When we say biosolids, we think about some kind of organic fertilizers made from domestic waste, right? There is no deeper understanding of how the waste was treated and how it came to be the way it is—safe to use for crop production and vegetation. In turn, most are left wondering if biosolids is the future of farming.
The treatment of wastewater has two end-products—effluent and biosolids. Effluent is discharged to a receiving water—either a stream or a river. On the other hand, the solids or biosolids can be beneficially used when further treated by another facility. Or, as some have done in the past, the solids are either dumped in landfills or incinerated.
The process of treating wastewater varies from plant to plant, but in general, a treatment facility works like this: the wastewater goes through a preliminary treatment after which it will be separated with the liquid going through aeration and chlorination. The solid or raw sludge, on the other hand, goes through a separate process of primary and secondary digestion before being filtered, pressed, and dried.
After being packed, the solid materials derived from the domestic wastewater will then be disposed off in a landfill or turned into organic fertilizers. There are basically three ways to manage biosolids: through its beneficial use, through incinerating, and through landfilling.
The use of biosolids as organic fertilizers is beneficial and essential to keeping the soil nutritious enough for vegetation and crop production. The application rates of biosolids depend on how it is going to be used—on farmland, public works projects, forest land, landscaping activities, and land reclamation. There are many techniques to apply biosolids—either direct land application, composting, chemical stabilization, or heat drying.
Biosolids can also be disposed off by firing it with high temperature in an enclosed device. It will then turn into ash that should be properly disposed in another location.
Landfills is the most common way of disposing garbage, including semi-hazardous waste. There are two kinds of landfills—monofills *sludge-only landfills) and mixed solid waste. Landfills are required to have liners, groundwater monitoring, and comply with other regulatory design and operational criteria.
With the use of biosolids as fertilizers, the method that benefited from it the most is landfilling. Instead of the wastewater sludge being carted off to landfills, it can now be turned into fertilizers that will, in turn, put back needed nutrients into the farming soil.