Moroccan dairy cuts carbon footprint with liquid waste recycling

Generating energy instead of consuming it: the joint treatment of liquid waste and wastewater, which produces biogas, is an attractive alternative to conventional wastewater treatment and disposal for dairies.

A large dairy in Morocco that belongs to an international food company was looking for a sustainable solution for the disposal of liquid waste. Using the slurry in agriculture was not an option. The costs for the disposal of liquid waste and product returns needed to be sustainably reduced to provide planning security for the coming years.

EnviroChemie developed a sustainable plant concept. Instead of disposing of the liquid waste completely, it focused on biogas production. For this, EnviroChemie designed and installed a Biomar® anaerobic bioreactor, in which methane, that is biogas, and carbon dioxide are produced from the liquid waste in the absence of oxygen.

More than 95% of the COD load of up to 13 t/day is converted into biogas in the bioreactor. In addition to approximately 80 m³ of whey from production, the flotation sludge and sludge from the aerobic wastewater treatment are also fed into the anaerobic reactor. That amounts to about 160 m³ of additional liquid waste with a high energy value. Up to 12 m³ of product returns and expired milk are also recycled daily.

Anaerobic technology uses less energy than the conventional aerobic process. The reduction in aerobic wastewater treatment means electricity consumption can be reduced by up to 30%.

The dairy uses the biogas obtained in this way to generate steam to heat and pasteurise the milk, making an oil saving of around 30%.

The amount of waste to be disposed of, and with it the disposal costs, is also significantly reduced. With the installed plant solution from EnviroChemie, the dairy gains planning reliability and is less affected by any increases in disposal costs.