The document discusses various biological methods for waste disposal, including biological oxidation, biodegradation, and biosynthesis. It describes several treatment processes like activated sludge, trickling filters, rotating biological contractors, anaerobic digestion, and upflow anaerobic sludge blanket reactors. The key factors and working principles of each process are explained along with their advantages and disadvantages. Calculations for process variables like hydraulic retention time, organic loading rate, and sludge volume index are also presented.

1. PRESENTED BY:
KRATIKA SINGHAM
INT. FOOD TECHNOLOGY
GAUTAM BUDDHA UNIVERSITY
FOOD INDUSTRY WASTE MANAGEMENT
(FT-609)
“BIOLOGICAL METHODS OF WASTE
DISPOSAL”

2. INTRODCUTION
• Biological treatment of wastewater subsequent to the removal of suspended solids by microorganisms such as algae, fungi, or bacteria under aerobic
or anaerobic conditions during which dissolved organic matter in wastewater is oxidized & into a dense biomass (The sludge contains bacterial cells
rather than fecal solids.)
• BIOLOGICAL PROCESSES: BIOLOGICAL OXIDATION AND BIOSYNTHESIS
• PURPOSE :To remove
B.O.D
70-90 %
A Dissolved
solids
80-90%
B C.O.D
80%
C Nutrient
removal
N= 50%
P= 30%
D

3. BIOLOGICAL OXIDATION AND BIO-SYNTHESIS
•
• The biological oxidation forms
some end-products, such as minerals
BIOLOGICAL
OXIDATION
• Transforms the colloidal and
dissolved organic matter into new
cells that form in turn the dense
biomass
BIO-
SYNTHESIS

4. BIOLOGICAL GROWTH EQUATION
The biological growth can be described according to the Mond equation
• μ = specific growth rate coefficient
• λ =maximum growth rate coefficient that occurs at 0.5 μmax
• S = concentration of limiting nutrient (BOD and COD)
• KS= Monod coefficient
BACTERIAL GROWTH CAN BE EXPLAINED BY SIMPLIFIED EQUATION:
→
Organic matter + Bacteria + Nutrients + Oxygen
New Bacteria + CO2+ H2O + Residual Organics +
Inorganics

5. ANAEROBIC TREATMENT
STEPS INVOLVED IN ANAEROBIC DIGESTION
TEMPERATURE RANGE
 MESOPHILIC = 30-38˚C
 THERMOPHILIC = 38- 50˚C

6. APPROACHES TO SECONDARY
TREATMENT
DISPERSED GROWTH/SUSPENDED FILM SYSTEMS
 Activated sludge
 Oxidation ditches/pond
 Aerated lagoons, stabilization ponds
FIXED GROWTH/ FIXED FILM SYSYTEMS
 Trickling filters
 Rotating biological contractors

7. TRICKLING FILTERS
It is an Aerobic attached growth bioreactor
PURPOSE:
1) Removal of soluble organic matter
2) Oxidation of ammonia and nitrate
MECHANISM- filteration, adsorption, assimilation to remove
contaminants
Filter bed= uniform rock, gravels, crushed PVC bottles (1-3m) or 3-10 ft deep
EFFICIENCY= 80-90% BOD removed

8. CLASSIFICATION BASED ON RATES
1) LOW-RATE FILTERS
Organic loadings capacity =<40 kg(BOD5 )/100 m3 per day
Range depth = 0.9 to 2.4 m
2) INTERMEDIATE RATE FILTERS
loaded up to 64 kg BOD5 /100 m3 per day
3) HIGH-RATE FILTERS
loading capability = 64 to 160 kg BOD5 /100 m3 per day
4) ROUGHING FILTERS
Loading capacity= 160-480 kg BOD5 /100 m 3 per day
CONSTRUCTION
 Rock or slag beds = 60.96 m (dia)
 Depth= 0.9-2.5 m
 Packed plastic= (6 to 12 meters dia and range in depth from 4.3 to 12.2 m)
 Slime layer thickness = 0.1- 0.2 mm (outer part)

9. WATER RECIRCULATION
ADVANTAGES
• To reduce the organic loading,
• Improve sloughing, reduce odors
• Dilute influent organic concentrations
• Adds dissolved oxygen to the primary effluent to freshen the trickling filter
influent
FACTORS INFLUENCING SLIME GROWTH
 pH
-M.O for BOD removal pH = 7
-M.O remove ammonia effective at a pH =8
 Concentration of food and concentration of oxygen.
•
•
D.O drops below 1.5 mg/L = Increase recirculation
D.O above 2.0 mg/L = Decrease recirculation

