Sludge Dewatering Glossary

B

Belt Press Sludge Dewatering

A belt filter press dewatering machine sandwiches sludge between two tensioned belts to mechanically press liquid out of sludge, producing drier cake.

C

Centrifuge Sludge Dewatering

A centrifuge sludge dewatering machine rapidly rotates a cylindrical bowl to drive liquid out of sludge in order to produce drier sludge cake.

D

Disposal Costs

Disposal costs refer to the expenses related to disposing sludge / sludge cake, including trucking and landfill tipping fees.

Dry Solids (%DS)

Dry solids refer to the solids remaining (volatile and fixed) after the original sludge is dried at 105 degrees Celsius. Eg. sludge cake exiting ELODE may be 45%DS.

Leachate

Leachate is generated when water percolates through waste, dissolving and transporting contaminants at landfills and WWTPs.

Pyrolysis

Pyrolysis thermochemically breaks down dried sludge into more manageable, less harmful compounds, and creating useful products like biochar, syngas, and bio-oil.

E

Electro-osmosis is a chemical separation technique where an electrical current is applied to drive a positively-charged liquid like water through a solid like sludge cake toward a negatively-charged cathode.

L

Landfill Tipping Fees

Landfill tipping fees refer to the price per ton it costs to dispose of waste at a landfill. These fees represent a large portion of sludge disposal costs.

P

PFAS

Per- and polyfluoroalkyl substances (PFAS) are a group of over 6,500 synthetic chemicals that pose new challenges in biosolids and sludge management.

S

Screw Press Sludge Dewatering

A screw press utilizes a rotating screw within a drum, compressing sludge against a permeable filter to expel water and produce drier sludge cake.

Sewage Treatment

A sewage treatment plant (STP) is a type of wastewater treatment plant focused on households and businesses, as opposed to industrial or agricultural organizations.

Sludge

Sludge is a mixture of liquid and solids, typically produced in industrial, water, wastewater, and sewage treatment processes.

Sludge Cake

Sludge cake (aka. cake) refers to the drier waste output produced from sludge dewatering.

Sludge Conditioning

Sludge conditioning prepares sludge for thickening and dewatering, usually by applying chemicals to improve the dewatering characteristics.

Sludge Dewatering

Sludge dewatering removes liquid from sludge to produce drier cake, reducing waste weight and volume for easier, safer, and more cost-effective disposal.

Sludge Dewatering Equipment

Sludge dewatering equipment removes liquid from sludge to produce drier cake. Eg. ELODE, thermal dryers, centrifuges, belt presses, screw presses, etc.

Sludge Dewatering Methods

Sludge dewatering methods refer to mechanical (eg. centrifuge, screw press) and other (eg. electro-osmosis, thermal drying) ways of drawing liquid from sludge.

Sludge Digestion

Sludge digestion reduces the amount of organic matter and microorganisms through aerobic, anaerobic, and other biological processes.

Sludge Disposal

Sludge disposal refers to how an organization gets rid of its dewatered sludge, typically through landfills, incineration, or recycled as fertilizer.

Sludge Dryer

A sludge dryer further dewaters cake produced by mechanical dewatering equipment. Sludge dryers include machines like ELODE and thermal dryers.

Sludge Drying

Sludge drying is a second stage sludge dewatering process that further dries cake produced by mechanical dewatering equipment.

Sludge Drying Bed

A sludge drying bed is a large space that holds and dewaters sludge simply via natural evaporation and gravity drainage through sand.

Sludge Drying Methods

Sludge drying methods refer to non-thermal (eg. electro-osmosis) and thermal (eg. convection, conduction) ways of further drying sludge cake.

Sludge Drying System

A sludge drying system includes a sludge dryer (eg. ELODE, thermal dryer) as well as the respective additional equipment required (eg. conveyors, scrubbers).

Sludge Thickening

Sludge thickening concentrates solids and decreases free water to reduce overall sludge volume, but thickened sludge still acts like liquid rather than solid cake.

Sludge Treatment

Sludge treatment broadly describes the processes used to manage and dispose of sludge including thickening, digestion, dewatering, and disposal.

Sludge Uses

Depending on its dryness, chemical makeup, and contamination levels, sludge cake can be used as fertilizer, biofuel, or biochar.

T

Thermal Dryer

Thermal dryers transfer heat to evaporate water from sludge to produce drier cake. Thermal drying methods include convection, conduction, and radiation.

W

Wastewater Treatment Plant

A wastewater treatment plant (WWTP) speeds up the natural processes by which water is purified by removing contaminants from wastewater and returning the treated effluent back to the water cycle. WWTPs produce sludge as their primary byproduct.