STUDY ON POLYVINYL ALCOHOL GEL BEADS AS BIOCARRIER APPLIED IN ANAEROBIC SLUDGE IMMOBILIZATION IN THE UASB REACTOR

Abstract

In this study, the biocarrier was made of 8 % (w/v) polyvinyl alcohol (PVA) solution dropped into saturated solution of boric acid (6 %, w/v), then immersed for 2 hours to form PVA-boric bead. In order to maintain the crosslinked beads, it is subsequently immersed in 1M sodium sulfate solution for 1 hour. PVA gel beads have the diameter of 3.5 - 5.0 mm, a specific gravity of 1.03 - 1.08 g/cm3, high mechanical strength and good elasticity. The surface and internal structure particle were observed under a scanning electron microscope (SEM). The application of PVA beads in microbial immobilization was initially examined in three UASB reactors treating rubber wastewater with sludge and PVA beads ratios of 1/1, 2/1, 3/1 (v/v), respectively. Promising result of bio-immobilization was achieved, at ratio of 1/1, the SMA of PVA beads was 0.133 g COD/gVSS/day, corresponding to 17 % of the suspended sludge’s value in the same reactor and the attached biomass was 0.936 g VSS/g dried PVA bead after 90 days.