Breathable membrane enclosures for fecal sludge stabilization

Purpose

To test the use of breathable membranes to protect surrounding groundwater or floodwaters from contamination, while allowing fecal sludge to condense and stabilize.

Activities

We’re using “breathable membranes” to improve the performance and usability of basic latrines. Unlike most membranes used in environmental applications, these are hydrophobic in nature, which means they block the passage of liquid water and anything dissolved or suspended in the water, including pollutants and pathogens. However, they do allow water vapor to pass through. Because of this property, the membranes can be used as a latrine pit enclosure, allowing the sludge to dry while the heat from intrinsic biodegradation or from solar heat gradually expels water vapor, but preventing escape of particulate or dissolved constituents. This enables the protection of groundwater or floodwaters near the latrine pit, as well as the health of workers who often must empty filled pits under unsanitary conditions.

The breathable membrane is primarily intended to be used as an enclosure in waterless basic pit toilets worldwide, but its applications can be extended to uses in toilets with/without urine diversion, pumped latrine wastes, combined with other evolving toilet technologies, and commercial applications at larger scale.

Countries of activity

Location of main activity

Objectives

The goal of this project is to test the use of breathable membranes to protect surrounding groundwater or floodwaters from contamination, while allowing fecal sludge to condense and stabilize. We have verified the concept and are now quantifying the drying rates under differing conditions. We’re also running experiments with “mini-latrines” to observe behavior under fairly realistic conditions.

Filter tags

Bill & Melinda Gates Foundation East Asia & Pacific Emptying and transport (non sewered) Fundamental research and engineering Global North America Peri-urban Product design and engineering Toilets or urinals (user interface) University, education or research institution

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