5th lecture Wastewater

+-1

Most bacteria donot grow at values_____ unit of their optimum pH

4, 9.5

Most bacteria cannot tolerate pH values below ____ or above ____

6.8-7.2

Biological treatment may experience operational problem at ph value below or above neutral

Operational problem occur in pH values lower than 6.8

-decrease enzymatic activity

-increase in hydrogen sulfide production

-inhibition of nitrification

-interruption of floc formation

-undesired growth of filamentous fungi and some nocardia

Operational problem occur in pH values lower than 7.2

-decrease enzymatic activity

-increase in ammonia production

-inhibition of nitrification

-interruption of floc formation

Thiobacillus and sulfolobus

Acid loving organism grow at Ph values lower than 5.4 (Acidophiles)

Most bacteria in STP

Grow at pH values 5.4-8.5(Neutrophiles)

Nitromonas and nitrobacter

Grow at pH values from 7-11.5 (Alkalonophiles)

Thiobacillus and sulfolobus

Acidophiles

Most bacteria in STP

Neutrophiles

Nitrosomonas and nitrobacter

Alkalinophiles

denitrifying bacteria

Increase the pH of a biological treatment unit through the release of hydroxyl ions

Fermentative bacteria

Decrease pH of an anaerobic digester through production of fatty acids

Methane forming bacteria

Increase in pH through anaerobic digester through use of fatty acids, esp. Acetate

Nitrifying bacteria

Decrease the pH of an aeration tank throught the use and destruction of alkalinity

Organotrophic bacteria

Decrease the pH of a biological treatment unit through the production of carbonic acid (H2CO3)

Bacteria

Grow in the presence or absence of free molecular oxygen

Aerobes

Haliscomenobacter hydrossis and sphaerotilus natans, zooglea ramigera, nitrosomonas and nitrobacter

Facultative anaerobes

Bacillus, escherichia and pseudomonas

Anaerobes

Sulfate reducing and methane forming bacteria

Floc forming bacteria

Produce the necessary cellular component needed to stick together or agglutinate

Denitrifying bacteria

Are facultative anaerobic bacteria that use nitrate in the absence of free molecular oxygen to degrade soluble cBOD

Denitrifying bacteria

Causes clumping in se ondary clarifier abd foaming in anaerobic digester

gliding bacteria

Contribute to settleability problem

Nitrifying bacteria

Strict aerobes, they oxidize ionize ammonia to nitrite (nitrosomonas and nitrosospira) and oxidize nitrite to nitrate (nitrobacter and nitrospira

Poly-P bacteria

Or Phosphorus accumulating organism are used in biological phosphorus removal unit

Saprophytic Bacteria

They feed upon dead organic matter

Saprophytic Bacteria

They are organotrophs and many are floc forming bacteria

Sheath bacteria

They are consists of a chain of gram-negative cells that are surrounded by transparent tube

Swamer cells

Whentbe cell leaves the sheath they become motile by means of flagella and are reffered to as

sulfur-oxidizing bacteria

Oxidize inorganic sulfur by adding oxygen to sulfur thus obtaining energy from oxidation of sulfur

Haliscomenobacter hydrossis and sphearotilus natans

There are two sheated, filamentous bacteria in the activated sludge process

Nonfilamentous bacteria

Thiobacillus, thiospirillopsis and thiovulum

Filamentous bacteria

Beggiatoa and thiothrix

Sulfur reducing bacteria

Anaerobes and use sulfate to degrade substrate

dedulfovibrio and desulfotomaculum

Principsl sulfur reducing bacteria are

Oxygen uptake rate

The rare at which they use oxygen known as the OUR

Specific Oxygen uptake rate

Is a measure of the the amount of oxygen usedby the microorganism and is reported as mg O2 /g MLVSS-hr

SOUR

Change in _______ value

may also be used to asses thr presence of toxic or inhibitory substance in the influeant

