Biodegradation And Biofilm Attachment Characteristics Of Cellulose Carriers For Water Treatment

Porous carrier, with advantages of high microorganism loading, high treatment efficiency and low energy consuming, is one of the directions of carrier for fluid bed biofilm reactor. In this paper, a novel porous carrier made from wheat straw was researched. This carrier has hydrophilic and biophile character, high porosity and specific surface area, and it is low cost and biodegradable. Influencing factors on the biodegradation of carriers and SRB biofilm attachment to the carriers were investigated to study the characteristics of the carrier degradation and biofilm attachment.The effects of temperature, concentration, pH and modification methods on the biodegradation of carriers and biofilm attachment to the carriers were investigated in sulfate reduction system. Results showed that, the final degradation rate of unmodified, crosslinked, crosslink-cationic carriers were 55.2%, 23.9%, 20.5% respectively, which suggested that crosslink and cationization can restrain the degradation of carriers. The volume of biofilm on crosslink-cationic carriers achieved maximum, 0.247g/g, which showed cationization helped the attachment and growth of biofilm. The most suitable temperature for biofilm adherence was 36℃, at which temperature the degradation rate of carriers was higher than at others. When 0.70<[COD]₀/[SO₄^2-]₀<1.40, the degradation of carriers can offer part of carbon source for the bacteria, which accelerated the initial degradation rate of carriers, as well as improved the water treatment efficiency by 51% at the most. In addition, with the augment of pH from 5.0 to 6.5, the final degradation rate of carriers declined from 36.7% to 20.7% and biofilm volume increased gradually to 0.252g/g.