Recovery Technology

In any given context, the technology choices for sanitation system components generally comprise the following factors:

  • Socioeconomic characteristics
  • Cultural considerations
  • Availability of space
  • Soil and groundwater characteristics
  • Type and quantity of input products
  • Local availability of materials
  • Desired output products
  • Availability of technologies for subsequent transport
  • Financial resources
  • Management considerations
  • User preferences
  • Maintenance requirements

These factors are both interdependent and delimiting. Ultimately, decisions are made according to what is feasible, what the local priorities are, and what is necessary.

What is exciting about sanitation technologies today, beyond the growing number of solutions that mitigate wastewater pollution and its impact on the oceans, is that the industry recognizes this as a growth area, and that human waste products have great value, both in the marketplace and the environment. It is a game changer for the health of oceans, the environment, and for human beings. This section highlights some resource recovery technologies that are part of this change.

Biochar is a stable form of carbon, with a charcoal-like appearance, consisting of carbon (70%), hydrogen, oxygen and nitrogen (CTCN). It is made by burning organic material in a controlled process called pyrolysis. The table below provides an overview of the process typically used to recover biochar for reuse.

Data chart of resource recovery potential of human excreta
Resource recovery potential of human excreta (Source: Time)

The process is efficient, producing biochar that is a fine-grained, highly porous structure that can be used as an ideal soil amendment for carbon sequestration (Lehmann, 2007). It is useful for soil amendment and remediation (Agriculture Nutrient Management and Fertilizer), as fuel (Biochar Stoves), and as water treatment (Biochar-Based Water Treatment Systems) among other uses. Biochar from human waste is a high value resource. While human waste is the main source of interest in this context, it is important to be aware that crop residues, yard waste, food and forestry wastes and animal manures are also viable and valuable targets for creating biochar. Currently, agricultural, municipal, and forestry biosolids are burned or left to decompose, releasing CO2 and methane into the air. Livestock as well as human wastes are significant sources of ground and surface water pollution. Unsafe disposal from on-site sanitation negatively impacts public and environmental health in developing regions. Implementing biochar production technologies (Biochar Technology) protects surface and groundwater, directly affecting ocean health and sustainability.

Resource recovery and biochar characteristics from full-scale fecal sludge treatment and co-treatment with agricultural waste
Resource recovery and biochar characteristics from full-scale fecal sludge treatment and co-treatment with agricultural waste (Source: Krueger et al., 2020)