Glossary

B

Baffle

A wall or fitting inside a septic tank or grease interceptor that slows the incoming flow and holds back floating material, so only clarified liquid leaves through the outlet. A damaged or missing baffle lets solids and grease escape downstream.

Biofilm

A slimy layer of bacteria that grows on wet surfaces inside water tanks and pipes. It shelters bacteria from normal chlorine levels, which is why water tank cleaning scrubs surfaces physically before disinfecting them.

C

CCTV inspection crawler

A remotely driven camera on wheels or skids that travels inside a drain or sewer line and records its condition. It shows cracks, root intrusion, displaced joints and buildup, so repairs are decided on evidence rather than guesswork.

Chlorination

Disinfection with a chlorine compound. For tank surfaces a high strength solution, typically dosed around 50 parts per million, is applied and left for a set contact time, then rinsed until levels return to normal supply water values.

Confined space

Any enclosed space with limited entry and exit where hazardous gases or low oxygen can build up, such as a septic tank, sump pit, manhole or large interceptor. Entry requires gas testing, ventilation, a harness and a trained standby person.

D

Descaling

Removing hardened mineral or soap scale from the inside of pipes or tank surfaces, usually with a rotating descaling head on a jetting hose. Scale narrows pipes and gives grease and debris a rough surface to cling to.

Disposal record

The document proving where collected wastewater or sludge was discharged. Licensed operators in Dubai discharge at approved facilities and can show the record for every load, which is the clearest test of a legitimate provider.

Duty and standby pumps

A pair of pumps in a sump pit where one does the daily work and the other takes over if the first fails or the inflow is high. Many controllers alternate them so both stay exercised. Each should be tested individually.

E

Effluent

The liquid wastewater that flows through and out of a septic tank after the solids have settled. Effluent still carries contaminants and must go to a soakaway, sewer connection or a vacuum tanker, never onto open ground.

Ejector pit

A sewage sump pit that collects wastewater from fixtures below the level of the building's sewer connection, such as basement bathrooms or laundries, and pumps it up into the drainage system.

F

FOG

Fats, oils and grease from cooking and dishwashing. FOG is liquid when hot and sets hard as it cools in pipes, which is why food establishments use grease interceptors to capture it before it reaches the drains.

Float switch

A floating sensor in a sump pit or tank that switches a pump on when the level rises and off when it falls. A float jammed by sludge is one of the most common reasons sump pumps fail or run constantly.

G

GRP tank

A water storage tank made of glass reinforced plastic panels bolted together, common on Dubai rooftops and in buildings. Its gelcoat surface needs non abrasive cleaning tools, and its panel seams are checked for leaks during service.

Gas detector

A handheld meter that measures oxygen, hydrogen sulphide, methane and other gases at a tank or pit opening. It is used before and during any confined space work, because sewage gases can be dangerous without any warning smell.

Grease interceptor

Also called a grease trap. A chamber on a kitchen drain line where wastewater slows down so fats float and food solids sink, letting cleaner water pass on. It works only when emptied completely and regularly.

H

Holding tank

A sealed tank that stores wastewater with no outlet to a soakaway or sewer, so everything that enters must be removed by vacuum tanker. Common at labour accommodation, construction sites and remote facilities.

Hydro jetting

Cleaning a drain or sewer line with water at high pressure, delivered through a hose and a specialised nozzle. Working pressures typically run between 150 and 250 bar, matched to the pipe material and condition.

Hydrogen sulphide

A toxic gas produced by decomposing sewage, known by its rotten egg smell at low levels. At higher concentrations it deadens the sense of smell, which is why gas testing, not the nose, decides whether a space is safe.

I

Inspection chamber

An access point on a drainage line, usually covered by a small cover in paving or a basement floor, used to inspect, clear and jet the line. Larger and deeper versions are called manholes.

Invert level

The level of the lowest inside surface of a pipe at a given point. Invert levels determine whether a line falls correctly towards its outlet, and a line laid with too little fall collects silt and grease.

L

Line flushing

Running a high volume of water through a drain line, often with a flushing nozzle, to carry loosened sand, silt and debris back to an access point where it can be extracted rather than pushed downstream.

N

Non return valve

A valve on a pump discharge pipe that lets water flow out of the pit but not back in. A failed non return valve lets pumped water fall straight back, so the pump runs far more than it should.

S

Scum layer

The floating layer of grease, oils and light solids at the top of a septic tank. Together with the sludge blanket at the bottom, it is measured with a dipping rod to decide whether a tank needs pumping or a full clean.

Septic tank

An underground tank that receives wastewater from a property, lets solids settle and scum float, and passes the clarified effluent to a soakaway or sewer connection. It must be emptied by vacuum tanker before the solids reach the outlet.

Sludge blanket

The layer of settled solids at the bottom of a septic tank or pit. Routine pumping removes liquid and floating waste, but a compacted sludge blanket needs agitation and a full clean to lift completely.

Soakaway

An underground pit or trench that lets the effluent from a septic tank seep into the surrounding ground. Solids escaping from an overfull tank clog a soakaway, which is far more expensive to rebuild than a tank is to clean.

Sump pit

A pit at the lowest point of a basement, car park or plant room that collects wastewater or groundwater so pumps can lift it away. Sludge and sand gradually fill it and stop the pumps working.

V

Vacuum tanker

A truck carrying a sealed tank and a powerful vacuum pump that draws wastewater, sludge and grease through a suction hose. Tankers come in different sizes, and the right size depends on the tank volume and the access at the property.

Put the Terms to Work

See the terms in context in our guides and advice, or read how each service uses them on the septic tank cleaning, sump pit cleaning and water tank cleaning pages.