Understanding Mechanical Dewatering and Its Purpose

Mechanical dewatering aims to reduce sludge volume and, ultimately, the ultimate disposal by removing water. This process is commonly required at STP before the disposal of sludge and biosolids or as a prelude to further treatment or stabilization.

What is Mechanical Dewatering?

Mechanical dewatering separates sludge (residual sludge from wastewater treatment plants or fecal sludge from on-site sanitation) into a liquid and a solid part. It makes the sludge easier to handle, transport, compost, or incinerate, reducing landfill disposal volume. Removing moisture from sludge with mechanical dewatering systems is much less energy intensive than evaporation and far more cost-effective for most industries. A 1-4% change in moisture can result in hundreds of thousands of dollars in gas savings annually for a single evaporator!

Dewatering Processes

Dewatering is crucial for many industries, from construction and wastewater treatment to mining and agriculture. It separates water from solids and prevents environmental problems like erosion and flooding.

There are several different dewatering processes, and choosing the right one for your project will be essential to your success. These include wellpoint, open sump pumping, eductor wells, and deep wellpoint.

These methods diverge groundwater into good points in the excavation area to keep the excavated part dry. This ensures a stable work area and prepares it for excavation and cement footing.

Sludge Dewatering

Sludge dewatering is a process that removes water from sludge (residual sludge from wastewater treatment plants or fecal sludge from on-site sanitation such as septic tanks). This allows for easier handling and less expensive transportation. Several methods can dewater sludge, including presses or centrifuges, filtration, and drying beds. Sludge dewatering is often done for many reasons, such as to reduce the volume of sludge, to reduce haulage costs, or to enable the sludge to be used in compost, small or large-scale incineration, or disposal. Mechanical sludge dewatering is an essential part of the sewage treatment process. It includes using various equipment, such as vacuum filters, pressure filter presses, and centrifuges. The main purpose of mechanical sludge dewatering is to reduce sludge volume.

Biosolids Dewatering

Biosolids are solid materials produced from the treatment of wastewater (sewage). They are then applied to the land for nutrient recovery and soil improvement. These waste materials are beneficial in reducing the environmental impact of disposal methods such as ocean disposal, landfills, or incineration. They can also be used as soil conditioners to improve crop growth and enhance surrounding soils’ health. The biosolids undergo mechanical dewatering to produce a more liquid or semi-solid state. This enables them to be transported and applied to the land using tractors, tank wagons, trucks, or other special application vehicles.