Heathfield IVC Facility
The Heathfield Composting Facility was designed and built by CRS as turnkey contractors for Viridor and the Devon Composting Partnership.
This In-Vessel Composting facility processes a wide variety of kerbside collected organic wastes and has a design capacity of up to 25,000 tonnes per year.
The Heathfield Composting Facility is designed to meet the latest ABPR legislation with the use of the innovative one-way flow system through the composting tunnels.
The waste is delivered into the enclosed reception building by the refuse collection vehicles.
After being unloaded on the floor the material is checked for obvious and removable contamination. It is then loaded into the pre-treatment line by loading shovel for shredding. Water is added to the waste in order to optimise the moisture content for rapid composting. This is done using both high and low pressure water in the CRS Hybelt system. The water used in the pre-treatment is recycled from other parts of the process plant, including leachate and rainwater as required.
Loading of the waste into the first barrier composting tunnels is undertaken by loading shovel.
The CRS composting tunnels have a door at both ends so that the waste can be loaded into one end and emptied at the other. This design has been developed in response to the ABPR and it enables a one way flow of waste through the plant. This approach, preferred by many vets, reduces the risk of cross contamination.
Once a tunnel has been loaded it is then assigned a batch number, and the doors closed whilst the material heats up to thermophillic temperatures.
The CRS composting tunnels are equipped with a floor aeration system which blows air in through pipes on the floor and removes air from above the waste in the tunnel. To monitor the composting process and to ensure compliance with the regulations, temperature probes are inserted through the roof of the tunnel. These probes are connected to radio transmitters which send the data back to the monitoring computer.
After the waste has achieved the ABPR requirement for 60°C for two days, it is transferred to the second barrier composting tunnels. In these tunnels the processes of thermophillic composting continues for a second period. Again, the requirement is for the waste to be held at temperatures in excess of 60°C for two days. Operational requirements usually mean that the overall in-vessel composting time is between 14-28 days. After the waste has been removed from the second barrier tunnels it is placed on the maturation pad. By this stage, the material is starting to cool down and the readily digestible materials have been broken down. The material is held on the pad in windrows and turned on a regular basis.
After a few weeks, the compost is screened to remove the unwanted plastics and oversize. The final product can now form the organic soil conditioner for many applications including land remediation.
The amount of waste being diverted from landfill to the compost facility, for the homes with organic source separation is approximately 30%.
Heathfield Statistics
| Plant Design | CRS |
| Civil Works | CRS |
| Project Management | CRS |
| Operating contractor | Viridor |
| Plant Owner | Viridor |
| Funding | Project part funded by DEFRA |
| Plant construction | 26 weeks from start of construction to first waste input |
| Composting Vessels | Two door tunnels |
| Pre-treatment process | Shredder, Hybelt, screening |
| Maturation | On-site, Open windrow |
| Process monitoring | CRS Batchtrack |
| Number of tunnels | 8 off |
| Tunnel waste capacity | approx 140 tonnes |
