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Water Treatment. Prague , January of 2007. By : Julio Costa n. 384657 Pedro Vasconcelos n. 384394. Water Treatment. Water Contamination Prompt sources of pollution Linear sources of pollution Diffuse sources of pollution Contaminant substances of the water
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Water Treatment Prague , January of 2007 By : Julio Costa n. 384657 Pedro Vasconcelos n. 384394
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
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
Disinfection • By chloride • 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 micro-organisms • 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
Braga • 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 • 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 Population931, 1 hab/km² • Zones of Dispersed Population • Served Population
Sanitation of Braga Commune Project Existing Infrastructures
Sanitation of Braga Commune Project Infrastructures to Renew/Extend/Benefit
Sanitation of Braga Commune Project Infrastructures to build
Treatment Processes • Lagooning
Procedural Description of the Diverse Stages of Treatment • First and second aerating lagoon • Preparation stage • Maturation Lagoon • Sedimentation lagoon
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)