Please enable JavaScript.
Coggle requires JavaScript to display documents.
Water Quality Control (WASTE WATER TREATMENT ( Primary and secondary…
Water Quality Control
WASTE WATER TREATMENT
Municipal waste water typically 99,9% water
Characteristics differ dependent on point source of waste water
Composition of untreated domestic waste water includes BOD’s, COD’s, TDS’s, SS’s, TKN’s and TP’s
-
After primary and secondary treatment waste water still contains nutrients, dissolved metals and salts and biologically resistant substances
-
-
Pg 21 
PRIMARY TREATMENT
Purpose of primary treatment is to screen the water, remove the grit, allow for particle settling, disinfection and release
-
Grit removal:
Detention time very quick
Allows sand, grit and other heavy materials to settle
Non-offensive sludge's, easy to dispose
Sedimentation
Particle settling, 1,5 to 3 hours
50 – 65% of SS and 25 – 40% BOD removed
Primary sludge as well as floating oils and scum
processed in secondary treatment
Disinfection
Chlorine or UV
Kill pathogens, control odours
EXAMPLE 8 NB!
-
-
-
SLUDGE TREATMENT
Quantity only about 2% of the original volume of wastewater
Consists of about 97% water
Separate as much water from the solids as possible to reduce the cost of processing the sludge
Anaerobic digestion
Organics converted to CO2 and Methane gas
First phase: complex organics converted to simple organics, acid formers
Second phase: methane formers digest the simple organics to produce stable
end products