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The Biochemical Oxygen Demand BOD<sub>5</sub> is the amount of oxygen consumed in biochemically oxidizable organic substances contained in one litre of water  in 5 days under the corresponding metabolic activity of the microorganisms at 20 °C in dark (in mg O2/l).
 
The Biochemical Oxygen Demand BOD<sub>5</sub> is the amount of oxygen consumed in biochemically oxidizable organic substances contained in one litre of water  in 5 days under the corresponding metabolic activity of the microorganisms at 20 °C in dark (in mg O2/l).
  
''Note:'' If the BOD<sub>5</sub value attains a value of <10 mg / litre (organically biodegradable load), then it is no longer putrefactive under normal conditions. <ref name="H.M.">Hans Mönnighoff, 1993, Ökobuchverlag</ref>
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''Note:'' If the BOD<sub>5</sub> value attains a value of <10 mg / litre (organically biodegradable load), then it is no longer putrefactive under normal conditions. <ref name="H.M.">Hans Mönnighoff, 1993, Ökobuchverlag</ref>
  
 
This value is critical if the water is to be stored for a longer period, without formation of any odour. (For instance, absence for few days).
 
This value is critical if the water is to be stored for a longer period, without formation of any odour. (For instance, absence for few days).
  
The '''Total Organic Carbon''' TOC (mg/l) content is the amount of organic carbon compounds in a sample. These are burnt during the analysis and the amount of the resulting CO2 is measured. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>
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The '''Total Organic Carbon''' TOC (mg/L) content is the amount of organic carbon compounds in a sample. These are burnt during the analysis and the amount of the resulting CO2 is measured. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>
  
 
''Note:'' The TOC is a sum parameter in the water analysis as well as run-off water analysis and reflects the contamination of water with organic matter. Clean spring waters indicate a TOC content of 1 - 2 mg/l. slightly contaminated rivers and streams show values around 2 - 5 mg/l. The mesotrophic lakes already have the values of 5 - 10 mg/l, and a productive carp pond has a typical value around 15 - 25 mg/l. The value many exceed over 100 mg/l in highly contaminated sewage water.
 
''Note:'' The TOC is a sum parameter in the water analysis as well as run-off water analysis and reflects the contamination of water with organic matter. Clean spring waters indicate a TOC content of 1 - 2 mg/l. slightly contaminated rivers and streams show values around 2 - 5 mg/l. The mesotrophic lakes already have the values of 5 - 10 mg/l, and a productive carp pond has a typical value around 15 - 25 mg/l. The value many exceed over 100 mg/l in highly contaminated sewage water.
  
'''SAK245''', die UV- Absorption ist ein Summenparameter für die Gewässerbelastung durch gelöste organische Substanzen wie z.B. aromatische Verbindungen und Huminstoffe. Bei einer Messwellenlänge von 254 nm wird der Spektrale Absorptions-Koeffizient auf Extinktion pro Meter umgerechnet (ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen).
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'''Spectral Absorption Coefficient''' 245 nm SAK (1/m)
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The UV absorption is a sum parameter for water pollution by dissolved organic substances such as aromatic compounds and humic substances. The Spectral Absorption Co-efficient and Extinction per meter is converted with a measurement wavelength of 254 nm. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>
  
''Hinweis:'' Der SAK245nm entspricht somit in etwa der elektrischen Leitfähigkeit als Summenparameter für die anorganische Salzbelastung. Zahlreiche organische Stoffe absorbieren ultraviolettes Licht. Grundlage ist die DIN 38404-3 (2006), die die Messung bei einer Wellenlänge von 254 nm vorsieht. Die Lichtschwächung pro Meter Wasser (daher die Dimension 1/m) ist gleichzeitig ein Maß für die organische Belastung des Gewässers. Dadurch ist es auch möglich, den Messwert näherungsweise in verwandte Kohlenstoffparameter wie TOC (Total Organic Carbon), CSB (Chemischer Sauerstoffbedarf) oder BSB (Biochemischer Sauerstoffbedarf) umzurechnen (Landesamt für Natur, Umwelt und Verbraucherschutz NRW).
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''Note:'' Thus, Spectral Absorption Co-efficient 245nm corresponds as sum parameter for the inorganic salt contamination in approximate electrical conductivity. A number of organic substances absorb ultraviolet light. It is based on DIN 38404-3 (2006), which enables measurement at a wavelength of 254 nm. The light attenuation per meter of water (hence the dimension 1 / m) simultaneously functions as a measure of organic contamination of the water. Thus, it is also possible to convert the measured value into approximately related carbon parameters such as TOC (Total Organic Carbon), COD (Chemical Oxygen Demand) and BOD (Biochemical Oxygen Demand). (State Office for Nature, Environment and Consumer Protection, North Rhine-Westphalia).
  
