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Nutrients

! nitrogen and phosphorous are essential for the growth of plants and animals! consequently they are referred to as nutrients

Nitrogen

! important constituent of protein and nucleic, that is required in greatest quantity next tocarbon and oxygen

! special importance are

< ammonia (NH3)< nitrite (NO2

-)< nitrate (NO3

-)< nitrogen gas (N2)< urea [CO(NH2)2]< organic nitrogen

TKN: Total Kjeldahl Nitrogen: ammonia not driven off before digestion; thus the total oforganic and ammonia nitrogen

! nitrogen cycle (see Fig. 3.6 in text)

Phosphorous

! as nitrogen, phosphorous is cycled between organic and inorganic phosphorous compounds

< PO4-3, HPO4

-2, H2PO4-, H3PO4

! orthophosphates, consisting in some form of PO4-3 is the only form of phosphorous readily

used by plants and animals! other important phosphorous compounds is polyphosphates, which provides luxury uptake

in secondary treatment for sludge! phosphorous cycle involves two major steps

< conversion of organic (dead plant and animal tissue and animal waste) to inorganicphosphorous via bacteria

< conversion of inorganic to organic phosphorous (plant and animal tissue)

! natural water has low phosphorous content, resulting in low algal growth! discharges containing excessive amounts of phosphorous result in algal blooms! phosphorous needs to be removed from source, e.g. soap formulation or at wastewater

through chemical or biological means

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Nutrient Concentrations from Non-Point Sources(Novotny and Bendoricchio, 1989 in WS&T)

SOURCE NITROGENmg/L

PHOSPHOROUSmg/L

Atmospheric Deposition 1-10 0.02-2

Surface Animal Feed Lot

>30 >10

Urban Stormwater Runoff 1-10 0.2-2

Irrigation Excess Flow 10-30 2-10

Septic Tank Surface Leak >30 >10

Construction Site Runoff 1-30 0.2-10

Combined Sewer Overflow >30 >10

Subsurface Farm Drainage

10-30 0.2-2

Intensive Farm Drainage >30 0.2-2

Septic Tank Leakage >10 0.2-2

Eutrophication

! natural waters are classified according to their ability to support life; oligotrophic,mesotrophic and eutrophic

< oligotrophic: young with low nutrient content, little biological activity and cleanbottom sediment

< mesotrophic: middle aged with modest amounts of the three parameters< eutrophic: aged, with large concentrations of nutrients, excessive biological

activity and large volumes of organic sediments on bottom< extinction: lake no longer capable of supporting life

! natural process taking thousands of years to complete! mans activities have speeded up the process! nutrient discharge must be halted or removed

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Figure 1: Eutrophication

Figure 2: Temperature Profile

Eutrophication

(1) abundance of nutrients (N, P) and organic Matter

(2) decay of organic matter. Production of CO2 andconsumption of O2

(3) blooms of algae and excessive vegetation growth.(faster it grows faster it dies)L production of O2 and consumption of CO2

during daylight hoursL consumption of O2 during the evening with

odour problems in early morning

(4) death of Algae and vegetation and settling

(5) becomes anaerobic through bacterial decay ofdead algae, vegetation and organic matter

(6) reduction in oxygen available for fish and otheranimals

! halt cycle by ceasing nutrient discharges, removing sediments and harvesting aquatic plants

Epilimnion, Thermocline, and Hypolimnion

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Figure 3: Water Temperature

! epilimnion

< few metres deep< well mixed< relatively high DO< sunlit

! thermocline

< in summer temp changes 1°C/m< no mixing occurs across this layer

! hypolimnion

< weakly mixed< low DO< nutrient density< lower temp ----> high density water

Thermal Stratification

! occurs because water densest @ 4°C< summer, warm water floats over cold water< winter, colder water floats over cold water< summer epilimnion is well mixed

! two "bodies" of water exist< epilimnion 1-3 meters< hypolimnion 20 m or more< since no O2 is transferred across thermocline, fish

tend to live in upper layer

! water too warm (increases with turbidity) fish go to deeper layers and die

! bottom layers can go anaerobic

! turnover occurs in spring and fall

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2.5 Chemical Characteristics of Water: Gases

Gases found in water include nitrogen (N2), oxygen (O2), carbon dioxide (CO2), hydrogen sulfide(H2S), ammonia (NH3) and methane (CH4).

