Composting is an aerobic process in which bacteria and other organisms feed on organic material and decompose it. Composting (one material) and co-composting (two or more materials) represent generally accepted procedures to treat excreta. To start the composting process, the blended compostable material is placed in windrows (long or round piles). The `recipe' combines high-carbon and high-nitrogen materials. Air is added to maintain aerobic conditions, either by turning the windrows or by forcing air through them. To adequately treat excreta together with other organic materials in windrows, the WHO (1989) recommends active windrow co-composting with other organic materials for one month at 55-60°C, followed by two to four months curing to stabilise the compost. This achieves an acceptable level of pathogen kill for targeted health values. Adding excreta, especially urine, to household organics produces compost with a higher nutrient value (N-P-K) than compost produced only from kitchen and garden wastes. Co-composting integrates excreta and solid waste management, optimizing efficiency.