Abstract: Aluminum sulfate reacts with phosphates to createaluminum phosphate and a sulfate. The conversion of the phosphateto aluminum phosphate is very important because this allows thephosphate to be easily extracted. This manipulation is used todayin industrial waste treatment sights. The removal of phosphates isvery important for if phosphates are not removed, they plaguebodies of water by feeding algae which clog the surface waters andeventually effect every living and nonliving thing in thatenvironment.
Chemical Process: The reactions which occur are the following:Aluminum sulfate(alum) in combination with wastewater canflocculate phosphorus. The Flocculation that happens with aluminumsulfate addition is the formation of aluminum phosphate particlesthat attach themselves to one another and become heavy and settleto the bottom of a clarifier. The aluminum sulfate and phosphorusmixture can then be withdrawn, thereby removing the phosphate orphosphorus from the wastewater flow. Industrial Applications: The application of this reaction to theindustrial world consists of a set of processes to filter out thephosphate. The setup is the following:Purpose: Restrict phosphates to aluminum phosphates for easierdisposal of phosphorus.
The first step in phosphorus removal is the Rapid Mix. Inthis stage, alum and waste or water runoff(known as effluent) isblended together as rapidly as possible with the use of a high-speed mixer called a “flash mixer. ” After this instant mixing, aslower moving process called coagulation and flocculation followsto allow the formation of a floc. These processes occur in aFlocculation Chamber.
This floc consists of suspended and colloidalmatter, mainly including the aluminum phosphate. Next, theeffluent travels to a clarifier in which sedimentation occurs. Theheavier aluminum phosphate settles to the bottom then pumps at thebottom of the clarifier pump out the aluminum phosphate via pipes. This aluminum phosphate is then disposed. Currently, there are noeconomical uses for aluminum phosphate.
Also, this chemical process is similar to the process used bylaundry detergents. Many detergents contain synthetic phosphates,called tripolyphosphates(TTPs). These chemicals cling to greaseand dirt particles(alum in the previous example), keeping them insuspension until the wash water is flushed out of the washingmachine. Impact on Society: This reduction in phosphorus is very important. This added phosphorus disrupts the natural cycle of phosphorus.
Oneresult of this is an algal blooms, or exponential growth in algae. When algal blooms occur, the surface of a freshwater lake isclouded with an almost finite amount of bacteria because of anincrease in a nutrient. In this case an increase in phosphate, afavorite for algae. This deprives the bottom of the lake bycutting off light. A dense mat of algae choke off the lake.
Also,phosphates are nutrients for plantlife. When fall approaches, orwhen phosphate levels are decreased, the algae die and fall to thebottom, changing the bottom from a silt, sand and clay bottom to asand gravel and rock bottom. When the plants die, they aredegraded by aerobic bacteria, which can deplete dissolved oxygen,killing aquatic organisms. As oxygen levels drop, anaerobicbacteria resume the breakdown and produce noxious products.
All ofthis impairs navigation, fishing, swimming and recreationalboating. Total phosphorus removal through filters after using alum asa filtering aid achieves 70 to 95 percent efficiency. Phosphatesmust be filtered out before the water or wastes are dumped backinto bodies of water. GlossaryFlocculation: The gathering together of fine particles to formlarger particles. Effluent: Wastewater or other liquid — raw, partially orcompletely treated — flowing from a basin, treatment process, ortreatment plant.
Coagulation: The use of chemicals that cause very fine particlesto clump together into larger particles. This makes it easier toseparate the solids from the liquids by setting, skimming, drainingor filtering. Floc: Groups or clumps of bacteria and particles or coagulants andimpurities that have come together and formed a cluster. Colloidal: Very small and finely divided.
Referring to solids. Does not dissolve and remains dispersed in a liquid for a long timedue to small size. Algal blooms: Rapid growth of algae in surface waters due toincrease in inorganic nutrients. BibliographyKerri, Kenneth D.
Advanced Waste Treatment. Sacramento, Ca. : CSU,Sacramento, 1987. Adams, Melinda. Environmental Science.
Redwood City, Ca. : TheBenjamin/Cummings Publishing Company, Inc. , 1991.
