Food for thought, manure to energy

How pig farms can benefit from on-farm anaerobic digestion to better manage odour

Written by Plistina Almeida and Simon Welchman

 

Anaerobic digestion is a great source of renewable energy that is becoming an important part of the “circular economy” around the world.
Livestock farms face several everyday challenges. Managing wastes is definitely one of the more unpleasant tasks. Traditionally, poor management of manure, effluent and sludge has caused a range of environmental and other concerns.

 

Piggeries with on-farm biogas production can greatly benefit from the large volume of waste that is produced. Think about what could be done with about 5kg of poop per pig per day!

• Using an anaerobic digestor, waste is essentially eliminated and odour and ammonia emissions into the atmosphere are reduced
• Manure and other farm wastes can be used to produce biogas
• The biogas generates energy to power the farm or the power can be sold to the energy grid
• The digestate (the “garbage” of the anaerobic digestion processing) may be used as fertiliser at the piggery or sold.

 

Whilst there are many benefits to anaerobic digestion, there are some environmental risks and so they commonly need to be approved under planning and environmental laws. A key air quality risk is odour emissions and nuisance in the community.

 

While odours are not normally harmful to health, they can negatively impact neighbours, generating complaints that must be investigated by regulators. What if there is a way reap the benefits of biogas production while complying with regulation and with the community’s expectation in sustainable pig farms?

 

In the following section, we provide an overview of the best practices to manage odour and air emissions from anaerobic digestion. Effective odour management may be only 7 steps away. We will also tell you how Katestone can help you achieve success with anaerobic digestion at piggeries or other facilities.

 

1. Determine regulatory/approval requirements

In most jurisdictions, new anaerobic digestion facilities will require planning and environmental approval.

 

2. Identification of Odorous sources

To assist with approval processes for an AD plant, the key sources of odour and their emissions should be determined. The key odour sources at an AD plant are associated with the storage of raw materials. The digestion process itself is contained and odorous gases are captured for energy recovery.

 

3. Evaluate the existing environment of the farm

Existing sensitive receptors in the vicinity of the piggery should be identified. This can be done through aerial imagery and ground truthing. Other odour producing activities in the vicinity of the subject farm should also be identified.

 

4. Development of a suitable meteorological dataset

A thorough evaluation of the meteorological patterns and terrain features in the vicinity of the subject site is important.
Meteorological data collected from the facility can be particularly useful where it is available.

 

5. Air dispersion modelling to determine potential impacts and controls

Combustion gas and odour emission sources at the proposed facility will be modelled to determine potential impact on existing and future sensitive receptors.

 

6. Recommendations and Suggestions

Site-specific recommendations based on best practices will help control the emissions to the extent possible and mitigate the odour risk from the operations.

 

7. Development of an odour management plan

An odour management plan is a critical step towards the proper management of piggeries, anaerobic digestion or other similar facilities.

It includes, as a minimum, the following elements for all odour emission sources at the site:

1. Key performance indicator(s) for emission controls and mitigation measures
2. Monitoring method(s) including location, frequency and duration
3. Response mechanisms
4. Responsibilities for demonstrating and reporting achievement of key performance indicator(s)
5. Record keeping
6. Compliance reporting.

 

Katestone has had extensive experience in the assessment and management of odours from anaerobic digestion activities. Our high-quality odour management plans and impact assessments help clients ensure that nuisance odour and other potential impacts of biogas production are appropriately managed.

Contact us today for Clear Skies.

 

This article featured in the Katestone’s Clear Skies 2020 Spring edition. Click here to view other featured articles.