GREASE INTERCEPTION
Grease management systems have developed significantly over the last decade to deal with food, oil and grease from a growing food industry, as Dux explains.
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usiness is not ‘as usual’ for plumbing and food service professionals when it comes to combatting the large amounts of fat, oil and grease generated by a growing food industry. Guarding against sewer blockages, expensive clean outs and damage to sewer lines is an increasing focus of local councils. To meet growing demand, grease management systems have been developing
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significantly over the last decade, with more advanced features to increase their level of performance. The wide choice can make life difficult for professionals evaluating, selecting and installing. Choosing the wrong system can have a negative impact, but times are changing and grease management is advancing; from simple capture and contain systems, to systems that capture, separate and even convert.
How we talk about grease management systems is changing. The term ‘grease trap’, which is still widely in use, is making way for more specific terms. ‘Trap’ suggests the presence of a water seal, whilst ‘grease interceptor’ more appropriately describes the modern unit. Generically the application of a grease interceptor, regardless of type, is defined as follows: “A plumbing appurtenance or appliance that is installed in a sanitary drainage system to intercept non-petroleum fats, oil, and grease (FOG) from a wastewater discharge.” Specific characteristics define the three types of interceptor: 1. Hydromechanical Grease Interceptor (HGI) These units are sized by flow rate (litres per minute) and qualified separation/ retention efficiency. They control the flow to entrain air into the effluent, with baffles and/or barriers promoting hydromechanical separation. Most HGIs can be installed inside or outside the facility they serve and either above or below the grade. 2. Gravity Grease Interceptor (GGI) Characterised by volume, generally GGIs have a minimum 30-minute retention time, more than two compartments, over 100 litres total volume as per the NZBC, and gravity separation. They are generally installed outside the building below the grade. 3. Grease Removal Device (GRD) GRDs come in a variety of forms with various methods for removing fats, oil and grease either through heat, enzymes or bacteria/ enzyme combination.