! first three are common gases! remaining are the result of bacterial metabolism and respiration; hydrogen sulfide from

bacterial reduction of sulfate under anaerobic conditions, while ammonia and methane arederived from anaerobic decomposition of organic matter

< hydrogen sulfide

organic matter + sulfate (SO4-2) bacteria sulfide (S-2) + H2O + CO2

S-2 + 2H+ -----> H2S

" colourless, inflammable and rotten egg odour" Henry’s law constant HH2S @ 25°C (Ray, 1995;51)

0.01mol/LAatm=(0.01mol/LAatm)(34g/mol)(1000 mg/g) = 340 mg/LAatm" if it reacts with iron forms ferrous sulfate, causing wastewater and sludge to go

black" hydrogen sulfide is toxic to many organism" hydrogen sulfide can precipitate heavy metals (e.g.,iron, zinc and cobalt)" current treatment includes dosing with ozone, O2, H2O2, Cl (forms THMs), FeO4

2

(ferrate, very strong), ClO2 (chlorine dioxide)" danger for sewers as it is very corrosive and especially in low slope sewers

< methane

" usually not found in untreated wastewater because oxygen present" toxic to organisms" high heat value" explosion hazard

Solubility of Gases

Relationship exists between the solubility of the gas in water and the partial pressure of the gas inthe atmosphere above the water L HENRY’S LAW

Cs = HcPg

whereCs = mole fraction or concentration of gas at equilibrium (saturation) in liquid

phase; (mol/L) or (mg/L) Hc = Henry's Law Constant; (mol/L•atm-1) or (mg/L•atm-1)Pg = Partial pressure of gas in atmosphere, atm

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Henry's Law constant can also exist in dimensionless form. Some dimensional values are given inthe text.

! function of

< solubility of gases< temperature of the water< purity of water, i.e. presence of suspended solids and salt

! "-factor, for example = Hww/Hclean

Gas Transfer

The rate of which gas transfers from one solutionto another according is described by two-filmtheory developed by Lewis and Whitman (1924).For addition of gas to liquid it is expressed as:

where

dm/dt = mass transfer (g/h)K = coefficient of mass transfer (m/h)A = area of diffusion (m2)Cs = saturation conc. of liquid (g/m3)C = actual conc. of liquid (g/m3)

Now,

or

Furthermore

where

kR = liquid phase mass transfer coefficient (m/h)kg = gas phase mass transfer coefficient (m/h)

However, for many volatile compounds (dimensionless Hc > 0.1), kR << kg, making mass transferliquid phase controlled. Accordingly, K is replace with KL .

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(7)

(8)

Furthermore, A/V is A/V normally not measurable, and it is replace with a, specific area. Therefore,

Lwhere,

Kla = overall mass transfer coefficient (1/h).

Giving,

Integration and rearranging gives:

whereCt = liquid concentration at any time t (g/m3) or (mg/L)Co = initial liquid concentration (g/m3) or (mg/L)

For the situation of gas leaving the solution (VOLATILIZATION), then:

Note: Eq. 2.86 in text wrong

For temperature change of KLa, use 2 = 1.024 for all temps.

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2.6 Biological Characteristics of Water

Primarily related to the resident aquatic population of microorganisms:

Most important biological organisms in water and wastewater are pathogens, as they transmitdiseases.

