ENHANCING OF UASB EFFICIENCY BY MIXING THE SEEDING SLUDGE WITH CLAY MINERALS

One of the main challenges facing wastewater treatment reactors remains the enhancement of its

design and/or operation. In recent years, numerous designs and/or configurations of these reactors

have been developed to optimize the anaerobic treatment of wastewater. The ability of clay

minerals to create a favorable environment for the growth of microorganisms as well as to work

as a catalyst of the reactions and degradation of organic compounds has been addressed for long

time.

The present study investigated the influence of mixing the seeding sludge with clay minerals on

the efficiency of raw sewage treatment in a pilot-scale model simulating UASB reactor. Kaolinite

and montmorillonite are utilized in the present work as clay minerals, while organics (BOD and

COD) and solids (SS and DS) are selected as assessment parameters of the treatment process.

While the two UASB models constructed and operated within the work-frame of the present work

are identical and operated under the same operation conditions and scenario, one of them was

seeded with a mixture of sludge and kaolinite and the other was seeded with a mixture of sludge

and montmorillonite. Different mixing ratios (weight-basis) of clay minerals and sludge (Wc:Ws)

ranged from 0% to 80% have been investigated in the present study.

Among the results obtained from the experimental program executed within the scope of the

present work is that montmorillonite enhances the UASB efficiency regarding the removal of

organics and solids from raw domestic wastewater better than kaolinite. The enhancement

reached 20%, 30%, and 25% in the % removal of BOD, COD, and SS respectively upon mixing

the sludge seeded to the UASB with montmorillonite at a mixing ratio (Wc:Ws - weight-basis) of

40%. While mixing ratios higher than 40% doesn’t rise the gained enhancement that much

amount, the mixing ratios lower than 40% yield a considerable enhancement.