3+1 R’s of Direct Water Footprint Conservation

In my second post from this series — Zooming into India’s water bubble, I emphasised on the need for every Indian citizen to participate in continuous water conservation efforts in their homes and elsewhere. Water conservation has become an all the more necessity in view of the Corona virus pandemic as explained in my last post — Has Covid-19 pierced the water bubble?

Water crisis prevailing in both rural and urban India has different dimensions and characteristics depending on the availability of freshwater resources, water supply systems and water usage patterns associated with lifestyle choices. Being a city dweller, I will focus this discussion on the conservation of water in urban households.

To have a holistic approach on water conservation, it is necessary to understand and be aware of the invisible reality of water consumption — the water footprint (WF) of our houses.

So far so long, we seem to have concern only for saving the water we use for our household activities like cooking, drinking, cleaning, washing, toilet flushing, bathing and all other direct uses of water received at our tap points and water using gadgets in the house. The figure below shows the direct use points in a domestic city house. This water is visible and in terms of water footprint it measures the amount of fresh water consumed for all household activities. This is called Direct Water Footprint of the house.

Figure 1: A layout of direct water use points in domestic city households

On the other hand, we consume huge quantities of invisible water in the foods we eat as well as the commodities and services we use in our houses. This is called Indirect Water Footprint or Virtual Water Footprint.

Virtual water of a product is measured as the amount of fresh water used to produce the product throughout its production history.

In the fast growing economy of India, increasing share of the urban population is deemed to surpass 50% mark by 2050 from its present share of 35% as shown in the figure below.

Figure 2: India Population Forecast (Source: Worldometers)

The increasing trend of consumption due to ever increasing demand of consumerist lifestyle choices results in an increase of water footprint of Indian cities. This is the Invisible Reality of water consumption as I mentioned earlier. The enormity of the problem of water crisis in Indian cities will be better understood due to the increase of city population shown in Figure 2 as against the backdrop of diminishing fresh water availability with time shown in Figure 3.

Figure 3: Annual Per Capita Availability of Water (Source: Reassessment of water availability in India using space inputs by CWC)

As the reasons behind the water crisis lie in everyone’s life, everyone choosing to be the consumer of this special commodity — water, directly and indirectly, should take shared responsibility with national impact.

Hence, it is very much relevant to conserve both Direct and Indirect water footprints of our houses. The discussion that follows will, therefore, be in two parts. Part I and Part II on conservation of Direct and Indirect water footprint, respectively, followed by case studies.

PART I — CONSERVATION OF DIRECT WATER FOOTPRINT IN URBAN HOUSEHOLDS

Before we enter into the discussion on how to conserve, let us first review the systems or methods of water supply in urban households. The three different ways urban people get their daily supply of potable water are enumerated below:

1. Centralised water supply system run by government agencies like municipalities or municipal corporations.
2. Bore wells or hand tube wells, dug and maintained by the owners of the individual houses or housing complexes. Hand tube wells at street side locations are also dug and maintained by municipality or municipal corporations.
3. Water tankers provided by government agencies and also by private suppliers in case of emergency.

A flow chart of the centralised water supply system is shown below.

Figure 4: Flow chart of centralised water supply sytem

3 R principles of conservation

The 3 R principles — REDUCE, REUSE and RECYCLE are very much in vogue for solid waste management. The same principles can be used effectively to conserve water footprint in urban households.

3 R Principles of Water Conservation. Image courtesy: srip from Flaticon

REDUCE — First and foremost we have to reduce over-consumption of water in our houses. To do that effectively, we must know the causes. One can analyse this through an Ishikawa diagram named after Dr. K. Ishikawa from Japan. It is also called cause and effect diagram.

Figure 5: Ishikawa (Cause & Effect) Diagram for over consumption of water in city houses

A thorough analysis of the causes of over-consumption under different categories as depicted under the diagram is shown in the tables below. It should be realised from the analysis that the causes of over-consumption of water in our houses lie mainly in MAN and METHOD related categories.

REUSE — A generic scenario in our day-to-day use of water in our houses is that once the water is used, it goes down the drain and that’s the end of it. Instead this water can be redirected for reuse.

Water once used for household activities except toilet flushing, is called Grey Water. This Grey Water can be reused for many household applications in as it is condition, or with minimum physical and/or chemical treatment.

Reuse opportunities which may be available in a city house are shown in the figure below.

Figure 6: Opportunities in city households for reuse of waste (grey) water

RECYCLE — The Recycle of waste water in urban households seems to be very similar to reusing it. In the true sense, recycle of waste water is the act of converting the same to be used as fresh water. The system and technology to do that is elaborate and complex, not possible in domestic households. The black water generated in the toilet is discharged along with grey water in the sewage line, and can be treated in recycling plants for effluent treatment. To convert the same to drinking quality or at least to a quality sufficient for town irrigation can go a long way in avoiding pollution of rivers, canals, and sea.

Rainwater as a substitute to fresh water supplied by municipality

Besides the 3 R principles of water conservation, there is a 4th R — “Rain Water Harvesting” (RWH). In Indian cities, it is emerging as an important potential substitute of municipal-supplied fresh water for urban household requirements. A discussion on the opportunities and benefits of RWH in Indian city houses will be covered in my next post with a case study followed by Part II — Conservation Of Indirect Water Footprint.