Effluent Treatment Plant for Shopping Malls

Effluent treatment means wastewater generated from shopping malls has to be treated before it can be discharged to waterways. This treatment aims at reducing the contaminants/pollutants to acceptable levels to make the water safe for discharge back into the environment. This treatment is very much essential to prevent pollution of the receiving water.



Conventional wastewater treatment technologies improve the quality of wastewater discharged into the environment and those are as follows:
1. Physical treatment method
2. Chemical treatment method
3. Biological treatment method

Various levels of processes involved in effluent treatment plant for Shopping Malls are listed below:
1. Preliminary Treatment
2. Primary Treatment
3. Secondary Treatment
4. Tertiary Treatment

1. Preliminary or Pretreatment: This treatment is considered as a very first treatment level in most of the wastewater treatment plants. It uses bar screens of various sizes to remove large sized solids like sticks, rags, plastic materials etc. In order to achieve this it involves a process called floatation and sedimentation. If these are not removed it would cause damage to other parts of the plants. It uses comminutors to breakdown large solid materials and grit chamber is also used to remove sand, dirt, stones and etc. It removes many waste materials in wastewater but still contains various harmful contaminants which need to be treated before its discharge.

2. Primary Treatment: This is the second level treatment in ETP. Its main objective is separation of solid matter from wastewater using physical treatment methods. During this process, wastewater held in a tank called primary sedimentation tank where heavier solids settle to the bottom and are removed as a primary effluent which will be treated in further stage and lighter solids and scum & grease are skimmed from the surface using bar screens and grit chamber. The remaining liquid wastewater is now pumped for secondary treatment process. This process removes about 70% of TSS(Total suspended Solids).

3. Secondary or Biological Treatment: It removes soluble organic matter that escapes from previous stages and this is done by using aerobic biological method called “activated sludge process”. It consists of aeration tank followed by secondary sedimentation tank or secondary clarifier. When compressed air mixes with liquid wastewater growth of microorganisms takes place and thereby decomposition the organic matter occurs. When aerated water enter into secondary clarifier organic matter settles to bottom called as secondary effluent and part if which will be re-circulated and remaining will be subjected to sludge digester for sludge processing. This process removes around 70-80% of organic matter.

4. Tertiary or Disinfection Treatment: This is the last stage in most of the effluent treatment plants in malls. This is the only stage which has ability to remove up to 99% of disease-causing micro-organisms from the wastewater. It also removes residual suspended solids and organic matter which couldn’t be removed in earlier stages. It involves a process called disinfection which uses disinfectants like UV light etc., to substantially reduce the number of microorganisms in the water which is to be released into natural water bodies. The quality of effluent produced is almost equal to potable water quality.

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