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ENVIRONMENTAL PROTECTION Anita SZABÓ András OSZTOICS Dóra LAKY. D rinking W ater. Other aspect:. 1. Domestic - water for drinking, cooking, personal hygiene, lawn sprinkling, etc.
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ENVIRONMENTAL PROTECTION Anita SZABÓ András OSZTOICS Dóra LAKY
Other aspect: 1. Domestic - water for drinking, cooking, personal hygiene, lawn sprinkling, etc. 2. Public - water for fire protection and street cleaning and water used in schools or other public buildings 3. Commercial and Industrial – water used by restaurants, laundries, manufacturing operations, etc. 4. Loss - due to leaks in mains and house plumbing fixtures
WATER SOURCES • Surface waters: • river • lake • reservoir • Subsurface waters: • ground water • water of deep confined aquifers • karstic water • bank filtered water
water table This water source is the most sensitive to pollution from point or non-point source. Pollutants occur here are most often due to human activity. well manure fertilizer back-house waste disposal
WATER OF DEEP CONFINED AQUIFERS well water table 1st aquifer 2nd aquifer 3rd aquifer no pollutants of human activity origin
KARSTIC WATER CO2 containing precipitation (rain water, melted snow) dissolves limestone limestone no protecting layers (clay, or any others) during the water transportation from the surface into the deep vulnerable to pollution
Karstic water The carbon-dioxide containing precipitation (rain, water, melted snow) have produced for itself corridors, tunnels and caves in limestone hills. H2CO3 + Ca CO3 Ca2+ + 2 HCO3- Taking into consideration the geological structure of the limestone hills, in a lot of cases do not exist any protecting layers (clay or any others) during the water transportation from the surface into the deep.
BANK FILTERED WATER For abstraction of bank filtered water the wells can be set up on river banks, were hydrogeological conditions are favourable for the flow of high quantity river water towards to the water containing zone. Most of the water of such wells originates from the rivers, but groundwater from the background (back side feeding) may also play a role.
During the low water level period in the river, the quantity and quality of groundwater originated from the background can be significant.
Possible pollutans of drinking water sources: 1. Surface waters a.) River water: • turbidity (suspended solids, phytoplankton) • pathogen and other microorganisms • organic matter • humic, fulvic and lignine substances • organic and inorganic micropollutants • oil • ammonium ions (especially in cold water)
b.) Lake water: • turbidity ( phytoplankton, suspended matter ) • pathogen and other microorganisms • humic, lignine and fulvic substances • organic matter • oil • ammonium ions (especially in cold water)
c.) Reservoir water: • turbidity ( phytoplankton ) • pathogen and other microorganisms • humic, fulvic and lignine substances • organic matter • ammonium ions (especially in cold water or • lack of dissolved oxygen)
2. Subsurface waters a.) Ground water: • pathogen and other microorganisms • lack of dissolved oxygen • ammonium, nitrite, nitrate • iron and manganese compounds • organic matter • organic and inorganic micropollutants
b.) Water of deep confined aquifers: • iron and manganese • humic fulvic and lignine substances • ammonium, H2S • volatile hydrocarbons (methane) • high salt content • high temperature • high CO2 content • arsenic ( geochemical origin)
c.) Karstic water: • pathogenic and other microorganisms • ammonium and nitrate • turbidity • organic and inorganic micropollutants • organic matters
d.) Bank filtered water: • microorganisms • iron and manganese • ammonium • organic substances • organic and inorganic micropollutants • hydrocarbons
Criteria • colourless • odourless • does not contain: turbidity poisonous matters pathogenic microorganisms high salt content high organic content
What to do if criteria are not met? • abandone that source – bring water from other source • regional systems • TREATMENT
What to remove? 1. pathogen microorganisms 2. toxic components 3. precursors 4. N forms (ammonium, nitrite, nitrate) 5. substances causing aesthetic problems (e.g. suspended solids, humic substances, iron content, odour)
To what limit we should keep? STANDARDS: commendations – WHO regional regulation – EU national standards
Factors effecting treatment: • what parameters are problematic • how much water is needed (huge quantities, demand changes in time) • extent of the net • delivery time to the outermost consumer