'''Sauerstoff'''
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'''Oxygen'''
  
Je kälter das Wasser, desto mehr O<sub>2</sub> kann gelöst werden, je salzhaltiger oder je niedriger der atmosphärische Druck, desto weniger. Beispiele:  
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As the water becomes colder, the amount of O<sub>2</sub> that can be dissolved increases and decreases depending on the salinity or decrease in the atmospheric pressure.  
:0 °C, Normaldruck, Süßwasser: 14.6 mg/l = 100% Sättigung
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Examples:
:10 °C, Normaldruck, Süßwasser: 11.3 mg/l = 100% Sättigung
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:0 °C, standard pressure, fresh water: 14.6 mg/l = 100% saturation
:20 °C, Normaldruck, Süßwasser: 9.1 mg/l = 100% Sättigung
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:10 °C, standard pressure, fresh water: 11.3 mg/l = 100% saturation
Je nach Sauerstoffanteil im Wasser werden folgende Milieus unterschieden: 
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:20 °C, standard pressure, fresh water: 9.1 mg/l = 100% saturation
* '''aerobes Milieu''' = Vorhandensein von molekular gelöstem Sauerstoff (O<sub>2</sub>) und chem. gebundenem Sauerstoff, > 0,5 mg O<sub>2</sub>/l
 
* '''anoxisches Milieu''' = Vorhandensein von an Stickstoff gebundenem Sauerstoff (z. B. NO<sub>3</sub>- ; NO<sub>2</sub>- ), < 0,5 mg O<sub>2</sub>/l
 
* '''anaerobes Milieu''' = weder molekular gelöster noch an Stickstoff gebundener Sauerstoff vorhanden, < 0,5 mg O<sub>2</sub>/l
 
  
Ist zu wenig Sauerstoff im Wasser, kommt es durch die Anwesenheit bestimmter Mikroorganismen zur Bildung übler Gerüche und toxischer Gase. Bei diesem Vorgang wird der für die Bakterienatmung benötigte Sauerstoff aus sauerstoffhaltigen Verbindungen wie Sulfaten, Sulfiten usw. abgespalten, wobei erhebliche Mengen an Sulfiden und H2S gebildet und freigesetzt werden. <ref name="Schikowski">Diplomarbeit Schikowski, 10'1988, Prof. Olschewski</ref>  
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The following environments can be distinguished depending on the percentage of oxygen in the water:
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* Aerobic environment = Presence of dissolved molecular oxygen (O<sub>2</sub>) and chemically bound oxygen, > 0.5 mg O<sub>2</sub>/l
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* Anoxic environment = Presence of a nitrogen bound oxygen (for instance, NO<sub>3</sub>- ; NO<sub>2</sub>- ), < 0.5 mg O<sub>2</sub>/l
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*Anaerobic environment = neither dissolved molecule nor nitrogen bound oxygen is present, < 0.5 mg O<sub>2</sub>/l
  
Gegenmaßnahme: Belüftung, der Sauerstoffanteil muss jederzeit hoch genug sein.
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If there is less oxygen in water, then it could be attributed to the presence of certain microorganisms for formation of unpleasant smells and toxic gases. In this process, the oxygen required for respiration of bacteria is separated from oxygen-containing compounds such as sulphates, sulphites, etc. which leads to the formation of sulphides and H2S in significant quantities and are released. <ref name="Schikowski">Diplomarbeit Schikowski, 10'1988, Prof. Olschewski</ref>
  
'''Leitfähigkeit'''
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Counter action: aeration, the content of oxygen must always be high in enough quantity.
  
