Study of the treatment of domestic sewage using PVA gel beads as a biomass carrier

Abstract

Technologies for domestic sewage treatment with low excess sludge yield rate and highly efficient biological treatment methods are needed, and the moving-bed biofilm reactor has great promise for meeting this need. To provide technical support for the treatment of typical domestic sewage, this paper provides an estimate of the bacterial diversity in polyvinyl alcohol (PVA) gel beads determined by a 16S-rRNA gene-based polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) approach, proposes a method for reducing the excess sludge yield rate, and describes the startup and continuous operation of the PVA technology. Domestic sewage was treated by a moving-bed biofilm reactor system using PVA gel beads as a biomass carrier. A significant amount of sphalerite, filamentous bacteria and bacillus were observed on the surface and internal structure of the PVA-gel beads by scanning electron microscope. Clostridiaceae bacterium, Alpha proteobacterium, Phenylobacterium haematophilum and Rhodobacter were identified as dominant bacteria strains using 16S-rRNA PCR-DGGE. The active sludge tanks were found to play a significant role in the reduction of excess sludge.

Keywords

• domestic sewage
• organic loading rates
• PCR-DGGE
• PVA-gel beads
• sludge yield rate