Principles Of Liquid Waste Management -

            Most human activities generate waste water and like all wastes needs to be properly managed. However, there is a general perception that waste water is harmless & is hence disposed off indiscriminately. However, as these wastes need to be properly managed to make villages clean and an integral component of the Swachh Bharat mission it is essential that waste water is properly managed.

Key Principles of Liquid Waste Management

  1. Judicious use of fresh water : helps to reduce / Minimize generation of waste water
  2. Separation of Black Water (if any) , Grey Water, cattle shed waste water and storm water
  3. Reuse of Waste Water to maximum extent possible
  4. Treatment of Waste water at source or as close to the source of generation (Adoption of decentralized systems)
  5. Adequate arrangement to prevent mixing of solid waste with liquid waste ( Plastic bags , house level sweepings , clothes containing menstrual waste /children feces etc )

Disposal or Management?

Wastewater should be viewed as a resource and not as a problem. Greater emphasis should be placed on conservation (as it impacts wastewater generation) and promoting recycling and reuse of wastewater. Waste management should be seen as an opportunity and not as a problem.

Reuse of waste water : Need of the hour

Most grey wastewater is free of impurities and could be reused. Grey wastewater which is impure could with minimum treatment also be reused for several purposes other than drinking. Black water, on the other hand, would require treatment for the organics and pathogens. Wastewater reuse after proper treatment, reduces the need for fresh water which is welcome in a water stressed world.

My waste water : My responsibility

Polluter pays principle should apply for wastewater and one who generates wastewater should be responsible for its safe management. Unfortunately, in our country this is considered to be the responsibility of governmental agencies. Although the role of PRI in waste water management cannot be denied, efforts should be made to make people aware of their responsibility of managing the same.


Subsidiarity is an organizing principle which is based on the understanding that what can be done at the household level should be done at the household level, OR what can be done near the source of waste generation should be adopted. The hierarchy / preference of treatment should be household, neighborhood (cluster of households) and village level. Only waste that cannot be managed at the household level should be part of the collective or public waste management system.

Decentralized v/s centralized systems

It is a well known fact that decentralized management of any waste is advantageous as it is economical (low capital cost), easy to maintain (low operation cost), requires less space, leaves least burden on GPs for O&M. Centralized or semi-centralized waste management should be opted only when other options are not possible.

Difference between Decentralized & Centralized LWM

Decentralized Systems Centralized Systems
1. Low capital cost 1. High Capital cost
2. Low maintenance cost 2. High Maintenance cost
3. Maintenance also decentralized : by the HH owner 3. Maintenance centralized needs to be done by GP
4. Less space required 4. Large space required
5. Technologies are simple, easy to make & operate 5. Technologies are complex, require highly skilled manpower to make & operate.