Water recycling

Water recycling
Reciclado del agua

1. WATER RECYCLING Raquel Gavilán Párraga Manuel Andrés Holgado Almaraz Teresa Juan Mangas Luis Francisco Mezquita Ayla Pérez Díaz-Mingo David Sánchez Serrano

2. Introduction What is water? Chemistry : 2 hydrogen atom jointed to a oxygem atom. Physics: Polar liquid with boiling temperature of 100ºC that is solid below 0ºC. Key point : Water is an essential and limited element for human life .

3. Introduction Why recycle water ? Limited recourse of the planet . Water is recycled by itself but if we contaminate just one of the step in the water cycle, all the cycle is contaminated too. So this shows us the importance of recycling water .

4. Introduction Pollution and water purification Water pollution affects rainfall, surface water, groundwater and the resulting degraded natural ecosystems. Since 1900 the population has quadrupled while water extraction has increased sixfold . In addition to sustainable development policies, purification systems are required to improve the quality of discharges generated by human activity.

5. Introduction Residual water purification By applying those purification treatments we remove from water most of the residuals that are present there and we achieve a reduction of the negative effect that human activities have in the nature. Treatments : P hysical treatments C hemical treatments Biological treatments

6. Introduction Drinking water disinfection Each country legally regulates the quality of water intended for human consumption. Water must be treated for human consumption and may require removal of dissolved substances, undissolved substances and microorganisms harmful to health. There are different technologies for drinking water treatment.

7. Introduction Water feautures There are two important features : Alkalinity : Colloids: Particules of 1-100microns. Removed by coagulation or floculation .

8. Introduction Water feautures BOD (Biochemical Oxygen Demand) Normally BOD5 is measure -> Oxygent demand after 5 days Used to determine the degree of water pollution Low leves of BOD does not necessarily imply little pollution .

9. Water Pollutants Solids Excepting gases, all substances, either organic or inorganic, which are diluted in water are called solids In this sense, solids or total solids (TS) are defined as any substances which remain as a solid residue in a water sample which has been heated to a temperature within 100ºC and 105ºC , evaporated and dried According to their size we can find to different groups of total solids:

10. Water Pollutants Solids Excepting gases, all substances, either organic or inorganic, which are diluted in water are called solids In this sense, solids or total solids (TS) are defined as any substances which remain as a solid residue in a water sample which has been heated to a temperature within 100ºC and 105ºC , evaporated and dried According to their size we can find to different groups of total solids: DISSOLVED SOLIDS Can be retained by a 2.0 micron pore filter Usually salts or organic residues A filtering and drying process is carried out to eliminate it

11. Water Pollutants Solids Excepting gases, all substances, either organic or inorganic, which are diluted in water are called solids In this sense, solids or total solids (TS) are defined as any substances which remain as a solid residue in a water sample which has been heated to a temperature within 100ºC and 105ºC , evaporated and dried According to their size we can find to different groups of total solids: DISSOLVED SOLIDS TOTAL VOLATILED AND FIXED SOLIDS Can be retained by a 2.0 micron pore filter Usually salts or organic residues A filtering and drying process is carried out to eliminate it Are those solids which volatilize at a temperature of 550º C These organic solids may be bacteria and viruses and other organic substances

12. Water Pollutants Solids Excepting gases, all substances, either organic or inorganic, which are diluted in water are called solids In this sense, solids or total solids (TS) are defined as any substances which remain as a solid residue in a water sample which has been heated to a temperature within 100ºC and 105ºC , evaporated and dried According to their size we can find to different groups of total solids: DISSOLVED SOLIDS TOTAL VOLATILED AND FIXED SOLIDS SETTLEABLE SOLIDS Can be retained by a 2.0 micron pore filter Usually salts or organic residues A filtering and drying process is carried out to eliminate it Are those solids which volatilize at a temperature of 550º C These organic solids may be bacteria and viruses and other organic substances S olids over 10 micron in size and which sediment These suspended solids will settle to the bottom of a conic shaped recipient

13. Water Pollutants Organic Residuals Chemical oxygine demand (COD) is defined as the amount of diatomic oxygen O2 needed to oxidize that matter which is susceptible of being oxidized in a liquid sample Is a good indicator of the amount of organic matter in water The most common method to determinate COD consists of using potassium dichromate Pathogens (pathogenic agents) Pathogenic agents which cause the transmission of multiple diseases Bacteria Viruses Protozoa

14. Water Pollutants Minerals High concentrations of heavy metals can occur in some water bodies Zinc, mercury, manganese and lead are among the most frequently heavy metals found in water bodies Maximum Contaminant Level (MCL) is the highest level of a contaminant that is allowed in drinking water. PHYSICAL & MINERALS CHARACTERISTICS CHART for Calendar Year 2012 Constituent Annual Range Detected Annual Average Copper, ppm ND - 0.011 0.002 Hardness, ppm 10.0 - 29.0 19.6 Iron ND - 0.071 0.018 Magnesium, ppm 0.70 - 2.00 1.35 Manganese, ppb ND - 0.010 0.003 Nickel, ppm ND - 0.003 0.000 Phosphate, ppm 0.37 - 1.38 0.92 Potassium, ppm 1.10 - 2.70 1.67 Silica, ppm 5.44 - 15.72 10.46 Zinc, ppm 0.074 - 0.252 0.153

