Solution Overview

Solution Name

Bilge Vessel

One-line solution summary.

A decentralized greywater treatment unit which is an easy and DoItYourself home solution which can be implemented at individual homes with no changes in the existing home plumbing network.

Elevator pitch

What is your solution?

India & the world is facing acute freshwater shortage. Most of the countries will have no portable water by 2025.Greywater is an integral part of our water consumption pattern & this got me thinking on how to filter Greywater at individual level. BILGE VESSEL(BV) is an indigenous,sustainable,cost effective solution to our problem of water shortage. BV has three buckets stacked one over the other. A small submersible pump in the lowermost bucket will pump the greywater to the topmost bucket through a pipe. The lowermost bucket also has water level controller wires to ensure that the pump gets switched off when the water drops down below a certain minimum level. This will protect the submersible pump from burning out. The topmost bucket has different layers of fine aggregate,sand,activated charcoal,peels of orange,coarse aggregate & water hyacinth(or Pisticia). 

Sand & fine aggregate will strain out-suspended matter, solids
Activated charcoal will remove-organics(color, odour)
Coarse aggregate will capture-larger particulate matter
Water hyacinth or Pisticia will remove-metals,etc, thus bio-cleaning the water

The wastewater will trickle through these different layers & get filtered.  The treated water gets stored in the middle part of the BV which can be used for flushing or non-potable uses such as mopping,irrigation,car wash. 

What specific problem are you trying to solve?


India and the world is facing acute freshwater shortage. There is
an urgent need to reduce, recycle and reuse the water in whichever way
possible. As a nation we are facing an acute water crisis, especially in summers. Recently the western suburbs of Mumbai, a metropolitan city of India had no water supply. Chennai was struggling with water crisis and last summer it became the first Indian city to go dry. The private water tank supply units were on an indefinite strike and there was a panic situation among the residents citing this scarcity. The Niti Aayog, National Institution for Transforming India, is working extensively on a proposal to set up desalination plants along the coastline to tide over water crises. 

With this system, a family can recycle and reuse 50% of their water demand through this system resulting in less input or load on fresh water and at the same time less output of sewage. This leads to savings and have an impact not only at household level but in the whole water supply network/system i.e., desalination, energy in moving water, leakage of fresh water in supply network, spillage of sewage, treatment of sewage and other running costs.

Who does your solution serve? In what ways will the solution impact their lives?


END USER: A single family home of 4 people with an initial investment of around ₹1,000 can save around 5000-6000 litres of precious potable water per month. 1,000 litres of water cost around ₹20- ₹30 resulting in a saving of ₹1,200 per year. A household  can recover the money in a year through savings in their water bill and at the same time save around 50,000 litres of water annually.

CITY LEVEL: If adopted and implemented by the end user it will result in saving potable water and infrastructure cost, operation, and maintenance of sewage treatment plants.

  • Potable Water Savings: As per 2011 census 29,06,987 households in Delhi have proper bathing facilities within the premises. If 20% homes adopt this and considering 100 liter savings per day, then Delhi city can save 58,139,740 liters of fresh water per day. 
  • Infrastructure, Operation and Maintenance Savings: The BV unit is filtering and recycling the grey water which will result in less sewage i.e., 58,139,740 liters per day of less sewage will be generated and hence less load on sewage treatment plants. Just to put the picture in perspective, the capacity of Pappankalan sewage treatment plant is equivalent to water treated and reused by BV, if 20% of homes in Delhi adopt it. The STP construction cost is around ₹1 per litre and operation cost is around ₹100,000 per day. This would result in one time infrastructure cost savings of ₹56,000,000 and operation cost savings of ₹36,500,000 annually.

What steps have you taken to understand the needs of the population you want to serve?

