Human Waste

Human waste refers to the urine and faeces that all people produce. Faeces contain a multitude of pathogens that, when improperly contained or handled, can cause serious illness and pollute the environment. For example, diseases such as cholera, typhoid and dysentery are caused by pathogens excreted through faeces. The simplest way to reduce the spread of these diseases is through well-managed sanitation: even the most basic toilet that contains human excreta can significantly reduce the prevalence of these common illnesses. Unfortunately, nearly 3 billion people still lack access to safe sanitation, and every year nearly 500,000 people die from exposure to excreta-related pathogens. However, human waste also has benefits: the carbon in faeces can be easily converted into energy through anaerobic digestion, while urine rarely contains infectious pathogens and is highly concentrated in valuable nutrients such as nitrogen and phosphorus, which are important for agriculture.

Though toilets are a necessary first step to reduce the spread of faeces in the environment, further treatment is required to ensure the complete destruction of pathogens in the human waste. Most cities in rich countries operate a sewer system to convey human waste and wastewater to a treatment facility where a combination of chemical and/or biological treatment ensures that the resulting liquid, or effluent, is pathogen free, and suitable for discharge into the environment. However, in rural settings or in countries where sewer systems don’t exist, the excreta must be collected in tanks and transported by truck for treatment. Though simple in concept, this type of sanitation system requires complex cooperation between many stakeholders, a significant amount of time and fuel for transport, and treatment technologies that can be operated with few resources in complex environments.

Our research related to human waste asks several questions:

1. Why is safe sanitation not yet universal and what policies and interventions can accelerate the rate of toilet use?;
2. What are the technologies that are effective enough to destroy pathogens, yet simple and affordable enough to install in the most complex environments?; and
3. How can we harness the water, nutrients and energy contained in human waste in beneficial forms?
   

Safe sanitation is not only a health issue, but a human right; and because pathogens and toxins can travel in air, through soil, and down rivers without respecting borders or income, it is a human right that affects all of us.