Chemisch reines Wasser ist bei einem [[pH-Wert]] von 7 nur in geringem Umfang in die elektrischen Ladungsträger H<sub>3</sub>O+ und OH− dissoziiert. Es besitzt daher einen hohen spezifischen Widerstand von 18,2 M Ω • cm (= 1,82×10^13 Ω • mm²/m) bei 25 °C. Dieses entspricht einem spezifischen Leitwert von 54,9 nS • cm. Die Temperaturabhängigkeit beträgt dabei ungefähr 1,5 bis 2 % pro Kelvin. Gelöste Salze und Säuren erhöhen die Ladungsträgerkonzentration. Bereits Leitungswasser erreicht je nach Mineralgehalt bis etwa die 10.000-fache Leitfähigkeit von durchschnittlich 500 µS • cm.
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'''Conductivity [µS/cm]'''
  
Der '''pH-Wert''' ist ein Maß für den sauren oder basischen Charakter einer wässrigen Lösung. Der pH-Wert ist eine dimensionslose Zahl.
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The chemically pure water with pH of 7 is dissociated only to a limited extent in the H3O+ and OH-electric charge carriers. Therefore, it has a specific high resistance of 18.2 M Ω •cm (= 1.82×1013 Ω •mm²/m) at 25 °C. This corresponds to a specific conductance value of 54.9 nS•cm−. Thereby the effect of variation of temperature is about 1.5 to 2% per Kelvin. Dissolved salts and acids intensify the concentration of charge carrier. Already the mains water reaches up to about 10,000 times the conductivity of an average of 500 µS•cm−1 depending on the mineral content. <ref name="Wiki">Wikipedia</ref>
Durch die Autoprotolyse ergibt sich das Ionenprodukt des Wassers bei 25 °C zu
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The '''pH value''' is a measure of the acidic or basic character of an aqueous solution. The pH value is a non-dimensional unit.
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The ionic product of water at 25 °C gives following results with autoprotolysis.
  
 
K<sub>W</sub> = ''c''(H<sub>3</sub>O+) • ''c''(OH−) = 10^(−14) mol²/l²
 
K<sub>W</sub> = ''c''(H<sub>3</sub>O+) • ''c''(OH−) = 10^(−14) mol²/l²
  
und teilt pH-Werte von verdünnten wässrigen Lösungen ein in:
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And divides the pH values of dilute aqueous solutions into:
* '''pH < 7''' als saure wässrige Lösung, hier ist ''c''H<sub>3</sub>O+ > ''c''OH−
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* pH < 7 as acidic aqueous solution, here it is cH3O+ > cOH−
* '''pH = 7''' als neutrale wässrige Lösung, hier ist ''c''H3O+ = ''c''OH−; auch eine Eigenschaft von reinem Wasser
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* pH = 7 as neutral aqueous solution, here it is cH3O+ = cOH−; along with a property of pure water
* '''pH > 7''' als basische (alkalische) wässrige Lösung, hier ist ''c''H<sub>3</sub>O+ < ''c''OH−
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* pH > 7 as basic (alkaline) aqueous solution, here it is cH3O+ < cOH−
Chemisch reines Wasser von 22 °C hat einen theoretischen pH-Wert von 7 (die Gleichgewichtskonstante für die Dissoziation von Wasser beträgt dann genau 10^(−14)). Dieser Wert ist als chemisch neutral definiert. Allerdings hat chemisch reines Wasser keinen Puffer und reagiert damit auf geringste Verunreinigungen mit einer deutlichen pH-Wert-Änderung. So stellt sich in zuvor chemisch reinem Wasser bei Luftzutritt infolge Lösung von CO<sub>2</sub> sofort ein pH-Wert zwischen 4,5 und 5 ein.<ref name="Wiki">Wikipedia</ref>
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Theoretically, chemically pure water at 22 °C has a pH value of 7 (the equilibrium constant for dissociation of water is about 10-14). This value is specified as chemically neutral. However, chemically pure water has no buffer and hence reacts to the slightest contamination with a significant change in pH value. Therefore due to CO2 solution, a pH value of 4.5 and 5 is immediately set in previously chemically pure water with admission of air. <ref name="Wiki">Wikipedia</ref>
  
Die '''Trübung''' (1/m) ist ein Maß für den Anteil von fein verteilten Partikeln und ungelösten Stoffen in der Wasserprobe. Sie wird bei 860 nm Wellenlänge bestimmt.<ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>  
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'''Turbidity''' is a unit measuring the proportion of finely divided particles and suspended solids in the water sample. It is determined at 860 nm wavelength. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>  
  
