Mannvit provides consulting in all areas of facility planning, permitting, design, construction and operation of composting plants.


Composting plants are designed to utilize organic waste materials from slaughterhouses, meat and fish processing, as well as food waste, paper, timber, garden waste and animal manure. Composting plants are an important step in minimizing the landfilling of organic waste and, in reaching environmental goals for a given area. The plants must fulfill the EU’s animal by-product regulation (EU ABPR). 

The waste is shredded to a uniform size and then mixed in a controlled way to ensure desired properties of the composting mixture (C/N-ratio, moisture content, etc.).  Digestion time in drums is 8-12 days followed by a maturing period outdoors, which is typically 3-6 months. 

Composting offers the benefits of resource efficiency and creating a useful product from organic waste that would otherwise have been landfilled and can offset a need for chemical fertilizer. 

Project experience

Mannvit played a lead role in the design and construction of a composting plant in North Iceland that opened in 2009, and is owned by municipalities in Eyjafjördur, food production companies and others


A full list of services includes:

  • Planning Studies
  • Waste Stream Assessments
  • Technology Assessments
  • Process Evaluations
  • Economic Studies
  • Siting Analysis
  • Environmental Impact Assessments
  • Environmental Permitting

Materials Recovery Design

  • Material Flow Analysis
  • Building Design
  • Storage Requirements
  • Material Handling Design
  • Sorting Systems
  • Baling Systems
  • Emission Odor Control
  • Instrumentation/Control
  • Vendor Procurement
  • Plans & Specifications

Composting Design

  • Pre-processing Considerations
  • Process Design and Modeling
  • Materials Handling and Transport
  • Size Reduction Requirements
  • Mixing Requirements
  • Aeration Requirements
  • Digestion Systems
  • Instrumentation/Controls
  • Emission Odor Control
  • Indoor Air Quality
  • Facilities
  • Facility Enclosure
  • Plans and Specifications
  • Bid Documents

Construction Services

  • Construction Inspection
  • Construction Management
  • Start-up Testing
  • Performance Testing
  • As-built drawings
  • Claims Management

Composting offers the benefits of resource efficiency and creating a useful product from organic waste in an eco-friendly way and can offset a need for chemical fertilizer.