We conducted a survey to understand the awareness, acceptability and

barriers towards greywater reuse at home. The survey had three sections.
Section 1 had basic information about the respondents such as name, city
and number of members in the family. Section 2 had questions related to the
awareness of waste-water reuse. Section 3 had questions on barriers towards
using wastewater at home. The outcomes of the survey is as follows: 

Awareness: Most of the respondents (91.3% ) strongly agreed that water recycling and reuse was the need of the hour. They were aware that
wastewater from bathing, washing clothes, utensils cleaning could be recycled and reused for non-potable uses such as flushing, car washing, gardening, mopping etc. Around 58.8% people were already recycling and reusing waste water at home.

Barriers: The survey concluded that space constraints and lack of implementation knowledge were a few of the top barriers in reusing waste water at home. Few respondents also highlighted bad odor and health concerns as the reason for not having a greywater recycling system at home.

In order to combat this, there is an AI component which will predict in advance when the cleaning or replacement of filtration media is required.

Which aspects of the Challenge does your solution most closely address?

Taking action to combat climate change and its impacts (Sustainability)

Our solution's stage of development:

Prototype: A venture or organization building and testing its product, service, or business model

Explain why you selected this stage of development for your solution—in other words, what have you accomplished to date?

I have converted my solution from just an idea to a working prototype which is actually usable. I am using it at my home. I am planning on getting in touch with a few companies to help scale this. 

Some of my future plans are - 

1. To test other natural waste materials like pistachio shells, coconut husks, seashells etc. as replacement to the existing filter media.
2. To install this system in 100 200 household and get their feedback for improvising the product.
4. To connect the water meter of 100-200 homes to online central website to monitor and quantify the water recycled and saved.
5. Finally, to develop this concept and prototype into an aesthetically pleasing product that can be bought off the shelf.

Where our solution team is headquartered or located:

Delhi, India

Team Lead:

Mannat Kaur

More About Your Solution

Which of the following categories best describes your solution?

A new project or business that relies on technology to be successful

Describe the core technology that powers your solution.

This project is intelligent and smart as it has an Arduino Uno

which will switch the pump on /off depending on the water level. It
will also log water usage through a line water meter. This would help
15 to control water level and switching on/off of the pump without any
human intervention. The user can also see the amount of water saved
on a daily, monthly or annual basis. 

There is also an AI component which will predict in advance when the cleaning or replacement of filtration media is required (effectively meeting all the barriers)

Please select the technologies currently used in your solution:

  • Artificial Intelligence / Machine Learning
  • Other

In which countries do you currently operate?

  • India

How many people does your solution currently serve, and how many do you plan to serve in the next year? If you haven’t yet launched your solution, tell us how many people you plan to serve in the next year.

Right now, I am just using this at my home to look for the shortcomings and improve them. Later on, I plan on installing this system in 100-200 household and get their feedback for improvising the product. I also plan on connecting the water meter of 100-200 homes to online central website to monitor and quantify the water recycled and saved.

Overall, I am trying to make it into an aesthetically pleasing product that can be bought off the shelf.

What are your impact goals for the next year, and how will you achieve them?

Although, I have mentioned the IMPACT of the solution earlier, but in the near future I wish to see my system in every house where people are, at their own individual levels are recycling water, generating less input or load on fresh water, less output of sewage, supply network. 

How are you measuring your progress or planning to measure your progress toward your impact goals?

I am using the turbidity sensor, pH sensor and a few others to test the filtered water quality allowing me to understand on how to modify the filter media accordingly. 

The UN SDG I am focusing on is SDG Goal 6 - Clean water and sanitation

What barriers currently exist for you to accomplish your goals in the next year?

- Modifying the filter media better

- Looking into the foul smell that starts to come after 3-4 months

About Your Team

How many people work on your solution team?


How long have you been working on your solution?

1-2 years

Your Business Model & Resources

Do you qualify for and would you like to be considered for The HP Girls Save the World Prize? If you select Yes, explain how you are qualified for the prize in the additional question that appears.


If you selected Yes, explain how you are qualified for this prize. How will your team use The HP Girls Save the World Prize to advance your solution?

I feel this project is compact, easy to setup and can be used easily not requiring any human effort. 

Do you qualify for and would you like to be considered for The Pozen Social Innovation Prize? If you select Yes, explain how you are qualified for the prize in the additional question that appears.


Solution Team

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