There is increasing interest in the concept of the circular economy and “closing the loop” in our use of various vital resources – including water, energy and mineral resources. This is driven not only by an interest in reducing the social and environmental damage linked to resource extraction and waste disposal, but also in optimizing the use of resources in preparation for the end of the era of cheap oil and raw materials.

While the focus has been largely on industry, the case for “closing the loop” in relation to wastewater, sanitation and food and other organic waste is becoming ever stronger.

REVAMP is a tool being developed at SEI for quickly estimating, visualizing and valuing the resources that could be recovered from a city’s organic waste streams: sewage sludge, faecal sludge, and food and other organic solid waste.


  • estimate the resources that could be recovered in various forms (such as plant nutrients, insect fat and protein, biogas);
  • estimate the total quantities of reuse products that could be produced;
  • estimate the potential revenues from different reuse products; and
  • compare the reuse options on the basis of energy content, nutrient content and potential revenues, to support decision-making on city sanitation and waste management plans.