Water Quality

Water quality

Water quality is the physical, chemical and biological characteristics of water. The primary bases for such characterisation are parameters which relate to potability, safety of human contact and for health of ecosystems. The vast majority of surface water on the planet is neither potable nor toxic. This remains true even if sea water in the oceans (which is too salty to drink) isn’t counted. Another general perception of water quality is that of a simple property that tells whether water is polluted or not. In fact, water quality is a very complex subject, in part because water is a complex medium intrinsically tied to the ecology of the planet. While industrial pollution is a main cause of water pollution.

Contaminants that may be in untreated water include microorganisms such as viruses and bacteria; inorganic contaminants such as salts and metals; pesticides and herbicides; organic chemical contaminants from industrial processes and petroleum use; and radioactive contaminants. Water quality depends on the local geology and ecosystem, as well as human uses such as sewage dispersion, industrial pollution, use of water bodies as a heat sink, and overuse as in spear water (which may lower the level of the water).

Environmental Protection Agencies

Normally “Environmental Protection Agencies” prescribes regulations that limit the amount of certain contaminants in the water provided by public water systems for tap water. Food and Drug Administrations in various countries (FDA) regulations establish limits for contaminants in bottled water that must provide the same protection for public health. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of these contaminants does not necessarily indicate that the water poses a health risk. But I have stated before, in Thailand – stick to the brewery brands.

Water Purification

Some people use water purification technology to remove contaminants from the municipal water supply they get in their homes, or from local pumps or bodies of water. For people who get water from a local stream, lake, or groundwater, their drinking water is not filtered by the local government. Both of the above is where my company helps.

Toxic substances and high populations of certain microorganisms can present a health hazard for non-drinking purposes such as irrigation, swimming, fishing, rafting, boating, and industrial uses. These conditions may also impact wildlife which use the water for drinking or as a habitat.

Basic Chemistry

An understanding of the basic chemistry of many water quality parameters is an essential first step to making good decisions with water filtration. Most citizens harbor great concern over the purity of their drinking water, but there is far more to water quality than water treatment for human consumption.

Technical measures of water quality — that is, the values obtained when making water quality measurements—are always subject to interpretation from multiple perspectives. Is it reasonable to expect a river to be pristine in a landscape that no longer is? If a river has always carried sediment, is it polluted even if the cause is not man induced? Can water quality be maintained when water quantity can not? The questions that arise from consideration of water quality relative to human uses of the water become more complex when consideration must also be given to conditions required to sustain aquatic biota. Yet inherent in the concept of preserving uses is a mandate that waterways must be much more than conduits for a fluid we might want to drink, fill our swimming pool with, or carry our wastes out of town.

Here is a short list of the main measurements

Conductivity (salinity), Dissolved Oxygen (DO), pH, Color of water, Taste and odor, Turbidity Total suspended solids (TSS), Chemical oxygen demand (COD), Biochemical oxygen demand (BOD), Microorganisms such as fecal coliform bacteria (Escherichia coli), Cryptosporidium, and Giardia lamblia, Nutrients (fertilizers: nitrates, phosphates), Dissolved metals and metalloids (lead, mercury, arsenic, etc.), Dissolved organics: Colored Dissolved Organic Matter (CDOM), Dissolved Organic Carbon (DOC), Temperature, Pesticides & Heavy Metals:

Most of the simple measurements listed above can be made on-site, in direct contact with the water source in question. More complex measurements that must be made in a lab setting require a water sample to be collected, preserved, and analyzed at another location. Making these complex measurements can be expensive, and it is important to understand in advance the reasons for making such (or any) complex measurements. Also, since millions of substances might be present in a water sample, it is not financially reasonable to establish what all might be in a particular sample without a very large budget for lengthy analysis.

One effective way to improve water quality

Is to get more oxygen in the water. Aeration is often performed by sending compressed air to an air diffuser at the bottom of the pond. The deep water rises to the surface and the water molecules grab oxygen from the atmosphere. As the pond water circulates, soon the oxygen levels in the water from top to bottom increase. By increasing oxygen levels, the consumers in the water source will be more successful and the overall quality of water for aquatic life, at least, will improve.

See you next issue.


Steve Johnson is a director of “WET” Water Engineered Technologies (Thailand). WET offers innovative water treatment solutions both commercially and domestically as well as Swimming Pool Design, Construction, Equipment, Trouble Shooting & Advice.

info@poolsasean.com  Mob# +66 (0) 848 428317


Back to the Blog


Leave a Reply

Your email address will not be published. Required fields are marked *