1. ERT 417 Waste Treatment In Bioprocess Industry
Semester /2012
Huzairy Hassan
School of Bioprocess Engineering
UniMAP

2. Biological Treatment Processes of Industrial Wastes

3. “Evaluate the biological treatment methods for waste treatment in
industries. Calculate and design the basic structure of waste Treatment
Unit operations”.
Biological treatment / Unit operation

4. Biological Processes for wastewater treatment
Activated sludge process
Aerated lagoons

5. INTRODUCTION Objectives of Biological Treatment:
a) Transform (i.e., oxidize) dissolved and particulate biodegradable constituent s by microorganisms into acceptable end products,
b) Capture and incorporate suspended and non-settleable colloidal solids into a biological floc or biofilm,
c) Transform and remove nutrients, such as nitrogen and phosphorus.. why???
d) In some cases, remove specific trace organic constituents and compounds.

6. Rotating biological contractors
Trickling filters
Rotating biological contractors

7. Trickling filter

8. Aerobic biological oxidation of organic matters
Nutrients for microbes to
Converts organic matters to
CO2 and H2O
Biomass produced
vi = stoichiometric coefficient

9. Composition & Classification of Microorganisms
** Revise the cell components, compositions, structure, DNA, RNA, microbial Growth & metabolism, C & N sources …

11. Aerobic, heterotrophic
Aerobic, autotrophic
Anaerobic, heterotrophic

12. Bacterial reproduction:
In 30 min of generation time (time required bacteria to divide into 2 organisms)
1 bacterium would yield ~ 17 x 106 bacteria in 12 h and the mass ~ 8.4 µg
Biomass yield Y = g (biomass produced) / g (substrate consumed)

13. Microbial Growth Kinetics
Growth kinetics govern the substrate oxidation and biomass production TSS conc. in biological reactor
Organic compounds mostly defined as biodegradable COD (bCOD) or ultimate carbonaceous BOD (UBOD). bCOD and UBOD comprise of soluble (dissolved), colloidal and particulate biodegradable components.
Biomass solids in bioreactor = TSS & VSS
The mixture of solids resulting from combining recycled sludge with influent wastewater in bioreactor = mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS)

14. Rate of utilization of soluble substrates
(-ve : substrate decreases with time)
rsu = rate substrate conc. change due to utilization, g/m3.d
k = max specific substrate utilization rate, g substrate/ g microbe . D
Ks = substrate conc. at one-half max substrate utilization rate g/m3

15. 2) Rate of Biomass Growth with soluble substrate 3) Rate of oxygen uptake

16. 4) Effects of temperature

17. 5) Total volatile suspended solids & Active biomass

19. Example 7-5 Determine Biomass and Solids Yields
For an industrial wastewater activated sludge process, the amount of bsCOD in the influent wastewater is 300 g/m3 and the influent nbVSS concentration is 50 g/m3 . The influent flowrate is 1000 m3 /d, the biomass concentration is 2000 g/m3 , the reactor bsCOD concentration is 15 g/m3 , and the reactor volume is 105 m3. If the cell debris fraction fd is 0.10, determine:
The net biomass yield
The observed solids yield
And the biomass fraction in the MLVSS

20. Solution: ?

21. Aerobic Biological Oxidation
Wide range of microorganisms used:
Ex: Aerobic heterotrophic bacteria able to produce extracellular biopolymers that result in the formation of biological flocs, then separated by gravity settling.
Protozoa: consume free bacteria and colloidal particulates – aid effluent clarification.

22. Stoichiometry:
Electron acceptor
Electron donor

23. Biological Nitrification
2-step biological processes;
Ammonia (NH4-N) is oxidized to nitrite (NO2-N)
Nitrite is oxidized to nitrate (NO3-N)
Why??
Ammonia – associate DO conc. & fish toxicity
Need for nitrogen removal:
– control eutrophication & water-reuse application

24. Stoichiometry: 2NH4+ + 3O2 2NO2- + 4H+ + 2H2O
Nitroso-bacteria (Nitrosococcus, Nitrosospira, etc):
2NH O NO H+ + 2H2O
(Nitrobacter, Nitrococcus, Nitrospina, etc):

26. Anaerobic Fermentation & Oxidation
Three basic steps in anaerobic oxidation of wastes:
Hydrolysis:
particulate material is converted to soluble compounds that can then be hydrolyzed further to simple monomers that are used by bacteria that perform fermentation.
2) Fermentation (or acidogenesis):
Amino acids, sugars, and some fatty acids are degraded further.
The principle products are acetate, H2, CO2, and propionate and butyrate.
Acetate, H2, CO2  precursors of methane formation (Methanogenesis)

27. 3) Methanogenesis: – split acetate into methane and CO2
Carried out by 2 groups of microorganisms (or Methanogens):
a) Aceticlastic methanogens
– split acetate into methane and CO2
CH3COOH CH4 + CO2
b) Hydrogen-utilizing methanogens
- use H2 as electron donor and CO2 as the electron acceptor to produce methane

28. How?? Nuisance organisms in anaerobic fermentation
- When the wastewater contains significant concentrations of sulfate
- Sulfate-reducing bacteria can reduce sulfate to sulfide (toxic to methanogenic bacteria)
- Then, how to solve??
How??

29. Environmental factors:
Anaerobic processes are sensitive to pH & inhibitory substances (ex: NH3, H2S, etc.)
pH near neutral  preferred ;
pH below 6.8  methanogenic activity is inhibited
Due to about % CO2 (high) produced in anaerobic process, high alkalinity is needed to neutralize pH
Range of alkalinity, i.e., mg/L as CaCO3 is often found.
In industrial wastewater applications which mainly contain carbohydrates, it is necessary to add alkalinity for pH control.

30. THANK YOU