Stuchtey, M. Rethinking the Water Cycle: How moving to a circular economy can preserve our most vital resource

With Uber and AirB2B, we have all heard of the “sharing economy”, but the “circular economy” has noWith Uber and AirB2B, we have all heard of the “sharing economy”, but the “circular economy” has not gained as much popularity in public conversation. A recent article by Martin Stuchtey in McKinsey&Company’s online newsletter addressed the circular economy in reference to water. The title of the article, "Rethinking the Water Cycle: How moving to a circular economy can preserve our most vital resource," linked the two concepts, circular economy with water conservation.

The Ellen MacArthur Foundation defines "circular economy" as constructed to produce goods "for remanufacture, . . .  for disassembly, . . . for 'decomponentization'", allowing the reuse of goods. The Foundation explains that such a system would have "the materials that sit within the global economy that currently flow off the end of the conveyer belt can go back in"  (Navigating the circular economy: A conversation with Dame Ellen MacArthur, McKinsey&Company). Stuchtey called this a "zero-waste imperative".

Stuchtey begins the article by affirming the strain on natural resources with population growth and an expanding middle class. The current economic model that supports the maintenance, growth, and expansion of production to provide goods to current and future populations, the supply chain, is linear. Therefore, Stuchtey contends that water used in these processes gets degraded as it moves through the chain. Stuchtey views the application of water rather than the political or economic organizational management of water as the primary cause for pollution.

 

Transforming the supply chain from a linear to an iterative one, evolves from three basic principles, according to Stuchtey:

"All durables, which are products with a long or infinite life span, must retain their value and be reused but never discarded or down-cycled (broken down into parts and repurposed into new products of lesser value).

All consumables, which are products with a short life span, should be used as often as possible before safely returning to the biosphere.

Natural resources may only be used to the extent that they can be regenerated."

The result of this change in how the supply chain works influences the public view of water as a product, a resource, and, in terms of water management, as a utility.

 

Viewing water as a product focuses on reuse and water quality, "something that is processed, enriched, and delivered". As Stuchtey described, water "should be kept in a closed loop under zero-liquid-discharge conditions and reused as much as possible. The major goal is . . . to manage the integrity of the closed-loop cycle". Stuchtey pointed to the Pearl Gas to Liquids water recycling plant in Qatar, the largest of its kind. To attain the water quality that a circular system aspires, requires a radical change in the use and treatment of water. Stuchtey lists the chemicals that should not contaminate water, "estrogenic hormones, toxic ink . . .or textile dyes". He does differentiate types of water and their quality levels and purpose--consumable water, freshwater, and graywater.  

 

In the water purification process of a closed-loop system, the outputs can contribute through energy extraction, nutrient extraction, and the end product--reused water. The Billund BioRefinery in Denmark "sterilizes the sludge and makes it more biodegradable". Nutrients derived from water purification include potassium hydroxide, polyhydroxyalkanoates, other polyesters, and ammonia.

 

Stuchtey's premise for water as a resource stems from the balance of supply and demand. His model conforms to the basic hydrologic cycle as a closed system. He argued for the enforcement the principle of supply and demand to rivers and aquifers, watersheds, forests, and agricultural lands. This would encourage such practices as aquifer recharge, drip-irrigation systems, and irrigation scheduling, among others.

 

Lastly, water as a utility concentrates on the primary assets of a utility, its infrastructure. Stuchtey estimated the total worth of the infrastructure at $140 billion. Stuchtey suggested ways that utilities could generate revenue from its existing right-of-ways, from its sludge that generates heat, from creating conservation credits, from infrastructure asset reuse, and from using renewable energy sources.

 

In the final section