Appropriate Assessment of Anaerobic Digestion Facilities, Ireland


BSG Ecology was commissioned by ORS Consulting Engineers to prepare Appropriate Assessment screening reports for Anaerobic Digestion (AD) facilities in Counties Kildare, Westmeath, Meath and Dublin, Ireland.

The proposals concerned the development of anaerobic digestion facilities to process a variety of products including foodstuffs beyond their ‘sell by’ dates, domestic (brown bin) food and agricultural waste. Each facility will produce a digestate to be used as organic fertiliser. Rainwater harvesting systems will be employed at all of the anaerobic digestion facilities to reduce their water demand.

BSG Ecology’s Role in the Project

Our approach to preparing the Appropriate Assessment reports began with reviewing the design, construction methods and operational details of each proposed development. Initial desk-based work also included a review of the interest features and conservation objectives of Natura 2000 sites (Special Areas of Conservation (SACs) and Special Protection Areas (SPAs)), in the area of the development concerned, and the identification of other plans, projects and strategies that might lead to in-combination effects.

Working closely with the design team enabled us to gain an understanding of the processes involved in the construction and operation of the AD facilities, and in turn to identify potential ecological impacts. For example, AD facilities operate as a closed system that result in no net increase in gases emissions to the atmosphere or increase in atmospheric deposition of particulates upon habitats, The schemes also included detailed drainage plans, designed to minimise the risk of emissions to water.

This understanding allowed us to screen out potential impacts from emissions on habitats and species listed as qualifying interests of Natura 2000 sites.

The output in each case was an Appropriate Assessment screening report. Each report included a summary of the requirements of relevant legislation and guidance, in addition to summarising the assessment methods and criteria for the screening process.

The reports provided the basis from which to consider the potential for significant adverse effects to occur at any stage in the development process (construction, operation and decommissioning).


In all cases the screening report, which was submitted as part of the planning application, considered the proposed anaerobic digestion facility to be unlikely to give rise to significant impacts on Natura 2000 sites.

This outcome was largely due to the contained nature of the anaerobic digestion facilities which minimise the risk of emissions to either air or water. By considering these details early in the process, and working closely with the project design team, we were able to produce a positive screening report in each case.



ORS Consulting Engineers

Key Services

Appropriate Assessment

Energy, Ireland