Water Treatment Equipment

Water Treatment Equipment: Is used in Water Purification - the process of removing contaminants and other harmful microorganisms from a raw water source.  The goal is to produce water for a specific purpose with a treatment profile designed to limit the inclusion of specific materials; most water is purified for human consumption.  Water purification may also be designed for a variety of other purposes, inlcuding to meet the requirements of medical, pahrmacology, chemical and industrial applications. 

Industrial Waterwater Treatment: Covers the mechanisms and processes used to treat waters that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-use.  Most industries produce some wet waste although recent trends in the developed world have been to minimise such production or recycle such waste within the production process.  However, many industries remain dependent on processes that produce wastewaters.

Many industries have a need to treat water to obtain very high quality water for demanding purposes.  Water treatment produces organic and mineral sludges from filtration and sedimentation.  Ion exchange using natural or synthetic  resins removes calcium, magnesium and carbonate ions from water, replacing them with hydrogen and hydrocyl ions.  Regeneration of ion exchange columns with strong acids and alkalis produces a wastewater rich in hardness ions which are redily precipitated out, especially when in a mixture with other wastewaters. 

The different types of contamination of wastewater require a variety of strategies to remove the contamination.  Solids removal: most solids can be removed using simple sedimentation techniques with the solids recovered as slurry or sludge.  Very fine solids and solids with densities close to the density of water pose special problems.  In such case filtration or ultra-filtration may required.  Alternatively, flocculation may be using alum salts or the addition of poly-electrolytes.

Oils and Grease Removal: Many oils can be recovered from open water surfaces by skimming devices.  However, hydraulic oils and the majority of oils that have degraded to any extent will also have a soluble or emulsified component that will require further treatment to eliminate.  Dissolving or emulsifying oil using sufgactants or solvents usually exacerbates the problem rather than solving it, producing wastewater that is more difficult to treat.  The wastewaters from large-scale industries such as  oil refineries, petrochemical plants, chemical plants, and natural gas processing plants commonly contain gross amounts of oil and suspended solids.  Those industries use a device known as API oil-water seperator which is designed to seperate the oil and suspended solids from their wastewater effluents. 

The API Separator is a gravity seperation device designed by using Stokes Law to define the rise velocity of oil droplets based on their density and size.  The design is based on the specific gravity difference between the oil and the wastewater because that difference is much smaller than the specific gravity defference between the suspended solids and water.  The suspended solids settles to the bottom of the separator as a sediment layer, the oil rises to top of the separator and the cleansed wastewater is the middle layer between the oil layer and the solids. 
Typically the oil layer is skimmed off and subsequently re-processed or disposed of, and the bottom sediment layer is removed by a chain and flight scraper (or similar device) and a sludge pump.  The water layer is sent to further treatment consisting usually of a dissolved air flotation (DAF) unit for additional removal of any residual oil and then to same type of biological treatment unit for removal of undesirable dissolved chemical compounds.

Parallel plate separators are similar to API seperators but they include tilted parallel plate assemblies (also known as paralell placks).  The parallel plates procide more surgace for suspended oil droplets to coaleasce into larger glocules.  Such separators still depend upon the specific gravity between the suspended oil droplets to coalesce into  larger globules.  Such separators still depend upon the specific gravity between the suspended oil and the water.  however, the parallel plates enhance the degree of oil-water separation.  The result is that a parallel plate separator requires significantly less space than a conventional API separator to achieve the same degree of separation. 

Removal of Biodegradable Organics Biodegradable Organic material of plant or animal origin is usually possible to trate using extended conventional wastewater treatment processes such as activated sludge or trickling filter.  Problems can arise if the wastewater is excessively diluted with washing water or is highly concentrated such as neat blook or milk.  The presence of cleaning agents, disinfectants, pesticides, or antibiotics can ave detrimental impacts on treatment processes.

Activated sludge is a biochemical process for treating sevard and industrial wastewater that uses air (or oxygen) and microorganisms to biologically oxidize organic pollutants, producing a waste sludge (or floc) containing the oxidized material.  In general, an activated sludge process includes: 

- An aeration tank where air (or oxygen) is injected and thoroughly mixed into the wastewater.
- A settling tank (usually referred to as a "clarifier" or "settler") to allow the waste sludge to settle.  Part of the waste sludge is recycled to the airation tank and the remaining waste sludge is removed for further treatment and ultimate disposal.

A trickling filter consists of a bed of rocks, gravel, slag, peat moss, or plastic media over which wastewater flows downward and contacts a layer (or fil) of microbial slime covering the bed media.  Aerobix xonditions are maintained by forced air flowing through the bed or by natural convection of air.  The process involves absorption of organic compounds in the wastewater by the microbial slime layer, diffusion of air into the slime layer to porvide the oxygen required for the biochemical oxidation of the organic compounds.  The end products include carbon dioxide gas, waster and other production of the oxidation.  As the slime layer thickens, it becomes difficlut for the air to penetrate the layer and an inner aneorobic layer is formed. 

The components of a complete tricking filter system are: fundamental components:
- A bed of filter medium upon which a layer of microbial slime is promoted and developed
- An enclosure or a container which houses the bed of filter medium
- A system for distributing the flow of wastewater over the filter medium
- A system for removing and disposing of any sludge from the treated effluent

The treatment of sewage or other wastewater with trickling filters is amoung the oldest and most well characterised treatment technologies.

A trickling filter is also often called a trickle filter, trickling biofilter, biofiller, biological filter or biological trickling filter. 

Treatment of other organics synthetic organic materials including solvents, paints, pharmaceuticals, pesticides, cooking products and so forth can be very difficult to treat.  Treatment methods are often specific to the material being treated.  methods include distillation, absorption, vitrification, incineration, chemical immobilisation or landfill disposal.  Some materials such as some detergents may be capable of biological degratation and in such cases, a modified form of wastewater treatment can be used.

Acids and alkalis can usually be neutralised under controlled conditions.  Neutralisation frequently produces a precipitated that will require treatment as a solid reside that may also be toxic.  in some cases, gasses may be evolved requiring treatment for the has stream.  Some other forms of treatment are usually required following neutralisation.  Waste streams rich in hardness ions as from de-ionisation processes can readily loose the hardness ions in a buildup of precipitatied calcium and magnesium salts.  This precipitation process can cause severe furring pipes and can, in extreme cases, cause the blackage of disposal pipes.  A 1 metre diameter industrial maine discharge pipe serving a major chemicals complex was blocked by such salts in the 1970s.  Treatment is by concentration of de-ionisation waste waters and disposal to landfill or by care pH management of the released wastewater. 

Toxis materials including many organic materials, metals (such zinc, silver, cadmium, thallium etc) acids, alkalis, non-metallic elements (such as arsenic or selenium) are generally resistant to biological processes unless very dilute.  Metals can often be precipitated out by changing the pH or by treatment with other chemicals.  Many, however, are resistant to treatment or mitigation and may require concentration followed by landfilling ro recycling.