Causes for Water Concerns
Why is this a concern?
Bacteria, protozoa and viruses are common in open water sources such as rivers and lakes. Consuming water contaminated with these pathogens are harmful to human health and can even lead to death in extreme cases.
how does bacteria affect
me? Bacterium such as S. typhi, E. coli, and Vibrio cholerae are commonly found in many water sources and have been linked to common diseases such as salmonellosis, severe diarrhea, abdominal cramps, typhoid fever and cholera.
how does protozoa affect
me? Protozoa such as Giardia and Cryptosporidium are usually found in water with high level of faecal pollution. Protozoa is more difficult to treat as it has high resistance to chlorination, a common disinfection method.
Health problems caused by this pathogen include Giardiasis, Cryptosporidiosis and dysentery, with symptoms from bloody diarrhea, intense abdominal pain, nausea, headaches to fever. how does viruses affect me?
Apart from bacteria and protozoa, virus in drinking water have been accounted to numerous cases of severe diarrhea and deaths in children across the globe.
Poor sanitation and improper handling of food are some ways viruses such as hepatitis A and rotavirus infect the hosts. Infected person may show symptoms such as jaundice, dark urine, loss of appetite, nausea, vomiting and fever. In severe cases liver failure can occur, leading to death. |
why is this a concern?
There are various concerns of chemical contamination of water ranging from damage to water distribution systems to severe health issues such as deformities in infants.
Consuming water that are chemically contaminated may only show its observable adverse effects to the human health after prolonged period as opposed to consuming biological contaminated water which takes only days for symptoms to develop. what is hardness & how
does it affect me? Water hardness is the amount of calcium and magnesium dissolved in the water. Hard water can damage water distribution systems due to the formation of scales, which are deposits on the surface of pipes.
Water hardness is not known to cause adverse health effects in humans, however in high concentration minor problem such as difficulty in soap lathering may be observed. how does the presence of
heavy metals affect me? Heavy metals appear naturally in the ground, or can be released by human activities.
In trace amounts certain heavy metals such as copper, selenium and zinc are essential to maintain the metabolism of the human body. However, there are elements such as arsenic, lead and mercury that are harmful to the body even in small concentration. At high concentration heavy metals are poisonous to the body and chronic exposure can damage the human body indefinitely. Heavy metal also pose a problem as it readily accumulates in the body and the effects can be passed on to our offspring in the form of deformities. what are organics & how
does it affect me? Organics in water is a term used to describe man-made and natural compounds with chemical structure based on carbon. They include hydrocarbons, proteins, plastics, petroleum compounds, pesticides, herbicides and chlorinated-carbon compounds.
The concerns of organics are those that are non-volatile and can be present in contaminated untreated drinking water. They are toxic and when consumed can cause adverse health effects. |
why is this a concern?
Aesthetic water problems are usually not harmful for health, but they affect the taste, odour and colour of the water. This may cause the water to be deemed undrinkable by some people's standards.
what is turbidity and how
does it affect me? Turbidity is the presence of fine solid particles in water, usually identified as cloudy or murky water. Turbidity is usually found in water coming from lakes, rivers, ponds and floods.
Turbid water is unsightly and most people will deem it as not potable due to its cloudiness. In addition, studies have shown that there a direct correlation between turbidity and biological contamination, due to the tendencies of bacteria and pathogens to adhere to the surface of solid particles. what causes colour &
how does it affect me? Colour can be caused by different compounds that are present in the water.
The presence of iron for instance, can be easily identified by the reddish colour in water. In addition, the water will also have distinctive metallic taste. Iron is an essential part of human nutrition, however in excess it can affect the human body adversely and even cause death. What causes taste & odour,
& how does it affect me? Taste and odour can be caused by a variety of reasons.
A fishy or musty taste and odour might be caused by algae or organic materials present in the water. A metallic taste might be caused by the presence of iron bacteria or elements such as iron or manganese. The presence of chemical dissolved in the water can also affect the taste. An example would be chlorine, which is widely used for disinfection but if used in excess leaves a strong chemical aftertaste. Taste and odour makes the water unappealing to drink. |
Know your Water Source
River
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Lakes
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Wells
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what are the types of contamination in river water?
Further treatment is required to make river water drinkable.
Bacteria and viruses can be found naturally in rivers. However, the effects of human activities can also introduce chemical contamination to rivers. Thus the main causes of concern for river water includes biological, chemical and aesthetics. how does it happen? (biological)
Other than naturally occurring bacteria and viruses that are present in water, carcasses of animals and fishes are great breeding grounds for bacteria and viruses.
