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Anaerobic digestion in secondary cities to produce energy and fertilizer from organic waste, remaining waste is recycled or landfilled



Waste in secondary cities is often abandoned within the city and not transferred to landfills or dumps.  Establishing a waste management systems that collects waste from households and other waste producers enables a city to address the challenge emissions from wste disposal.  Through anaerobic digestion, methane emission from waste can be trapped and utilized to the benefit of the community.  This will not only reduce emissions it will also provide numerous public health and safety benefits, while creating jobs, improving the socio-economic conditions within communities.  Waste collected can be sorted into three streams; organics for treatment in the digestor, Plastics, Papers, Metals for resell to be recycled and reused, and inorganic solid waste to be landfilled.  These three streams should substantially reduce the volume of waste in landfills or abandoned within cities, though reducing emissions.

Category of the action

Reducing emissions from waste management

What actions do you propose?

The creation of a waste management system within secondary cities and the construction of anaerobic digesters.  By encouraging households to separate their waste into two piles, organic and other, will greatly facilitate the process of waste management.  Local residents will be trained on the construction of anaerobic digestions, designs for waste tricycles, and paid to collect waste from households and other waste producers within a city.  Additional workers would be paid to ensure waste is properly sorted, and fed into the digester.  After digestion is operational, workers would be trained on drying bioslurry and packaging for use as fertilizer.  Methane will be used to power generators or small niche customers in the community.

Who will take these actions?

These actions can be undertaken by anyone.  I am interested in testing this concept and approach as a social venture.

Where will these actions be taken?

As I have recently spent some time in Guinea, Conarky, I will use the city of Kankan, as a test and pilot of this idea.

What are other key benefits?

Key benefits are improved public health and sanitation.  Increased employment opportunity.  Skills training.  Greater access to energy or power.  Greater access to organic fertilizer.

How much will emissions be reduced or sequestered vs. business as usual levels?

Because there is no base line of current emission levels it is hard to determine how much is being currently released.  However, because an individual produces approximately .35 kg of waste per day, a city of 500,000 inhabitants produces approximately 170 tons of waste per day.  If approximately 50% of this is organic, the city produces 85 tons of organic waste a day.  If even 1 ton of waste produced 10 m3 of GHG, this would result in over 850 m3 of gas per day.  This approach aims to collect at least 75 % or all waste, or 127 tons, of which 63 tons would be organic.  Reducing the emissions of GHG from waste by this much.

What are the proposal’s costs?

The proposal cost approximately $50,000.  This include airfare, food and lodging for 3 years.  Airfare to Guinea, is approximately $1,500.  allowing for 5 trips to the US during this time, $7,500.  Room and board is calculated at $700 per month, with $500 being the cost of a house that would function as an office.  Tricycles are believed to cost approximately $300 per, the pilot will require 20 to serve 6,000 households or 42,000 residents, full operations would require an additional, 200 tricycles.  Waste collections are paid $40 per month, the pilot requires 20 collections, while full operations requires 200. For this 1 year of the pilot this means $9,600 and for the full operations $96,000.  I will include the combined salary for waste operations.  Digestion construction is estimated to cost approximately $6,000 for the pilot, and $15,000 per digestion in full operations.  Uniform and equipment for operators is estimated at $35 per, $750 in the pilot year, $7,000 in the second test year.  Office supplies and equipment are estimated at no more than $5,000 over the two years.  Land rent is estimated at $400 per month, $4,800 - year 1 and $9,600 - year 2, totaling $14,400.  As a precaution .35 of the sum of cost is included and accounted for as incidentials or unexpected occurrences.

Cost summary: Airfare = $7,500; Room and Board = $25,200; Waste Tricycles = $6,000; Salaries for waste collectors for 2 years = 105,600; Digestions = $21,000;  Uniform and equipment = $7,750; Office supply = $5,000; Land Rent = $14,400, Unexpected cost = $67,375

Total estimated cost = $259,825



Time line

This proposal would begin as a pilot project, operation for 1 year for a designated number of households within the city.  The first three months would be a period of obtaining local recognition, permission and support.  After which, the building of waste tricycles would be commissioned and individuals hired to collect waste.  A digestion would be constructed after 3 months of waste collection operations.  If operations for the first year demonstrates that waste can be effectively collected and organics fractions are reasonable, operations would expand to cover the entire city.  The process would require the constructing of additional tricycles and the training of additional collectors.   Digestors will be constructed to after 1 month of waste collection.  

Related proposals

There are several projects that aim to conduct the same general idea of transforming waste to energy.  However, at present, none have focused on the scale of secondary cities, or on solid waste management.  The focuses of other proposals have been either recycling and reuse of waste, or the collection of human waste to generate energy.


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