The availability of inexpensive membrane materials has revolutionized pure water production, and provided one of the largest markets for such materials. There is now a relatively straight trade-off between the desired purity of the product water and the money available to achieve that purity. There are four main processes utilizing membranes for the separation of […]
Not only boiler feed, but a wide range of other applications require a high degree of influent water quality, much purer than available from mains water distribution. In the electronics industry, components (especially semi-conductor materials) must be washed in water that is sufficiently pure as to leave no residue behind after the washing process, even […]
Ion exchange processes have been in use for many years to soften water, their disadvantage being that they are batch operations, with a regeneration stage between each softening stage, the regeneration requiring the use of another chemical to restore the soluble ion content of the ion exchange materials. The basic process involves passage of the […]
Steam is a universal processing fluid, for the generation of electric power, as a heating medium or as a process input. Most boiler circuits involve recycle of some or all of the condensed steam after use. A typical circuit (Figure 4.18 ) involves: 1. raw or mains water intake, to make up for steam consumed […]
In the same way that bulk water treatment may not provide a sufficient degree of raw water purification to satisfy the needs of domestic users, it may also be insufficiently pure for the needs of industrial process operators, whether as input to a steam boiler system, or as a process input itself. There has thus […]
A packed bed of activated carbon, acting as an adsorbent, is a very good purification means for small to medium-sized water treatment systems. However, it is not suitable for removing suspended biological material. This can be done in an element that combines adsorption with biological activity. This process combines the use of biological activated carbon […]
Hundreds of thousands of touring recreational vehicles, caravans and mobile homes, together with pleasure boats of all types and sizes, rely on onboard tanks for personal water supply. There is a correspondingly large number of temporary water users, such as construction sites, camps in remote areas, fishing boats, and so on, all needing a supply […]
Tests confirm the presence of these toxic substances in drinking water, but few mains cold water lines into residential properties incorporate an effective filtration system. Ideally, drinking water should be organoleptically neutral, clear and mineralized sufficiently to give it the ‘ fresh ’ taste. It should be free from any organic matter that reacts with […]
According to a US congressional study, groundwater contamination will become a principle environmental concern for the next decades. Once contaminated by toxic organic chemicals, groundwater can remain polluted for hundreds or thousands of years, if not for geological periods of time, because nature supplies few, if any, cleansing or diluting processes for groundwater. The most […]
The World Health Organization has identified 752 substances that can be present in tap water. Water authorities are obliged to monitor the levels of only 66 of them, and bottled water manufacturers only 28. Up until about 30 years ago, lead was thought to be the only dangerous pollutant in drinking water. Today, in addition […]
