Frequently Asked Questions | Centre for Science and Environment

Frequently Asked Questions

1. What is Decentralised wastewater treatment system?
Decentralised wastewater tretment system (DWWTS) is an approach consisting of different technologies to provide wastewater treatment solutions for small, individual or cluster type facilities. It is a sustainable method to treat domestic wastewater which is generated from the office campuses, residential societies and institutional premises.

2. Why should I adopt this method?

This method is a sustainable alternative to manage wastewater both as a resource as well as a pollutant. The domestic sewage generated can be recycled and reused at local level which significantly reduces the burden on the centralised treatment plant and also help in managing and reudcing demand of fresh water . See here to know more..

3.What is the principal behind this approach?
In the decentralised wastewater treatment systems ,wastewater can be treated on-site through combination of aerobic and anaerobic techniques. The wastewater is treated and recycled through a three step process-
a) Primary treatment, which includes pre-treatment and sedimentation in settlement tank or septic tank;
b) Secondary anaerobic treatment in baffled reactors;
c) Tertiary aerobic/anaerobic treatment in reed bed system; and polishing in Ponds

4.What are the components of DWWT system?

DWWT system has four basic components : Settler or septic tank, baffled reactor, planted filter or rootzone treatment system and polishing pond. This combination is also known as DEWATS.

5.How does this system work?
To read about the whole process see here..

6.What are the benefits of implementing such systems?
Click here to read..

7.How much space is required to install the DWWT system?

These systems are requirement specific and site specific. Area requirement of the DWWT  system is based on the the total volume of the wastewater generated. This depends on the nature of wastewater and depth of the unit tanks. To read further see here ..

8.What is the cost involved for the implementation of such systems?

Average cost of construction is Rs. 25,000-30,000 per KL flow per day (approximately).To know the details see here ..

9.What is the operation and maintenance cost of the system?

Decentralised wastewater treatment systems are low cost on site treatment approach but continuous operation and maintenance is necessary to maintain the desirable performance of the plant. The annual O&M cost for the plant is generally in the range of Rs. 3000-5000.

10.What is the range of capacity of this system?

The capacity of the system may vary from 1KLD to 100 KLD . To treat large amount of wastewater multiple units of wastewater can be installed.

11.How treated wastewater could be reused?
Treated wastewater can be used to meet the demands for horticulture purpose, irrigation, landscaping, fish- farming. (Note:  The reuse of the treated wastewater depends upon its quality)

12.How economical is this as compared to centralised treatment options?

Decentralised wastewater treatment system has the potential of being more economical in comparison to other centralised treatment options.These systems are not capital and energy intensive. These does not require skilled labour for O& M. Different decentralised systems can be combined with natural or already existing treatment facilities so that the most appropriate solution may be chosen.

13. I am interested in implementing  DWWT system , whom should I contact?
To contact CSE for technical support See here ..


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