Reduction of Excess Activated Sludge by Ferrite Particles:Methods for Practical Use

Abstract

Activated sludge method is widely being used for wastewater treatment in many countries including Japan. This method is very useful, as its running cost is very cheap. However, every year a large amount of excess sludge is being produced in the Waste Water Treatment Plants (WWTPs) which is a serious problem in terms of both economical and environmental. So, the experiments on reduction of excess sludge are carried out in many countries.
We have introduced Magneto-ferrite treatment on activated sludge in order to reduce excess sludge in the laboratory scale. This magneto-ferrite treatment is a new approach for reduction of excess sludge by using ferrite particles and permanent magnets. A rotary treatment plant was introduced which showed good possibilities of this method for applying it in the practical WWTPs. The parameters of the method were determined. Two miniature WWTPs were used at the laboratory, where one was run with magneto-ferrite treatment while another was run without any treatment. The observations showed good results in reduction of excess sludge growth. The growth of excess sludge was controlled at 72% comparing to that of non-treatment system running WWTPs with CAS. The results showed good possibilities of reducing sludge in the area of biological wastewater treatment.