Grease trap - EN1825 - Instruction and capacity calculation

Oct 23, 2026

Grease trap document describes the purpose and operation of grease traps for separating animal and vegetable greases and oils from waste water, including when installation is required for homes and hospitality or food-related businesses. It explains design options with built-in or built-on sludge traps, how grease separates by density and clumping, and notes regular cleaning and emptying. It also provides compliance information for NEN-EN 1825 and guidance for sizing via capacity calculation using sludge volume requirements and cleaning-agent factor.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages16

Reading Time40 min

AccessFree to download

A grease trap and how it works

Characteristics

Operation

Grease trap conform NEN-EN 1825

Capacity calculation

Brought into in use and emptying

Grease trap EN1825 Grease trap Contents • 03 A grease trap and how it works • 04 Grease trap conform NEN-EN 1825 • 06 Capacity calculation • 07 Single sink trap, round • 08 Grease trap 2l/sec, rectangular • 09 Grease trap 2l/sec, round • 10 Grease trap 4l/sec, rectangular • 11 Grease trap 4l/sec, round • 12 Grease trap 7l/sec, rectangular • 13 Grease trap 7l/sec, round • 14 Sizes and weights • 15 Bringing into in use and emptying 2 Grease trap A grease trap and how it works CHARACTERISTICS A grease trap is an appliance to remove grease (vegetable and animal greases and oils) from waste water. The installation of a grease trap can be required in the following cases: • With homes: If water treatment takes place, this is recommended if water treatment happens too far from the kitchen to prevent pipe blockages. • At hotel and catering establishments, companies, schools, butchers, domestic caterers, etc.: A grease trap is always required in these cases. The volume of the grease trap depends on the discharged flow rate, the temperature of the water, the use of cleaning products and the waste load. Please contact our technical department to identify the appropriate type. There are two types of grease trap with sludge trap: • Built-in sludge trap: Here a partition is welded in the tank so the first compartment serves as a sludge trap. The advantage here is that installation is simpler and quicker than with a separate sludge trap. • Built-on sludge trap: Here a tank is installed before the grease trap. DYKA will be happy to assist you in determining the correct capacity of the grease trap by including a capacity calculation, see page 6. OPERATION The greasy water originating from the kitchen and/or dishwasher arrives in the tank through a baffle. The greases separate from the water for two reasons: • The grease has a lower density than water (so it is lighter) • The grease clots as soon as it arrives in the colder water in the trap The grease trap is constructed in such a way that the collected grease stays on the surface and practically no grease is discharged (this involves the condition that the grease trap is cleaned and emptied at regular intervals, seethe user instructions) . Grease trap in the initial phase (clean water) Grease trap saturated (grease layer floats) 3 Grease trap GREASE TRAP conform NEN-EN 1825 Provided with: QUALITY DECLARATION and CE MARK Suitable for the separation of animal and/or vegetable greases and/or oils The sludge trap content of grease traps must be least 100 litres per litre second. Example: a 2 l/s grease trap has a minimum sludge volume of 200 litres a 4 l/s grease trap has a minimum sludge volume of 400 litres The standard uses a factor of x 1.3 for the use of cleaning agents. This must be applied at all times. All standard HDPE grease traps have been given the CE mark. The HDPE grease traps have successfully completed efficiency tests (PA mark) with the German LGA TÜVRheinland approval body. This means first class materials and accredited welders guarantee quality as well as efficiency. 4 Grease trap Applicable at businesses and establishments such as: • Restaurants, hotels, pubs and cafeterias • Nursing homes, rest homes and hospitals • Butchers, slaughterhouses and meat product producers • Fishmongers and fish-processing companies • Sports, local authority and works canteens The big advantages of our grease traps: • Robust construction • High quality, so long-lasting • Low installation cost • High efficiency conform NEN-EN 1825 • Also available for heavy traffic loads • Simple cleaning and maintenance • Fast delivery times, normally available from stock The grease traps are available in the following materials: • High quality High Density Poly Ethylene (standard) • Prefab reinforced B45 concrete provided with a grease-resistant epoxy coating (on request) • Prefab rein

FAQs

When is a grease trap required?

Installation is recommended when water treatment happens too far from the kitchen to prevent pipe blockages, and it is always required for hotel and catering establishments, companies, schools, and comparable food-related operations.

How does a grease trap separate grease from wastewater?

Greasy water enters the tank through a baffle, and greases separate because they have a lower density than water and they clump when they contact colder water in the trap.

What standard requirements apply to sludge volume and cleaning agents?

The sludge trap content must be at least 100 litres per litre second, and the standard applies a factor of x 1.3 for the use of cleaning agents, which must be applied at all times.

Oct 23, 2026

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