Water enters your home from a variety of sources. These could be either coming from.
1. Surface water/River water – In most cases the water coming in through the city municipal water supply is usually surface water from rivers and lakes.
2. Borewell –This is the underground water in the aquifers which is accessed by digging a borewell. Quite a few houses be it independent homes or apartments have an independent borewell through which they source the water that is stored at the overhead tank and used for various purposes. As the requirement of water goes up, the depth of the borewell increases.
3. Tanker – In places where there is low availability of water in the immediate vicinity or from the city municipal council, separate water tankers are brought in to fill up the storage tanks in independent homes or apartments. Most times you would be unaware of the source of this water.
While these might be the various sources of water, it is important to understand that while the water goes through the water cycle, it goes from being in a state of high purity to collecting contaminants by the time it reaches your houses.
Water Quality Parameters
Various water quality parameters must be checked to understand the usability of water be it potable water or utility water.
Since the water that reaches your home is at a different stage in its water cycle, the amount and type of contamination differs in each. The list of contamination and the permissible amount tells your everything you need to know about keeping your family safe.
Hard water is a type of water that contains bicarbonate, sulphate and chloride salts of magnesium and calcium. These impurities react with higher fatty acids present in soap to form insoluble scum and thereby hindering the soaps’ action. There are two type of hardness:
1. Temporary hardness
Temporary hardness is caused by the presence of bicarbonate salts of calcium and magnesium in water. By simply boiling the water, the temporary hardness precipitates out of the water, settling on surfaces it comes in contact with, such as geyser coils, solar heater coils, taps, inner layer of the pipes, etc. This shows up as white scales that you can see on your faucets, etc.
2. Permanent hardness
If the water contains chloride or sulphate salts, then the water cannot be made soft by simply boiling. There are special methods to make such water soft. This hardness again leads to various issues depositing itself on the scalp of our hair making it frizzy that might lead to hairfall.
The temperature of the water body in consideration is an important parameter to take into account. Higher temperature may favour certain highly toxic compounds to have a greater solubility than needed. Metals like cadmium, zinc and lead are examples of toxic materials.
The amount of dissolved oxygen present in water is also an important parameter. If more oxygen is present, the water tastes better. But high levels of dissolved oxygen result in corrosion of the pipes through which water reaches our home. Therefore an optimum level of oxygen is maintained in drinking water.
pH affects the solubility of toxic chemicals in water. For humans, pH values above 11 and below 4 can cause skin and eye irritations. pH levels outside 6.5 – 9.5 can also corrode pipes.
Chemical Threats and Contamination
The most common form of drinking water contamination leads to the presence of pathogenic bacteria, viruses, protozoa and helminths. Ingestion of water contaminated by such pathogens can result in chronic as well as acute health effects. However, not all bacteria cause diseases in human beings. The disease causing bacteria are known as pathogens, and have to be removed from drinking water. Some of them are listed below:
• Vibrio cholera (Cholera)
• E. Coli
• Salmonella typhi (Typhoid causing bacteria)
Many compounds are present naturally in surface and ground water resources. Some of these chemicals have positive effects on humans, while others have adverse effects. Also, some chemicals can have both positive and negative effects depending upon the amount of that substance which is present in the water source.
Arsenic and Fluoride compounds
The two most important compounds that to lead to serious health conditions are arsenic and fluoride compounds. Exposure to arsenic in the long run can lead to arsenicosis; which results in skin problems (change in skin colour), skin cancer, cancers of the bladder, kidneys and lung. Exposure to fluoride can result to crippling skeletal fluorosis which is a major cause of morbidity in the world.
Selenium and Uranium
Apart from these compounds, selenium and uranium occur naturally in water as well. Gastro-intestinal disturbances, discoloration of the skin and decayed teeth are some of the symptoms that are associated with excessive intake of selenium.
Lead is one of the most harmful element to the human body. In fact, it has no known biological benefit to humans. The most common source of lead poisoning is in household pipes that supply drinking water to homes. It affects children’s physical and mental development and also affects children’s attention span. For adults, lead poisoning can lead to kidney problems and high blood pressure.
