Transcript Drink and Waste water treatment in Portugal

Water Treatment
By :
Julio Costa
n. 384657
Pedro Vasconcelos
n. 384394
Prague , January of 2007
Water Treatment
• Water Contamination
• Prompt sources of pollution
• Linear sources of pollution
• Diffuse sources of pollution
• Contaminant substances of the water
•
•
•
•
•
•
•
Pathogenic micro organisms
Organic dejects
Chemical inorganic substances
Organic composites
Sediments and materials in suspension
Radioactive substances
Thermal contamination
Water Treatment
• Water Treatment Processes
• Amount
• Quality
• Economy
• General aspects on unitary operations
• Harrowing
• Straining
• Pre-oxidisation
• Aeration
• Pre-oxidisation by chlorine
• Pre-oxidisation by chlorine dioxide
• Pre-oxidisation by ozone
Water Treatment
(Continuing)
• Coagulation/Flocculation
• Decantation
• Filtration
• Chemical stabilization
• Disinfection
• Physical disinfection
• Mechanical Disinfection
• Chemical Disinfection
It is important to relate that the predominant chlorine forms in water are related with pH
Water Treatment
• Treatment of the water VERSUS control of pathogenic agents
• Pre-treatment
• Coagulation, Flocculation and Sedimentation
Removal of bacteria (E. coli e Clostridium) and protozoa (Giardia e
Cryptosporidium) on the optimal coagulation conditions (Le Chevallier,
M.W.; Kwok-Keung Au, WHO, 2004)
Water Treatment
•Treatment of the water VERSUS control of pathogenic agents
Removal of virus (bacteriophage MS-2; phage PRD-1; poliovirus e
echovirus) on the optimal conditions of coagulation (Le Chevallier, M.W.;
Kwok-Keung Au, WHO, 2004)
Water Treatment
•Treatment of the water VERSUS control of pathogenic agents
• Ionic exchange
• Filtration
Size of
do pore
(µm)
Type of Filter
Operating pressure
(kPa)
main
application
MF
30-50
≥ 0.1
Removal of particles and
turbidity
UF
30-50
≥ 0.01
Removal of non ionic
solved solutes
NF
500-1000
≥ 0.001
RO
1000-5000
≥ 0.0001
Removal of
bivalent ion
(softening) and solved
organic matter
Removal of ions monovalents
(desalinization)
microbiological Removal
Algae, protozoan
and Bacteria
Algae, Protozoan,
majority of Bacteria e
Virus
Algae, Protozoan, majority
of Bacteria e Virus
Algae, Protozoan, majority
of Bacteria e Virus
Water Treatment
•Treatment of the water VERSUS control of pathogenic agents
Relationship between the size of pores of the filtering layer and the size of the
microbiological particles (Le Chevallier, M.W.; Kwok-Keung Au., WHO, 2004)
Disinfection
• Disinfection
• Parameters
–
–
–
–
Disinfectant concentration
Time of disinfection
pH
Temperature
• Agents of Disinfection
•
•
•
•
chloride
chloride dioxide
Ozone
U.V. light
Disinfection
• Mechanims of Disinfection
• Destruction of the cell
• Changes in the metabolism
• Interference in the biosynthesis growing
of the cell
• Stages of the Disinfection Process
• Oxidation
• Disinfection
» Efficient steps means efficient process
Disinfection
• Oxidation
• Oxidants are used in a pre-treatment stage
– Reasons for this stage
• Improve particle removal of next stage
• Control of micro-organisms
• By chloride
Disinfection
• chemical oxidation process
• Most common process nowadays
• reactions are strongly dependent of the pH
• By chloride dioxide
• control the amount of iron
• Highly soluble in water
• By ozone
• inactivates micro-organisms
• Reaction with micro-organisms
– Direct
– Aqueous solution
Disinfection
• By U.V. Light
• U.V.-B and U.V.-C innactivates micro-organisms
• Wavelengh 210-300nm
• Most eficient at 265nm
– Unwanted activantion of inactive microorganisms
• Solved using a high dose of radiation
• Influence Factor
– Suspended organic matter
Disinfection
• By U.V. Light
• Disinfection is done in few seconds
• Tanks are not needed
– Electromagnetic Process
• Efficiency is not dependent from the previous factors
Distribution systems
