A study of aerobic digester performance with the use of methanol for biological nutrient removal in a full-scale sequencing batch reactor

Abstract

The primary goal of this research was to determine whether the use of methanol in a full-scale sequencing batch reactor (SBR) affected the subsequent aerobic sludge digester performance. The methanol injection into an experimental SBR resulted in a significant increase in the solids level in the SBR, increased wasting into the digesters, and a lower sludge age. When the methanol dosage in the SBR was 81 L/d, the dissolved oxygen level in the subsequent aerobic digesters became inadequate for proper digestion. The net result was a drop in solids reduction efficiency. However, the methanol injection appeared to have no effect on the dewaterability of the digested sludge, as samples from the experimental and control units had very similar capillary suction time (CST) results. It was found that the dewaterability was affected not only by the total suspended solids concentration of the digested sludge, but even more by the temperature of the digested sludge, through a change in filtrate viscosity. Key words: aerobic digestion, biological nutrient removal, denitrification, methanol, sludge dewaterability.

A New, Pellet‐Forming Fungal Strain: Its Isolation, Molecular Identification, and Performance for Simultaneous Sludge‐Solids Reduction, Flocculation, and Dewatering

“…In this study, 40 to 68% of suspended solids was degraded under different experimental conditions, which is consistent with observations made by other researchers (Mason et al, 1987;Koh et al, 2002;Novak et al, 2003), but was higher (three to six times) than the control used in these experiments. The solids-reduction rate is higher or equivalent to solids reduction typically observed in large-scale, conventional aerobic digestion.…”

“…Several authors have studied total-and volatile-suspended-solids (VSS) reduction in aerobic digesters using different configurations (batch mesophilic, semicontinous, thermophilic, sludge pretreatment through chemical, or enzyme methods). They found that degradation ranged from 50 to 80% VSS reduction (Mason et al, 1987;Koh et al, 2002;Li et al, 2003;Novak et al, 2003;Barbusinski and Filipek, 2003).…”

Green Biotechnology for Municipal and Industrial Wastewater Treatment

“…Several authors have studied the total and volatile suspended solids (VSS) reduction in aerobic digesters employing different process configurations (batch mesophilic, semi-continous, thermophilic, sludge pre-treatment through chemical or enzyme methods), and the degradation varied in the range of 50-80% VSS reduction [39][40][41][42]. The degradation of sludge solids mainly depends on solids retention time (SRT), solids concentration, microbial community and operating conditions [e.g., dissolved oxygen (DO), temperature and pH].…”