10. WORKING PRINCIPLE
 As the wastewater flows microorganisms already in the water
gradually attach themselves to the rock, slag, or plastic surface
and form a film
 As the layer thickens an anaerobic organisms develop the
microorganisms near the surface lose their ability to cling, the
slime layer falls off the filter. This process is known as sloughing.
The sloughed solids are removed .
FILTER MEDIA SHOWING BIOLOGICAL ACTIVITIES THAT TAKE PLACE ON SURFACE AREA

11. CALCULATIONS
TOTAL FLOW/ RECIRCULATION
HYDRAULIC LOADING
ORGANIC LOADING : (lbs/day/1000ft3)
Total flow, mgd = Influent flow (recirc. rate + 1.0)
TREATMENT CAPACITY
 BOD reduction= 70- 90% at loading rates (1 kg BOD/m3/day)
 Bacterial reduction = 1 to 2 log (fiscal coliform), 60- 90% of
total coliform
 TSS removal = very low
 Nitrogen removal= 0 to 35%
 Phosphorous removal = 10 to15%

12. INEFFICIENCIES
 DISAGREEABLE ODORS FROM
FILTER
Excessive organic load & Inadequate
ventilation
 PONDING ON FILTER MEDIA
Excessive foreign matter/ biological
growth
 FILTER FLIES (PSYCHODA)
Poor house keeping
Inadequate filter media moisture
 ICING
Low temp of waste water
 Suitable in areas where large tracts of land are
not available for land intensive treatment
systems.
 Effective in treating high concentrations of
organics
 Rapidly reduce soluble BOD5 in applied
wastewater.
 Efficient nitrification units.
 Low power requirements.
 Possible accumulation of excess biomas
 Requires regular operator attention.
 Incidence of clogging is relatively high.
 Requires low loadings depending on the
medium.
 Vector , odor and odor problems.
ADVANTAGES DISADVANTAGES

13. ACTIVATED SLUDGE
REMOVE: dissolved solids, coarse, & colloidal organic matter
FUNCTION: Oxidize carbonaceous biological matter, nitrogenous matter: mainly ammonium and nitrogen in biological matter,
removing nutrients (nitrogen and phosphorus)
MICROBES INVOLVED
Bacteria: Bacillus subtilis, Alcaligenes, Chromobacterium, Pseudomonas, Achromobacterium, Spirillum, Sphuerotilus natans, etc.
Fungi, Protozoa, rotifers
DETENTION TIME = 6 to 8 hrs
BOD REMOVAL = 90-95%
Aerobic bacteria+ effluent-------------------------------------→New cells + CO2+ H2O
The bacteria flora remains in suspension form in a floc is called “Activated sludge”
oxygen
Degradation
(Mechanical aeration)

14. PRINCIPLE
• In activated sludge process wastewater containing organic
matter is aerated in an aeration basin in which micro-
organisms metabolize the suspended and soluble organic
matter.
• A part of this settled biomass, described as activated sludge is
returned to the aeration tank and the remaining forms waste or
excess sludge.

15. CONSTRUCTION AND WORKING
COMPONENTS
1)AERATION SOURCE - to introduce oxygen
2) AERATION TANK - provide pure oxygen /compressed air
3)SECONDARY CLARIFIER - activated sludge solids separate from the surrounding waste water
4) ACTIVATED SLUDGE OUTFLOW LINE - pump activated sludge back to the aeration tank
5)EFFLUENT OUTFLOW LINE - discharge effluent into tertiary plant/ water bodies
WORKING:

16. FACTORS AFFECTING THE PERFORMANCE
 Temperature
 Amount of organic matter & oxygen
 pH
 waste rates & aeration time
 Wastewater toxicity
 Aeration process- Diffused ,Surface or Pure oxygen aeration
 Process health is depends on - Sludge blanket level, sludge volume
index (SVI), mean cell residence time (MCRT), food to
microorganism ratio (F/M), dissolved oxygen (DO), BOD and COD
FINAL PARAMETERS
FOAM - crisp white
COLOR- dark chocolate brown
ODOR- musty/earthy odor
FLOW PATTERN- uniformly distributed

