Oil separators are a central element of water protection wherever work is carried out on a construction site, in yard depots, or during deconstruction with hydraulic equipment. When using concrete demolition shear, Hydraulic Rock and Concrete Splitters, Steel Shears, Multi Cutters, Tank Cutters, as well as associated Hydraulic Power Units, leaks, maintenance operations, or cleaning of attachments can result in oil-bearing wastewater. A suitable oil separator separates such light liquids from water before it is routed into the local sewer system or to further treatment. This reduces the risk of contamination of soil, surface water, and groundwater and supports construction site safety.
Definition: What is meant by oil separator
An oil separator (also light-liquid separator or coalescence separator) is a system that is based on the density difference between water and light liquids such as mineral oils, diesel, or lubricants. It collects and separates floating substances as well as settleable solids, often in combination with a preceding sludge trap. Coalescence elements enlarge the droplets so that oil settles more efficiently. Oil separators are built in different performance levels (e.g., separator class I/II) and are used stationary in wash bays and yard depots as well as temporarily on the construction site and in special demolition.
Function and design
Oil separators operate predominantly on physical principles. The wastewater flows calmly through the separator; lighter substances rise, heavy particles sink into the sludge trap. Coalescence inserts promote agglomeration of finely dispersed oil droplets. A sampling or inspection point enables visual checks. Optionally, a level indicator warns of overfilling.
- Sludge trap: captures sediments and protects the separator from silting.
- Separation chamber: tranquil flow zone in which light liquids float to the surface.
- Coalescence insert: increases separation efficiency, especially with fine emulsions.
- Retention and removal: the floating phase is collected and disposed of properly.
- Inspection/sampling chamber: for inspection, sampling, and maintenance.
Application areas on construction sites and in deconstruction
Wherever hydraulic drives are operated, maintained, or cleaned, oil-bearing wastewater is possible. This applies to the deconstruction of concrete structures as well as to natural stone extraction and tunnel construction. Oil separators serve here as an interface between efficient construction logistics and environmental protection.
Concrete demolition and special demolition
When using concrete demolition shear, Steel Shears, Multi Cutters, and Tank Cutters, oil-bearing drip water and cleaning volumes can potentially occur (e.g., after uncoupling, when changing hoses, in the event of hose defects). A wash or service area with oil separator and sludge trap receives flushing and cleaning water; sediments from concrete debris remain in the sludge trap, light liquids are retained in the separator.
Building gutting and cutting
In building gutting projects, attachments are cleaned regularly before they move to another area. A temporarily established, liquid-tight cleaning area with inflow to a mobile oil separator helps safely control leaks from Hydraulic Power Units and attachments.
Rock excavation and tunnel construction
In tunnel construction and underground tunneling, water that accrues is often collected and discharged. If lubricants from hydraulic hoses enter this water, an upstream oil separator may be necessary before discharge or further treatment. Adequate pre-treatment via a sludge trap is important to retain fine particles from drilling or blasting works.
Natural stone extraction
During the extraction and processing of natural stone, stone and concrete splitters as well as stone splitting cylinders are used. Maintenance and cleaning areas with oil separators reduce the risk of hydraulic oils entering rainwater drainage. Robust designs with generously sized sludge traps are advantageous, as abrasive fine dust is generated.
Special deployments
For deployments with the Tank Cutter or when working in sensitive areas (e.g., near water bodies), restrained, safe water routing is crucial. Temporary containment surfaces, pumping systems, and mobile oil separators form a coordinated chain to retain light liquids in a controlled manner.
Sizing and selection criteria
The selection of an oil separator depends on the type and quantity of water, the light liquids to be expected, and local conditions. The goal is stable separation even when peak loads occur.
- Wastewater volume: design based on peak inflow (e.g., wash bay, rain inflow, sump pumps).
- Pre-dimensioning of the sludge trap: sufficient volume to bind sediments from concrete and rock abrasion.
- Separation efficiency: coalescence technology (Class I) for fine droplets; with coarse loading, Class II can sometimes suffice with a preceding sludge trap.
- Chemical resistance: materials and seals suitable for mineral oils, temperatures, and outdoor conditions.
- Stationary or mobile: mobile, transportable systems are suitable for construction sites; stationary systems with permanent connection are preferred in yard depots.
- Maintenance accessibility: good access to coalescence insert, sludge trap, and removal openings.
Note: For concrete design, local requirements and recognized rules of the art must be taken into account; requirements can vary by location.
Operation, inspection, and maintenance
An oil separator operates reliably when the system is used properly and inspected regularly. This includes visual inspections, measuring the separated oil and sludge quantities, and timely emptying by a certified disposal company. Coalescence elements are cleaned or replaced when separation efficiency declines. Optional warning devices support operational monitoring.
- Keep the inlet calm; avoid shock loads.
- Remove solids from the sludge trap regularly.
- Collect the floating phase in suitable containers and dispose of it properly.
- Clean coalescence inserts and verify function.
- Document results and adjust intervals to loading.
Information on inspection intervals, leakage test requirements, and documentation obligations depends on location and applicable rules and should be coordinated in advance with the competent authorities.
Special technical aspects for hydraulic attachments
Hydraulic Power Units and attachments such as concrete demolition shear, rock and concrete splitters, Multi Cutters, or Steel Shears operate with pressure oil. In practice, a combination of prevention and separation has proven effective for reliably retaining light liquids.
- Liquid-tight service areas: perform maintenance, lubrication, and cleaning only on areas connected to a sludge trap and oil separator.
- Leakage prevention: check hoses and couplings regularly; use protective caps to minimize residual oil when uncoupling.
- Cleaning in moderation: use the high-pressure washer only as intensively as necessary to avoid emulsification; first wipe mechanically, then rinse with water.
- Immediate measures: secure drip points immediately with absorbents; dispose of absorbents properly and do not introduce them via the separator.
- Media selection: use hydraulic oils according to the equipment manufacturer’s specifications; for rapidly biodegradable oils, consider their behavior in the separator.
Temporary and mobile oil separators
On changing construction sites or in special demolition, mobile oil separators are useful. They can be operated as compact units with a sludge trap and supplied by pump or gravity. A stable setup, frost-proof routing of lines, and a clear separation between clean and contaminated water are important.
- Setup: catch pan or area, preliminary screening/sludge trap, coalescence separator, control point.
- Proximity to hydraulics: locate near maintenance zones for concrete demolition shear and rock and concrete splitters to keep distances short.
- Load management: provide intermediate storage (buffer tanks) for high peak inflows.
Downstream treatment and disposal
The separated light liquids and sludges must be collected separately and sent for appropriate disposal. Specialist contractors handle transport and treatment. Depending on the location, further steps may be provided for the pretreated water, such as discharge into the local sewer system after approval or additional filtration. The specific requirements are governed by local regulations.
Planning and integration into the construction process
Early planning facilitates safe operation of an oil separator. This includes a logistically favorable location, sufficient access for disposal vehicles, frost-proof installation, protection against mechanical damage, and clearly marked water routing. In work planning, maintenance windows and disposal intervals are taken into account so that the separator remains fully functional at all times.
Interfaces to products and areas of application
Whether in concrete demolition with concrete demolition shear, in deconstruction with Steel Shears and Multi Cutters, in rock excavation with rock and concrete splitters, or in special deployments with Tank Cutters: oil separators provide the technical basis for safe treatment of cleaning and surface water. This allows demanding tasks in deconstruction, building gutting, tunnel construction, and natural stone extraction to be combined with a high level of environmental protection.