Reducing the amount of bio-waste that will be landfilled waste can be done also through anaerobic fermentation into sealed tanks with the biogas production.
The technology require an high quality operating and maintenance personnel, a certain quality and specific composition of wastes used, also higher costs than aerobic composting.
Anaerobic fermentation is a biological treatment method which can be used to recover both the nutrients and energy contained in biodegradable municipal waste. Further, solid residues generated during the process are stabilized.
The process generates gases with a high content of methane (55-70%), a liquid fraction with a high content of fertilize content (not in all cases) and a fibre fraction. Waste can be separated into liquid and fibre fractions before fermentation, liquid fraction being move away by an anaerobic filter with a retention period shorter than the required brief for waste gross treatment. Separation may be executed after fermentation gross waste fibre fraction so that it can be recovered for use, such as a breeder soil. Fibre fraction tends to be small in volume but rich in phosphorus, which is a valuable resource and poor globally.