Sludge Dewatering:
Definition & Overview
What is sludge dewatering?
Sludge Dewatering is the practice of removing liquid from sludge to produce drier, more solid sludge cake. Sludge dewatering reduces the weight and volume of sludge for easier, safer, and more cost-effective sludge disposal.
What are the most common sludge dewatering methods?
The most common sludge dewatering methods are (1) mechanical and (2) non-mechanical.
The mechanical sludge dewatering method applies physical pressure to squeeze liquid out of sludge.
The most common mechanical sludge dewatering equipment include:
Plate presses
Filter presses
Fan presses
The non-mechanical sludge dewatering method applies energy to draw liquid out of sludge whether in the form of electricity as with electro-osmosis, or heat as with thermal drying evaporation.
The most common non-mechanical sludge dewatering equipment include:
Electro-osmosis dehydrators (ELODE)
Convection thermal dryers (belt dryers, drying beds)
Conductive thermal dryers (paddle dryers)
Wastewater treatment plants often dewater sludge in two stages, utilizing both mechanical and non-mechanical methods:
First, mechanical sludge dewatering equipment like a screw press physically forces water out of sludge and produces sludge cake. These mechanical sludge dewatering machines typically dewater sludge from 2%DS to 20%DS and are limited in how much water they can remove from sludge.
Second, non-mechanical sludge dryers like ELODE further dewater the sludge cake from the first stage, usually to 40%DS and above.
What are the benefits of sludge dewatering?
Benefits of sludge dewatering include:
Reduced waste volume
Removal of liquid from sludge reduces the weight and volume of the final waste product, reducing the ultimate cost of disposal.
Reduced storage and transportation costs
Lighter, drier, more compact solid sludge cake improves operations by reducing costs for subsequent handling, storage, processing, transfer, end use, and disposal.
Greater landfill acceptance
Drier sludge cake reduces groundwater leachate contamination and improves landfill operator safety by preventing landfill mudslides.
Fewer leaks and spills
Drier cakes virtually eliminate the risk of leaks or spills during transportation and storage.
Water reuse and recycling
Water removed from sludge can be treated to remove contaminants, then reused as greywater in municipal or industrial processes, lowering overall water demand.
Automated operations
Modern sludge dewatering equipment offer automated components, reducing the amount of labor required to run dewatering operations.
Easier incineration
Drier sludge cake can be incinerated without burning additional fuel.
Land applications
Dried sludge cake can be used as fertilizer or biochar in some jurisdictions.
Dewater sludge with ELODE
Our ELODE non-thermal sludge dryer further dewaters sludge cakes produced by mechanical sludge dewatering equipment. Compared to thermal dryers, ELODE is more cost-effective, energy-efficient, and has a small footprint.
Save on operating costs by reducing your sludge cake by 50% or more in just 3 minutes with ELODE.