ISO 7027:1999 is an ISO standard for

water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

that enables the determination of

turbidity Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids ...

.ISO 7027:1999 - Water quality -- Determination of turbidity http://www.iso.org/iso/catalogue_detail.htm?csnumber=30123 The ISO 7027 technique is used to determine the

concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', '' molar concentration'', ''number concentration'', ...

of suspended particles in a sample of water by measuring the incident light scattered at right angles from the sample. The scattered light is captured by a

photodiode A photodiode is a light-sensitive semiconductor diode. It produces current when it absorbs photons. The package of a photodiode allows light (or infrared or ultraviolet radiation, or X-rays) to reach the sensitive part of the device. The packag ...

, which produces an electronic signal that is converted to a

References

#07027 Water quality indicators {{Watersupply-stub