17. ACTIVATED SLUDGE PROCESS VARIABLES
 MIXING REGIME
(1) Oxygen transfer
(2) Susceptibility of biomass to shock loads
(3) local environmental
(4) The kinetics
 HYDRAULIC RETENTION TIME (HRT)
Where, V= volume of aeration tank(m3), and Q= sewage inflow, m3/d
 MEAN CELL RESIDENCE TIME OR SLUDGE RETENTION TIME (SRT), QC, D
q= v/Q
qc = Bioreactor solids+ clarifier solids
waste solids + effluent soilds

18. CALCULATION
Activated sludge process control calculations may include determination of the 30 & 60 minute settled sludge volume
(SSV30 and SSV60), sludge volume index (SVI) of waste activated sludge removed from the process.
SETTLED SLUDGE VOLUME (SSV)
SETTLESD SLUDGE INDEX (SVI)

19. ROTATING BIOLOGICAL CONTRACTORS
REMOVE: Nitrogenous + carbonaceous compounds (Aerobically)
3-STEP BIOLOGICAL TREATMENT
1) B.O.D removal
2) Nirtrification i,e, (NH3-N )
3) Denitrification
CONSTRUCTION
Large dia wheel, closely spaces circular plastic media mounted on horizontal shaft
which is slowly rotated by a electric motor.
PLASTIC MEDIA = corrugated polystyrene, polyethylene.
DISCS = High density plastic sheets eg: polyethylene, polystyrene, polyvinylchloride
Surface- ridged, corrugated or lattice like (↑ S.A)
PARAMETERS
1) Disc speed=1-2 rpm
2) Submerging levels= 40-80%
3) Disc diameter= 0.6 to 3m

20. WORKING PRINCIPLE
 Discs S.A submerged= approx. 40%
 The oxygen is obtained by adsorption from the air as the biofilm on the
disc is rotated out of the liquid & passes through the liquid phase ,
nutrients and organic pollutants are taken up .
 Film of biomass (microbes) continue growing on discs and forms slime
layer over it while old ones get deactivated
CAPACITY
 Effectivity= 8 to 10 times higher than T.F
 BOD reduction = 80-90% for disc surface loading of 80- 120
 M.O removal – 1 to 2 log unit
 Nitrogen removal= high

21. ADVANTAGES
• High contact time and high effluent quality (both BOD and nutrients)
• High process stability, resistant to shock hydraulic or organic loading
• Short contact periods are required because of the large active surface
• Low space requirement
• Low sludge production
DISADAVNTAGES
• Continuous electricity supply required
• High investment as well as operation and maintenance costs
• Must be protected against sunlight, wind and rain
• Odor problems may occur
• Requires permanent skilled technical labour

22. UP FLOW ANEROBIC SLUDGE
BLANKET REACTOR(UASB)
REMOVE = sludge, liquid , bio-gas
MAXIMUM UPFLOW VELOCITIES= 1-3m/hr for min hydraulic times = 4 to 5 h
WORKING
• Wastewater enters into a UASB reactor at the bottom and exits at the top, and the
biomass is developed as a flocculent mass in an upward flowing water stream.
• A gas–solids separation system is used in this type of reactor to collect the biogas
and to separate the biomass from the effluent.
• Biomass falls back in the reactor because of a decreased up-flow velocity
APPLICATION
Anaerobic treatment of wastewater if well-settling biomass with high methanogenic
activity is developed.
ADVANTAGES DISADVANTAGES
High organic loading
capacity
Granulation process difficult to
control
Short HRTs Granulation depends on
wastewater properties
High COD removal
efficiency
Granule floatation
No need for support media Restriction on nearly solids-
free wastewater
Simple reactor construction Sensitive response to organic
shock loads
Low energy demand

23. STABILIZATION PONDS
Most economical ways of treating sewage and producing a highly purified effluent .
REMOVAL : BOD 5 , solids, fecal coliform bacteria.
DEPTH = < 5 feet.
TYPES (BY LOCATION)
Raw Sewage Stabilization Pond
CAPACITY= 50 pounds of BOD 5 per day/ acre
TIME PERIOD: min 45 days
Oxidation Pond
Polishing Pond
DEPTH : 5 to 10 feet.
Water remains in polishing ponds for only 1 to 3 days.

