Saving water the right way! 52% reduction in water consumption!
No, doing save water campaigns doesn’t save you any water. Neither does educating people on reduced groundwater levels help. After a lot of failed campaigns and blame games, we decided to take a couple of steps that would change the way residents consume water. Before we get into the details on how we saved water let me introduce myself,
Another sheep in the herd here at Bangalore, I code to earn my bread. Over the weekend I spend time either travelling, volunteering at www.sodews.org, or having a ball drinking some locally brewed beer we have in our lovely garden city. Another role I took up a few years ago was to run the association at our apartment — a thankless job, but one gets to understand the disastrous waste management, water wastage and many other things in urban life.
We are a mid-range 10-year-old society with 171 flats spread across four blocks, having a swimming pool, a small clubhouse, and a gym. We had a well functioning STP plant that is managed by a decent provider from a very long time. The water consumption of the apartment was skyrocketing for a few years as most of our bore-wells went dry with depleting underground water levels in Bengaluru.
Water expense spiralling out of control
Past few years the water expenses have been skyrocketing and we have been consistently increasing the maintenance. There was no sight of a reduction in water consumption because residents were not reducing the usage by any means. I even remember doing a drawing competition for kids hoping them to educate the folks at home about saving water. Of course, nothing helps as long as you don’t hold people accountable for their individual consumption.
Holding people accountable
Most of the societies don’t come with water flow meters for individual flats. So was the case with us and we figured that the only way to hold people accountable was by installing water flow meters for individual flats. With no single entry point of water inlets to individual flats, the flow meter installation work was easier said than done. The two bedroom flats had 3 separate water inlets — the first one for the kitchen, and two individual inlets for the bathrooms. The plumbing was such that the builder took the pipe from the nearest point in the duct to save cost. So there were two clear options ahead of us,
- Install individual water flow meters for every inlet to a flat.
- Connect all the individual inlets to a single point on the terrace and install a single water flow meter.
Option 1 of installing individual water flow meter was less work but getting a reading from inside the ducts monthly was practically impossible. Over time the labour involved in doing meter readings would offset the savings as well. Even the cost of maintaining remotely readable smart water flow meters was not manageable over time. So we narrowed down on the option 2 of doing extensive plumbing work to fix the multiple inlet issues by connecting all the inlets of a single flat to a single water source on the terrace where the water flow meter will be installed.
Reusing the treated water for flush tanks
Sewage Treatment Plant (STP) water reuse was another big ticket item on our agenda which we were sure will reduce a lot of water wastage. The biggest challenge there was replenishing of the STP plant to an execution point which enables the output water to be usable for flush tanks without compromising on health and comfort. In other words, the processed water should have parameters within the limits prescribed by the agencies and it must not have bad odour or colour.
The connecting of STP water to the flush tanks was a lot of work as well, but we decided to not measure the STP water used by individual flats to save cost on material and labour. This was a well-thought decision taking into consideration that we were going to have more processed STP water than what we can consume for flush tanks and garden area.
We decided to have two large tanks on one of the blocks close to the sewage treatment plant which will supply water to other smaller tanks for each of the blocks to which the flush tanks will be connected. The work was done after identifying safe column points with the help of civil engineers to keep the water tanks without causing any danger to the building.
In the image, two big black Sintex plastic tanks to the left are on a higher elevation metal fabrication which feeds the smaller black Sintex plastic tanks to the right. The lower tanks works on floats and the entire solution works on gravity. From the STP water gets pumped to the larger tanks which then feeds other smaller tanks by gravity as well. The smaller tank then supplies the water to all flush tanks and garden area.
Rainwater harvesting from all terraces
Bangalore receives a lot of rain even during the summer and we were sure of the savings we can make if we use it to recharge our water sumps and the bore-wells. We connected all our open terraces (which we clean every fortnight) to two separate filters and the filtered water is connected to our underground sumps and to the bore-well recharge points. This invariably saves us from procuring water from outside on many occasions even if the rains are for short durations like less than an hour.
Expenses incurred for the whole project
The overall cost of works is described here.
Flow meter project
25mm Dashmesh B class meter
Astral SDR 11 CPVC pipes
Astral plumbing fittings
Total cost comes around — 24,06,850₹
STP Water reuse project
Astral SDR 13.5 CPVC
Astral plumbing fittings
Sintex plastic water tanks
Metal and concrete tank mounts
STP additional tank and replenishment
Total cost came around — 22,81,927₹
Rainwater harvesting
Concrete tank for filters
PVC pipes for terrace to tank and sump connection
Filtering materials
Total cost — 500000₹
The million dollar question — Did it work? How much did it save?
We collected data. A lot of data during the work to be sure that at the end of it we will have concrete evidence to prove the results.
Reduction in water expenses
Water expenses drastically went down. It was surprising to see an average savings of 52% for a year. 2016–17 and 2017–18 we had no water metering, enough rainwater collection or STP water reuse. It was from the beginning of 2018–19 when we implemented these three water-saving measures.
Per flat savings
Since the flow meter is used for water billing the individual flats that are willing to save water is highly benefited. Since the water billing separated from the maintenance we now reduced the maintenance by 25 paise. Along with it if we measure the savings of individual flats the data looks like,
The average per flat savings after the completion of the project since April 2018 is around 5213₹ without taking inflation into account. Comparing this to the total investment of 30343₹ within five months of project completion we can conclude to break-even within 30 months.
To conclude
We would love to help you in order to save water in your society. Imagine the amount of water we can save if we take up this project everywhere? We have now reduced the tanker counts from 200 to 60 on average and that’s a lot of water and money to be saved.
This project was completely done in-house without involving any contractors. We used high-quality products that suit the application and didn’t compromise on quality anywhere.
