Biosolids or sludge present in sewage water brings considerable challenges in treatment and disposal. Historically, biosolids were disposed of by methods such as landfill or ocean disposal. However, stricter environmental norms and costs associated with such disposal methods made them unviable.
Biosolids are a by-product of the sewage water treatment process. In the course of water treatment, the solids are separated from the liquid. They are then treated further with chemical as well as physical methods to produce a semi-solid product. known as biosolids. The contents of biosolids can include traces of metals, organic compounds such as phthalates, pesticides, phenols, polychlorinated biphenyls, dioxins and pathogens. The levels of these contaminants in biosolids are determined by the wastewater sources and the method used to treat the sewage water.
Biosolids are classified into two classes
Biosolids are generally classified into two classes: Class A and Class B. Each class of biosolids has a specific treatment mechanism.
Class A biosolids
Class A biosolids are a relatively cleaner variant of biosolids. They are treated to reduce pathogens to a level below the detectable. They can be turned into products such as manures which can be packed and sold to the public for use in agriculture.
Class B biosolids
Class B biosolids contain a considerable amount of pathogens. They can not be allowed to come in direct contact with the public. In developed countries, special permits and site restrictions are applied for treating class B biosolids. Class B biosolids are typically re-used for purposes such as land reclamation, or in highly managed forestry applications. These applications have been deemed safe for class B biosolids natural forces such as air and heat kill off the pathogens in these materials.
Treatment of biosolids
Biosolids are created in a variety of different forms. These include thermally dried granules, sludge cakes or digested liquids.
The following methods are used to treat biosolids
Dewatering: dewatering or thickening is a mechanical process performed using centrifuges, presses, and vacuum filtration. It reduces the water content in the sludge
Digestion: The digestion process uses bacteria to break down the organic matter in the sludge and reduce the volume of biosolids.
Composting: Composting involves aerobic fermentation of the sludge material.
Thermal drying: Thermal drying process converts the sludge into granular form which is 80%solid in nature. This is done by exposing the sludge to high temperature
Incineration: In the incineration process, the sludge is incinerated into ash with high-temperature oxidation.
Conclusion
Most biosolids are re-used in various applications. Class A biosolids are particularly important because they are packaged as fertilizers and sold to the public. However, the odor in biosolids can be a cause of concern for the general public. Inovar works to address the most pressing concerns of customers in water treatment. We have developed a special odor-free technology that eliminates odor from your water treatment plant when processing biosolids.
Inovar provides water treatment solutions of any capacity to serve a designated population size. All of our systems are highly automated, efficient, and cost-effective. Additions of odor-free technology can be made on client’s request.