Sludge. Just pronouncing the word may result in a grimace for most. Sludge is the semi-solid material left over from industrial wastewater or any sewage treatment processes. Even the settled particles collected from a water treatment process is referred to as sludge. Raw primary sludge is primary fecal material, while secondary sludge consists of organisms that help remove contaminants from wastewater. But what do you do with it?

There are many options to contain and treat sludge which result in turning into biosolids (compacted sludge). Such procedures include digestion (using living organisms), thickening, drying, lime/alkaline stabilization, and dewatering. The more effective the wastewater treatment, the higher the concentration of biosolids as an end result — which can save companies a ton of money. Sludge dewatering systems are generally the best option.

Sludge dewatering systems are a useful tool when it comes to treating industrial wastewater. Dewatering is the process of removing water from solid materials, which could be contaminated, and soil. Sludge dewatering systems are the last step in the water treatment process because they can extract the water and reuse it.

This beneficial process saves tons of water every year, and approximated 400 billion gallons of water are used every day in the U.S. alone — so every bit counts. The wastewater treatment process usually results in high water content in the sludge, and this needs to be extracted so that the sludge does not take up too much space in the dewatering facility.

Many industrial companies produce contaminated water and need to dispose of it properly, but water is very dense (thus making it heavy), and the heavier and more sludge a company creates, the more expensive it is to get rid of. Thus construction dewatering and mine dewatering systems were created to remove as much water as possible to lighten the load and, as a result, decrease disposal costs.

Usually, sludge dewatering systems literally squeeze the water from the sludge. However, depending on what type of industry a company is in and how they want to dispose of their sludge, different methods can be used:

• Pressure filtration dewatering
• Sludge dewatering centrifugation
• Vacuum filtration
• Air sludge drying
• Belt press dewatering filtration

Primary and secondary wastewater treatments can remove up to 85 and 95% of pollutants from wastewater before it is treated with disinfectant. Sludge dewatering can often remove whatever contaminants that are left suspended in the water.