling of landfill-clogging greenwaste extends future capacities of these community facilities leading to reduced land area requirements and cost to municipalities.
The level of acceptance by the industry indicates that the DLT system will continue to dominate the design of new facilities, and renovation of older confined pig facilities throughout Pacific-Basin island nations. The transfer of technology into the Pacific Basin will continue to depend on the local conservation districts, local governments, the US Environmental Protection Agency and the USDA Natural Resources Conservation Service.
The level of acceptance by the industry indicates that the DLT system will continue to dominate the design of new facilities, and renovation of older confined pig facilities throughout Pacific-Basin island nations. The transfer of technology into the Pacific Basin will continue to depend on the local conservation districts, local governments, the US Environmental Protection Agency and the USDA Natural Resources Conservation Service.
Pen Slope
The key to the system is the sloping pen floors and the carbon source in your area. The sloping floors and the force of gravity cause the carbon material to flow out of the pen and into the holding trench. Steeper slopes result in a higher flow of materials through the pens. The movement of material out of the pens will also depend on the type of dry litter material used. The cement slabs should be sloped at approximately 3-5 degrees towards the waste alley with at least a 6” drop at the back of the pens to allow for piling up of the bedding material. At the bottom of the pig pens, there should be a gap between the floor and the back wall so that the carbon material can slide through fairly easily. This gap does not need to go completely across, just enough to allow for an even flow of materials.
Carbon Materials
Various types of carbon materials have been used for litter material, including macadamia nut husks, wood chips from commercial tree trimmers, and coconut husks. After many piggery visits, carbon resources have been observed to be plentiful throughout the islands. However a coordinated educational effort needs to be developed for future collaboration in creating centralized hubs for carbon collection and processing and distribution to interested farmers. The photographs below show a couple of examples of excellent carbon material for use in dry litter and composting systems. The branches would need to be chipped, manually or by proper equipment, for use in these systems.
A coarse (> 5 cm) carbon material will require a steeper slope compared to moderate-sized particles (3-5 cm) used as litter material. The most effective slope for macadamia nut husks is 20 to 1; the steeper slope, 8:1, works better for commercial tree trimmings. Materials with a low bulk density, like a long hay-type of material, tends to mat down in the pens and clog the system and is not recommended as a carbon material for this system. The carbon-nutrient mix needs to flow out of the pens in order to achieve the second benefit of the system. The separate composting trench is the second critical design element that prevents the pigs from exposure to the pre-compost material where excessive heat is generated or may be a reservoir of diseases and/or parasites.
A coarse (> 5 cm) carbon material will require a steeper slope compared to moderate-sized particles (3-5 cm) used as litter material. The most effective slope for macadamia nut husks is 20 to 1; the steeper slope, 8:1, works better for commercial tree trimmings. Materials with a low bulk density, like a long hay-type of material, tends to mat down in the pens and clog the system and is not recommended as a carbon material for this system. The carbon-nutrient mix needs to flow out of the pens in order to achieve the second benefit of the system. The separate composting trench is the second critical design element that prevents the pigs from exposure to the pre-compost material where excessive heat is generated or may be a reservoir of diseases and/or parasites.
Water
Animal Performance
Odor
Odor is minimized through the carbon interaction with nitrogen in the co-composting process. In a study conducted in 2002 (Fukumoto & Tulang, 2002), odor levels were measured using the hydrogen sulfide parameter. The DLT system offers a management technique to controlling critical odor generating points by adjusting the carbon allocation to the pens. Worker safety and risks, in regards to hydrogen sulfide exposure, is very low. Workers do not enter the production area during normal daily operations. The facility has a high roofline and no solid vertical walls, which allow for more than adequate ventilation.
Pest Control
Animal hoof action effectively reduces fly breeding sites. Heat of composting reduces parasite and other vector buildup.
Labor
Collecting manure and carbon material from the waste alley
From experiences in American Samoa, DLT operators spend less time managing and operating the system compared to a wash down system. Adding and maintaining the dry litter in the pens takes approximately 3 days per week to make sure that there are adequate levels of new dry material to absorb the manure and liquids. This would take approximately 1 hour per week (4 hours per month). Every two weeks, the waste alley is cleaned up and placed into the first composting bin. If all bins were fully loaded, management time to transfer the compost material from bin to bin would take approximately 2 hours (4 hour per month). Collecting carbon and grinding would take about an hour per week (4 hours per month). The total labor is 12 hour per month toward a potential revenue generating activity (composting) compared to an activity (wash down) that will not generate any future revenues. At $2.00/hour labor cost, the annual carbon management cost would be $288.