Carbon sequestration of organic wastes via pyrolysis. Waste to energy and biofertilizer approach, and farm dispersal vs landfilling.
The energy and nutrient value of organic wastes are recovered via a combination of pyrolysis and composting. Biochar derived from pyrolysis of woody wastes are mixed with wet food wastes to enhance and accelerate composting while reducing methane, nitrous oxide and ammonia emissions.
Heat and power from pyrolysis will be used to drive an in-vessel compost bioreactor.
Biochar-compost blends are then used for tree nurseries, parks, and community vegetable gardens to enhance plant biomass and carbon sequestration.
Excess woody wastes are used to create more biochar for use in municipal sewage treatment plant to reduce carbon dioxide and nitrogen emissions. The spent biochar will be collected and applied as a soil amendment for parks.
Category of the action
Reducing emissions from waste management
What actions do you propose?
Who will take these actions?
Where will these actions be taken?
I believe that Marikina city in the Philippines is a suitable place to implement a pyrolysis project. The city has an effective solid waste management program with segregation at source is a practice, and households and communities participate and a strong public policy. It is considered as one of the greenest city in the Phililppines and has been recognized internationally.
Most of the recyclables are recovered while less than 6% of organic wastes are diverted from landfills via rapid composting with an in-vessel bio-reactor.
Marikina city has a population of 500,000 and produces 350 tons of garbage everyday, composed of 21% of food wastes, much of this comes from households at 74% while the market generates 8% of the solid wastes, mostly in the form of crop/plant and animal residues. Household wastes also contributes as much 18 tons per day of grass clippings and woody materials.
What are other key benefits?
The biochar-composting strategy will affect local biodiversity and aquatic resources, as well as human resources and the local economy. Surrounding farmlands close to the capital would benefit from organic fertilizers that can be subsidized by the national and local government units.The need for the dispersal of biochar-composts would warrant end-user farmers for tons of materials that are generated on a daily basis. Farmers who would recieve "free" organic fertilizers would have significant gain with minimal costs to grow crops.
A successful implementation will result to significant reduction of landfill's overall environmental impact upon scale-up for the cities of Metro Manila, Philippines. Green jobs can be created for the pyrolysis facilities that would be built, and for the operation of more composting facilities that would be required, gardeners who will tend to urban tree nurseries and community vegetable gardens.
How much will emissions be reduced or sequestered vs. business as usual levels?
For Marikina city, as much as 24 tons per day of woody organic wastes can be diverted from landfills and as much as 25 to 50% carbon content can be sequestered in the form of biochar, usually produced at 20% of the original weight of the wastes. Using the combined heat and power produce to operate the thermophilic bioreactor, shredders and mixers may also reduce the carbon footprint of the composting facility.
Adding biochar at a rate of 3% to compost mixed with sawdust, horse manure and food wastes may reduce nitrous oxide emissions by 24%.