Wastewater treatment uses microorganisms like bacteria, viruses and protozoa to break down organic contaminants. There are three main approaches - fixed film systems where microbes grow on substrates, suspended growth systems where microbes are suspended in wastewater, and membrane bioreactors which improve on conventional activated sludge using a membrane to filter treated water. Common biological wastewater treatment methods include activated sludge, trickling filters, rotating biological contactors, stabilization ponds and constructed wetlands. Advanced technologies are being developed that combine membrane separation with microbial processes to provide more effective wastewater treatment and reuse of resources.

1. MICROBES IN WASTEWATER
TREATMENT

2. WHAT IS WASTEWATER TREATMENT
• USUALLY REFER TO SEWAGE TREATMENT, OR DOMESTIC
WASTEWATER TREATMENT
• PROCESS OF REMOVING CONTAMINANTS FROM
WASTEWATER, BOTH RUNOFF AND DOMESTIC TO
PRODUCE WATER THAT IS SAFE FOR ENVIRONMENT
• PHYSICAL TREATMENT
• BIOLOGICAL TREATMENT
• CHEMICAL TREATMENT

4. BIOLOGICAL WASTEWATER
TREATMENT
• BIOLOGICAL TREATMENT
INVOLVES USE OF
MICROORGANISMS SUCH
AS BACTERIA, VIRUSES
AND PROTOZOA
• THEY METABOLIZE THE
BIOLOGICAL CONTENT
(DISSOLVED ORGANIC
MATTER) OF THE SEWAGE
• THE CONTAMINANTS OF
ORGANIC SUBSTANCES
ARE DIGESTED AS FOOD
ALONG WITH OTHER
ENERGY SOURCE BY THE
CELL

5. AEROBIC
DIGESTION
• NEED OXYGEN
• CONVERT INTO
CARBON DIOXIDE
(CO2)
ANAEROBIC
DIGESTION
• DO NOT REQUIRE
OXYGEN
• PRODUCE BIOGAS, WHICH
CAN BE USED IN
GENERATORS FOR
ELECTRICITY

6. THREE APPROACHES
• FIXED FILM SYSTEMS
• GROW MICROORGANISMS ON
SUBSTRATES SUCH AS ROCKS, SAND
OR PLASTIC
• WASTEWATER IS SPREAD OVER THE
SUBSTRATE
• EX: TRICKLING FILTERS, ROTATING
BIOLOGICAL CONTACTORS

7. TRICKLING FILTERS BED
• MEDIA MADE OF COKE
(CARBONIZED COAL),
LIMESTONE CHIPS OR
SPECIALLY FABRICATED
PLASTIC MEDIA
• MICROORGANISMS ARE
ATTACHED TO THE MEDIA
IN THE BED AND FORM A
BIO FILM OVER IT
• SPREAD WASTEWATER
OVER THIS BIO FILM OF
AEROBIC
MICROORGANISMS THAT
WILL OXIDIZE THE
ORGANIC MATTER

8. COMPONENTS OF TRICKLING
FILTERS
SEPTIC TANK
REMOVAL OF THE SOLIDS PRESENT IN THE
WASTEWATER
CLARIFIER
BIOLOGICAL MATERIALS TO SETTLE OUT OF THE
WASTEWATER
APPLICATION SYSTEM
DISTRIBUTION OF THE TREATED WASTEWATER TO
THE PROPER SITE

9. ROTATING BIOLOGICAL
CONTACTORS
• DISC, BIO FILM, AEROBIC REACTOR SYSTEM
• SOLID MEDIA ENCOURAGES MICROBIAL GROWTH IN A STATIC BIO
FILM
• PRIMARY FUNCTION IS REDUCTION OF ORGANIC MATTER

11. • SUSPENDED FILM SYSTEMS
• STIR AND SUSPEND
MICROORGANISMS IN WASTEWATER
• SETTLED OUT AS A SLUDGE
• PUMPED BACK INTO THE INCOMING
WASTEWATER
• EX: ACTIVATED SLUDGE, EXTENDED
AERATION

12. ACTIVATED SLUDGE
• PRIMARY WASTEWATER MIXED WITH BACTERIA
RICH (ACTIVATED) SLUDGE AND AIR OR OXYGEN IS
PUMPED INTO THE MIXTURE
• MIXED COMMUNITY OF MICROORGANISMS
• BOTH AEROBIC AND ANAEROBIC BACTERIA MAKE
UP ABOUT 95% OF THE ACTIVATED SLUDGE
BIOMASS.
• THEY GROW IN WASTEWATER BY CONSUMING
BIODEGRADABLE MATERIALS SUCH AS PROTEINS,
CARBOHYDRATES, FATS AND SIMILAR
COMPOUNDS.

