Before the turn of 1950, most communities and residents in the United States discharge their wastewater into rivers and streams. There’s little or no treatment at all which leads to the pollution of said waterways. Populations increased and the practice continued but soon thereafter, the ability of rivers and streams to handle the waste being discharged into it declined. This caused the quality of the water there to deteriorate and therefore, it could not be used to handle menial household jobs. As a result, sewage sludge and biosolids entered the conversation.
The concerns about water degradation led the United States government to construct a wastewater treatment system during the 1950s and the 1960s. The result is a better quality water in rivers and streams. However, there’s also one byproduct that we don’t know then how to deal with: sewage sludge. Technically, sewage sludge is a semiliquid waste obtained from the processing of municipal sewage. Once treated and gone through various treatment processes, the sewage sludge will turn into biosolids. This, then, are used as sound alternative to chemical fertilizers.
Approximately 99% of the wastewater stream that enters a treatment plant is discharged as “rejuvenated water.” The remaining 1% is a dilute suspension of solids that has been filtered through the treatment process. These wastewater treatment solids are commonly referred to as sewage sludge.
Difference between sewage sludge and biosolids
Biosolids is defined as treated sewage sludge. This is sewage sludge that has gone through sufficient treatment for stabilization and pathogen reduction. It is of high quality and without any traces (mostly) of pathogens and other contaminants that it can be applied on land, farms, ranches, and the like. The term biosolids is being used to distinguish high quality and treated sewage sludge from raw sewage sludge that contains large quantities of pollutants and contaminants.
Biosolids is also produced through a biological process, further distinguishing them from sewage sludge produced by industrial plants. However, the problem is that there’s criticism in the use of the term because some see it as a way to disguise the real source and nature of sewage sludge. This means that communities allow the land application of biosolids even though it may be sourced from industrial plants.
Sewage sludge, on the other hand, refers to water that was used in urban and suburban area homes or businesses. This water is used for washing, bathing, and flushing toilets. To remove the chemicals and pollutants, the water must go through various processes that will turn it into biosolids.