Lectures

Question 1

COD

Answer 1

Chemical Oxygen Demand: Amount of O2 that bacteria need to degrate the organic matter into CO2 and H2O

Question 2

BOD

Answer 2

Biological Oxygen Demand: Amount of O2 that bacteria need to degrate the organic matter (only in biological processes)

Question 3

TOC

Answer 3

Total Organic Carbon: Quantify the carbon that is present in all different compounds in the wastewater

Question 4

Kjeldahl-Nitrogen (KN)

Answer 4

Organic Nitrogen (e.g.. Proteins)
Ammonium Nitrogen (NH4+ -N)

Question 5

Inorganic Nitrogen

Answer 5

• Ammonium Nitrogen (NH4+ -N)
• Nitrate (NO3- -N)
• Nitrite (NO2- -N)

Question 6

Mixing “ideal” reactors
CSTR ?

PFR ?

Answer 6

Completely stirred tank reactor: The concentration is the same at any point in the reactor.
Plug flow reactor: no axial mixing, concentration gradient along the reactor

Question 7

Si
Ss
Xi
Xs
Xba
Xbh

Answer 7

Si: Soluble inert COD
Ss: Readly biodegradable COD
Xi: Particulate inert COD
Xs: Slowly biodegradable COD
Xba: Autotrophic biomass
Xbh: Heterothophic biomass

Question 8

SNO
SNH
SND
XND

Answer 8

SNO: Soluble Nitrate and Nitrite N
SNH: Soluble Ammonium and Ammonia N
SND: Soluble biodegradable organic N
XND: Particulate biodegradable organic N

Question 9

Why we use static simulation? (Flow and concentration is not changing over time)

Answer 9

• Design study and evaluation.
• Testing different operating parameters or load conditions.
• Comparison of treatment processes

Question 10

when do we use dynamic simulation? (Flow and concentrations change over time)

Answer 10

• Investigation of time-dependent response e.g. inflow fluctuations
• Design and testing of control strategies.

Question 11

Autotrophic biomass?

Answer 11

obtain energy by oxidation of inorganic compounnds (NH4) Ammonium

Question 12

Heterotrophic biomass?

Answer 12

obtain energy by oxidation of organic carbon

Question 13

Disturbances in the operation of the anaerobic digester?

Answer 13

Decrese in pH
increase in volatile fatty acids /alkalinity ratio
increase in the %CO2 in the biogas
Inhability of biogas to burn

Question 14

What is removed in the AST?

Answer 14

C, N and P are removed and new sludge (biomass) is formed.

Question 15

Anaerobic digestion process?

Answer 15

0. Desintegration of particulate matter (Physycal process)
1. Hydrolysis (big compounds (polimers) become smaller molecules (monomers)
2. Acidogenesis (Monomers are the substrate)
3. Acetogenesis (Convert organic acids to acetate
4. Methanogenesis (Microorganisms produce methane by using acetate or using CO2 and H2)