Wastewater Engineering - 02 (Related Technologies)

Detritus Tank

Square tank grit chamber incorporating a revolving rake to scrape settled grit to a sump for removal.

Activated Biofilter

A fixed-film biological wastewater treatment process in which a portion of the secondary sludge is returned to the reactor influent.

Membrane Filter

A paper-like filter, with small pore sizes, that is capable of retaining bacteria for use in the laboratory examination of water.

Slow Sand Filter

Sand filter characterized solids generated within the wastewater treatment process that has not undergone a stabilization process.

Mixed-media Filter

Granular media filter using two or more types of filter media of different sizes and specific gravities, usually silica sand, anthracite, and ilmenite or garnet.

Comminutor

A circular screen with cutters that grinds large wastewater solids into smaller particles.

Coarse Screen

A screening device typically having openings greater than 6 mm.

Drum Screen

A cylindrical screening device used to remove floatable and suspended solids from water or wastewater.

Paddle Flocculator

A flocculation device that uses rotating baffles to accomplish mixing.

Vacuum Filter

A dewatering device that uses a cloth-covered cylindrical drum slowly rotating in a tank of sludge subjected to the internal vacuum. Sludge is drawn to the filter cloth, while water passes through the cake.

Air Diffuser

A devise designed to transfer atmospheric oxygen into a liquid.

Upflow Filter

Granular media filter characterized by an upward flow of liquid through a filter bed.

Gravity Filter

Granular media filter that operates at atmospheric pressure.

Orifice Plate

Flow measurement device that indicates flow as a function of differential pressures across a flow-restricting orifice.

Compressor

A mechanical device used to increase the pressure of a gas or vapor.

Blower

Air-conveying equipment that generates pressures up to 103 kPa (15 psi); commonly used for wastewater aeration systems.

Overflow Weir

A weir over which excess water or wastewater is allowed to flow.

Brush Aerator

Mechanical aeration device most fequently used in oxidation ditch wastewater treatment plants; consists of a horizontal shaft with protruding paddles that is rapidly rotated at the water surface.

Aerator

A device used to introduce air or oxygen to water or wastewater.

Proportional Weir

A weir whose discharge is directly proportional to the head.

Grit Washer

A device used to wash organic matter from grit.

Baffle

An obstructing device or plate used to provide even distribution or to prevent short-circuiting or vortexing of flow entering a tank or vessel.

Tipping

The dumping of the contents of a waste truck at a waste disposal facility.

Septic Tank

A wastewater treatment system principally used for individual residences that combines sedimentation, sludge digestion, and storage in a single or,dual compartment tank.

Dosing Tank

A tank into which raw or partly treated wastewater is accumulated and held for subsequent discharge and treatment at a constant rate.

Holding Tank

A tank used to recieve and store wastewater before ultimate disposal.

Hydrocyclone

A conical-shaped device that uses centrifugal force to separate grit and other solids from a liquid.

Condenser

A heat-transfer device used to cool steam and convert it from the vapor to the liquid phase.

Biomonitoring

The use of living organisms to test water quality at a site farther downstream.

Sullage

All non-toilet houshold water, including the water from sinks, baths, and showers.

Jar Test

A test procedure using laboratory glasswares for evaluating coagulation, flocculation, and sedimentation in a series of parallel comparisons.

Cesspool

A covered tank with open joints constructed in permeable soil to remove raw domestic water and allow partially treated effluent to seep into the surrounding soil while solid are contained and undergo digestion.

Air Scour

The agitation of granular filter media with air during the filter backwash cycle.

Chlorine Contact Chamber

A detention chamber to diffuse chlorine through water or wastewater while providing adequate contact time for disinfection.

Roughing Filter

A high-rate filter designed to recieve high hydraulic or organic loading rates as a first, or intermediate, treatment step.

Fine Screen

A screening device typically having openings less than 6 mm.

Surface Aerator

Mechanical aeration device consisting of a partially submerged impeller attached to a motor and mounted on floats or fixed structure.

Aspiring Aerator

Aeration device using a motor-driven propeller to draw atmospheric air into the turbulence caused by the propeller and cause the formation of small bubbles.

