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WHAT IS WATER AND WASTE WATER TREATMENT?
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Water treatment generally involves the purification of feed water to produce potable, pure or ultrapure water for human consumption or industrial usage. The water purification process typically includes several processes such as screening, sedimentation, filtration, chlorination or ozonation. Other processes such as microfiltration, ultrafiltration, reverse osmosis and ultraviolet disinfection can also be involved. The type and number of processes are determined by the quality of water required.
Wastewater treatment is the treatment of used water released from residences, businesses (such as restaurants and food courts) and industries. It is a multi-stage treatment process to eliminate or reduce the pollutants and toxins in wastewater to an acceptable level before the water can be safely discharged into the environment. Wastewater treatment may also include the recycling of wastewater for re-use, primarily by industries, and as potable (drinking) water.
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TYPICAL WATER TREATMENT PROCESS
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Water is collected in the reservoir. The pump station pumps the water from the reservoir for treatment.
Mixing Chambers/Settling Tank :
Aluminium sulphate and lime are added to the raw water to cause the impurities in the water to flocculate in the mixing chambers and settle to the bottom in the settling tank.
Sand Filters :
The clarified water goes through sand filters which remove the finer particles of impurities.
Clear Water Tank :
The clear water tank holds the treated water before it is pumped into the distribution system. Chlorine is added to kill bacteria and lime is used to neutralise the acidity of water.
Service Water Tank :
The pumps at the pump station pumps the water to the service water tank where the water is stored. Service water tanks are usually built on higher ground, and store water for distribution to the community during peak periods. This reduces pumping cost.
For our water treatment projects, our Metax is usually involved in steps (2) to (7) in the above typical water treatment process illustration.
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TYPICAL WASTE-WATER TREATMENT PROCESS
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Wastewater is collected in underground sewers and delivered to treatment facilities. The wastewater goes through a grit removal chamber to remove sand and other abrasive materials and then goes through a multi-stage treatment process.
Primary Settling :
Wastewater is held in a series of sedimentation tanks to allow particles to settle to the bottom and the scum to float to the top. These particles and scum are then removed as sludge.
Biological Aeration :
A process to convert organic matter to cell tissue in wastewater. In the aeration tank, this is done in the presence of oxygen.
Final Settling :
Wastewater is held in a second series of sedimentation tanks to allow the suspended solids in the water to settle to the bottom.
Disinfection :
A process to protect public health by inactivating organisms, such as bacteria and viruses.
Dissolved Air Flotation :
A process to remove suspended solids, oils and other contaminants through the use of air bubble flotation.
Blending :
A process to make the sludge more uniform.
Mechanical Sludge Dewatering :
Water is removed from sludge before it can be used for drying and land fill.
For wastewater treatment projects, Metax is usually involved in all the steps in the above typical
wastewater treatment process illustration.
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ANAEROBIC WASTEWATER TREATMENT PROCESS
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Anaerobic wastewater treatment is an alternative form of treatment of industrial and municipal wastewater. The selection of the treatment method is dependent on the characteristics of the wastewater, treated wastewater discharge specifications and economic considerations. Anaerobic wastewater treatment provides high treatment efficiency for biodegradable sludge and is suitable for wastewater with high BOD (Biological oxygen demand, an index of pollution) and COD (Chemical oxygen demand, an index of pollution which an alternative method of measuring pollution to BOD).
For projects which utilise anaerobic wastewater treatment, Metax is involved in step (2) of the above anaerobic wastewater treatment process illustration.
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