Ecological sanitation, often referred to as eco-san, is an approach to managing human waste that emphasizes sustainability and environmental protection. It aims to close the nutrient loop by treating waste in a way that allows it to be safely reused as fertilizer for crops. This method reduces pollution and conserves water, making it particularly beneficial in areas with limited resources. The core principle of ecological sanitation is to treat waste on-site, minimizing the need for extensive sewage systems. Techniques can include composting toilets and biogas systems, which not only manage waste but also produce valuable resources like compost and biogas for energy.