1. POLLUTANTS IN WASTEWATER
Microorganisms (pathogens)
Nutrients
Metals
Other inorganic substances
Radioactive substances
Biologically degradable organic substances
Other organic substances
Odor and taste matters
Heat

2. CHARACTERISATION OF POLLUTANTS
Chemical characterisation
Individual components:
Sewage – impossible
Industrial wastewaters – sometimes there is a possibility
Municipal wastewater - impossible

3. CHARACTERISATION OF POLLUTANTS
Group characterisation
Carbon
Chemical Oxygen Demand (CODMn, CODCr)
Biochemical Oxygen Demand (BOD5, BOD7, BOD20)
Total Organic Carbon (TOC)
Dissolved Organic Carbon (DOC)
Volatile Organic Carbon (VOC)
Nitrogen
Phosphorus
Suspended solids
Extractable matters
Detergents

4. MEASURE OF ORGANIC SUBSTANCES
CHEMICAL OXYGEN DEMAND
Quantity of the pollutants in water that can be oxidised by a chemical oxidant
Consumption of oxidant (potassium dichromate - CODCr or potassium permanganate - CODMn) gives the content of organic substances
CODCr = 250 – 900 mg O2/l in raw wastewater

5. MEASURE OF ORGANIC SUBSTANCES
BIOCHEMICAL OXYGEN DEMAND
Measure of the content of biologically degradable substances
Quantity of oxygen consumed by microorganisms over a period of 5 days (BOD5) or 7 days (BOD7) in decomposing the organic pollutants (carbon)
BOD5 = 120 – 400 mg/l in raw wastewater
BOD7 = 1.15  BOD5
BOD20: including decomposition of organic nitrogen as well

6. BIOCHEMICAL OXYGEN DEMAND
time
BOD [mg/l]
NBOD = BOD20
CBOD = BOD5, BOD7

7. MEASURE OF ORGANIC SUBSTANCES
TOTAL ORGANIC CARBON (TOC)
Quantity of carbon dioxide produced from oxidation (combustion, ultra violet radiation, chemical oxidants) of a sample
CO2 is measured by infrared analyser for example
DISSOLVED ORGANIC CARBON (DOC)
Sample filtered through 0.45 m pore size membrane filter (colloidal matter is included as well)
VOLATILE ORGANIC CARBON (VOC)
Organic compounds with boiling point  100 °C

8. MEASURE OF ORGANIC SUBSTANCES
THEORETICAL ORGANIC CARBON : ThOC = 100%
can be calculated if we now the chemical formula of the organic matter
TOC %
DOC %
CODCr %
CODMn %
BOD %
BOD %

9. PROPORTION OF ORGANIC CARBON [%]
ORGANIC POLLUTANTS
SUBSTANCE
PROPORTION OF ORGANIC CARBON [%]
Carbohydrates
Proteins
Free amino acids
Higher fatty acids
Dissolved organic acids
Esteres fatty acids (fat)
Tensides
Other

10. INORGANIC SUBSTANCES NITROGEN PHOSPHORUS HEAVY METALS
DISSOLVED SALTS MAINLY
DETERMINED BY THE IONIC COMPOSITION AND SALT CONCENTRATION OF WATER
NORMALLY UNIMPORTANT
WHAT IS IMPORTANT?
NITROGEN
PHOSPHORUS
HEAVY METALS

11. NITROGEN mg/l 20-700 mg/l 30 mg/l ORGANICALLY BOUND INORGANIC
AMMONIUM (NH4-N)
NITRATE (NO3-N)
NITRITE (NO2-N)
TOTAL KJELDAHL NITROGEN (TKN)
NON-OXIDISED FORMS (NH4-N + orgN)
TOTAL NITROGEN (TN)
No exact values!!!

