Chemicals used by wastewater treatment manufacturers Philippines
Wastewater treatment manufacturers Philippines uses mainly three main chemicals for Chemical Precipitation of Phosphorus in Wastewater; Aluminum, Ferric iron or Lime. Each has different handling issues. Look for the following in the designs:
Aluminum Sulfate (Alum)
The pH of Alum is 3.0-3.5 so pH control will be needed afterwards.
Corrosive when wet. All storage bins and piping should be constructed with stainless steel, fiberglass-reinforced plastic, PVC or other plastics, or concrete tanks.
Shall be stored and added at temperatures 25 degrees F and above to prevent crystallization.
Works best at wastewater pH of 5.5-6.5.
Sodium Aluminate
Formation of NaOH increases pH. This is a strong caustic and is not corrosive.
Shall be store and used within three months. Dry Aluminate deteriorates with exposure to the atmosphere.
Store in stainless Steel or concrete. Wastewater treatment manufacturers Philippines generally avoid alloys, rubber and aluminum parts.
Ferric Chloride
Has a pH of 2.0 and is very corrosive. Will require pH control.
Corrosive, use steel lined with rubber or plastic or synthetic resin storage tanks.
Wastewater treatment manufacturers Philippines generally stores ferric chloride in heated building or in heated tanks to prevent crystallization.
Pump component should be constructed of graphite or rubber lined pumps with Teflon seals. Metering pumps are typically of the positive displacement type, either diaphragm or plunger.
Piping, use steel lined with Saran, FRP or plastics. Valves should be rubber or resin lined diaphragm valves, Saran lined valves with Teflon diaphragms, rubber sleeved pinch valves or plastic ball valves.
Works best at wastewater pH of 4.5-5.0.
Ferrous Chloride
Corrosive. Same storage, pumping and piping as Ferric Chloride.
Precipitation will not occur until ferrous ion is oxidized to ferric ion.
Works best at wastewater pH of 8.0.
Ferrous Sulfate.
Acidic when dissolved in water.
Phosphorus precipitation does not occur until ferrous ion is oxidized to ferric ion.
Oxidizes and hydrates in moist air. Must be kept in dry area and out of humidity.
Will cake up at storage temperatures greater than 68 F, must be kept cool.
Storage containers may be constructed of concrete, synthetic resin or steel and wastewater treatment manufacturers Philippines gives and additional lined with asphalt, rubber, PVC or chemically resistant resins.
Works best at wastewater temperature of 8.0.
Lime (Calcium Carbonate)
Creates significant increases in sludge up to 2-3 times the normal amount generated.
Must be added till pH is up around 10. This often causes the biological upsets in treatment facilities.
Phosphorus is released under anaerobic conditions. Sludge handling must be addressed.
Polymer – dry or liquid form
Used in conjunction with aluminum and iron salts to assist in flocculation and settling of metal phosphate floc.
Added at least 10 seconds after metal salt addition, preferably 2-5 minutes later.
Dry polymers require mixing and aging before use. Liquid polymers can be used immediately.
Must be stored in cool, low humidity areas. Storage tanks are FRP, type 316 stainless steel, or plastic lined steel tanks.
Do not store polymer for a long time, three days after dry solution is mixed.
BIOLOGICAL PHOSPHORUS REMOVAL
Biological phosphorus removal is carried out by wastewater treatment manufacturers Philippines when wastewater is cycled through alternating anaerobic and aerobic conditions. Wastewater sludge must first pass through an anaerobic condition where bacteria release stored phosphorus. The wastewater then passes through an aerobic phase where bacteria store excess phosphorus in their cells. Design calculations shall show the sludge retention time, the anaerobic contact time and the aerobic detention time.
