Testing Water

Water Quality

Water Quality Testing

A water quality Lab establishes standards for drinking water which fall into two categories, Primary Standards, and Secondary Standards. Primary Standards are based on health considerations and are designed to protect people from three classes of toxic pollutants: pathogens, radioactive elements, and toxic chemicals. The Secondary Standards are mostly about minor dissolved solids and mineral contaminants and pH (acid or alkaline) for which you can use various meters and tests strips to detect the contaminants. Iron will turn your water rust colored and stain your sinks, tubs showers and toilets. Contaminants like Manganese turn your water black and make a shower an unpleasant experience.

In the US and Canada, for example, Bacterial contamination falls under the category of pathogens. The EPA (USA) Maximum Contaminant Level (MCL) for coliform bacteria in drinking water is zero (or no) total coliform per 100 ml of water. The number of coliform colonies found in the incubated water sample, if any, is reported and the form is checked to indicate if the water meets the EPA bacteriological standard of zero. At times, excessive numbers of other bacteria in a sample can interfere with the counting of coliform types. These samples may be classified as "too numerous to count" or "confluent growth."

If the laboratory report indicates the presence of coliforms, or states "too numerous to count," or "confluent growth," the State Department of Health recommends another sample be analyzed to help evaluate the contamination. If you suspect bacterial contamination in your water supply, use an alternative water supply or disinfect your water supply while waiting for test results.

The Canadian Guide to well water treatment can be found here.

If you are purchasing meters to determine how you can treat your own water or determine if it needs treatment you should search out documents provided by your local government. You should be able to find information that tells you what normal readings are, and what typical readings might be in your area.

Our RV has a filter housing. We normally install a filter which is a carbon filter or has a carbon component as it can remove many mineral contaminants. Sediment (particle) filters remove only sand and solid contaminants like rust (iron). They do not remove dissolved substances or mineral "salts". Bottled water often has high levels of dissolved solids and some brands are no better than campground or tap water. Our local town water has a TDS (Total Dissolved Solids) reading of 120ppm. Some bottled water we bought for the RV had a reading of 220ppm.

In a house, we would use media beds or water softeners or a combination of treatments including carbon filters.

Bleach is your friend. Chlorine kills bacteria. Use it as directed on the bleach bottle for quantity depending on the amount of water in the system. The use of a charcoal filter will clean out the bleach taster after you decontaminate your system.

Meter Types

You can see some of our water quality testing meters here at this link.

EC

An Electrical Conductivity or EC meter determines how easily an electrical current moves through the water. Electrical conductivity also gives a strong indication of the amount of minerals and salts that are dissolved in the water -- but not which ones. Pure water is an effective insulator and will not conduct an electrical current.

Temperature

Most tests are designed to be carried out at 25 degrees Celsius.

TDS

Total Dissolved Solids meters detect how much is dissolved in the water you’re testing. It can give you an indication of how much minerals are dissolved, or mineral “salts”. Only a competent lab can tell you all the contaminants present and give you accurate levels of the minerals and salts.

pH

Potential Hydrogen (pH) meters are meters that detect whether a solution is acid (0 to 7), neutral (7.0) or Alkaline (7-11). Most meters and test strips can give you accurate readings. Meters though should be washed with distilled water between readings and tested with solutions of known pH -- at least occasionally.

ORP

Oxidation-reduction potential meters will show a negative or positive value and give an indication of whether a solution can provide or will absorb the charge on ions. It will tell you if the solution is positively or negatively charged.

Potential Contaminants

The Water Research Center can be found here. It offers a great deal of information about chemical and mineral contaminants and a synopsis is provided in the following tables.

Primary Standards (A Selection)

Contaminants

MCLG

MCL

Potential Health Effects from Ingestion of Water

(mg/L)

(mg/L)

Inorganics

Antimony

0.006

0.006

Cancer

Asbestos (>10m)

7MFL

7MFL

Cancer

Barium*

2

2

Circulatory system effects

Beryllium

0.004

0.004

Bone, lung damage

Cadmium*

0.005

0.005

Kidney effects

Chromium* (total)

0.1

0.1

Liver, kidney, circulatory disorders

Cyanide

0.2

0.2

Thyroid, nervous system damage

Mercury* (inorganic)

0.002

0.002

Kidney, nervous system disorders

Nitrate*

10

10

Methemoglobinemia

Nitrite

1

1

Methemoglobinemia

Selenium*

0.05

0.05

Liver damage

Thallium

0.0005

0.002

Kidney, liver, brain, intestinal

Notes: *Contaminants with interim standards which have been revised.

MFL=million fibers per liter.

