Environmental Technology ChimH409 (2-0-1) Michel Verbanck 2012 Universite Libre de Bruxelles Bruface Dept Water Pollution Control

Course structure Part 1. Introduction (incl. generic methods) Part 2. Air pollution control engineering Part 3. Water & wastewater treatment Part 4. Solid and hazardous wastes

Part 3. Water & wastewater treatment

Total Solids ( 400 –1200 mg/L) often a function of parasitic clearwater infiltration into the sewers Inorganic (ash) 50% Organic (volatile) 50% Dissolved inorg. 35% Suspended (>1 µm) 45% (15% inorg) (30% org) Dissolved organic 20% Non-settleable inorganic 40% Settleable (“>10µm”) 25% (10% inorg ; (15% organic) Non-settleable organic 35% Typical composition of untreated domestic wastewater

Archimedes screws for initial wastewater pumping

bar screen separation

Grit and grease removal

counter-current washing and extraction of the grits

Typical steps in municipal wastewater treatment

DECANTATION Gravity – Archimedes buoyancy Terminal settling velocity v s

DECANTATION Terminal settling velocity v s We define a = b = Gravity – Archimedes buoyancy

vsvs = v s d vsvs

Boycott effect

v s can now be reduced to

LAMELLA SETTLING TANKS: Shortening the settling distance Pipe bundles also used

Actiflo process (OTV - Krüger) coagulation, flocculation, settling assisted by 125µm microsand injection, lamellar gravity separation residence time lower than 15 min

Module for flow repartition (between dry-weather and wet-weather treatment lines)

Parshall flume for flow-rate measurement (at the outlet of the plant)