The dairy industry produces liquid wastes composed of whey and tank washing waters, and solid waste that can be used in biodigesters for the production of biogas and the generation of electric power and heat. Spills of whole milk, fat, etc. occur throughout the production chain. Approximately nine to ten liters of whey are discarded for each kg of cheese produced. The whey, depending on the type, can have an organic load COD between 25000 - 80000 mg/l, and contains about 50% of the initial nutrients of the same. The whey obtained in the production of cheeses is rich in lactose and protein, but poor in fatty substances. In the case of butter the polluting value is very high, it is between 30000 mg/l and 90000 mg/l of COD.    

The whey  represents 80 to 90% of the volume of milk processed by the dairy industry and that for a conventional biological treatment demands a high amount of oxygen (energy). It is estimated that 90% of the COD of wastewater from a dairy industry is caused by milk residues and only 10% by substances foreign to it. Milk in addition to water is made up of fats, proteins (both in solution and in suspension), sugars and mineral salts. 

Dairy industries discharge wastewater  is characterized by high chemical oxygen demand, biological oxygen demand, nutrients, and organic and inorganic contents. 

• High market organic character (high BOD5 and COD), due to the presence of milk components.
• Milch has a BOD5 of 110,000 mg/l and a COD of up to 210,000 mg/l.
• High biodegradability.
• Presences of oil and fats.
• Presences of solids in suspension, in case of  cheese production.
• High concentrations of phosphorus and nitrates, mainly due to cleaning and disinfection products.

The whey obtained in the production of cheeses is rich in lactose and protein, but poor in fatty substances.

The whey, depending on the type, can have an organic load COD between 25,000 - 80,000 mg/l. In the case of butter the polluting value is very high, it is between 30,000 mg/l and 90,000 mg/l of COD.

For every 100 tons of whey that can be treated in covered lagoon digester,  a biogas production of approximately 2,000 m3 can be obtained. With this biogas production, a 150 kW generator can be installed to operate 24 hours a day.

Aqualimpia  is a key-player in providing solutions for the dairy industry,  in the treatment of process wastewater, high strength whey and UF permeate from milk processing, yogurt and cheese production. Aqualimpia, provides integrated solutions for the dairy and cheese producer as for the world’s global food processors.