The Environmental Pyramid

A powerful meme in environmental engineering is the pyramid.  I first encountered this when I was working on hazardous waste in the 1980’s.  In that context, the pyramid has the more preferable alternatives (e.g. waste prevention) towards the base.  In recent years, the inverted pyramid has become more popular, and I think it more preferable, since it includes the more preferred alternatives on the top.  An example of this in the waste management context is:



This meme has broad utility outside the waste management hierarchy, and integrates well with the general movement towards sustainability.  Let me give two examples.

In water supply when additional sources are needed, this meme might include (going from the top of the inverted pyramid to the bottom):

  • Use reduction (conservation) (most preferred)
  • Internal recycling (e.g. recycling within a building or block — for example, use of cooling water for toilet flushing)
  • System wide reuse (and possible dual supply)
  • Abstraction of water from a new source and treatment

In energy supply, a possible set of hierarchies might be:

  • Demand reduction (conservation, incentives, …)
  • Internal recycling (heat recovery; energy recovery from on-side discarded materials)
  • System wide re-engineering of energy consumptive processes and operations
  • Abstraction of new sources (with ranking based on environmental/sustainability metrics)

Using such memes, in making decisions it should be incumbent on decision makers (and their consultants) to indicate why upper levels of the pyramid might not be feasible, might be too costly, might impose other environmental risks, etc., before proceeding to lower levels of the pyramid.

How do we train/retrain students, practitioners and the public towards this goal?