24. TYPES OF POND BY PROCESS
• AERATED PONDS
Ponds which add oxygen to the water in this way are known as aerated ponds
 DEPTH= <1m
 Active algal photosynthesis
 Organic matter converted to- CO2, NO3-,HSO4-,HPO42-
• ANAEROBIC PONDS
Used for- high strength, high temp waste.
TWO STAGES:
Acid Fermentation : organics------→ organic acids
Methane Fermentation : organic acids ---------→ methane( CH4) + CO2

25. CALCULATIONS
 POND AREA IN ACRES
 POND VOLUME IN ACRE FEET
 FLOW RATE IN ACRE-Ft/DAY
 HYDRAULIC DETENTION TIME, DAYS
 HYDRAULIC LOADING, INCHES/DAY
 ORGANIC LOADING

26. LAGOON SYSTEM
Lagoons are pond-like bodies of water or basins designed to receive, hold, and treat wastewater for a predetermined period of
time. If necessary, they are lined with material, such as clay or an artificial liner, to prevent leaks to the groundwater below.
TREATMENT- combination of physical, biological, and chemical processes.
ANAEROBIC LAGOONS
TREAT: Animal wastes from dairies and pig farms, commercial or industrial wastes
HOLDING TIME: 20 to 150 days
DEPTH: (8 to 15 feet)
WORKING
Top layer - grease, scum, and other floating materials.
The layer of sludge that settles at the bottom of an anaerobic lagoon eventually accumulates and must be removed.
DISDVANTAGES
Odor (managed by adding sodium nitrate, recirculating pond effluent, and through regular maintenance)

27. NATURALLY AEROBIC LAGOONS
• RETENTION TIME: 3 to 50 days to receive adequate treatment.
• MICROBES: aerobic bacteria , algae
These systems use aerators to mix the contents of the pond and add oxygen to the
wastewater.
ADVANTAGES
 Aeration makes treatment more efficient
 Aerated lagoons require less land area and shorter detention times.
AERATED LAGOONS

28. CHARACTERSTICS
 DEPTH OF LAGOONS: 2-5m
 PERIOD OF DETENTION: 2-5 days
 BOD REMOVAL EFFICIENCY: 90%
 SLUDGE ACCUMULATION = 0.04 cum/person/yr
ADVANTAGES OF LAGOON SYSYTEM
1.Less machinery used
2.Low power consumption (0.75 w/cum lagoon volume)

29. OXIDATION DITCHES
It is a modified form of activated sludge process (extended aeration type)
ADVNATAGES
• It is highly efficient involving simple waste treatment
• They can treat waste efficiently having BOD as high as 8000 mg/l
WORKING
MECHANISM : oxygenation and circulation.
• Depth (0.9-1.5m) forming a continuous circuit.
• The mixed liquor in the ditch flows to the clarifier for separation. The clarified liquid passes over the effluent well for disposal into receiving streams, while
the settled sludge from the bottom of clarifier is removed by pumping and returned to the ditch for undergoing treatment.
PARAMETERS
 Detention period = upto 24 hrs
 Mixed liquor suspended solid conc= 3000-8000 mg/l
 Minimum circulation speed = 25 cm/sec

30. TYPES
• The anaerobic zone is the outermost rectangular tank attached to the far east end
of the oxidation ditches.
• It is loaded with oxygen starved bacteria.
THE NO-OXYGEN
(ANAEROBIC) ZONE
• It has very little free oxygen (one half milligram per liter or less)
• The anoxic zone is located between the anaerobic tank and the oxidation
ditches.
THE LOW-OXYGEN
(ANOXIC) ZONE
• The abundant oxygen supply contributes to the breakdown of the major contributor
of nitrogen to create nitrate (NO3).
• Replenish the oxygen-phosphorous compounds in their cells.
THE HIGH-OXYGEN
(OXIC/AEROBIC) ZONE

31. BIOLOGICAL NUTRIENT REMOVAL
NITRIFICATION
During nitrification, ammonium (NH4
+) is oxidized to nitrite by ammonium oxidizing bacteria (AOB) and then to nitrate by nitrite
oxidizing bacteria (NOB)
SOURCES : Protein and nucleic acid, chemical fertilizers, improper disposal of waste
EFFECTS: Direct toxic effect on fish and other animals, causes significant oxygen depletion.
LIMITS: (US EPA )level of nitrate in drinking water at 10 mg of NO3-
PROCESS (nitrifiers-aerobes)
• Nitrosomonas spp : transformation of ammonium to nitrite ( NO2−)
• Nitrobacter spp : transformation of nitrite to nitrate (NO3
-)
OVERALL EQUATION (Ammonium to Nitrate)
NH4 + 2O2 -> NO3- + 2H + H2O (water)