Rapid rate

Indicates young sludge or high F/M

Low rate

Indicates Old sludge or low F/M

Zero rate

Indicates tocix subs that harmedvor kill microbes

20-30 mg/L/hr

Process control level of Activated sludge

1.5mg/L/hr

Process control level of Aerobically digested sludge

Pili/fibrils, polysaccharides, poli B-hydroxybutyrate

Floc forming bacteria are able to produce three necessary cellular components that enable them to stick together or agglutinate

poli B-hydroxybutyrate

Starch granules

Filamemtous bacteria

Perform a significant role im floc formations as they provide internal backbonr or network strenght

Normal flocs

A balance between floc forming and filamentous bacteria results in a strong flocs that keep their integrity in the aeration basin and settle well in tue sedimentation tank

bulking sludge

MLSS does not settle properly

filamentous bulking

-due to excess filamentous bacteria

-competitive at low substrate

-lightly loaded complete mix activated sludge system

Beggiatoa

-Grow well in H2S

-whiteor a colorless filamentous org

Thiothrix

-Reduced substrate

-can profilate when an influent cointains fermentation products such as VFA and reduce sulfur compounds

Prechlorination

______of wastewater has been done to prevent their growth

F. S. Beggiato

Beggiatoa named after the italian medic and botanist ______ which live sin sulfur rich environment

Chlorine and hydrogen

These toxicants are chlorine and hydrogen peroxide (H2O2)

Chlorine

May be applied as gaseous chlorine

hypochlorous (HOCL) and hypochlorous ion

Cl2 (gaseous chlorine) + final effluent =free chlorine as

Calcium hypochlorite or sodium hypochlorite

Chlorine may be introduced into the activated sludge process in RAS, sidestream, aeration tank and mixed liqour effluent

Settleometer

Has a capacity of 2000 mL and graduated in mL/Liter

Viscous Bulking

Is caused by an excessive amouny of extracellular biopolymer, which process a sludge with a slimy. Jelly like consistency

Animal glue

Zooglea or

VFA

volatile fatty acids containing 2 or less carbon atoms

-solube in water

-steam distilled

-punget odor

Ozonation

Leads to replacing of open structures of fingered zooglea colonies by dense compact flocs

6-8 mg/l

Critical NO3 concn

Sludge clumping

Large clumps or masses of sludge rise up throughclear supernatant in clarifier and burst at the surface

Pin point floc

Small dense particles (<1/32 inch diameter) of floc due to old sludge that is breaking down

Ashing

Small ashlike particle om surface of clarifier

Straggler floc

Light fluffy sludge particles, small, almost transparent, very fluffy, buoyant solid particles (1/8 to 1/4 dia rising to the surface)

Foaming

Is the condition deacribing a buildup of foam or froth in the surface of the aeration tank

Fresh, crisp, white foam

Excellent final effluent

Thick, greasy, drak tan foam

-old sludge

-high mixed liqour concentration

-waste rate too high

White billowing foam

-very young under oxidized sludge

Nocardia and mocrothrix parvicella

2 bacteria genera assocoated with extenaive foaming in actibated studge process

Nocardia

Has a filamentous structure and filaments are very short and are contained withi the floc particles

Microthrix parvicella

Thin filaments extending from the floc particle, these org have hydrophobic cell surface and attach to air bubbles where day stabilized the bubble sto cause foam

Acinomycetes

A group of filamentous, fungus like bacteria gram positive and pore forming bacteria

Filamentous bacteria

Haliscomenobacter hydrossis, microthrix parvicella, nocardioform

Floc forming bacteria

Achromobacter, aerobacter, citromonas, flavobacterium, psuedomonas, and zooglea

gliding bacteria

Beggiotoa, flexibacter and thiothrix

Denitrifying bacteria

Alcaligenes, bacillus and pseudomonas

Nitrifying bacteria

Nitrosomonas, nitrosospira, nitrobacter and nitrospira

Poly-P bacteria

Acinobacter, aerobacter, beggiatoa, enterobacter, klebsiella and proteobacter

Saprophytic bacteria

Achromobacter, alcalogenes, bacillus, flavobacterium, micrococcus, pseudomonas

Sheath bacteria

Haliscomenobacter hydrossis, sphaerotilus natans

Sulfur oxidizing bacteria

Nonfilamentous: thiobacillus, thiospirillopsis and thiovulum

Filamentous: beggiatoa and thiothrix

Sulfur reducing bacteria

Desulfovibrio and desulfotomalucum