Thermal Oxidizer

An emission-control device that uses heat to accomplish volatile organic compound oxidation.

Dual-media Filter

Granular media filter using two types of filter media, usually silica sand and anthracite.

Moving-bed Filter

A granular media filter that continuously cleans and recycles filter media while the filter continues to operate.

Deep-bed Filter

Granular media filter with a sand or anthracite filter bed up to 1.8 m deep.

Aspirator

A hydraulic device that create a negative pressure by forcing liquid through a restriction and increasing velocity head.

Microscreen

A surface filtration device consisting of a rotating drum with a fine-mesh screen fixed to its periphery. As water flows through the drum, solids are retained by the mesh for removal by a high-pressure spray wash.

Doctor Blade

A scraping device used to remove or regulate the amount of material on a belt, roller, or,other moving or rotating surface.

Grit Classifier

Mechanical device that uses an inclined screw or reciprocating rake to wash putrescible organics from grit.

Trash Rack

A course screening device that uses parallel set of stationary bars typically spaced at 38 to 150 mm (1.5 to 6 in.).

Guide Vane

A device used to direct or guide the flow of a liquid or vapor.

Walking Beam Flocculator

A mechanical flocculation device whose mixing paddles are attached to a horizontal beam that oscillates to produce a reciprocating motion.

Sludge Dryer

A device that uses heat to remove a large portion of the water within the sludge.

Broad-crested Weir

A weir having a substantial crest width in the direction parallel to the direction of water flowing over it.

Clearwell

A tank or reservoir of filtered water used to backwash a filter.

Submerged / Drowned Weir

A weir that, when in use, has a water level on the downstream side at an elevation equal to or higher than, the weir crest.

Sedimentation Basin / Settling Tank / Clarifier

A quiescent tank used to remove suspended solids by gravity settling.

Surcharge

The height of wastewater in a sewer manhole above the crown of the sewer when the sewer is flowing completely full.

Ejector / Educator / Jet Pump

A device that uses steam, air, or water under pressure to move another fluid by developing suction through the use of a Venturi.

Thickener

A tank, vessel, or apparatus that is used to reduce the proportion of water in a slurry or sludge.

Bench Test

A small-scale test or study used to determine whether a technology is suitable for a particular application.

Imhoff Tank

A two-story wastewater treatment tank in which sedimentation occurs in the upper compartment and anaerobic digestion occurs in the lower compartment.

Calciner

A device in which the moisture and organic matter in phosphate rock is reduced in a combustion chamber.

Perc Test

Test used to determine the water-absorbing capacity of soil, where the drop in water level in a test hole is measured over a fixed time period.

Leaping Weir

Most commonly used weir to divert excessive flow from combined sewers.

Relative Stability

The ratio of oxygen available to the oxygen required for stabilization of sewage.

Lateral Sewer

Sewer that recieves the discharge of a number of house sewers.

Egg-shaped Sewer

Preferred type of sewer for combined system of sewage.

House Sewer

A pipe conveying sewage from plumbing system of a single building to common sewer or point of immediate disposal.

Combined System

The suitable system of sanitation for area of distributed rainfall throughout the year with less intensity.

Skimming Tank

Tank used to remove grease and fatty oils in sewage.

Tapered Aeration

A modified activated sludge process that uses different spacing of air diffusers over the tank length.

Belt Press

Mechanical de-watering device that operates on a batch system with highest sludge cake concentration.

Sparger

A rapidly rotating mechanical device that breaks large or coarse bubbles that is not prone to plugging and achieves its effectiveness by the use of mechanical energy.

Underdrains

In trickling filters, it serves to support the filter medium, carry away the liquid effluent and sloughed solids, and distribute air through the bed.

Filter Leaf Test / Buchner Funnel

Test useful in evaluating vacuum filter performance.

Membrane BioReactor (MBR)

It defines a combination of an activated sludge process and a membrane or filtration separation.

High Purity Oxygen Process

The modification of the activated sludge which allows the closest match between the amount of oxygen supplied and the OUR (oxygen uptake ratio) of the mixed liquor.