EPS characteristics according to addition of clinoptilolite into activated sludge

초록

This study was carried out to compare the extracellular polymeric substances ( EPS) compositions between conventional activated sludge (AS) and activated sludge dosed with clinoptilolite (CAS). Additionally, performances of two systems were compared with organic removal efficacy in the effluent in conjunction with EPS concentrations. The experiments were conducted at solids retention time (SRT) ranging from 5 to 100 d. For CAS, proteins were more readily observed for SRT 20 and 100 d compared to that of AS. The polysaccharide concentration in the sludge greatly increased for CAS, but it significantly diminished when the SRT was extended. The level of EPS concentration observed from the effluent had the same pattern of variation for the two different types of systems. Regardless of the type of reactor, the ratio of proteins for sludge versus effluent was independent of SRT, but the ratio of polysaccharides diminished as SRT increased. It caused starvation and microbes could consume polysaccharides as carbon or energy sources whereas the polysaccharides observed from the CAS were relatively independent of F/M ratio. In the long run, the degree of protein synthesis could be directly ascribed to concurrent enhancement of SCOD removal efficiency slightly more in the CAS.