Close to half of the population of New England and eastern Canada live in suburban and rural areas where wastewater from homes and businesses are treated in on-site septic systems. These systems trap solids and return cleaned water to the ground. Septage is the mix of solids and thick liquid that accumulates in a septic system's septic tank.
Specialized tanker trucks with pumps remove septage and transport it. In New England and eastern Canada, most septage is brought to wastewater treatment plants for treatment, where it adds to the production of sewage sludge and biosolids. Some septage is managed by:
Land Application of Septage
In many states and provinces, some proportion of the septage pumped from septic systems is treated and directly land applied to farm fields, just like Class B biosolids. It adds organic matter, nutrients, and moisture, helping improve the soil and crops.
Land application of treated septage is regulated by U. S. EPA and state environmental agencies; the rules are similar to those required for biosolids. For example pathogens must be killed, which is often done by raising the pH with lime treatment, and nutrients must be applied at the "agronomic rate" - just the amount needed to grow the crop.
Septage has been applied to this central New Hampshire farm field every year for decades to support the growth of grass for hay.