The Study of Sludge Characteristics for One-Stage Autothermal Thermophilic Aerobic Digestion Process

Abstract

One-stage Autothermal Thermophilic Aerobic Digestion was autonomously designed to treat municipal sludges. By the way of batch operation experiment, the influence of removal rates of volatile suspended solids(VSS), total suspended solids(TSS), auto-rise temperature, and COD concentration, volatile fatty acid concentration of sludge, were investigated respectively. The results showed that a large part of reactor temperature was in thermophilic statues at 56°C-60°C during sludge digestion period; Municipal sludges treated have achieved stabilization standard of 503 articles of EPA while removal rates of VSS and TSS at 38.9% and 31% respectively for 360h retention time. Resulting from micro-organisms hydrolysis reaction, total COD concentration of sludge supernatant (SCOD) was increased firstly and then dropped afterward during the process of digestion while total COD concentration of solid phase of sludge(TCOD) still fall down with removal rate of TCOD at 35.6% for 360h retention time. A sum of concentration of volatile fatty acid(VFA) was accumulated gradually in the sludge supernatant at 2745mg/L for 360h retention time because of micro-aerobic situation in the beginning of digestion process, and can be use as the carbon sources for wastewater treatment process.