GreaseBeta 

FOG disposed of down sinks or directly from ovens and dishwashers may flow away quickly and appear harmless. Still, as it cools, it congeals and hardens within the drainage system, resulting in internal and external blockages.

Detergents will emulsify fats temporarily, but fats can reform when the effects of the detergent become diluted. Once this happens, the fat sticks to the inner surface of the drainage pipes and restricts water flow, causing the line to block. The result is overflowing sewers, odour problems and a greater risk of vermin.

Blockages build up over time and can occur further down the drainage run, affecting neighbouring premises. Apart from the inconvenience, financial cost, fines and hygiene risks associated with drain and sewer blockages, they can damage the reputation of a food business.