12. NITROGEN NITRIFICATION NH4+ + 1,5 O2  NO2- + H2O + 2H+ + energy
Nitrosomonas
NO2- + 0,5 O2  NO3- + energy
Nitrobacter
necessary:
ammonium-N
aerobic condition (DO)
bacteria – pH, T, toxic matters, operation

13. NITROGEN DENITRIFICATION 2 NO3- + org C + 2H+  CO2 + H2O + N2+ energy
NO3-  NO2-  NO  N2O  N2
necessary:
organic carbon (easily degradable)
anoxic condition (DO=0, NO3-, NO2-)
bacteria – pH, T, toxic matters, operation

14. PHOSPHORUS MAIN SOURCE ORGANICALLY BOUND INORGANIC DETERGENTS (50%)
HUMAN EXCRETA (50%)
ORGANICALLY BOUND
SOLID
INORGANIC
POLYPHOSPHATES
ORTHOPHOSPHATES (PO43-)
DISSOLVED TP

15. PHOSPHORUS ORGANICALLY BOUND POLYPHOSPHATES ORTHOPHOSPHATES (PO43-)
mg/L
POLYPHOSPHATES
mg/L
ORTHOPHOSPHATES (PO43-)
mg/L
TOTAL PHOSPHORUS
mg/L

16. OTHER POLLUTION PARAMETERS
TOTAL SOLIDS (TS)
SUM OF PARTICULAR AND DISSOLVED MATTERS (residue remaining after a wastewater sample has been evaporated and dried at 105 ºC)
TOTAL VOLATILE SOLIDS (TVS)
Solids that can be volatilised and burned off when TS are ignited (550 ºC)

17. OTHER POLLUTION PARAMETERS
TOTAL SUSPENDED SOLIDS (TSS)
Portion of the TS reatined on a filter (0.45 ; 1.58 m), measured after drying at 105 ºC)
SETTLEABLE SOLIDS
suspended solids, expressed in mL/L, that will settle out of suspension within 30 min (1 h)
Imhoff cone (1 L)
60% of TSS is settleable

18. OTHER POLLUTION PARAMETERS
EXTRACTABLE MATTERS (fats and oils)
DETERGENTS (surface active matters)
METALS (dissolved or particulate, heavy metals)
Fe, Hg, Ni, Cd, Zn, Cu, Cr, Pb, Mn, As pH

19. pH OF WATER Dissociation of water = self ionisation
2H2O = H3O+ + OH-
[H3O +][OH-] = Kw = (constant at constant temperature)
pH = parameter describing acidity or basicity
pH = - log [H+]
range:
natural waters: pH = 6.5-9
importance: natural processes take place in a certain interval of pH
how can we influence pH
addition of acid/base
addition of salts
NH4+ + H2O = NH3 + H3O+

20. OTHER PARAMETERS MEASURED AT A WWTP
anions: Cl-, SO3-, HCO3-, CO32-, F-
cations: K+, Na+, Ca2+, Mg2+, Fe2+, Fe3+, Mn2+
organic micropollutants
phenols (C6H5OH)
chlorinated hydrocarbons
detergents
pesticides, herbicides, fungicides, etc

21. OTHER PARAMETERS MEASURED AT WWTP
ALKALINITY (amount of hydrocarbons)
amount of matters in water that can be titrated with acids caused by hydro-carbons (mainly Ca- and Mg-hydro-carbons)
analysis with titration
SALT CONTENT (electric conductivity)
DRY MATTER CONTENT (dried at 105 ºC)
TEMPERATURE
WASTEWATER VOLUME
INGINITION LOSS (TVS)
TECHNOLOGICAL PARAMETERS
Recirculation rate, sludge concentration, sludge age, etc.

22. BIOLOGICAL PARAMETERS
viruses
bacteria (Total Coliform, Faecal Coliform, Streptococcus, Salmonella)
Most often indicator parameters

23. ESTIMATING POLLUTANT LOAD AND CONCENTRATION
BOD5: 60 g/d/person
COD: 120 g/d/person
TSS: g/d/person
TN: g/d/person
TP: g/d/person
drinking water consumption: qd = l/d/person 

24. ESTIMATING POLLUTANT CONCENTRATION
BOD5: 60 g/d/person
TN: g/d/person
TP: g/d/person
calculating with 200 l/d/person:
BOD5 concentration: 60/200 = 0.03 g/L = 300 mg/L
TN concentration: 11/200 = g/L = 55 mg/L
TP concentration: 2.5/200 = g/L = 12.5 mg/L 

