Since the late twentieth century, nations have implemented treatments to remove nitrogen and phosphorus from bioorganic wastes to reduce the eutrophication of surface waters. The most common processes to remove nitrogen and phosphorus from wastewater are biological and chemical denitrification and chemical precipitation. Solid wastes and biosolids from waste treatment have traditionally been dumped in landfills or the ocean, or applied to land, while recently, waste biosolids have been incinerated which reduces the volume of waste but still produces ash. Overapplication of manure or treated biosolids to land can result in nutrient buildup and runoff that also results in eutrophication of surface waters. Odors, pathogens, heavy metals, or other micropollutants such as drugs and hormones are also a source of concern for land application or release of effluents to waterways. To address these problems, alternative systems and processes are being developed to provide new uses for waste while reducing contamination and thus their harm to human and environmental health.