Effect of Deflocculation on the Efficiency of Disperser Induced Dairy Waste Activated Sludge Disintegration and Treatment Cost

Bioresource Technology 167 (2014) 151–158

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Bioresource Technology

journal homepage: www.elsevier.com/locate/biortech

Effect of deflocculation on the efficiency of disperser induced dairy waste activated sludge disintegration and treatment cost

T. Poornima Devi a, A. Vimala Ebenezer a, S. Adish Kumar a, S. Kaliappan b, J. Rajesh Banu a,⇑

a b

Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli, India Department of Civil Engineering, Thiagarajar College of Engineering, Thiruparankundram, Madurai, India

h i g h l i g h t s

 Chemo mediated disperser pretreatment was an innovative approach.  0.04 g/g SS of sodium dodecyl sulphate enhanced deflocculation of sludge matrix.  Chemo mediated dispersion pretreatment enhances solubilisation at 5013 kJ/kg TS.  Hydrolysis and biogas production potential was improved in deflocculated sludge.  Deflocculated sludge showed net energy savings of 43% during cost analysis.

a r t i c l e

i n f o

a b s t r a c t

Excess sludge disintegration by energy intensive processes like mechanical pretreatment is considered to be high in cost. In this study, an attempt has been made to disintegrate excess sludge by disperser in a cost effective manner by deflocculating the sludge using sodium dodecyl sulphate (SDS) at a concentration of 0.04 g/g SS. The disperser pretreatment was effective at a specific energy input of 5013 kJ/kg TS where deflocculated sludge showed higher chemical oxygen demand solubilisation and suspended solids reduction of 26% and 22.9% than flocculated sludge and was found to be 18.8% and 18.6% for former and latter respectively. Higher accumulation of volatile fatty acid (700 mg/L) in deflocculated sludge indicates better hydrolysis of sludge by proposed method. The anaerobic biodegradability resulted in higher biogas production potential of 0.522 L/(g VS) for deflocculated sludge. Cost analysis of the study showed 43% net energy saving...