* i.d.R. handelt es sich um ungefährliche Sedimente, ungelöste Partikel, sogenannte. Schwebstoffe
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* Generally, it deals with safe sediments, undissolved particles, also known as suspended particles
* Wasserinhaltsstoffe, die Kleinlebewesen als Nährsubstanz dienen und so deren Wachstum fördern
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* Dissolved matter, the microbes serve as a nutritive medium and thereby their growth is fostered
* sie verhindern eine effektive Desinfektion (Chlorzehrung, Chlor lagert sich an den Partikeln an), daher muss trübes Wasser vorher gefiltert werden
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* They prevent an effective disinfection (chlorine uptake, chlorine attaches to the particles); therefore, turbid water must be filtered first
* Maßeinheit für Trübung: NTU, nach WHO soll TW < 1 NTU aufweisen (Katadyn Wasserfibel)
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* Measuring unit of turbidity: NTU, according to WHO TW (turbidity value) should be <1 NTU (Katadyn Water Guide)
  
'''Schwermetalle''' sind Blei, Cadmium, Chrom, Nickel, Kupfer, Zink, Quecksilber.
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'''Heavy metals''' Lead, cadmium, chromium, nickel, copper, zinc, mercury are heavy metals.
Gelangen über das Regenwasser, welches durch die Gesteinsschichten gefiltert wird, in das Grundwasser. Schwermetalle können sich im menschlichen Körper ablagern.<ref name="WHO">WHO Richtlinien für TW</ref> Schwermetalle lassen sich nur über aufwändige Verfahren, wie der Destillation oder der Flockung, aus dem Wasser entfernen. Schwermetalle können aber auch aus Metalldächern gelöst werden und so in den Regenwasserspeicher gelangen
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They are obtained via rainwater in groundwater which is filtered through the rock bed. Heavy metals can accumulate in the human body. (WHO Guidelines for TW [sticky limit]). Heavy metals can be removed from water only via complex processes such as distillation or flocculation.
  
==Quellen==
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=Sources=
 
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Aktuelle Version vom 7. November 2018, 16:05 Uhr

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Chemical Oxygen Demand (mg/L) The Chemical Oxygen Demand (COD) indicates the amount of oxygen that is required for the chemical oxidation with potassium dichromate in the substances contained in water. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>

Note: The COD is always higher than the BOD5; the ratio COD / BOD5 lies at 1.5 – 2 with well biologically degradable materials.

Biochemical Oxygen Demand 5 (mg/l) The Biochemical Oxygen Demand BOD5 is the amount of oxygen consumed in biochemically oxidizable organic substances contained in one litre of water in 5 days under the corresponding metabolic activity of the microorganisms at 20 °C in dark (in mg O2/l).

Note: If the BOD5 value attains a value of <10 mg / litre (organically biodegradable load), then it is no longer putrefactive under normal conditions. <ref name="H.M.">Hans Mönnighoff, 1993, Ökobuchverlag</ref>

This value is critical if the water is to be stored for a longer period, without formation of any odour. (For instance, absence for few days).

The Total Organic Carbon TOC (mg/L) content is the amount of organic carbon compounds in a sample. These are burnt during the analysis and the amount of the resulting CO2 is measured. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>

Note: The TOC is a sum parameter in the water analysis as well as run-off water analysis and reflects the contamination of water with organic matter. Clean spring waters indicate a TOC content of 1 - 2 mg/l. slightly contaminated rivers and streams show values around 2 - 5 mg/l. The mesotrophic lakes already have the values of 5 - 10 mg/l, and a productive carp pond has a typical value around 15 - 25 mg/l. The value many exceed over 100 mg/l in highly contaminated sewage water.

Spectral Absorption Coefficient 245 nm SAK (1/m) The UV absorption is a sum parameter for water pollution by dissolved organic substances such as aromatic compounds and humic substances. The Spectral Absorption Co-efficient and Extinction per meter is converted with a measurement wavelength of 254 nm. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>

Note: Thus, Spectral Absorption Co-efficient 245nm corresponds as sum parameter for the inorganic salt contamination in approximate electrical conductivity. A number of organic substances absorb ultraviolet light. It is based on DIN 38404-3 (2006), which enables measurement at a wavelength of 254 nm. The light attenuation per meter of water (hence the dimension 1 / m) simultaneously functions as a measure of organic contamination of the water. Thus, it is also possible to convert the measured value into approximately related carbon parameters such as TOC (Total Organic Carbon), COD (Chemical Oxygen Demand) and BOD (Biochemical Oxygen Demand). (State Office for Nature, Environment and Consumer Protection, North Rhine-Westphalia).

