Anaerobic Digestion (AD) is a biological process in which bacterial microorganisms break down organic material in the absence of oxygen.

One of the end products is biogas, a mixture of Carbon Dioxide (CO2) Methane (CH4). Biogas can be combusted to generate electricity and heat, or can be processed into renewable natural gas and transportation fuels.

Anaerobic digestion systems are converting livestock manure, agricultural residues, municipal wastewater solids, food waste, high strength industrial wastewater and residuals, fats, oils and grease (FOG), and various other organic waste streams into biogas, 24 hours a day, 7 days a week.
 
Another product resulting from Anaerobic Digestion is digestate.  Separated digested solids can be composted, utilized for dairy bedding, directly applied to cropland or converted into other marketable products.  because of the high nutrient content in the resulting liquid effluent stream it can can be used in agricultural applications to displace fossil fuel based fertilizers.
 
Layne Heavy Civil offers complete EPC (Engineer Procure Construct) services utilizing proven European biogas technology for your renewable energy project. 
 
Layne has partnered with experienced industry leaders in the AD field offering over 30 years of experience in the design, construction and commissioning of biogas plants worldwide.  This teaming arrangement provides the renewable energy industry the full service construction capabilities of a nationally recognized water resources contractor with proven performance of state of the art European technology. 

 

BENEFITS OF ANAEROBIC DIGESTION
  • Renewable and Sustainable
  • Continuous Energy Delivery 24/7/365
  • Environmentally Responsible Management of Organic Waste
  • Reduction of Carbon Footprint
APPLICATIONS FOR ANAEROBIC DIGESTION
Food, Municipal, and Industrial Waste
  • Market and restaurant waste source separated organics
  • Food production industry (solid waste/wastewater)
  • Distilleries, bioethanol and biodiesel producers
Agriculture Waste
  • Livestock industries and/or agricultural production of energy crops
  • Rendering and animal processing plants
Municipal Sewage Sludge
  • Raw or treated biosolids
  • Co-digestion with biosolids
Determining the Right Digester System
  • Composition and physical/chemical characteristics of the input material
  • Characteristics of the industrial production processes
  • Condition of the construction site
  • Costs/benefits expectations of the client

To provide optimal performance, Layne can offer a number of different digestion systems to allow the most optimized process and highest biogas production yield for each application and project scale.

CSTR- Digester System

The most common biogas system is a complete mix CSTR-Digester.  The CSTR features a gas tight, vertical, cylindrical digester vessel.  The mixing of its contents is provided by a centered vertical low-speed agitator which is characterized by its high circulation rate.  Thus the digester content is perfectly mixed.

At the same time, the low rotation speed guarantees gentle treatment of the anaerobic microorganisms and due to continuous mixing, provides optimal substrate transport for the bacteriological degradation of the organic substances into biogas. 
 

The CSTR-Digester technology is suitable for the treatment of higher solid materials, such as bio waste and sludge, as well as for scum developing material. Sediments can be removed easily during operation. It is especially suitable for large scale biogas plants because of construction sizes of up to 1.9 million gallons (7,500 m3).

This digester type is commonly used for the treatment of all kinds of degradable organic wastewater or sludge, animal manures, industrial and commercial organic waste streams from the food industry, restaurants, grocery stores, etc.

TYPICAL Process FlOW DIAGRAM