A gully emptier is a type of specialized tanker lorry

Tank truck

A tank truck or road tanker is a motor vehicle designed to carry liquefied loads, dry bulk cargo or gases on roads. The largest such vehicles are similar to railroad tank cars which are also designed to carry liquefied loads...

 with suction gear which can suck wastewater

Wastewater

Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...

 and mud and sludge out of hollows such as the hollows below drain grids in street gutter

Street gutter

A street gutter is a depression running parallel to a road designed to collect rainwater flowing along the street and divert it into a storm drain. Where a curbstone is present, a gutter may simply be formed by the convergence of the road surface and the vertical face of the sidewalk; otherwise, a...

s and carry it to a suitable disposal point. It needs to be able to suck out and pump through into its tank any road grit and miscellaneous solids that have got into the hollow.

Some have a means of squeezing the water of its load and letting that water run down the drain or they can recycle the water for high pressure cleaning of the drain pipes.

Difference from cesspool emptier

A vehicle which is purely a cesspool emptier

Cesspool emptier

A cesspool emptier is a type of specialized tank truck which can suck contaminated water out of hollows such as cesspools and sewage tanks and carry it to a disposal point....

 has a long wide flexible hose without the big solid nozzle with controls on.

Gully emptiers are often outfitted with devices to separate the liquid content of its tank from solid matter, allowing the liquids to run to storm drain

Storm drain

A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...

. Since this is not done with cesspool content, cesspool emptiers have no need for such separative capability.

Sometimes a gully emptier also has a flexible hose without solid nozzle like on a cesspool emptier.