 

Secondary Standards

These standards would normally refer to dissolved solids and similar issues. These contaminants can usually be extracted with Media beds, carbon filters or water “softener” units.

Table 2  Secondary Drinking Water Standards.

Contaminant

Secondary Standard

Aluminum

0.05 to 0.2 mg/L

Chloride

250 mg/L

Color

15 (color units)

Copper

1.0 mg/L

Corrosivity

noncorrosive

Fluoride

2.0 mg/L

Foaming Agents

0.5 mg/L

Iron

0.3 mg/L

Manganese

0.05 mg/L

Odor

3 threshold odor number

pH

6.5-8.5

Silver

0.10 mg/L

Sulfate

250 mg/L

Total Dissolved Solids

500 mg/L

Zinc

5 mg/L

 

From here on this document is reference material. It won’t be of interest to everyone. If you really want to understand what the various tests mean and where to find additional information, read on.

Reference Section

Wikipedia provides a good source for definitions of the various terms like REDOX (Reduction-Oxidation) reactions.

REDOX

Redox (short for reduction–oxidation reaction) (pronunciation: /ˈrɛdɒks/ redoks or /ˈriːdɒks/ reedoks[1]) is a chemical reaction in which the oxidation states of atoms are changed. Any such reaction involves both a reduction process and a complementary oxidation process, two key concepts involved with electron transfer processes.[2] Redox reactions include all chemical reactions in which atoms have their oxidation state changed; in general, redox reactions involve the transfer of electrons between chemical species. The chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. It can be explained in simple terms:

Oxidation is the loss of electrons or an increase in oxidation state by a moleculeatom, or ion.

Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.

As an example, during the combustion of wood, oxygen from the air is reduced, gaining electrons from carbon which is oxidized.[3] Although oxidation reactions are commonly associated with the formation of oxides from oxygen molecules, oxygen is not necessarily included in such reactions, as other chemical species can serve the same function.[3]

The reaction can occur relatively slowly, as with the formation of rust, or more quickly, in the case of fire. There are simple redox processes, such as the oxidation of carbon to yield carbon dioxide (CO2) or the reduction of carbon by hydrogen to yield methane (CH4), and more complex processes such as the oxidation of glucose (C6H12O6) in the human body.

Molar Calculation Methods

Why is this here? First, if you want to determine the concentration of a chemical or contaminant you need to know how to calculate the amounts p[resent.  Next, if you want to calculate chemical reactions you need to understand Molar Calculations so that you can determine the concentration of solutions. If for example, you want to extract gold via the Thiosulfate treatment (which is potentially less ecologically damaging than cyanide treatment) you will need to determine the concentration of the chemicals and likely provide some heating as the process is less efficient than the cyanide system. If you are going to create an acid like HCl (Hydrochloric Acid) or H2SO4 (Sulfuric Acid) you need to have some grasp of the amount of material and the process. If you measure a known quantity of Sulfuric Acid of a given pH you should be able to determine how much Hydrogen, Sulphur, and Oxygen are present.

If you need to treat water for the significant presence of contaminants, whether it's Manganese, Tannins or Calcium (Hardness) you will likely have your water submitted to a company which can perform these tests, determine concentrations and then be able to recommend treatment methods whether it be a media bed or a water softener and perhaps filters. The companies I dealt with had a scientist with at least a Ma.Sc. degree supervising or performing the tests and calculations.

 

https://sciencing.com/how-to-find-molar-concentration-13710247.html

Determine Molar Mass

To find the number of moles of solute, you first need to calculate the molar mass of the substance. For the chemical formula for your solute, look up each element on the periodic table and write down the average atomic mass in atomic mass units (AMUs). For any element that appears in multiples, multiply the mass by the number of atoms per molecule of that element. Take care to include groups that also appear in multiple amounts. Add up the total AMUs to get the molar mass. For example, the formula for acetic acid is CH3COOH. Note that the molecule has a total of two carbon atoms, two oxygen atoms and four hydrogen atoms. You multiply the atomic mass of carbon by 2, oxygen by 2 and hydrogen by 4 and then add the results to get the total molar mass in grams per mole. The atomic masses of carbon, oxygen and hydrogen are 12.01, 16.00 and 1.008, respectively. Multiplying the masses and quantities gives you (12.01 x 2) + (16.00 x 2) + (1.008 x 4) = 60.05 grams per mole.

Calculate Moles of Solute

Calculate the moles of your solute by dividing the mass in grams by grams per mole. For example, you have 10g of acetic acid. Dividing 10g by 60.05 g/mole gives 0.1665 moles of solute.

Calculating Molar Concentration

Find the molar concentration by dividing the moles you calculated by liters of water used to make the solution. For example, the acetic acid in the above example is completely dissolved in 1.25 L of water. Divide 0.1665 moles by 1.25 L to get the molar concentration, 0.1332 M.

