Upgrading of suspended growth process using submerged media

Combined suspended / attached growth (CSAG) systems have been usedrecently to overcome some of the disadvantages of existing systems. Ittakes its importance from high biomass concentrations that can beachieved with, resulting in short hydraulic retention times (HRT)compared to suspended growth systems with equivalent solids retentiontimes. The present study investigated the enhancement of conventionalactivated sludge (AS) process performance using attached mediasubmerged in the aeration tank.The main purpose of this work is to find out the optimum combination ofattached growth and suspended growth systems that achieve the bestremoval ratios (RR) of pollutants.Two models have been set up and run treating primary treated domesticwastewater. One of these two models has been run as an aeration tankwithout any submerged media. This model has been utilized as areference for the other model that has been run as a combined suspendedattached growth process. These two models worked parallel with thesame influent wastewater and the same experimental conditions toinvestigate the effect of volume of submerged media added in theaeration tank, hydraulic retention time (HRT), and sludge retention time(SRT), on the removing BOD5, COD, and ammonia nitrogen.