RealOrganic Transfer Stations
Wherever concentrated organic waste is found, impurities are found as well;
- Municipal Solid Waste Transfer Station Waste – Organics are mixed with municipal solid waste, about 3 pounds per person per day
- Agricultural On-Farm Waste – Organics are mixed with ear tags, barbed wire, sand, bones and nondigestable lignin (woody waste) find out here
- Food Manufacturing/Retail Waste – Organics are found in plastic bottles, glass jars, cardboard boxes, metal cans, wood pallets, bins, plastic mesh bags
- Green Waste – Organics are mixed with nondigestable lignin (woody waste)
- Source Separated Food Waste – Organics are mixed with packaging, utensils
These impurities must be removed, preferably prior to anaerobic digestion at a RealOrganics Transfer Station. Each station is designed for the anticipated waste, but may include shredding, crushing, heating, pulping, extrusion, cyclone, settlement and storage technologies often designed into a building with negative air pressure and biofilters for odor control. An organic slurry or cake with nearly 95% purity is then ready for digestion onsite, or at a network of nearby anaerobic digesters.
Typically, a final water based organics cleaning step is applied at the digestion facility where recycled water is available and contaminated water can be managed. Heavies (grit, sand, batteries and glass) and lights (bits of plastic and film) are removed and an engineered slurry is dosed into the digester.
This may be a ‘dedicated’ private or municipal digester for producing biogas and a high-value liquid organic fertilizer, or a ‘non-dedicated codigester at a public waste water treatment. After digestion, the composted solids can be utilized for soils amendments, fertilizer and mulch in agriculture and horticultural markets. Biogas and compost utilized from organic waste will generate landfill diversion credits, and greenhouse gas/carbon credits for sale or use (from avoided landfill emissions, and potentially from decreased synthetic fertilizer usage, decreased water use, increased soil carbon storage, decreased soil erosion, and decreased herbicide use).
Biogas utilization may follow a hierarchy of use based on its value/demand. For example, biogas may be utilized;
first, for vehicles (estimated 5 million gallons equivalent in 2015, 111 million gallon in 2020)
second, for a stationary gas engine generating combined heat and power for onsite renewable electricity use
third, for exported renewable electricity
fourth, for natural gas pipeline injection as exported renewable gas (essentially using the public gas grid as storage)
Each of these utilization options requires different levels of cleaning, compression, metering, monitoring and verification. Whatever the use, compared to diesel fuel or traditional electricity generation, it’s cleaner, cheaper, abundant and domestic.
Biogas, renewable natural gas, can serve onsite cogeneration plants generating renewable electricity and thermal energy for onsite use or export to the grid. The thermal energy (heat/steam) is now used around the world for nearby digesters, food processors, cold storage, data center cooling and greenhouse heating.
RealBiogas CNG Filling Station
With 14.8 million natural gas vehicles worldwide, only 114,000 can be found in the United States.
These US vehicles are mostly buses and refuse vehicles. But with the recent accessibility to a 120 year supply of low cost domestic natural gas, lower engine operating costs, proven engine performance, lower emissions and quieter vehicles, 25% of new transit fleet orders are now natural gas powered. Over 1,100 natural gas fueling stations can be found in the United States.
Onsite biogas filling stations can serve biogas, natural gas and blends to achieve fleet sustainability goals. RealEnergy can sell biogas indexed to natural gas prices by keeping the low carbon fuel state and federal credits, holding these credits and selling them at the optimal time.
Gas storage is expensive. Today’s biogas plants serving vehicles must balance the consistent supply with intermittent demand by injecting gas into the public gas grid. This gas can be moved to natural gas fueling stations, cogeneration plants and public utility gas turbines to satisfy their renewable portfolio standards.