Improving BOD removal at SNJ wastewater treatment plant by biological treatment at low temperature

Abstract

Nowadays, the use of microorganisms in wastewater handling known as ‘biological treatment’ becomes more and more popular. Better results can be achieved with this process. SNJ, one of the biggest chemical wastewater treatments in Norway, projects to use biological treatment in the future in order to meet the European requirement for discharge of urban wastewater, which is equal to 125 mg COD/l. The pilot study performed at the University of Stavanger during three months (January 2010 to March 2010) permitted to acquire all the parameters necessary for the design of the new plant. In this matter, a maximum specific growth rate of 0.68 d-1 had been found for the bacteria li ving in the wastewater, and with a decay rate of 0.07 d-1 during the cold period (5oC). The biorea ctor volume required for the treatment varies between 3000 m3 to 190 000m3 depending on the treatment methods chosen.