25. POPULATION EQUIVALENT
converting industrial pollutant load - expressing it as a municipal load
The population equivalent is a unit of measurement of organic biodegradable pollution representing the average load of that pollution produced by one person in one day; in the EU Directive it is fixed at 60 grams of B0D5 per day.   
e.g. industry producing ww of 1000 pe means g/d BOD5 load

26. MAXIMUM ADMISSIBLE CONCENTRATIONS (MAC)
REGIONAL STANDARDS
COUNTRY STANDARDS

27. COUNCIL DIRECTIVE of 21 May 1991 concerning urban waste water treatment (91/271/EEC)
This Directive concerns the collection, treatment and discharge of urban waste water and the treatment and discharge of waste water from certain industrial sectors.
Member States shall ensure that urban waste water entering collecting systems shall before discharge be subject to secondary treatment or an equivalent treatment

28. Minimum percentage of reduction Reference method of measurement
Parameters
Concentration
Minimum percentage of reduction
Reference method of measurement
Biochemical oxygen demand (BOD5 at 20 °C) without nitrification
25 mg/L O2
70-90
40 under
Article 4
Homogenized, unfiltered, undecanted sample. Determination of dissolved oxygen before and after five-day incubation at 20 °C ± 1 °C, in complete darkness. Addition of a nitrification inhibitor
Chemical oxygen demand (COD)
125 mg/L O2 75
Homogenized, unfiltered, undecanted sample Potassium dichromate
Total suspended solids
35 mg/L
35 under
> pe)
60 under
( pe)
90*
90 under
(> pe)
70 under
·Filtering of a representative sample through a 0,45 m filter membrane. Drying at 105 °C and weighing
·Centrifuging of a representative sample (for at least five min with mean acceleration of to g), drying at 105 °C and weighing

29. Minimum percentage of reduction Reference method of measurement
Requirements for discharges from urban waste water treatment plants to sensitive areas which are subject to eutrophication. One or both parameters may be applied depending on the local situation. The values for concentration or for the percentage of reduction shall apply.
Parameters
Concentration
Minimum percentage of reduction
Reference method of measurement
Total phos-phorus
2 mg/L P ( pe)
1 mg/LP (> p e) 80
Molecular absorption spectrophotometry
Total nitrogen
15 mg/L N ( pe)
10 mg/L N (> p e)*
70-80
* Alternatively, the daily average must not exceed 20 mg/l N. This requirement refers to a water temperature of 12° C or more during the operation of the biological reactor of the waste water treatment plant. As a substitute for the condition concerning the temperature, it is possible to apply a limited time of operation, which takes into account the regional climatic conditions.

30. CONVENTIONAL TREATMENT OF SEWAGE
CONVENTIONAL TREATMENT OF SEWAGE
PHYSICAL (MECHANICAL)
SEPARATION OF SETTLEABLE and FLOATING SOLIDS
BIOLOGICAL
SEPARATION OF SUSPENDED OR DISSOLVED SOLIDS WITH THE USE OF MICROORGANISMS
CHEMICAL
PRECIPITATION, COAGULATION, FLOCCULATION

31.  MECHANICAL TREATMENT SEPARATION OF COARSE MATERIALS
SCREENING floating debrish, leaves, nylon sacks, etc.
GRIT (SAND) TRAP sand (inorganic, inert substances)
SETTLING OF OTHER SUBSTANCES
SEDIMENTATION TANK - organics (COD, BOD, TP, TN)
(OR FLOTATION)

32.  SCREENING BAR SCREENS aim: defending the subsequent instruments
retain floating debrish (wood, rags, etc.)
long, narrow metal bars 25 mm (1 in.) apart
in a frame
vertical or tilted
cleaned automatically (75-80°)
or by hands (60°, 1-2 times a day with rake)

33. BAR SCREENS increased clogging during winter time (ice)
debrish has to be collected
massive, oversized structures
if mechanical units  defense against overload
 shearing element
greater treatment plant  at least 2 parallel screens

34. BAR SCREENS COARSE SCREENS  20-30 mm FINE SCREENS  1.5-15 mm
mm free gap
 mm
FINE SCREENS
10-50 mm free gap
 mm
BOD removal  5%

