'Cleaning agents with chlorine are out of the question'

To ensure that fats in wastewater from hotel kitchens do not end up directly in the sewer or surface water, every hotel is required to have a grease separator in house. "However, having a grease separator emptied by a recognised clearing service is quite costly," says Thierry Desmet, CEO of Valor Services Group. He therefore gives practical tips on how to drastically reduce the number of grease separator empties.

Plates, pots and pans full of sauce being washed down. Soup kettles being poured. Kitchen floors being cleaned. And waste water from dishwashers. All in all, an average hotel kitchen produces a lot of fats and oils that need to be processed through a grease separator. "The required size and flow capacity - i.e. the number of litres of wastewater the grease separator can process per second - is determined by the NEN 1825 standard," says co-owner Desmet of Valor Services Group, which specialises, among other things, in supplying custom-made grease separators.

Although a grease separator stops practically 100 per cent of the grease in wastewater, it should still be emptied regularly to avoid problems with clogged drains. "In practice, however, this is quite often forgotten," says Desmet. "Because a grease trap is often located somewhere in the ground or in a basement, you are usually not confronted with it until it is too late. One possible solution is to install a grease layer meter that triggers an alarm the moment the grease trap urgently needs emptying."

According to the NEN 1825 standard, a grease separator should be emptied at least once every two months. "Most manufacturers also recommend this. However, sometimes you have regional municipal guidelines that state that it only needs to be done once every six months, for example," says Desmet. "Either way, emptying the grease trap should always be done by a specialised approved clearing service. However, this is quite costly. Moreover, it causes quite a lot of odour nuisance, as grease spreads a pungent odour. Fortunately, there are several ways in which you can drastically reduce the number of emptying operations. First, you can biologically treat the grease trap by injecting a micro-organism-based product. These largely break down the fats in the grease trap and also neutralise the odour."

Secondly, Desmet recommends cleaning all dishes - plates, cutlery, pans and the like - with kitchen roll before putting them in the dishwasher. "This way, a lot less grease already enters the grease trap. Thirdly, it is important to use the right cleaning products for dishes, dishwasher, hand soaps, floor cleaner and the like. Always choose biodegradable cleaning products. Detergents containing chlorine or bleach, on the other hand, are out of the question. By doing so, you kill the micro-organisms in the grease trap, which will make it work less efficiently."

Although the above measures can minimise the number of empties, a periodic clean-up is still necessary. Desmet gives the hotelier the following tip for this: "What you often see is that a cleaning service does suck all the grease out of the grease separator, but then fails to clean it. As a result, the sides of the grease separator are often still full of blocks of grease. Therefore, the grease separator should be thoroughly cleaned after emptying and then also refilled with clean water. The latter will cause the contaminated waste water to mix with the clean water first, reducing the amount of contaminated water going directly to the sewerage system and extending the life of the grease separator."