Measuring Acids and Bases

For acids and bases, you can determine the molar concentration of unknown solutions by measuring the pH or pOH of the solution. The math is slightly more complicated, involving the common antilogarithm or exponents of 10. To find the molar concentration of an acid, measure the pH, then multiply it by -1 and take the common antilog of the result. For example, you measure a sample of hydrochloric acid, and the pH reading is 2. Multiply 2 by -1 and get -2. The common antilog of -2 (10 to the -2 power) gives the concentration 0.01 M.

 

 

pH

In chemistrypH (/piːˈeɪtʃ/) is a scale used to specify how acidic or basic a water-based solution is. Acidic solutions have a lower pH, while basic solutions have a higher pH. At room temperature (25 °C), pure water is neither acidic nor basic and has a pH of 7.

The pH scale is logarithmic and approximates the negative of the base 10 logarithm of the molar concentration (measured in units of moles per liter) of hydrogen ions in a solution. More precisely it is the negative of the base 10 logarithm of the activity of the hydrogen ion.[1] At 25 °C, solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. The neutral value of the pH depends on the temperature, being lower than 7 if the temperature increases. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively.[2]

The pH scale is traceable to a set of standard solutions whose pH is established by international agreement.[3] Primary pH standard values are determined using a concentration cell with transference, by measuring the potential difference between a hydrogen electrode and a standard electrode such as the silver chloride electrode. The pH of aqueous solutions can be measured with a glass electrode and a pH meter, or a color-changing indicator. Measurements of pH are important in chemistry, agronomy, medicine, water treatment, and many other applications.

 

Redox potential (also known as oxidation / reduction potentialORPpeε, or {\displaystyle E_{h}}) is a measure of the tendency of a chemical species to acquire from or lose electrons to an electrode and thereby be reduced or oxidised, respectively. Redox potential is measured in volts (V), or millivolts (mV). Each species has its own intrinsic redox potential; for example, the more positive the reduction potential (reduction potential is more often used due to general formalism in electrochemistry), the greater the species' affinity for electrons and tendency to be reduced. ORP can reflect the antimicrobial potential of the water.[1]

 

Biological Treatment of Water

UV Irradiation

Ultraviolet (UV) rays are part of the light that comes from the sun. The UV spectrum is higher in frequency than visible light and lower in frequency compared to  x-rays.  This also means that the UV spectrum has a larger wavelength than x-rays and a smaller wavelength than visible light and the order of energy, from low to high, is visible light, UV, than x-rays. As a water treatment technique, UV is known to be an effective disinfectant due to its strong germicidal (inactivating) ability. UV disinfects water containing bacteria and viruses and can be effective against protozoans like,  Giardia lamblia cysts or Cryptosporidium oocysts. UV has been used commercially for many years in the pharmaceutical, cosmetic, beverage, and electronics industries, especially in Europe. In the US, it was used for drinking water disinfection in the early 1900s but was abandoned due to high operating costs, unreliable equipment, and the expanding popularity of disinfection by chlorination. 

https://www.water-research.net/index.php/water-treatment/water-disinfection/uv-disinfection

 

Chlorine Treatment

Chlorine is the primary disinfectant used in the United States and Canada. In order to be effective, the chlorine must be given time to react with the microorganisms.

The time required depends on the temperature and the pH of the water. Chlorine works best in water with a low pH and a high temperature. The concentration and contact time required to inactivate Giardia using chlorine is approximated by the following formula.

CT=.2828 * ( pH^2.69 ) * ( Cl^.15 ) * (.933^(T-5)) * L
 

Where: 

  • CT = Product of Free Chlorine Residual and Time required
  • pH = pH of water
  • Cl = Free Chlorine residual, mg/l
  • T = Temperature, degrees C
  • L = Log Removal

 

Use the following tables to fill in the CT number.

 

Water pH 6.0 at 0.5 C

Chlorine Conc 

1.0 log

2.0 log

3.0 log 

0.4 mg/L

46 (CT value)

91

137

1.0 mg/L

49

99

148

2.0 mg/L

55

110

165

 

Water pH 7.0 at 0.5 C

Chlorine Conc 

1.0 log

2.0 log

3.0 log 

0.4 mg/L

65 (CT value)

130

195

1.0 mg/L

70

140

210

2.0 mg/L

79

157

236

 


Water pH 8.0 at 0.5 C

Chlorine Conc 

1.0 log

2.0 log

3.0 log 

0.4 mg/L

92 (CT value)

185

277

1.0 mg/L

101

203

304

2.0 mg/L

115

231

346