Turbidity may sound like a complicated scientific term but in essence it is a simple definition concerned with the cloudiness of water. More specifically turbidity refers to the light that is able to pass through a water sample because of the sediment present in the liquid. In most cases it is measured using a meter although there are a variety of methods for obtaining a turbidity reading. Meters are normally best however as they are able to pick up on sediment particles that are so small that they will not settle to the bottom of the sample.
These meters are used for a range of purposes and test water from sources such as rivers and reservoirs. In rivers these meters are often used to find sediment and silt levels of the flowing water. By obtaining this turbidity it is possible to ascertain whether agricultural and building actions further upstream are affecting the river in certain ways. For instance, while a meter can detect silt and mud particles, more advanced models can also pick up bacteria and chemicals that could be a result of farming processes. Subsequently turbidity is important when realising the effect human actions are having on the environment and more precisely the effects of particular river systems.
This is not the only use however for the turbidity meter. The device is used extensively in the water purification industry. It is a vital piece of equipment that gives operatives the ability to test whether water is safe for human consumption. The meters are used at nearly every stage of the water treatment process to assess the quality of the water and the effectiveness of filters and other cleansing methods. In addition it is possible through the understanding of turbidity levels to assess the lifespan of filtering equipment. An example would be river water entering a treatment plant that has a known turbidity. If this is known, how hard the filters will have to work is also a known quantity and hence how long the filters will last is also understood.
There are two major ways in which turbidity is measured. More advanced purposes will require an electric meter while less sophisticated tasks will normally use the tube method. Both have their benefits and downsides and are suited to differing applications. In terms of units of measurement both nephelometric turbidity units (NTU) and Jackson turbidity units (JTLJ) are both used. These units differ slightly but for the purposes of most applications are considered equal and interchangeable.
The market today has a variety of meters available for public purchase. Electric meters are generally more accurate than tubes and hence are used for more precise applications. However needing a power supply and a large cost can be considered downsides to their usage. In addition, older models are not robust enough to cope with working with water on a day to day basis, although newer models have addressed this issue successfully.
Tubes on the other hand are a far more basic means of measurement, although are still regarded to be effective. The process of tubular measurement fills a clear tube with the sample and then the user views how much light passes through the sample. These tubes are hard wearing and can be used extensively in the field for less important measurements.
Whatever type of turbidity meter is being used it is hard to dispute that its uses are important to society and the environment. Without the use of these meters we would not be able to assess our impact on the environment while more importantly we would not have drinking water that is safe and disease free. It may not be the most interesting of topics but the uses of these devices truly assist the world greatly.
Science and technology expert Thomas Pretty looks into the uses of turbidity meters and how these devices are extremely valuable to society and the environment.