Major Groupings

Bacteria

! comes from Greek word rod or staff, the shape characteristic of most bacteria! smallest living thing, very efficient

Viruses

! smaller than bacteria! cannot live by themselves (do not have ability to synthesize new compounds) require a host! host specific, makes enumeration difficult

Plankton

! unattached microorganisms! dispersed individually or in colonies in water

< Phytoplankton (Algae): cannot see them with the naked eye

Daytime

sunlight + nutrientsnCO2 + nH2O --------------------------> (CH2O)n +nO2

new cellsNight

(CH2O)n + nO2 ----> nCO2 + nH2O

" usually nO2 sunlight > nO2 respiration" if not can cause anaerobic conditions and odours" nuisance as high temp and sunlight increase their growth" four important groups are:

• blue green algae• green algae• diatoms• pigmented flagellates

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< Zooplankton: Use oxygen and release carbon dioxide; are animal types." Nematodes - worms; 10,000 species" Water Flea" Cyclops" Rotifiers - simplest of multicellular animals, aerobic

Protozoa! lowest form of animal life: single cell! aerobic or facultative anaerobic! free-living or parasitic ! broken in four classes based on motility as outlined in Table 2.19

< Ciliata< Mastigophora< Sarcodina< Sporozoa

Fungi

! aerobic multicellular, nonphotosynthetic, heterotrophic! most are saprophytes, obtaining food from dead organic matter! principle micro-organism along with bacteria that decomposes carbon! without fungi, the carbon cycle would cease and organic matter would build up! ideal conditions are high moisture and low pH

Microorganisms (review on your own)

! to grow they must extract from the environment substances needed to produce new cellmaterial

! these substances are called nutrients! to continue growth, the micro-organisms require carbon, energy and as seen from CHONPS,

nitrogen, phosphorous and sulfur! carbon is obtained from carbon dioxide and the carbon found in organic matter

< CO2 --> autotrophic< if organic matter --> heterotrophic

! energy is obtained from light or chemical oxidation or reduction of organic and inorganicmatter< microorganisms that use light ---> phototrophs< microorganisms that use chemical energy ---> chemotrophs

photoautotrophs ----> light ------> CO2 -----> higher plants, algae, photosynthetic bacteriaphotohetrotrophs ---> light ------> organic matter --> photosynthetic bacteriachemautotrophs -----> inorganic matter--> CO2 ------> bacteriachemoheterophs ---> organic ---> organic -----> bacteria, fungi, protoza, animals

matter matter

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! oxygen also plays an important role< aerobic or anaerobic< facultative anaerobes; can grow in the presence or absence of O2

! temperature also important

Psychrophilic 10 to 30 optimum 12 to 18 °CMesophyllic 20 to 50 optimum 25 to 40 °CThermophilic 35 to 75 optimum 55 to 65 °C

2.6.1 Pathogens

! not native to aquatic systems and usually require an animal host for growth and reproduction! unfortunately, can be transported by water, becoming a temporary member of the aquatic

community! many species of pathogens are able to survive in water and maintain their infectious

capabilities for significant periods of time! include species of bacteria, viruses, protozoa, and helminths

BACTERIA

! gastrointestinal disorders are common symptoms of diseases transmitted by waterbornepathogenic bacteria

! Escherichia coli, is a common organism in human feces (fecal) ! Vibro cholerae

< caused Cholera, a disease which ravaged Europe during the 18th and 19th centuaries< caused vomiting, diarrhea, and without treatment results in dehydration and death< 1854 Hamilton had an outbreak of cholera; pop. 20,000 and 1 in 40 died< immunization and disinfection of water supplies have eliminated cholera and most

parts of the world, however, poor sanitary conditions can still cause an outbreak! Francisella tularensis; Tularemia

< deer fly fever

! Leptospira; Weils disease< jaundice, fever

! Salmonella typhosa; Typhoid fever< gastrointestinal disorders, high fever, ulceration of the intestines, and possible nerve

damage

! Shigella; Shigellosis (dysentery)< severe diarrhea

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VIRUSES

! need a host to live! Enteric cytopathogenic human orphan; aseptic meningitis, epidemic exanthem, infantile

diarrhea

! hepatitis A (destroys liver)

