Waste to Energy Plants Summary

Our Technology and Anaerobic Digestion (AD) is a proven, safe Waste to Energy process where organic materials are broken down by micro-organisms in the absence of oxygen, to produce renewable energy and a nutrient-rich biofertilizer.

Anaerobic Digestion Systems can be broadly classified into “wet liquid” digestion or “dry solid” digestion.

Wet Liquid or Low Solid Systems

Wet Digestion Systems are designed to process a dilute Organic Slurry with typically <15% Total Solids. For substrates with higher than >15% Total Solids, this slurry is created by adding Fresh Water, re-circulated Process Water, or another Organic Waste with a lower Total Solid’s percentage to the incoming Waste Stream(s), for example Co-Digestion.

Wet Systems have a successful track record in treating low Solid Materials such as Sewage Sludges and Food Industry Effluents; however, the Wet System approach has had to overcome several challenges to treat Bio-Degradable Municipal Waste or Organic Fraction of Municipal Solid Waste including:

• The production of a Wet Slurry from residual Municipal Solid Waste (MSW) can result in the loss of volatile Organics.
• Mixing is necessary as a wet Slurry inside the Digester will tend to separate into layers of material, with a floating layer of scum at the top of the Digester that may also require breaking.
• The heaviest Particles will settle to the bottom where they can accumulate and reduce the digester capacity over time, or cause damage to pumps.
• The Fibrous Material tends to form strings that wind around the Mechanical Stirrers in certain Systems.
• Minimizing the potential for “Short Circuiting” when particles of Organic Waste are removed from the digester before they have been fully digested, must be addressed at the Design Stage.

Providing that the above points are considered at the Design Stage, a Wet System can provide an effective and robust means of Treating Low Solid content Waste, or High Solid Waste that has been adjusted to <15% Total Solid content.

Dry High Solid Systems

Dry AD Systems digest a Waste Stream of 15% to 40% Total Solids. The physical characteristics of the Wastes at such High Solids Content impose technical approaches in terms of Handling, Mixing and Pre-Treatment, which are fundamentally different from those of Wet Systems. Transport and handling of the Wastes are carried out with Conveyor Belts, Screws and Powerful Pumps specially designed for Highly Viscous Streams such as cement.

The Waste to Energy Plants may require investment but this additional cost can be offset.

EnviroTech International provide Pyrolysis and Anaerobic Digestion Technology as Waste to Waste Energy, Waste to Fertilizer, Waste to Agri-feed, Aquaculture, Water Leachate Treatment with benefits including Less Waste to Landfill, Non Hazardous Residue Waste for Disposal, Less Costs All Round, Make Money with the Waste, Compact and Efficient as well as:

• Environmental Benefits by using Municipal Waste for Power, Fertilizer and RDF Products
• Robust and Low Maintenance Mechanical Solutions
• Environmental Impacts by Water and Land Pollution reductions
• Land Recovery for Re-Development
• Reduction or Elimination of Costs associated with Landfill Aftermath & Monitoring
• Land Remediation Undertaken Sand Reclaimed and Redistributed

Dry Fermentation Digester for MSW

As well as Pyrolysis Technology and Anaerobic Digestion, Dry Fermentation Technology differs from traditional “Wet Digester” Tank Systems that utilize Liquid Feedstock and physically Stir and Agitate Materials with Moving Parts.

Dry Fermentation Technology uses a Batch Style approach where waste material remains stationary during Anaerobic Digestion, requiring no internal moving parts. These attributes allow our Dry Fermentation Digester to Recover Energy from almost any kind of Organic Waste.

The System is comprised of individual Rectangular Fermentation Chambers where the Biomass is loaded by a Front End Loader and remains for 28 days. Modular Construction Design allows the System to be scaled according to the amount of Organic Material available at the Operation, with Annual Waste Streams starting at 8,000 tons.

Dry Fermentation is best suited for Operations that Process Organic Waste with a Total Solids Content greater than 25%, ideal for MSW Biogas produced is collected inside a Flexible Gas Storage Bag and is then continuously fed to the Biogas Utilization source.

Biogas can be either used in a combined Heat and Power (CHP) Unit to generate Electricity and Heat or upgraded to Renewable Natural Gas (RNG) for Gas Grid Injection and Vehicle Fuel as Compressed Natural Gas (CNG).

Advantages Dry Fermentation

Well suited to Process Municipal Organic Waste Basis for the creation of a Circular Economy unlike Thermal Processes being a Linear Economy Integrates well into Composting Operations virtually immune to Physical Contaminants as the input material remains stationary and does not meet any moving equipment inside Fermentation Chambers.

The Batch Process is more stable than a continuously fed complete mix system, so if Bacteria in one Fermentation Chamber are out of balance or underperforming, it is less devastating to the system than other Anaerobic Digestion Systems and the affected Chamber can be quickly remediated by exchanging the Substrate able to recover and recycle Metals. Textiles, Cardboard, Paper and inert materials all can be resold.

Leachate is controlled and Treated E-Waste such as Batteries PC’s TV, White Goods are recovered and disposed of using licensed E-Waste Sub Contractors compliant with the goals of 3 R’s of Waste Management and setting platforms to achieve 7R’s status.

Testing and Commissioning

EnviroTech International will Test and Commission their Pyrolysis Technology and Anaerobic Digestion Waste to Energy Plants as well as Operating and Maintenance Packages together with any Spare Parts.

Locations

Africa, Cairo Egypt, Ghana, Almaty Kazakhstan, Saudi Arabia, Nigeria, Muscat Oman, Doha Qatar, and London UK.