Officials celebrate a new Alltech effluent treatment plant in Senta, Serbia, that turns yeast-production waste into biofuel to generate heat and electricity for the plant. Pictured celebrating the opening of the cogeneration facility are Bojan Pajtić, far left, prime minister of the Serbian province Vojvodina; Pearse Lyons, Alltech president; and Zoltan Pek, Senta’s mayor.

A yeast factory’s waste now helps fuel its heating and power requirements.

A new cogeneration plant in Senta, Serbia, opened by Altech International, an animal nutrition company based in Lexington, Ky., uses its yeast-production waste as a raw material to create electricity instead of conventional fuel.

This waste is converted into biogas, which is used to power the cogeneration plant to produce both heat and power for the factory. Burning biogas in a cogeneration unit cuts down on harmful gas emissions. The plant is the first of its kind in Serbia.

According to Alltech, the biogas combustion will reduce the yeast plant’s natural gas use by 3.25 million Nm3per year, which is approximately 37 percent of current requirements, and contribute to approximately 34 percent of the factory’s electrical needs. Also, the hot water produced during cogeneration heats various processes in the production of the yeast.

“Benefits of this system include low energy consumption, no carbon source for de-nitrification, more chemical oxygen demand available for biogas production, lower excess sludge production in the aerobic stage, and lower consumption of polyelectrolyte for sludge dewatering,” says Alltech’s Jack O’ Shea, project manager.

The cogeneration process uses five technologies:
  • Anaerobic treatment.
  • Aerobic treatment.
  • Nitrogen removal.
  • Phosphate removal.
  • Sulfur removal from the biogas.
The nitrogen removal process, referred to as Deamon, uses novel bacteria to effectively remove the nitrogen from the waste. Virtually no energy or carbon is needed for this process, Alltech says.