! some viruses will live as long as 41 days in water or wastewater at 20°C and for 6 days in anormal river

! biggest concern in Eastern Europe (WQI-1994#4) as 100 million people still lacking accessto sanitation or safe drinking water

! Poliomyelitis; acute anterior poliomyelitis (infantile paralysis)< immunization has reduced the incidence of polio to a few cases a year in developed

nations

PROTOZOA

! pathogenic or non-pathogenic, microscopic or macroscopic

! highly adaptable and distributed in natural water, but only a few are pathogenic

! protozoal infections are usually characterized by gastrointestinal disorders that are milderthan bacterial infections

! Entamoeba histolytica; amoebiasis ( amoebic dysentery, amoebic enteritis andamebic colitis)< include diarrhea, nausea, indigestion, flatulence, bloating, fatigue and appetite and

weight loss

! Giardia lamblia; giardiasis< carried by wild animals who live near natural water systems< contracted by persons drinking untreated surface waters< difficult to deactivate by disinfection< complete treatment and filtration required to eliminate from water

! Cryptosporidium< protozoan parasite found in waste of most mammals< oocysts (parasitic "eggs") are ingested and invade intestinal tract< nausea, diarrhea, cramps< similar to "giardia" but half as big< serious problem

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HELMINTHS (Worms)

! life cycle involves two or more animal hosts, of which one may be human

! water contamination may result from human or animal waste that contains helminths

! modern water-treatment methods are very effective in destroying these organisms

! greatest risk is from untreated sewage, i.e. sewage plant operators, swimmers in recreationallakes polluted by sewage or stormwater runoff from feedlots

! Dracunculus medinensis; dracontiasis (dragon or guinea-worm infection)< arthritis of joints

! Echinococcus; echinococcosis (dog tapeworm)

! Schistosoma; schistosomiasis (blood fluke disease)

< tissue damage< blood loss in bladder< Fig. 3.11 for full cycle

2.6.2 Pathogen Indicators

! analysis of water for all known pathogens would be very time consuming and expensive

! usually specific pathogens are not tested for unless they are suspected, instead indicatororganisms are used

! indicator organisms suggest that contamination had occurred and the level of contamination

! need an ideal one

! selected Escherichia Coli

! other coliform groups exist outside the intestinal tract of animals

! usual practise is to use the total coliform group (fecal and non-fecal origin)

NOTE: Pathogens are not identified by coliform test, rather that the water has recentlycontacted soil, decaying vegetation or discharge from warm-blooded animal

< if coliform are present, pathogenic organisms may also be present< all pathogens are destroyed by the time coliform organism are destroyed< these assumptions are being questions for infectious hepatitis< enumeration does not apply for other biological contaminant; algae, cyclops, etc

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! if fecal coliform present, can also determine fecal streptococci

< ratio can indicate which animal was source of pollution< human FC/FS = 4.4

cow FC/FS = 0.2sheep FC/FS = 0.4turkey FC/FS = 0.1

NOTE: safe water does not necessarily mean absolutely no risk in drinking it, but rather thatthe danger, if any, it is so small that it cannot be discovered by available means ofobservation

Concern Identified (WQI-1990)

! tested 3 Ontario cities for coliphage and bacteriophage (virus infected coliform and bacteria);A - Lake Huron, B - Lake Erie, C - River Water

A B C UNITS

TC-R 52 <1 5900TC-T ND ND ND

colonies/100 mLFC-R 30 <1 420FC-T ND ND ND

COLIPH-R 18 10 1695COLIPH-T 15 10 0

plague forming/LBACTIP-R 40 10 20BACTIP-T 9 10 15

Free Cl2 0.4 0.7 2.7 mg/L

In Summary:

If coliforms are present:

(1) Water was contaminated by discharge from human sources(2) Pathogens may be present(3) Water should be treated prior to consumption

If no coliforms are present:

(1) pathogens were destroyed by the methods used to kill the coliform, provided they werepresent in the first place.