What EU ammonia rules could mean for UK pig producers

UK ammonia targets are under negotiation and if reductions are implemented it could cause extra pressure for pig producers and livestock farmers.

Nigel Penlington, head of research, development and knowledge exchange for AHDB Pork looks at what the rules could mean and how farmers can take action.

In particular, Mr Penlington considers how English producers can manage ammonia emissions in a cost-effective way.

Nigel Penlington, head of research, development and knowledge exchange for AHDB Pork

Nigel Penlington
Head of research
AHDB Pork

This includes a discussion of the possible value of using pH slurry reduction technology on UK farms to get ahead of the new targets. 

The technology also has the potential to improve the value of farm-produced fertiliser and the internal building environment for staff and pigs.

Why is the EU looking to set new ammonia livestock reduction targets?

Livestock production is the UK’s principal emitter of atmospheric ammonia, a large proportion of which originates from nitrogen (N) in manure and slurries.

Emissions are related to the type, number and genetic potential of the animals, as well as the feeding and management of the animals and the technology associated with housing and manure management.

Ammonia emissions play an important role in a number of different environmental issues, and can also be harmful to health when they react with atmospheric sulphur dioxide.

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For this reason, the EU is placing a greater emphasis on ammonia reduction from livestock buildings.

Importantly, both livestock farmers and government agencies recognise the need to accurately quantify gaseous pollutant concentrations from livestock buildings.

Are English pig producers using any systems to help them reduce ammonia and odour levels?

Not really. Elsewhere in the EU, air cleaning is commonly applied to reduce ammonia and odour.

However, it is expensive and does not provide any financial benefits for the farmer, therefore its uptake by English producers has been minimal.

That is why AHDB Pork is looking for a cost-effective alternative system to present to our producers.

AHDB Pork believes a cost-effective solution could be pH slurry reduction technology.

This also improves the fertiliser value of slurry, as well the internal building environment for pigs and staff.

Are other EU countries using pH reduction systems?

Yes. The Danish pig industry has been subject to some of the strictest environmental legislation in Europe since the mid-1980s.

These rules include fixed limits on the number of animals kept in relation to the land available for manure spreading, as well as detailed rules on slurry storage and its application.

Because of these regulations, about 75 of the 3,800 pig units in Denmark have pH reduction systems installed to acidify slurry.

AHDB Pork recently visited Denmark to see the systems working first hand and assess any practical and economic barriers that may prevent their use in England.

What pH reduction systems are being used in Denmark and how do they work?

The pH reduction system works quite simply. It adds sulphuric acid to separated slurry until the pH stabilises at 5.5. It then gets pumped back into the slurry pit located inside the pig house to a pit depth of 180mm, where it remains for a day or two while the pigs dung into the pit.

Once the pH has risen back up to 6.5 it is let out through a slurry separator.

A proportion is released into the slurry store, while the remainder goes into the mixing tank for more acid to be added so the process can begin again.

What is really encouraging is the entire system is run by a computer and therefore it requires no additional labour once it is all set up and working.

pH reduction system

Are there other benefits associated with the pH reduction system?

The reduced level of ammonia released from the slurry means ammonia within the pig buildings is depleted, which has health and productivity benefits for livestock and staff.

In Denmark, the number of flies in and around the unit was dramatically lower compared with some English pig units. In fact, there were hardly any flies and the overall environment seemed fresher and cleaner, which improves biosecurity.

There was also a significant reduction in the amount of ammonia and odour being released from the slurry stores.

The ammonia levels from one of the slurry stores was claimed to be about 1% – this means Danish farmers who have installed pH reduction systems don’t have to cover their stores and therefore make substantial cost savings.

What is more, the available nitrogen and phosphorus in the slurry is increased and the fact you are also adding sulphur to slurry means you are getting a sulphur benefit and therefore less fertiliser is required for use on arable crops.

What is the cost of one of these systems?

Installing a pH reduction system will obviously require capital expenditure, but the benefits available should balance out these costs long term.

Harry Heath, Newport, Shropshire

Harry Heath

Harry Heath

Farm emissions reduction helps improve slurry’s agronomic value

Farm manager Harry Heath, Whitley Manor Farm, Newport, Shropshire, recently visited Denmark with AHDB Pork to look at ammonia and odour reduction systems.

The farm he manages comprises a 560-sow farrow-to-finish pig unit, finishing about 14,500 pigs a year for bacon alongside an arable enterprise of 200ha of wheat, barley and oilseed rape.

Mr Heath says reducing farm emissions is an important consideration as they look to grow the business over the coming years.

“For this reason, I wanted to see the pH slurry reduction system working on farm to assess its feasibility.”

Mr Heath believes his plans to expand could be hampered by the EU ammonia reduction targets.

“We’re IPPC permitted and are located close to sensitive habitats.

“Therefore, if we want to expand we have to do it in such a way that results in a nil increase in ammonia emissions from our unit.

“This means emissions for every pig place need to be reduced to ensure we continue to comply with our original emissions allowance.”

He believes installing a pH slurry reduction system is a more attractive option compared with other available techniques such as “air scrubbing”.

“EU figures suggest if we implement a slurry acidification system and install shallow pits we can reduce ammonia by up to 73%.

“Whereas air scrubbing only provides benefits to the environment and no additional benefits to the slurry for use on arable land.

“The addition of sulphuric acid to the slurry increases ammonia retention, resulting in an increase in nitrogen content and its availability to the plant when applied.”

Mr Heath is carrying out a financial appraisal to assess the viability of installing the system within their finishing unit – where the majority of their emissions are attributed.

He adds: “Encouragingly, early indications suggest the capital costs of the system, as well as the operating costs, will be covered by the increased agronomic value of the slurry.”

Before committing to such a system Mr Heath wants to make sure it can be installed into the existing unit set-up.

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