Oxygen

As the water becomes colder, the amount of O2 that can be dissolved increases and decreases depending on the salinity or decrease in the atmospheric pressure. Examples:

0 °C, standard pressure, fresh water: 14.6 mg/l = 100% saturation
10 °C, standard pressure, fresh water: 11.3 mg/l = 100% saturation
20 °C, standard pressure, fresh water: 9.1 mg/l = 100% saturation

The following environments can be distinguished depending on the percentage of oxygen in the water:

  • Aerobic environment = Presence of dissolved molecular oxygen (O2) and chemically bound oxygen, > 0.5 mg O2/l
  • Anoxic environment = Presence of a nitrogen bound oxygen (for instance, NO3- ; NO2- ), < 0.5 mg O2/l
  • Anaerobic environment = neither dissolved molecule nor nitrogen bound oxygen is present, < 0.5 mg O2/l

If there is less oxygen in water, then it could be attributed to the presence of certain microorganisms for formation of unpleasant smells and toxic gases. In this process, the oxygen required for respiration of bacteria is separated from oxygen-containing compounds such as sulphates, sulphites, etc. which leads to the formation of sulphides and H2S in significant quantities and are released. <ref name="Schikowski">Diplomarbeit Schikowski, 10'1988, Prof. Olschewski</ref>

Counter action: aeration, the content of oxygen must always be high in enough quantity.

Conductivity [µS/cm]

The chemically pure water with pH of 7 is dissociated only to a limited extent in the H3O+ and OH-electric charge carriers. Therefore, it has a specific high resistance of 18.2 M Ω •cm (= 1.82×1013 Ω •mm²/m) at 25 °C. This corresponds to a specific conductance value of 54.9 nS•cm−. Thereby the effect of variation of temperature is about 1.5 to 2% per Kelvin. Dissolved salts and acids intensify the concentration of charge carrier. Already the mains water reaches up to about 10,000 times the conductivity of an average of 500 µS•cm−1 depending on the mineral content. <ref name="Wiki">Wikipedia</ref>

The pH value is a measure of the acidic or basic character of an aqueous solution. The pH value is a non-dimensional unit. The ionic product of water at 25 °C gives following results with autoprotolysis.

KW = c(H3O+) • c(OH−) = 10^(−14) mol²/l²

And divides the pH values of dilute aqueous solutions into:

  • pH < 7 as acidic aqueous solution, here it is cH3O+ > cOH−
  • pH = 7 as neutral aqueous solution, here it is cH3O+ = cOH−; along with a property of pure water
  • pH > 7 as basic (alkaline) aqueous solution, here it is cH3O+ < cOH−

Theoretically, chemically pure water at 22 °C has a pH value of 7 (the equilibrium constant for dissociation of water is about 10-14). This value is specified as chemically neutral. However, chemically pure water has no buffer and hence reacts to the slightest contamination with a significant change in pH value. Therefore due to CO2 solution, a pH value of 4.5 and 5 is immediately set in previously chemically pure water with admission of air. <ref name="Wiki">Wikipedia</ref>

Turbidity is a unit measuring the proportion of finely divided particles and suspended solids in the water sample. It is determined at 860 nm wavelength. <ref name="isa">ISA – Institut für Siedlungswasserwirtschaft der RWTH Aachen</ref>

  • Generally, it deals with safe sediments, undissolved particles, also known as suspended particles
  • Dissolved matter, the microbes serve as a nutritive medium and thereby their growth is fostered
  • They prevent an effective disinfection (chlorine uptake, chlorine attaches to the particles); therefore, turbid water must be filtered first
  • Measuring unit of turbidity: NTU, according to WHO TW (turbidity value) should be <1 NTU (Katadyn Water Guide)

Heavy metals Lead, cadmium, chromium, nickel, copper, zinc, mercury are heavy metals. They are obtained via rainwater in groundwater which is filtered through the rock bed. Heavy metals can accumulate in the human body. (WHO Guidelines for TW [sticky limit]). Heavy metals can be removed from water only via complex processes such as distillation or flocculation.

Sources

<references />