Any water that has been adversely affected in quality
by an anthropogenic influence.
Comprises liquid waste discharged by:-
Commercial properties or Industry
Human waste also known as black water
Septic tank discharge
Sewage treatment plant discharge
Washing water also known as Grey water
Groundwater infiltrated into sewage
Seawater ingress (high volumes of salt and microbes)
Direct ingress of river water (high volumes of micro-biota)
Direct ingress of manmade liquids (illegal disposal of pesticides)
industrial site drainage (silt, sand, alkali, oil, chemical residues)
Major Contaminations in Wastewater
• Major contaminants in wastewater. Adapted from Metcalf and Eddy (1991).
Treatment of waste water
• Physical process
• Biological process (Microbiological)
• Chemical process
Tertiary Treatment (Advanced)
Levels of waste water treatment
Removal of solid waste (sludge)
Screening : Coarse solid which may clog the
mechanical equipments and pipes.
Comminution: Grinding of coarse solids into
smaller and more uniform particles.
Flotation: Separation of suspended and floatable
solids particles by air bubbles.
Grit removal: Sand , ash, egg shell etc, of less
diameter than 0.2 mm. - inorganic – cannot be
broken down by biological treatment process.
• Biological treatment process
• Dissolved and non settling organic solids from the
primary efflient are removed.
• Microbes plays an important role
• Process envolved:-
• Stablizattion of organic matter :
Activated Sludge Process
• Oxidizing carbonaceous matter: biological matter.
• Oxidizing nitrogenous matter :
mainly ammonium and nitrogen in biological
• Removing phosphate.
• Driving off entrained gases carbondioxide,ammonia
• Generating a bacterial floc that is easy to settle.
• Generating a liquor that is low in dissolved or
• If disinfection is placticed ,it is always final process,
also called as “effluent Polishing”.
• Activated carbon removes residual toxins.
• Settlement of further biological improvement in
man made ponds or lagoons
• Highly aerobic and colonization by native
• A General Model for the Activated Sludge Process Dold, PL | Ekama, GA | Marais,
GR progress in Water Technology Vol 12, No 6 p Tor 47-77, 1980. 11 Fig, 2 Tab, 24
• Microbiological Basis of Phosphate Removal in the Activated Sludge Process
for the Treatment of Wastewater G. W. FUHS AND MIN CHEN
• Influence of bacterial extracellular polymers on the membrane
separation activatedsludgeprocessH. Nagaoka*, S. Ueda*, A. Miya*** Department
of Civil Engineering, Musashi Institute of Technology, Tamazutsumi 1-28-1,
Setagaya-ku, Tokyo 158, Japan** Biotechnology Department, Ebara Research Co.
Ltd, Honfujisawa 4-2-1, Fujisawa-shi, Kanagawa-ken 251, Japan
• Biological treatment of wastewaters from a dye manufacturing company using
a tricklingfilterM. Kornaros, , G. Lyberatos,Department of Chemical Engineering,
University of Patras, 1 Karatheodori St., 26500 Patras, Greece
• Microbiology of foaming in activated sludge plantsJ. A. Soddell, R.J.
Seviour,Article first published online: 11 MAR 2008 ;DOI: 10.1111/j.1365-
• Water Researcll Vol. 9, pp. 365 to 388. Pergamon Press 1975. Printed in Great
Britain. FILAMENTOUS ORGANISMS OBSERVED IN ACTIVATED SLUDGE
D. H. EIKELBOOM TNO Research Institute for Environmental Hygiene, P.O. Box
214, Delft, The Netherlands*