Case study: air scrubbers in pig housing – what’s my return on investment (ROI)?

What air scrubber system was used?

A finisher farm in the Netherlands commissioned Inno+ to install a biological air scrubber to their unit which houses 450 sows and 2,700 weaner pigs (up to 25 kg). After demonstrating the Energy, Efficiency and Environment (EEE) concept, in which heat recovery and a heat pump are used to offset traditional gas heating, the farmer agreed to install the EEE system.

The finisher building was equipped with a combo biological air washer in module form (multiple modules can be added or removed to create a system specially suited to the needs of the farm). The biological system removes ammonia, odour and particulate matter (PM10) in line with Dutch standards on air scrubber installations (BWL 2008.01.V6).

The addition of the heat recovery and heat pump allows the system to heat incoming air into the building from -10ﹾC to +10ﹾC by recovering animal body heat and repurposing it as building heat. This offsets the need for traditional gas heating and maintains a stable building environment for the pigs. It is important to note, the offsetting of traditional gas heating improves the farm’s carbon footprint.

With the Triple EEE system, ventilation airflow increased 15%, and sufficient heat was recovered to supply heat through underfloor and wall heating to ensure the optimum temperature for the pigs. As a result, the farm reported increased feed conversion ratio (FCR) amongst the pigs, improved piglet vitality, and lower costs.

Calculating the return on investment (ROI)

The triple EEE system on the farm saved 19,236 m³/year of gas or a 68% reduction by recovering heat and using it to heat the air in the finisher and piglet accommodation. In addition, FCR was improved with a 4.4% reduction. This saved an estimated €4,316 per year. Furthermore, mortality fell from 3.5% to 2.3% saving an additional €12,600 per year.

In total, the new system delivered €16,916 per year of production savings.

Inno+ provided the following costings as part of the ROI calculation:

*Over the use of conventional gas heating

**Over the use of electricity

Further benefits of air scrubbers

• The farmer reported lowered uses of key medicines, including antimicrobials (however, exact figures were not provided in this case study)
• Lower medicine usage may indicate less rectifiable conditions at slaughter, further improving the final yield of pork for which the producer is paid
• The exact change in the carbon footprint of the enterprise was not calculated, but a reduction in gas usage of 68% is a substantial difference and equates to a 35.78 t of CO₂ per annum reduction