Human activities such as bathing, washing, and sanitary purpose on the river may also introduce harmful pathogens. how does it happen?
(chemical) Agricultural runoff that contains herbicides and pesticides and improper disposal of factory wastes can introduce harmful chemical compounds in water.
how does it happen?
(aesthetics) The turbidity of river water varies with the season. During rainy seasons, rivers are usually more murky as more surface runoffs are collected.
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what are the types of contamination in lake water?
Lake water usually has a similar profile to river water. However, lake water may appear to be less murky as sediments are allowed to settle within the lake.
how does it happen? (biological)
Lake water contains many organisms and thus naturally occurring bacteria and viruses who lives in water will be present. Aquatic life present in the lake also contributes to biological contamination.
how does it happen?
(chemical) Lakes act as a collection point for surface runoff. Agriculture runoff from farms that use herbicides and pesticides will introduce chemical contamination into the lake.
Furthermore, illegal industrial discharge may contribute to the chemical contamination in lakes. how does it happen?
(aesthetics) Lakes are susceptible to seasonal changes as the temperature will affect the way the water mixes in the lake. During spring turbidity is higher as there is a higher volume of water leading to more erosion.
Agriculture runoff that contains herbicides and pesticides that enter the rivers may cause algae blooms as well. |
what are the types of contamination in well water?
Wells are usually catagorized into deep and shallow wells (less than 15 meter).
Shallow wells have relatively similar water quality with rivers however they are usually more susceptible to contamination than deep wells. Well water contains naturally occurring bacteria and also naturally occurring hardness and the presence of heavy metals. how does it happen? (biological)
Wells are susceptible to biological contamination due to naturally occurring bacteria in the soil and also possible leaching from a nearby sanitation system (eg. pit latrines, septic tanks).
If the wells are not covered properly it could be exposed to the environment such as wind-blown dirt, leaves and excrement from birds and animals. Bacteria and viruses are present in these and biological contamination will occur. How does it happen?
(chemical) The water from wells come from the surrounding ground water. This means it has already been filtered by the soil around it, however it could leach certain minerals along the way and thus hardness and heavy metals are part of the water's characteristics.
Additionally, factories who dump their chemical waste into the ground can leach into the well. Also agriculture runoff that seeps into the ground water can migrate to the well. All these introduces a variety of chemical into the well water. |
Rainwater Harvesting
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Flood Water
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Filtration Methods
PhysicalBoiling is the most conventional way to disinfect water, while filtration process has been performed as early as 2000 BC. Filtration process incorporates the screening of various pore sizes which only allows particles of a certain size to pass through. Particles larger than the pore size in the screens will be trapped and the water that passes through will be removed of those contamination.
Boiling
Boiling is the most common method used to purify water. The increase in temperature destroys/inactivates most pathogens, leaving a water that is biologically safe to consume. Certain pathogens however, can form protective layer when subjected to heat, allowing them to thrive in less favorable environment.
sand filtration
Sand bed filters is a very common setup found in rural places as it can be easily built using on the site materials. The filter work by trapping larger solid particles that are unable to pass through the pores of the sand bed thus purifying the water. However, it is possible that the filtered water is not consistent in quality.
microfiltration (MF)
The typical pore size for MF is usually ranges less than 1 micrometer (µm) (1µm = 0.000001m) and it is typically used to remove bacteria and sediments.
Ultrafiltration (UF)
The typical pore size for UF is around 0.01 micrometre (µm) (1µm = 0.000001m). The small pores are capable of trapping even virus.
nanofiltration (NF)
The typical pore size for NF is 0.001 micrometre (µm) (1µm = 0.000001m) and is usually used to remove multivalent ions. This process is also commonly utilized in seawater desalination process.
reverse osmosis (RO)
RO is a form of water purification technology that uses a semi-permeable membrane to remove particles from water. Although it can remove all contaminants (including organics and salt ions), the energy required is considerably huge.
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ChemicalActivated carbon is effective in removal of organic contaminants and is used to treat odor and color. Chlorination is a common disinfection method. Alum is used to coagulate smaller particles into larger flocs which is then removed through physical means.
activated carbon
Activated carbon is carbon that have been processed to have a higher surface area for contaminants to bind on to. These sites are effective at adsorbing organics. Activated carbon filter is typically used after mechanical filtration method to remove existing compounds that cause odour and color.
Chlorination
Chlorination is a disinfection process where chlorine or hypochlorite is added to water. Chlorine induces oxidation reaction when in contact with pathogens in water, killing most of the pathogens in the process.
Alum
Alum can be utilized to make minute size contaminants lump together, allowing easier removal through mechanical filtration.
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