Quickly after the development of sewage and septic tank systems, the next problem arose: what to do with all that waste? After years of dumping their waste and sewage into watersheds and city streets, we needed a better, cleaner and safer answer. The answer became the Biosolids Program.
What Are Biosolids?
All waste, from sewage or septic, is left with what is referred to as sewage sludge which are the solid materials found in sewage. When properly treated and processed this sewage sludge becomes known as biosolids. Biosolids are a nutrient-rich, organic material that has effective environmental practices as a recycled material.
Treatment of Biosolids
Whether the sewage sludge comes from a sewage treatment system or a septic system, the sludge must be treated before recycled for use.
Sewage sludge from sewage treatment facilities goes through rounds of treatment before being classified as biosolids. Physical, chemical and biological processes are used to remove solids and clean the water. The leftover materials are then treated with lime to raise the pH level to reduce and eliminate pathogens and other organisms capable of transporting diseases.
Sewage sludge from septic systems goes through a different process of treatment based on classification. The class is determined by the presence of pathogens.
- Class A / Class AA – Class A septic sludge is already considered biosolids after going through biological bacterial processes in septic tanks that stabilize the organic material. Class A biosolids can come from private or commercial septic systems, but both are required to have less than 25% Class B material.
- Class B – Due to too frequent pumping or an unhealthy system, Class B septic sludge must go through additional treatment before it can be classified as a biosolid.
Class A biosolids are ready for immediate land application. Class B biosolids must go through treatment and sanitation before they can be recycled. This treatment involves an alkaline process that raises the pH levels of the organic material to reduce and eliminate pathogens and odor-producing microbes.
In Florida, the highest quality of biosolids are known as “Class AA.” These are distributed and marketed like other commercial fertilizers. Application is usually in rural areas in the form of liquid or cake application. There are approximately 95 permitted land application sites in Florida which are regulated by the Florida Department of Environmental Protection.
Land and Site Testing For Biosolids Program
Testing isn’t exclusive to just the biosolid organic material, the land where it will be used must all go through testing. Land application of biosolids is used as fertilizer to improve and maintain productive soils including agricultural fields, gardens, parks and reclaimed mining sites in all 50 states. But, the land also must need the help.
Various government agencies consult to determine if the land in questions is healthy without their help before applying biosolids to the land. To keep it simple, if the land is healthy then it isn’t helped.
Once the site is deemed acceptable, there must also be a nutrient assessment and plan to make sure that the biosolids continue to increase productivity, not hinder it. The land and application must also comply with various setbacks from groundwater, wells, and property lines.
Is It Safe?
Yes. The National Academy of Science has gone on record saying the process of recycling biosolids in land application is safe. It’s also important to note the selection process of biosolids when determining where they are applied. Class A materials are the only biosolids allowed to be recycled to land with public access and crop productivity. Class B biosolids are reserved for land reclamation that is removed from the public.
The process of applying waste and sewage materials to land has been around for ages—since the development of farming. The question of safety has also been present. With the modern day use of treated biosolids from septic systems and waste treatment facilities, the process of land application is safer and more productive.