An Effective Technology to Produce Biosolid for Land Application:Autothermal Thermophilic Aerobic Digestion Process
Two laboratory-scale,first-stage,Autothermal Thermophilic Aerobic Digestion(ATAD)reactors which were configured in parallel were used to determine optimum sludge residence time(SRT)and aeration rates to achieve maximum pathogen reduction and best process performance.Feed sludge had to thicken by gravity because a minimal quantity of organic material is needed to sustain self-heating.In this experiment solid ratio ranged within 2％ to 7％.Total solids (TS),volatile solids(VS),and volatile Suspended solids(VSS)destruction rate reached 41.5％,43.8％,and 48.6％ in digestion time of 7 d when the air supply was at 1.0 volume of air per volume of secondary sludge per hour(vvh)aeration rate.The effect of aeration rate was studied at 0.5,1.0,1.5 and 2.0 vvh at unregulated pH,while pH always rise from 6.4 to 8.0 in differing experimental conditions.Medium aeration rate(0.75 vvh-1.5 vvh)and SRT(6 d-8 d)were efficient and economic.ATAD at temperatures≥45℃and SRT≥4 day reduced the feed sludge fecal colifornl density from 107 MPN/g TS to<103 MPN/g TS.Salmonella in the feed sludge was reduced to<1 MPN/4 g TS from 6 to 20 MPN/4 g TS by ATAD at temperatures≥ 45℃ and SRT>5 d.The study revealed when the sludge was not stabilized and the ratio between total chemical oxygen demand(COD) and TS were high.As the experiment progressed and the sludge became stabilized,this quotient was gradually reduced.From the results,a good correlation coefficient was recorded between both COD/TS and VSS destruction rate curves over the course,COD/TS ratio might be used to estimate the degree of biosolids stability as a complementary tool compared with the routine parameters(VSS destruction rates,the special oxygen uptake rate),due to its simplicity,speed and low costs.
Autothermal Thermophilic Aerobic Digestion SRT aeration rates VSS destruction rates
HUANG Shaobin JIANG Ran YANG Jun
College of Environmental Science & Engineering,South China University of Technology,China
国际会议
合肥
英文
90-93
2008-06-05（万方平台首次上网日期，不代表论文的发表时间）