First, it is important to understand what comprises sludge in normal cases. By definition, sludge is a slurry, semi-solid, thick and sometimes muddy waste that can originate from different sources such as industrial processes, natural settings with liquid flow, homestead sewage systems and so on. How heavy sludge is depends on its source but it is often a mixture of solids and liquids, which determine its ultimate thickness. There are various types of sludge that can be described as follows.

Types of Sludge

Sewage water or waste water sludge originates from industrial processes or homesteads. It is a by-product was various activities that take place within these sources. Often, it contains a lot of organic matter, many pathogens and sometimes other components like heavy metals. When this type of waste is treated to separate solids and liquids meeting specific standards like reduction of pathogens, it is called biosolids. The term refers to the solids separated because of their organic matter component.

Fecal sludge refers to human waste that is contained in pit latrines and septic tanks or other sanitary system present. To gain this definition, the human waste as the primary organic matter should not be transported in sewage systems. Notably, this type of waste is less likely to contain industrial components such as various chemical and the heavy metals mentioned above.

Industrial Sludge is the by-product of various activities happening within different industries. This type of waste is present in the settings without being transported in a sewer system. Therefore, its components depend on specific activities that are taking place within its sources

Fuel/Oil Sludge is found in engine crankcases and fuel tanks of vehicles that transport fuel. It is often a mixture of dirt, water and remnant fuel and at times metal particles. The exact composition of this sludge is dependent on the handling of the fuel being transported.

Finally, Biliary Sludge is a medical term that refers to the biological components of gallbladder, an organ that is responsible for storing and concentrating bile juice made in the liver of a living organism. Its composition is primarily mucus, cholesterol, calcium salts and bile occurring as a suspension. Therefore, it is important not to confuse between biliary sludge and other types of sludge described above in common usage of the terms.

Uses of Sludge and its Management

Sludge can become an environmental hazard if not well managed or handled. As such, it is important to understand how to properly take care of it when it is produced in any setting. Also, sludge can have various applications or uses especially after it has been treated. The following are ways of properly managing sludge as well as its potential uses. |Kindly note that the two processes, management and use, are intertwined because mostly both are required when it comes to its proper handling.

Landfilling is the most common way of properly managing sludge especially on a mass scale. In this process, raw sludge is typically dumped into sanitary landfills. Over time, this process can become an environmental hazard because if excessive sludge is deposited in an area, it overpowers natural processes of decomposition. As such, this sludge can lead above ground or into water aquifers deep below it. Also, using this process excessively poses the risk of soil poisoning and concentrating heavy metals in the soil, which becomes a hazard if such soil was to be used for agriculture or other human activities in the future.

Incineration is the burning of sludge at very high temperatures enough to evaporate liquids present and turn the solids into ash or oxidized components. The applicability versus hazard posed by this method depends on the actual components of the sludge burnt. If poisonous gases are released to the atmosphere it becomes an issue. Also, note the importance of not releasing gases that contribute towards the green effect which is seriously causing the current climate change issue. Handling of the ash components left of incinerated sludge depends on their exact composition.

Land Use or Application as Fertilizers is a process where properly treated sludge is turned into organic matter or chemicals that can be reapplied to land as soil fertilizers. Note that this process can only be used safely if its composition does not entail heavy metals. Additionally, proper treatment means eliminating pathogens that could infect humans, soil and other living organisms in land used for agriculture or where these applications are made.

Digestion is a process entailing either aerobic or anaerobic decomposition of sludge matter by microorganisms that have this capability. Such microorganisms could be bacteria, fungi or protozoa but must not be infectious or pathogenic. Anaerobic digestion of sludge is a common process that produces gases such as methane that can be used as energy sources. However, as mentioned before, it is important to care for the environment and methane is listed as one of the greenhouse gases.

Thickening/Dewatering comprises processes that turn sludge into a solid or cake like matter. These processes remove liquids present leaving behind the solid. They include processes such as filtration and centrifugation. Regardless of the process used, the solid left behind is easier to transport to disposal sites.

Having known about the most common types of sludge and its proper management or use, our next blog will cover tips for constructing a proper sludge management system. Be sure to check it out. As Francsoft Construction Company, we’re committed towards using green and environmentally friendly methods when working with different clients who want help with sludge management or use. Therefore, we emphasize on the need to protect our environment for the sake of sustainability and future generations. Thanks for reading!!