Download CVL212/CEL212 Lectures

CVL212/CEL212 Lectures
Wastewater Treatment
March 7th-10th, 2016
Dr. Arun Kumar
([email protected])
Courtesy: Dr. Irene Xagoraraki (USA)
and Dr. Arvind K. Nema (India)
Quiz 1
• Only feb 22,25,mar 7 lectures
07-03-2016
(C)Arun Kumar (IIT Delhi)
2
Municipal Wastewater Treatment
Systems
• Preliminary treatment (removes materials
that can cause operational problems,
equalization basins are optional)
• Primary treatment (remove ~60% of solids
and ~35% of BOD)
• Secondary treatment (remove ~85% of BOD
and solids)
• Advanced treatment (varies: 95+ % of BOD
and solids, N, P)
• Final Treatment (disinfection)
• Solids Processing (sludge management)
March 7, 2016
[email protected]
3
07-03-2016
(C)Arun Kumar (IIT Delhi)
4
Secondary Treatment/Biological
Treatment Process
• Secondary treatment is a biological
treatment process that removes dissolved
organic matter from wastewater.
• Sewage microorganisms are cultivated and
added to the wastewater. The microorganisms
use organic matter from sewage as their food
supply. This process leads to decomposition or
biodegradation of organic wastes.
• Two approaches are used to accomplish
secondary treatment; fixed film, and suspended
film systems.
March 7, 2016
[email protected]
5
Secondary Treatment
• Basic approach is to use aerobic biological degradation:
microorganisms
organic carbon + O2
CO2 + new cells
• Objective is to allow the BOD to be exerted in the treatment
plant rather than in the stream
March 7, 2016
[email protected]
6
How is this accomplished?
Create a very rich
environment for growth of a
diverse microbial community
March 7, 2016
[email protected]
7
Basic Ingredients
• High density of microorganisms (keep
organisms in system)
• Good contact between organisms and wastes
(provide mixing)
• Provide high levels of oxygen (aeration)
• Favorable temperature, pH, nutrients (design
and operation)
• No toxic chemicals present (control industrial
inputs)
March 7, 2016
[email protected]
8
Microbial metabolism
•
•
•
•
Energy source; Carbon for synthesis of new cells
Inorganic elements (N, P, S, etc.)
Carbon and energy sources:: substrates
Autotrophs
– Phototrophs: light as energy source; CO2 as carbon source;
example: algae /photosynthetic bacteria
– Chemotrophs: inorganic redox (NO3-, NO2-, S2-) as energy
source; CO2 as carbon source; example: nitrifying bacteria
• Heterotrophs
– Phototrophs: light as energy source; organic carbon as carbon
source; example: sulfur bacteria
– Chemotrophs: organic redox as energy source; CO2 as carbon
source; example: protozoa, fungi and bacteria
March 7, 2016
[email protected]
9
Types of Microbial metabolism
March 7, 2016
[email protected]
10
07-03-2016
(C)Arun Kumar (IIT Delhi)
11
07-03-2016
(C)Arun Kumar (IIT Delhi)
12
Growth and food utilization
ln
07-03-2016
(C)Arun Kumar (IIT Delhi)
13