Factors effecting treatment: • what parameters are problematic • how much water is needed (huge quantities, demand changes in time) • extent of the net • delivery time to the outermost consumer
What processes can we use? 1. oxidation-reduction 2. pH and buffering capacity adjustment (pH optimum of processes) 3. chemical precipitation (dissolved particulate) 4. adsorption (bind to surface) 5. phase separation (removal of different phases: solid/liquid and gas/liquid phase separation) 6. other (e.g. reverse osmosis)
What processes can we use? 1.oxidation-reduction 2. pH and buffering capacity adjustment (pH optimum of processes) 3. chemical precipitation (dissolved particulate) 4. adsorption (bind to surface) 5. phase separation (removal of different phases: solid/liquid and gas/liquid phase separation) 6. other (e.g. reverse osmosis)
Oxidation and reduction The processes are parallel with each other, they take place at the same time The oxidation agent will be reduced, while the reduction agent will be oxidized In drinking water treatment chemicals are oxidized in order to make them non-soluble, in order to make them less toxic or in order to kill bacteria (disinfection) Oxidizing agents are: oxygen, ozone, chlorine, potassium permanganate, chlorine dioxide, chloramines, …
What processes can we use? 1. oxidation-reduction 2. pH and buffering capacity adjustment (pH optimum of processes) 3. chemical precipitation (dissolved particulate) 4. adsorption (bind to surface) 5. phase separation (removal of different phases: solid/liquid and gas/liquid phase separation) 6. other (e.g. reverse osmosis)
Control of pH and buffering capacity pH control is important during several water treatment steps ( high efficiency )
What processes can we use? 1. oxidation-reduction 2. pH and buffering capacity adjustment (pH optimum of processes) 3. chemical precipitation (dissolved particulate) 4. adsorption (bind to surface) 5. phase separation (removal of different phases: solid/liquid and gas/liquid phase separation) 6. other (e.g. reverse osmosis)
solid-liquid: optimal removal of soluble compounds from the water transform into solid matters Chemical precipitation What is chemical precipitation? Transformation of water soluble compounds into poorly water soluble solid compounds in consequences of significant pH change or chemicals addition into water.
What processes can we use? 1. oxidation-reduction 2. pH and buffering capacity adjustment (pH optimum of processes) 3. chemical precipitation (dissolved particulate) 4. adsorption (bind to surface) 5. phase separation (removal of different phases: solid/liquid and gas/liquid phase separation) 6. other (e.g. reverse osmosis)
Adsorption What is adsorption? The physical and/or chemical process in which a compound is accumulated at an interface between phases (solid-liquid interface) The most important adsorbent is activated carbon: • able to remove dissolved organic substances from water • rremoval of organic micropollutants
What processes can we use? 1. oxidation-reduction 2. pH and buffering capacity adjustment (pH optimum of processes) 3. chemical precipitation (dissolved particulate) 4. adsorption (bind to surface) 5. phase separation (removal of different phases: solid/liquid and gas/liquid phase separation) 6. other (e.g. reverse osmosis)
Gas / Liquid Phase Separation • Removal of volatile compounds, gases • The mostly applied gas-liquid separation: aeration What is aeration? • The volatile matters leave the liquid phase by flowing a high volume of inert gases or air
During areation the water is saturated by oxygen ( by air flowing) • Two processes take place: • the stripping of volatile compounds • oxidation of compounds situated in their reduced form
Solid / Liquid Phase Separation Solid matters removal: • coarse and fine separation processes • screening coarse processes: • microstraining • sand removal (sand trip) • sedimentation • flotation
Transform colloid, quasi colloid particles for sedimentation and filtration ( coagulation, flocculation) Fine processes: • slow sand filtration • rapid filtration The fine particles are able pass through the filters too!
What processes can we use? 1. oxidation-reduction 2. pH and buffering capacity adjustment (pH optimum of processes) 3. chemical precipitation (dissolved particulate) 4. adsorption (bind to surface) 5. phase separation (removal of different phases: solid/liquid and gas/liquid phase separation) 6.other (e.g. reverse osmosis)
Reverse Osmosis Reverse osmosis consists of separating a solvent, such as water from a saline solution by the use of a semi permeable membrane and hydrostatic pressure