Gaia, a concept that has already been highly successful in Europe, Japan, USA and Canada, involves automatically heating, shredding, dehydrating and deodorizing organic waste in a closed chamber, usually on the premises where the waste is generated. The equipment should be located under cover, as close as possible to the main area of waste generation. The batch process requires only the input of electrical power for motors and heat energy (electricity or gas), while the outputs comprise condensed water and a dry biomass, both of which are free of pathogens.
Unlike many other processes, the Gaia system requires no additives:
- NO water
- NO sawdust
- NO woodchips
- NO enzymes
- NO microbes
Untreated organic waste is added to the Gaia chamber (either gradually or in batches from storage bins or buckets) until the chamber is two thirds full. Once the loading is complete, the lid is closed and latched securely before the “Start” button is pressed. The process thereafter is automatic and takes approximately 6 to 8 hours to complete.
The waste is kept in constant motion by the rotating agitator while thermostatically controlled hot air is circulated through it. In this way, the physical structure of the waste is broken down while the temperature is elevated -akin to the cooking process in a stirring kettle -creating an “organic stew” inside the machine. Bacteria that cause rotting are killed as the temperature rises above 40°C while thermophyllic bacteria (or archaea) are activated at 70°C and above. These latter cause rapid fermentation of the waste, breaking down the cellular structure while also promoting the production of yeast which is a highly desirable component of soil amendments.
The water content of the waste evaporates during this process and is passed over an ambient temperature condenser where it returns to liquid form and passes out of the machine at a temperature of approximately 40°C. This condensate is virtually pure but may have a slightly elevated mineral content. It may be drained to sewer without any environmental concerns or liquid trade waste issues or, if appropriate, it may be captured for use in water applications such as cleaning, toilet flushing or irrigation.
Once the dehydrating phase is completed, the heat source is switched off while the agitator, condenser and circulating fan continue to run, allowing the contents of the chamber to cool. At the end of this phase, the unit shuts down pending the intervention of an operator to initiate the unloading process.
Remaining in the chamber at this point is a dried, nutrient rich biomass that is between 10% and 15% of the original volume of the untreated waste, it is inert in that all bacteria, pathogens and seeds have been neutralized in the processing and it is so dry that it may be stored on site, if necessary, for many days. It is unloaded automatically from the Gaia unit through a hatch on the front face of the machine. The biomass is virtually odorless.
Options for disposing of the biomass include:
- use directly as a soil amendment,
- use as brown waste in a composting process,
- add to finished compost to achieve a desired nutrient balance
- use as a supplement for animal feed (subject to local regulations),
- conversion to heat briquettes for use in biomass boilers or in gasification systems
- dumping to landfill, in the knowledge that the volume, cost and “rotting factor” have been greatly reduced.
GAIA’s modular treatment units range from 30 kg to 2000 kg capacity per c y c Ie. The larger capacity units incorporate conveyors and other materials handling solutions according to site needs. “Capacity per cycle” is defined on the basis that in a single, 6 -8 hour shift one process will be completed and a second one will be started which can run unattended for unloading at the commencement of the following day’s shift.
Larger plants capable of processing up to 100 tons per day are also available -these and the 3000 kg unit perform a cycle in roughly 18 hours.
The sustainable benefits of the Gaia process are:
- The dramatic (if not total) reduction of organic waste in landfill saving landfill
space for other purposes and eliminating the anaerobic rotting of the waste
which generates methane and leachate.
- The elimination of carbon emissions that would otherwise result from
transporting the waste to disposal sites.
- The utilization of the condensed water within or outside the client’s business.
- It requires no additives such as water for the processing of the waste
- It is not a pulping system and therefore does not discharge water with high
Total Suspended Solids and / or generating a high BOD (Biological Oxygen
- It is not an enzymic system and does not discharge water from which solids
may precipitate downstream.
The economic payback from the process arises from the long term reduction or elimination of fees for collection organics in bins and paying landfill tipping fees
OTHER GAIA MODELS WITH SPECS