32. MECHANISM
The process in which Nitrosomonas bacteria oxidize ammonia
to nitrite and Nitrobacter bacteria oxidize nitrite to nitrate.
The nitrificaiton reaction consumes 7.1 mg/L of alkalinity as
CaCO3 for each mg/L of ammonia nitrogen oxidized.
PARAMETERS
 OPTIMUM TEMPERATURE = 30°C.
 DISSOLVED OXYGEN CONCENTRATION : 2.0 mg/L
or higher
 OPTIMUM pH =7.5 and 8.5

33. DENITRIFICATION
MECHANISM: Nitrate (NO3-)and Nitrite (NO⁻₂) are
transformed into nitrogen (N2) with organic carbon as the
electron donor.
PROCESS
Heterotrophic bacteria break apart nitrate (NO3) to gain
the oxygen (O2), the nitrate is reduced to nitrous oxide
(N2O), and, in turn, nitrogen gas (N2).
 TEMPERATURE: 5 and 30°C (41 to 86°F)
 pH: 7.0 and 8.5.
 TIME: 10- 20 min
ROLE OF DISSOLVED OXYGEN
 As D.O increases, denitrification rate decreases.
 Maintain DO = < 0.2 mg/L in the (anoxic zone i,e no
D.O)

34. PHOSPHOROUS (P) REMOVAL
MAXIMUM CONCENTRATION OF (P) DISCHARGES = 2 mg/l.
EFFECTS: Eutrophication in surface waters (D.O↓)
Increased growth of algae
Algae blooms that produce algal toxins
FORMS OF PHOSPHOROUS
 ORTHOPHOSPHATES
 POLYPHOSPHATES
MECHANISM: Phosphorous accumulating organism (PAO) which encouraged
to grow and consume phosphorous
 REMOVAL = 1-2 mg/l

35. MICROBIAL FUEL
CELLS
The microbial fuel cells (MFCs) allow
bacteria to grow on the anode by oxidizing the
organic matter that result in releasing
electrons.
The cathode is sparked with air to provide
dissolved oxygen which result in completing
the electrical circuit and producing electrical
energy

36. VERMIFILTRATION
Vermiculture is the implementation of some
species of earthworm, such as Eisenia fetida
and Lumbricus rubellus, to make
vermicompost, also known as worm compost,
vermicast, worm castings, worm humus, or
worm manure
Vermiculture can be implemented to
transform livestock manure, food leftovers,
and organic matters into a nutrient-rich
biofertilizer.

37. WASTE WATER DISCHARGE EMISSIONS

38. CASE STUDY- HINDUSTAN AQUA LIMITED (COCO- COLA)
PRODUCTS MANUFACTURED
CARBONATED BEVERAGES-
 LIMCA
 SODA WATER
 COCA-COLA
 THUMS-UP
 FANTA
 SPRITE
 FRUIT SODA
 GINGER ALE
 DIET DRINKS

39. EFFLUENT TREATMENT PROCESS FLOW CHART

40. PARAMETERS
OBTAINED

41. CONCLUSION
 The treatment of wastewater subsequent to the removal of suspended solids by
microorganisms such as algae, fungi, or bacteria under aerobic or anaerobic
conditions during which organic matter in wastewater is oxidized or incorporated
into cells that can be eliminated by removal process or sedimentation
 Transforming wastewater into secure end products that are able to be safely
disposed off into domestic water devoid of any negative environmental effects
 Recycling and recovering the valuable components available in wastewaters
 Complying with the legislations, acts and legal standards, and approval conditions
of discharge and disposal.

42. REFERENCES
• Gray N. F. (2005). Water Technology: An Introduction for Environmental Scientists and
Engineers (2nd Edition), Elsevier Science & Technology Books, ISBN 0750666331.
• Lin, S. D. (2007). Water and Wastewater Calculations Manual (2nd Edition), McGraw-Hill
Companies, Inc., ISBN 0-07-154266-3, New York, USA.
• Russell D. L. (2006). Practical Wastewater Treatment, John Wiley & Sons, Inc., ISBN-13:
978-0-471-78044-1, Hoboken, New Jersey, USA
• U.S. EPA (2002). Wastewater Technology Fact Sheet: Anaerobic Lagoons, U.S. Envi‐
ronmental Protection Agency, EPA 832-F-02-009, Washington