Special Topics on Wastewater Treatment Engineering

Jin woo ChoCell: 010-8978-8965

Office: 02-3408-3970 (Young-Sil 518)jinwoocho@sejong.ac.kr

Objectives

This class will incorporate fundamentals of biological wastewater treatment;

- Basics of Microbiology, Bacterial Energetics

- Microbial Kinetics

- Biological Reactors/Processes

ASM (Activated Sludge Modeling)

Activated Sludge process for WWT

Wastewater treatment

water reuse Water recycle

Frame is changing

Syllabus

GradingMid term exam 20%

Final term exam 30%

HW 20%, Attendance 10%, final term presentation 20%

Course Text

- Bruce E. Rittman & Perry L. McCarty, 2001, Environmental

Biotechnology: Principles and Applications,

McGraw-Hill

- Activated Sludge Models ASM1, ASM2, ASM2d and ASM3, Mogens

Henze et al., IWA publishing

Assignments

(1) Problem Exercise: homework problems will be delivered in every

two weeks. All

problems are selected from the exercise examples of main textbook in

consideration

of course progress.

(2) Journal paper review

(3) Modeling (MATLAB programming)

Syllabus

Week Course Contents

1 Introduction

2 Biological wastewater treatment: Fundamentals

3 Stoichiometry and Bacterial energetics

4 Microbial Kinetics, Reactors

5 SMP and EPS

6 Biofilm Kinetics (1)

7 Biofilm Kinetics (2)

8 Mid-term exam.

Syllabus

Week Course Contents

9 The activated Sludge process

10 Modeling (1): The activated Sludge process

11Modeling (2): The activated Sludge process(Matlab programming)

12Modeling (3): The activated Sludge process(Matlab programming)

13 Anaerobic Treatment and biogas production

14 Membrane Bioreactor

15 Term paper presentation (Journal review)

16 Final term exam.

Week 1

Fundamentals

8

Pre-treatment (Preliminary treatment)

Secondary Treatment

Aeration Tank + Clarifier

Secondary treatment is a biological process Utilizes bacteria (Activated Sludge) to degrade organic

matter in the wastewater by microbial metabolism

Activated sludge

Activated Sludge process: Description

5CO2 + NH3 + 2H2O + Energy

CO2 + NH3 + C5H7NO2 + other end products (new cells)

COHNS + nutrients + O2

Microbial metabolism

(organics)

C5H7NO2 + 5O2Microbial metabolism

(dead cells;

food for living cells)

General Stoichiometry

Substrates or Food for microorganisms

Activated Sludge process: Definition

The activated sludge process is a wastewater treatment method that treat a

municipal or industrial wastewater by use of biological floc composed of

numerous bacteria and protozoans which can transfer organic pollutants into

CO2 and H2O under aerobic condition.

Activated Sludge Floc

(discovered in 1913 in the UK by two Civil engineers, Edward Arden and W.T. Lockett)

Activated Sludge consists of numerous microorganisms

Settled down gravitationally so that the cleaned water can be separated easily

Dirty organic things

Inorganic things+ H2O

15

Stoichiometry and Bacterial energetics

16s-rRNA analysis (DNA analysis)

16

Oxidation-Reduction rxn

Oxidation-Reduction(Redox) Reaction Some of atoms or ions undergo a change of oxidation #

Cl2 + Mn2+ + 2H2O MnO2 + 2Cl

- + 4H+0 +2 +4-22+122 -22 -12 +14

Increase in #Loss of 2e-

Decrease in #Gain of 1e-

Electron donor: give its e- to others: make themselves oxidized, make others reduced = reductant

Electron acceptor: take e- from others: make themselves reduced, make others oxidized=oxidant

Substrates + O2 CO2+H2Ocataboilism

e-

See table 2.2 and 2.3 at page 135-146

Gibbs Free Energy, Gorxn

aA + bB cC + dD

(Kc)eq = {[C]c[D]d} / {[A]a[B]b} : concentration equilibrium constant

[X] = concentration of something in the equilibrium state

Small Keq = small fraction of reactant material was converted to product

Large Keq = large fraction of reactant material was converted to product

R=gas constant (1.987 cal/mol-oK)T=temp., K

In equilibrium state, there is no conversion of reactants to

products.

Gorxn = -RTLn[(Ka)eq] (E required for working in a rxn)

o : Standard state = 1 atm, 298 K (25oC)1 J = 0.24 cal

G < 0 :exergonic: reaction occur spontaneouslyG > 0 :endergonic: reaction occur not spontaneouslyG = 0 :in equilibrium

Gibbs Free Energy, Gorxn

ATP

ADP

AdenosinePhosphate

Electron and Energy Carriers

Energy Generation(e- carriers)

ATPE charged(E carriers)

ADPE uncharged

(E carriers)

Cell synthesis(Anabolism)

Cell maintenance(Catabolism)

E consumed

E consumed

Electron donor=substrates)

Electron acceptor

e-

Metabolism

Substrate partitioning and cell yield

Electrondonor

End Products(CO2, H2O, NH3)

e-

fe0

fs0

fs0 + fe

0 = 1

e-Active bacterial

cells

Energy production

Cell synthesis

Cell Residuals

Growth

Decay

Another Substrates:Energy production& call synthesis

Biomass energetics

Energy production: Oxidation-Reduction rxn

E donor + E acceptor Product

OrganicsAmmoniaSulfur

OxygenCO2NOxSOxOther organics

Cell

C6H12O6 + 6O2 6CO2 + 6H2O -2,880

kJ/mole glucose

5C6H12O6 + 24NO3- + 24H+

30CO2 + 42H2O + 12N2 -2,720

2C6H12O6 + 6SO42- + 9H+

12CO2 + 12H2O + 3H2S + 3HS- -492

C6H12O6 3CO2 + 3CH4 -428

C6H12O6 2CO2 + 2CH3CH2OH -224

Biomass energetics

5C6H12O6 + 24NO3- + 24H+

30CO2 + 42H2O + 12N2 -2,720

To develop total net reaction of oxidation-reduction, half-reaction for electron donor and acceptor should be considered

Oxidation rxn of Glucose + Reduction rxn of NO3- = total net rxn

Biomass energetics

Overall reactions for biological growth

R : Overall rxnRe : Rxn for energy production (catabolism)Rs : Rxn for cell synthesis (anabolism)Ra : Half-Rxn of electron acceptor (Reduced)Rd : Half-Rxn of electron donor (Oxidized)Rc : Half-Rxn of cell synthesis (varies with nitrogen source)fe : portion of e- used for E-productionfs : portion of e- used for cell synthesis

R=feRe+fsRs Re=Ra+(-Rd)

Rs=Rc+(-Rd)

Formula of synthesizedCell: C5H7O2N

R=feRa + fsRc - Rd Re=Ra+(-Rd)

Rs=Rc+(-Rd)

R=feRe+fsRs

Overall reactions for biological growth