15. Water Pollutants N itrogen & Phosphor Both, nitrogen and phosphor, are essential nutrients for aquatic life, but excessive amount s of any of them can produce serious problems. The main effect of nitrogen and phosphor contamination of water is the so called Eutrophication. This process produces an excessive growth of algae and aquatic plants which, after dying, degrade an decompose in riverbeds and reservoir funds.

16. Residual Water Physical Treatments Clean water Physical principles No new substances

17. Residual Water Physical Treatments Hydrocyclone Solid- liquid separation Centrifugal force Sand and particles heavier than water Conical or cylindrical

18. Residual Water Physical Treatments Dissolved Air Flotation Preconoces bassed on density Suspended solid and contaminant liquids Microbubble injection

19. Residual Water Physical Treatments API oil-water separator Oil separation Conventional separator : - Gravimetrical separation Parallel plate separator : - Higher surface - Less space

20. Residual Water Physical Treatments Membrane reactors Filtration process through membranes Submerged system External loop system

21. Residual Water Physical Treatments Adsorption Separating process in which some components of a liquid phase are transferred to a solid surface. Carbon filter Residual water Pesticides, dissolved organic matter , detergent , etc.

22. Residual Water Physical Treatments Filtration processes Granulated materials : sand Improve clarity and desinfect Slow filtration Fast filtration

23. Residual Water Physical Treatments Micro, ultra and nanofiltration Nanofiltration : Ions 0.01 microns membrane pores Microfiltration : Suspended solids 0.5 microns membrane pores Ultrafiltration : Macromolecules 0.1 microns membrane pores

24. Residual Water Physical Treatments Reverse Osmosis Filtration through a semi-permeable membrane with presure It can hold particles from 1 to 0.001 microns .

25. Residual Water Biological Treatments Lagoons Damming residual water organic matter contained is degraded by microorganisms Depending on oxigen level : Aerobic Loop : seaweed in the lagoon ( using light) produce high amount of oxygen aerobic bacteria break organic matter into inorganic compounds used by seaweed to grow Anaerobic organic charge is higher , so oxygen produced by seaweed is quickly consumed anaerobic bacteria Facultative Aerobic and anaerobic depending on water deepness The most used because of highest reduction in BOD (up to 90%)

26. Residual Water Biological Treatments Lagoons Usually system composed by an anaerobic and a facultative lagoon first one reduces solid and organic matter content second one produces high quality water Disadvantages large surface needed carefully land preparation located outdoors , and hence subjected to weather conditions

27. Residual Water Biological Treatments Biological Reactors FIXED FILM SYSTEMS : rotary bio -reactor Microorganisms fixed into an inert media, water is passed through it Biodiscs Biocylinders Control: S peed of the reactor Temperature W ater characteristics (pH, level of solved oxygen or organic charge ). Advantages : L ow energy consumption S mall land needed

28. Residual Water Biological Treatments Biological Reactors ANAEROBIC REACTORS Biogas production UASB ( Upflow Anaerobic Sludge Blanket ) C ylindrical reactors with an ascendant water flux IC ( internal circulation ) Two compartments : the lower one is fed with water with higher organic charge upper one with less residues U sed for highly contaminated residual water Advantages : high efficiency small retention time cheap energy production due to biogas produced easily adapted to seasonal industries

29. Water Desinfection Chlorination Cl 2 diatomic gas easily solved in water depending on pressure and temperature . Highly negative effects on microorganism that that live in water Types Marginal chlorination Chloramination Breakpoint Chlorination Superchlorination and dechlorination A dvantage : long protection time C arefulness with the doses of Cl added to water to avoid any side effect in human health or other smaller problems such as bad tastes or smells .

30. Water Desinfection Ozonization O zone (O 3 ) oxidizes organic compounds Water is maintained in tanks with different compartments and ozone is injected there . Advantage : production of O 3 is very easy ( using electrical discharges ) Disadvantages : O zone very toxic and corrosive C annot be used as method to prevent microorganisms over time This method has to be used instead of chlorination when water contains some determined substances . Example : phenols , which form chlorophenols that lead to very bad smells and tastes.

31. Water Desinfection UV Radiation Removal of organic matter by wet photochemical oxidation Nitrogen peroxide (NO2) is added to water , UV light used to start a reaction between organic compounds that produces their decomposition Disadvantages : generation of UV light energy expenses water has to be very clear maximum distance to the UV source Advantages : minimize chemical compounds added to water better water quality