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ECW542

Wastewater Engineering Lecturer:

Tower 1/ Aras

, Room

Ext. Sludge Treatment DA/RH


FLOWCHART OF SLUDGE MANAGEMENT Preliminary Treatment & Digestion

Untreated Sludge

Conditioning & Dewatering Process

Screening

Utilisation & Disposal

Primary Thickening

Aerobic Digestion (Optional)

Anaerobic Digestion (20/30 days @

30oC)

Possible Disposal of Liquid Sludge

Secondary Thickening (Optional) Chemical Conditioning Mechanical Dewatering

Drying Beds

Lagoons

Storage at Works (30 days) Composting Transportation from works

Trenching

Land Reclamation

Land Application

Supernatant to inlet of STP or to on site Liquor Treatment Plant

Landfill Site


SLUDGE ESTIMATION

 PRIMARY SLUDGE  Daily sludge volume produced per capita:  250 L/capita of wastewater  300 mg/L of SS will provide 0.075 kg/day.capita  ACTIVATED SLUDGE  For 200 mg/L BOD loading on secondary treatment,

0.05kg/day.capita. If 60% is converted to waste activated sludge, 0.03kg/day.capita produced.  If sludge is wasted at 99.3% moisture content (or 0.7% dry solids), approximately 4.3 L/day.capita of wet activated sludge  SLUDGE MASS AND VOLUME  Relationships between volumes (V) and dry solids contents (SC):  V2/V1 = SC1/SC2


SLUDGE ESTIMATION

ďƒ­EXERCISE

Kolej Mawar STP serves 7,000 PE. Assume sludge has 0.8% dry solids content, and 4.3 L/day.capita of wet activated sludge. (a) Estimate the volume of wet sludge wasted. (b) If the thickener thicken the sludge to 4% dry solids content, estimate the volume of thickened sludge. (c) If the drying beds dewater the sludge to 25% dry solids content, estimate the volume of sludge cake produced.


THANK YOU


ECW542-wk11-L32