How Does a Water Treatment Plant Operate?
To understand how a water treatment plant works it is first necessary to understand the nature of contamination. A simple way to illustrate this is to collect a tumbler full of liquid from a stagnant pond or puddle and leave it to stand overnight. In the morning you are likely to find that it has become a little less turbid, there may be a layer of solids on the bottom of the glass while the remaining liquid is still pretty turbid due to particles that were insufficiently dense to sediment out and have remained in suspension.
A microscopic examination is likely to reveal a complex mixture of inorganic solids along with various animal and plant cells. Some, like protozoa and bacteria, may be motile while others, though purely inorganic in composition, may appear to be living due to a constant state of agitation known as Brownian movement. In other words, this is a cocktail that no one would be keen to sample.
Depending upon the source and the circumstance of the contaminated liquid, various combinations of processing will be required to achieve the end result. The extent of purity required is also a variable and will range from a fully potable product to one that is sufficiently free of harmful contaminants for safe disposal or for re-use in irrigation or some industrial process such as washing or extraction.
Processes vary, Biological digestion is used to treat sewage, wastewater and even for treating aquaria and fishponds. WaterIcon offers dissolved air flotation in which bubbles carry large particles to the surface for skimming while other application may require mesh screening. The finer, suspended solids are then removed by filtration using filters of gradually decreasing porosity.
Reverse osmosis is another WaterIcon speciality in which pressure is applied to force the flow of solvent against the natural osmotic gradient freeing it from dissolved solids. The process may be used either to purify the solvent or to concentrate a solute. Examples of RO water treatment plants are found in the manufacture of fruit juice concentrates and maple syrup.