35. h =   vf2 / 2g DESIGN OF SCREENS HYDRAULIC HEAD LOSS (damming)
depends on :
size of free gap
velocity
slope of screen
shape of screen
h =   vf2 / 2g
ALLOWED MAXIMUM DAMMING
hmax = 5 – 15 cm

36. COMMUNITOR MECHANICAL CUTTING DEVICE
SLOTTED CYLINDRICAL SCREEN WITH MOVING CUTTER BLADE
CHOPS SOLIDS THAT PASSED THROUGH THE BAR SCREEN
SHREDDED MATERIAL IS REMOVED BY SEDIMENTATION OR FLOATING

37.  SEDIMENTATION DISCRETE PARTICLES (do not tend to flocculate)
HEAVIER PARTICLES FALL TO THE BOTTOM
v < vcr  SETTLING
CRITICAL VELOCITY – KEEPS THE PARTICLE SUSPENDED

38. SEDIMENTATION F Stokes’ law G S = f ()  - settling velocity
 - absolute viscosity of the fluid
 - mass density of fluid
s - mass density of particle
g - gravitational constant
d – diameter of the particle G

39. SEDIMENTATION v1 > vs  particles retain in a ratio of v1/vs
v1 < vs  particles settle

40.  GRIT TRAP / SAND TRAP SAND CAUSES WEAR-AND-TEAR ON PUMPS
 HAVE TO BE REMOVED
HEAVIER PARTICLES FALL TO THE BOTTOM
v < 0.3 m/s (1 ft/s)  SETTLING
OFTEN COMBINED WITH SOME FORM OF AERATION
TO MAINTAIN DO + SEPARATION OF GREASE

41. SAND TRAP VERTICAL FLOW HORIZONTAL FLOW
good efficiency difficult to place
AERATED
TANGENTIAL
high flow, uneven load DO oil skimming
like horizontal flow, but inflow from the side

42. SAND TRAP DESIGNING MIN 2 BASINS PARALLEL (dry flow and higher flow)
PEAK FLOW
RESIDENCE TIME (10 min)
HYDRAULIC SPECIFIC LOAD (30 m3/h/m2)
SLUDGE RAMOVAL:
MECHANICAL
GRAVITATIONAL

43.  SEDIMENTATION BASIN PRETREATMENT (no dissolved substances removed)
AIM: removal of suspended solids smaller than sand
REMOVES 25-35% OF THE ORGANIC MATTER
SPECIFIC LOADING : 1-3 m3/h/m2

44. SEDIMENTATION BASIN

45. SEDIMENTATION BASIN Q = 150 – 2000 m3/d h/l = 1/15 – 1/20
h = 1.5 – 3.0 m w= 4 – 8 m

46. SEDIMENTATION BASIN
D = 30 –40 m
h = 2-4 m

47. SECONDARY (BIOLOGICAL) TREATMENT
SECONDARY (BIOLOGICAL) TREATMENT
WITH THE USE OF MICROORGANISMS
ORGANIC MATTER
microorganisms oxidise the organic matter while producing new cell material, CO2 and H2O
NITROGEN
ammonification, nitrification, denitrification
PHPSPHORUS
Biological P-removal

48. Slowly degradable material Easily degradable material
CONVERSIONS IN BIOLOGICAL WWTREATMENT
biological growth
hydrolysis
decay
Slowly degradable material
hydrolysis
Easily degradable material
biological growth
Biomass
decay
Inert material 

49.  TYPE OF REACTORS activated sludge reactors biofilm reactors
microorganisms are suspended in water (mobilised)
different conditions at different places
biofilm reactors
microorganisms are hold on a fixed surface
different conditions are at the same place but at other time

50. BIOLOGICAL PARAMETERS
BIOLOGICAL PARAMETERS
Activated sludge processes
Aeration basin systems
Oxidation ditch
Aerated sewage lagoons
Biofilm processes
Trickling filters
Rotating biological contactors (biological rotors)
Thin biofilm systems

51. Rotating biological contactors

52.  SECONDARY TREATMENT Biological reactor Secondary settling
Disinfection