WELD separators are used to pre-purge waters originating from various objectives such as: kitchens of hotels, guesthouses, restaurants, slaughterhouses, meat processing factories. WELD-S.G. separators are the smallest fat separators (able to take over a flow rate of 0.5-1 l/s), have rectangular shape because they can be fitted in greenhouses (directly under the sink in the kitchen or in the basement of the restaurant) and other systems for separating fat from wastewater which have a capacity of greater separation, are designed in a cylinder shape. This form has been chosen to save space, by installing their underground.