• Evaluation of the sanitary risk
– Origin of the water
– adequate treatment
– conditions of storage and transport of treated
water
– Protection of the system
Distribution systems
• Evaluation of the sanitary risk
–
–
–
–
Origin of the water
adequate treatment
conditions of storage and transport of treated water
Protection of the distribution system
• Maintenance of the water quality in all the
system
– minimizing the microbial growing
– preventing the microbial recontamination
Distribution systems
• System
– Piping
– Connections
– Tanks
• How to mantain quality
– maintaining a residual part of disinfectant
– limiting the organic matter
– Controlling the corrosion
– temperature, materials of construction, time of
retention
• Geography
– North of Portugal
– Minho
– Area 183, 51 km²
– Altitude 20 - 572
meters
– Between two
rivers: Cávado
and Este
– Several hills
around the city
– Soil with plenty of
water
Braga
Braga
• Climate
– Atlantic
temperate
– four well defined
seasons
– Rainy and wet
– Winds from
the sea
• Maximum temperature average – 19ºC
• Minimum temperature average – 10ºC
Braga
• Demography
– 931, 1 hab/km²
– 170 858 habitants (2004)
• 171000 to 230000 people including temporary citizens
– 70628 houses
Sanitation of Braga Commune Project
• 2 distinct zones
– Zones of Intent Population 931, 1 hab/km²
– Zones of Dispersed Population
• Served Population
Year of entrance in functioning of the
Project
Served Population
(Nº Inhabitants)
Year 40
146184
274913
0
0
Industria (Equivalent Inhab.)
7735
14822
Total
153919
289735
Floating Population (Nº
Inhabitants)
Sanitation of Braga Commune Project
Existing Infrastructures
Existing ETAR´s
2000
Total Population (Equivalent Inhab.)
Flow (m^3/day)
Organic load - Total CBO5 - (Kg)
Treatment
100961
8512
6384
4 ETAR: 1 with treatment by average load
activated-sludge, 1 with treatment
physicist-chemistry, 1 with primary
and secondary treatment and 1 by
lagooning.
Sanitation of Braga Commune Project
Infrastructures to Renew/Extend/Benefit
Characteristics of the ETAR´s to renew
Year of entrance in
functioning of the
project
Year 40
118506
236809
Flow (m^3/day)
9480
18945
Organic load - Total
CBO5 - (Kg)
7110
14209
Total Population
(Equivalent Inhab.)
Characteristics of the lift station
1 Lift Station with Substitution of the electro-mechanic equipment
Treatment
4 ETAR: 1 with
tertiary/secondary
/ primary
treatment, 2 with
secondary/
primary treatment
and 1 for
lagooning
Sanitation of Braga Commune Project
Infrastructures to build
Characteristics of the ETAR´s to build
Year of entrance in
functioning of the
project
Total Population
(Equivalent Inhab.)
35413
Flow (m^3/day)
Organic load - Total
CBO5 - (Kg)
Year 40
Treatment
52926
2833
6351
125
3176
17 ETAR: 5 by lagooning
e 12 compacts
Intercepting and Lifting system
length
Diameter
Type
Lifting Station
71975
300-500
Gravitational
-
10823
160-250
Lifting
19
Treatment Processes
• Lagooning
Procedural Description of the
Diverse Stages of Treatment
• Preparation stage
• Sedimentation lagoon
• First and second aerating lagoon
• Maturation Lagoon
Braga Commune
Map Sanitation Net
Press release
IP/06/1769
Brussels, 12 December 2006
Environment: Commission takes Finland, Sweden and Portugal to Court over
waste water treatment
The European Commission is taking Finland, Sweden and Portugal to the
European Court of Justice (ECJ) for failing to ensure proper treatment of
urban waste water in a significant number of towns and cities. The failure of
Finland and Sweden to systematically remove nitrogen when treating the
waste water of their inland cities and towns is contributing to the
environmental problems of the Baltic Sea. Portugal has failed to respect a
special decision on urban waste water discharges from Estoril, near Lisbon,
and the surrounding area.
The end.
(Thank you for your attention)