Environmental Impacts and Benefits of an AD system
In terms of a local community plant with animal and food waste collection the benefits anticipated would be:
- Decreased volume to landfill.
- Decreased pathogen levels.
- Prevents methane release to the atmosphere.
- Collected biogas provides a source of renewable energy.
- Compliments existing waste source separation schemes.
- Fosters awareness and interest in organic waste minimisation.
- Decreased pathogen level in manure spread on crop land.
- Prevents methane release to the atmosphere
Certain communities and locations may encompass complex environmental issues:
Nitrogen Vulnerable Zones - these are areas of high potential leach rates from land to watercourses. With the advent of the EU Water Framework Directive these areas are under increasing pressure to ensure carefully monitoring and control to regulate nitrogen loading to watercourses.
These areas are governed by DEFRA and SEPA and are managed by imposing
- Strict limits on quantities of nitrate application to land to avoid watercourse loading
- Seasonal restrictions on manure and fertiliser spreading
The inclusion of an AD system in the locality could prove beneficial to communities in NVZ catchment areas, as this would help remediate the problem that faces many farmers in these areas at present; the storage and treatment of animal waste material that cannot be spread on the land due to seasonal and nitrate loading restrictions. At present there are restrictions in Scotland that prohibit application of manure to land from September to February. Nitrate applications must also be matched to limits which may also mean restrictions on manure spreading. This then necessitates a secure storage system for animal manure collected during this period and that is in excess of requirements for spreading on the farm. An AD system that could utilise the excess manure from farms within NVZ areas could have a beneficial financial impact on the farming community in that it could help reduce the need for costly manure storage facilities. Also as the liquor fertiliser is essentially a more tailored fertiliser than untreated manure as nutrient levels and composition is more consistent throughout the year, it could be applied in a manner that helps comply the NVZ nutrient loading limits in a more efficient manner than normal manure spreading.
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