Study of Reducing Waste Biosolids in Sequencing Batch Reactor by Ozonation to Waste Biosolids

Abstract

One of the problems of biological aerobic systems for example sequencing batch reactor, is production of waste biosolids. If we reduce the volume of this waste biosolids, we would be able to solve the important problems of aerobic processes in all over the world. One of the suitable ways to reducing the waste biosolids is oxidizing the wste biosolids by oxidants such as ozone. Waste biosolids ozonation, by reducing the biomass coefficient (Y), will result in easier sewage biosolids disposal. In this study we used two sequencing batch reactor reactors with 15 L capacity. One of these was the blank. We tested parameters such as COD, MLSS, SVI, residual ozone and yield coefficient (Y). During the solid retention time of 10 days, biomass coefficient (Y) was 0.51 (mg Biomass/mg COD). Then, we started adding ozone with different doses in waste biosolids and we rejected this waste biosolids to the reactor. The results showed that with adding 30 (mg O₃/g MLSS), the kinetic coefficient of Y, reduced from 0.51 to 0.24 (mg Biomass/ mg COD) and the volume of waste biosolids reduced about 0.53 %. From the other side, while adding ozone, the soluble COD in the effluent increased. So, the COD removal percentage decreased from 81.7 % in the blank to 56 % in the test reactor.