13. COMPONENTS OF ACTIVATED
SLUDGE PROCESS
 AERATION TANK
OXYGEN IS INTRODUCED INTO THE SYSTEM
 AERATION SOURCE
ENSURE THAT ADEQUATE OXYGEN IS FED INTO
THE TANK AND PROVIDED PURE OXYGEN OR
COMPRESSED AIR
 CLARIFIER / SETTLER
ACTIVATED-SLUDGE SOLIDS SEPARATE FROM
THE SURROUNDING WASTEWATER

14. ACTIVATED SLUDGE OUTFLOW LINE
PUMP ACTIVATED SLUDGE BACK TO THE
AERATION TANK
EFFLUENT OUTFLOW LINE
DISCHARGED EFFLUENT INTO BAY OR
TERTIARY TREATMENT PLANT

17. MEMBRANE BIOREACTORS
• IMPROVEMENT OF THE CONVENTIONAL ACTIVATED
SLUDGE PROCESS
• SECONDARY CLARIFIER IS REPLACED BY A BIOLOGICAL
AERATION BASIN FOLLOWED BY MEMBRANE UNIT FOR
THE SEPARATION OF TREATED WATER FROM THE MIXED
SOLUTION IN THE BIOREACTOR
• MEMBRANE FIBERS HAVE BILLIONS OF MICROSCOPIC
PORES ON THE SURFACE
• THE PORES FORM A BARRIER TO IMPURITIES , WHILE
ALLOWING PURE WATER MOLECULES TO PASS
• WATER IS DRAWN THROUGH THE PORES USING GENTLE
SUCTION

18. TYPICAL MEMBRANE
BIOREACTOR

20. FACULTATIVE STABILIZATION
POND
• SHALLOW PONDS TYPICALLY 1-2m DEEP
• DECOMPOSED BY SYMBIOTIC ACTION OF ALGAE AND
BACTERIA
• TOP LAYER IS AEROBIC WHILE THE BOTTOM LAYER IS
ANAEROBIC
• ALGAE UTILIZE CO2, SULPHATES, NITRATES,
PHOSPHATES, WATER AND SUNLIGHT AND GIVES OXYGEN
THAT IS AVAILABLE TO BACTERIA AND OTHER MICROBES

22. CONSTRUCTED WETLANDS
• SMALL ARTIFICIAL WASTEWATER TREATMENT SYSTEMS
CONSISTING OF ONE OR MORE SHALLOW TREATMENT
CELLS, WITH HERBACEOUS VEGETATION TO ENHANCE
POLLUTANT REMOVAL FROM STORM WATER RUNOFF
• MICROBIAL, BIOLOGICAL, PHYSICAL AND CHEMICAL
PROCESSES TO TREAT WASTEWATER
Free water
surface
systems
Subsurface
flow
systems

23. FREE WATER
SURFACE SYSTEMS
• MICROORGANISMS
(MOSTLY BACTERIA AND
FUNGI) LIVE ON THE
SURFACE OF THE AQUATIC
PLANTS AND SOILS
• DURING DECOMPOSITION,
OXYGEN IS UTILIZED BY
MICROORGANISMS
ATTACHED TO THE
AQUATIC PLANTS BELOW
THE LEVEL OF THE WATER
SUBSURFACE FLOW
SYSTEMS
• MEDIA TYPICALLY SOIL, SAND,
OR GRAVEL IS USED AS
SUBSTRATE FOR PLANT
GROWTH
• WATER FLOW PASSES
THROUGH SUBSTRATE AND
ROOT SYSTEM BY GRAVITY
AND HORIZONTALLY
• ORGANIC MATTER IS
BIOLOGICALLY DECOMPOSED
E.G. NITROGEN CAN BE
DENITRIFIED AND HEAVY
METALS AND PHOSPHOROUS
ARE FIXED TO THE SOIL

26. MICROBIOME AND RESOURCE
MANAGEMENT
UNDERSTAND
ING
MICROBIAL
PHYSIOLOGY
FORMULATING
APPROPRIATE
ENVIRONMENT
AL
BIOTECHNOLO
GY
ENGINEERING
OF
WASTEWATER
SYSTEMS

27. Since the microbes have a natural
ability to degrade pollutants from
wastewater, so advanced
technologies using microbes must
be applied such as Advanced
Oxidation Processes (AOPs) and
membrane-separation
technologies, and perhaps their
combined application may
constitute today, the best option
for wastewater treatment and
reuse schemes.
CONCLUSI
ON