Landelijke organisatie

Fat recovery from industrial wastewater for on-site biofuel production to reduce CO2 emissions

25 oktober 2021

Eline Anvik

Industrial wastewaters from the food and beverage sector often contain high calorific compounds which can be valuable to recover and reuse. For example, poultry slaughterhouse wastewater typically contains a high amount of fat. If such fat is recovered, it can be reused for heat production on site or sold as products such as biofuel or co-substrate in digesters. By reusing fat from the wastewater, industries can reduce CO2 emissions and achieve a more sustainable operation.

A fat recovery installation (AECO-FAT) was put into operation in 2020 at one of the largest poultry slaughterhouses in the Netherlands, with a slaughter capacity of around

250.000 chickens per day. The installation consists of a dissolved air flotation (DAF) unit removing solids and fat from the wastewater in the form of sludge without dosing chemicals, followed by the chemical wastewater treatment downstream. The sludge from the chemical-free DAF was then heated via the disconnector system and separated into solids, water and oil fractions in a three-phase decanter (picture 1 and 2). The oil is now used as biofuel in a hot water boiler with a specific liquid fuel burner, delivering heat to the slaughterhouse production process.

Throughout one year the obtained oil quality was measured. The recovered oil was more than 99% pure (Table 1). The higher heating value of 39.1 MJ/kg is around 90% of the energy content of fuel oil, showing the suitability to use the recovered oil as fuel.

Applying the fat recovery installation made the poultry slaughterhouse more sustainable in three ways. Firstly, the fat was recovered as fuel on site, saving gas consumption by 15%. Secondly, the use of chemicals can be reduced in the wastewater treatment system. Finally, the total amount of sludge in the wastewater treatment system was reduced by around 30% thanks to the upfront recovery process.

The fat recovery installation not only reuse a valuable compound from wastewater, but also leads to reduction of environmental impact and CO2 emissions. This innovation shows the potential of recovering fat from food and beverage wastewater, making the industries more sustainable and circular.

Source: Jen, C. Y. 2021. Fat recovery from industrial wastewater for on-site biofuel production to reduce CO2 emissions. Wastewater, energy production and emissions, Clean Water & Ecosystem Restoration. AIWW 2021