Upgrading of Small Municipal Wastewater Treatment Plants with Heavy Dairy Loading by Introduction of Aerated Submerged Biological Filters
Most of the dairies in Norway discharge their wastewater to the municipal sewers. Insufficient knowledge about the organic load coming from the dairies, has resulted in inadequate design and organic overloading in the municipal wastewater treatment plants of this category. Several of the plants that originally based their biological process upon RBC as the bioprocess, have experienced mechanical breakdown of the RBC system. The submerged biological filter (SABF) has been introduced as an alternative biofilm method that may be used when broken down RBC-plants (or activated sludge plants) are to be upgraded. The paper describes results from pilot-plant experiments on dairy waste when the SABF is used for pretreatment, as well as results from plants in practice where the SABF is used for combined treatment of the dairy and municipal wastewater. It is shown how pretreatment in a balancing tank may be established, and results from the use of an alternative floating biofilm media are given.