Benzene and Chlorobenzene
Benzene, another harmful chemical that causes anaemia, increased risk of cancer and decrease in platelet count, is found in drinking water in many parts of the world. It finds its way into fresh water mostly through industrial waste discharge from factories.
Chlorobenzene which is also found in drinking water also poses many threats to those consuming such water. Some of these threats are: Anaemia, damage to liver and kidney. Its main source of entry into drinking water is from the waste that enters fresh waters from chemical factories.
Organic contaminants are also present in water. Algae present in sea and fresh water release toxins that are harmful to health.
Chemicals like insecticides, pesticides and road salts cause contamination of ground water sources. When it rains, these chemicals are washed underground and seep into the water present underneath.
Exposure to pesticides can be harmful to the human nervous system. Memory loss, loss of co-ordination, reduced speed while responding to a stimulus are some of the health effects associated with them. They are also linked to cancer, hormone disruption and problems with reproduction.
Purify only Drinking Water?
While the water causes all of these problems, most times we only focus on purifying water for drinking purpose. However, we know that there is no life without Water. Water is used in our lives for everything from cooking, cleaning to brushing and bathing. Water Purification Systems are of two types:
1. Point of Entry Systems – Water Purifiers that are installed at the point where the water enters your home – be it the overhead tank or the point of entry to your flat (in case of apartments).
2. Point of use – These are the more commonly known water purification systems that are connected at the point where it is directly used – Be it drinking water purifiers at the kitchen or tap filters that provide only utility water for washing.
Water Purification systems can also be classified based on the output water they give:
1. Drinking Water Purifiers: Most common types of purifiers are the drinking water purifiers that use various technologies to purify contaminants including microbiological contaminants in water.
2. Utility Water Purifiers: The lesser known water purification systems that purify water(usually point).
There are various technologies that can help treat these contaminants:
Hardness can be treated using the following techniques:
1. Ion Exchange Technology
In this method, the hardness causing magnesium and calcium ions are exchanged with sodium ions by passing it through an ion exchange resin. A figure depicting the reaction is given below.
On the left we see Resin that holds the Sodium from Common salt (Sodium Chloride). The hardness ions such as calcium and magnesium in the impure water is made to pass through the resin. While doing so, the Calcium and Magnesium is held back by the resin and the sodium is released to form water soluble sodium salts which do not cause hardness, thus reducing the concentration of Calcium and Magnesium.
Sequestering agents are those that mask the effect of the calcium and magnesium ions in such a way that they do not impart their hardness property to water. They prevent the Ca and Mg ions from taking part in chemical reactions and hence they cannot from insoluble scum with soap.
While the above technologies purify water for utility purpose only, there are various technologies that help in eliminating all impurities required to get potable water:
Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove ions, molecules, and larger particles from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pressure. Reverse osmosis can remove many types of dissolved and suspended species from water, including bacteria, and is used in both industrial processes and the production of potable water.
As far as disadvantages are concerned, RO cannot differentiate between the quantity of essential minerals that are required by the body. Also, to remove the impurities the technology discards a certain percentage of water that is highly concentrated with impurities, thus wasting a lot of water.
Ultraviolet (UV) water treatment works by exposing microorganisms (such as cryptosporidium, giardia lamblia and more) to UV radiation, via a special UV light bulb, which disrupts their DNA and disables their ability to replicate. While UltraViolet Radiation is very active at deactivating cysts in low turbidity water, as the turbidity increases, the effectiveness of this radiation decreases.
3. I.M.PA.C.T. (Integrated Membrane Pre Activated Carbon Technology)
This 3M Proprietary technology uses a 2 stage thorough process to remove all contaminants in water to ensure potable water.
The first stage is pre filtration that uses a premium pleated membrane that does initial filtration to reduce dirt, rust and other particulate matter.
The second stage of filtration that is fine filtration combines a Patented pharmaceutical grade two-zone microporous membrane and a pre activated carbon block that reduces cysts and over 99.99% water-borne bacteria.
Approximately 3 grams of carbon can achieve the effective surface area of a football field.