Thousands of Litres of Sewage, No Way to Treat It

Refugee camps and disaster-affected areas housing tens of thousands of people generate enormous volumes of faecal sludge from pit latrines, septic tanks, and holding tanks. In a camp of 20,000 people, this can exceed 10,000 liters per day. Current emergency response relies on desludging trucks to transport waste to distant disposal sites — often open pits or poorly managed landfills that contaminate groundwater and surrounding communities. When trucks break down, fuel runs short, or disposal sites reach capacity, untreated sludge accumulates in the camp. UNICEF's TPP calls for field-deployable treatment products that can process faecal sludge to safe discharge or reuse standards on-site, but no product meeting emergency deployment requirements exists at scale.

Inadequately managed faecal sludge is a primary driver of disease outbreaks in displaced populations. Cholera, typhoid, and hepatitis outbreaks in refugee camps are frequently traced to faecal contamination of water sources and living environments. The problem compounds over time: camps originally planned for months often persist for years or decades, and the sludge management systems designed for short-term use deteriorate. With over 100 million people forcibly displaced worldwide as of 2024, the volume of untreated faecal waste generated in humanitarian settings is a public health crisis that is both growing and systematically under-addressed.

Conventional wastewater treatment plants require permanent infrastructure, continuous power, skilled operators, and months of construction — incompatible with emergency timelines. Waste stabilization ponds (the simplest treatment approach) require large land areas (1-3 hectares for a mid-sized camp) that are often unavailable in congested camp settings. Lime treatment can disinfect sludge but produces large volumes of alkaline waste that must be disposed of, does not reduce volume, and requires ongoing chemical supply chains. Small-scale constructed wetlands and planted drying beds work in development contexts but take weeks to establish and months to achieve treatment capacity. Pit additives (marketed as accelerating decomposition) have shown limited efficacy in controlled trials. The unifying failure mode is that all proven treatment technologies assume either permanent infrastructure, large land availability, long setup times, or continuous supply chains — none of which exist in acute emergency settings.

The UNICEF TPP specifies: rapid setup (days, not weeks), compact footprint, no requirement for grid electricity, achieves pathogen reduction to safe discharge standards (>=4 log reduction), operable by non-specialist staff, and transportable in standard shipping containers. Promising approaches include: (1) thermal treatment units (e.g., the Janicki Omni Processor concept — burning dried sludge to generate energy), (2) chemical-thermal lime stabilization with heat recovery, (3) membrane bioreactors scaled for containerized deployment, and (4) electrochemical treatment using solar-powered electrode systems. None has been validated for the specific combination of throughput, pathogen reduction, and field conditions the humanitarian context demands.

A team could design and test a solar-powered electrochemical faecal sludge treatment unit sized for a 500-person camp section (~250 liters/day), measuring pathogen log reduction (E. coli as indicator), chemical oxygen demand removal, and energy consumption. The engineering challenge is achieving adequate treatment at throughput scales compatible with camp operations while running entirely on solar power. Alternatively, a team could prototype a containerized lime-thermal treatment system that combines quickite lime addition with passive solar heating, measuring pathogen inactivation rates at different lime doses and temperatures under simulated tropical conditions. Relevant disciplines: environmental engineering, chemical engineering, humanitarian engineering, public health.