Water & Wastewater Treatment Magazine
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062 www.atiuk.com The Knowledge: FOG www.wwtonline.co.uk | WWT | JUNE 2017 | 35 T he impact on the UK sewer system of fats oils and grease (FOG), derived from food preparation and cleaning activities of restaurants and kitchens, has grown over the last 20 years. According to British Water, water companies are responding to over 370,000 sewer blockages every year, 80% of which are caused by FOG. This is cost- ing the country (government, businesses and customers) more than £88 million a year, and that excludes additional costs, such as when sewers collapse and the effect this has on people's lives and busi- nesses. Fats, oil and grease need clear thinking Latest research from Cranfield has shone a light on the characteristics of of fats, oil and grease (FOG) droplets entering sewer systems, and the different methods for their mitigation DR Rafaella Villa, SeniOr LeCturer in BiOprOCeSS teChnOLOGy CranFieLd univerSity Summary • Water companies are responding to 370,000 sewer blockages each year caused by fats, oil and grease (fOG) blockages, costing the country 88M a year • Preventing fOG being discharged is always preferable to treatment, which is why water companies are currently investing time and resources into education campaigns for customers, and particularly food service establishments (fSes). • Gravity separation, air flotation and electroflotation are the main techniques available for fOG removal • any system must respond to the fact that flows of FOG are sporadic, and research shows that longer retention times can improve performance • a new method for quantifying fOG will allow more rigorous testing of biological additives to be undertaken in the future • Water companies and their customers, businesses and local authorities will all need to collaborate to tackle the FOG problem effectively When you bear in mind an intensifica- tion of extreme rainfall events as a result of climate change, this combination has led to an increase in severity of flooding, environmental pollution and property damage associated with FOG-related blockages and sewer failure. Although relatively simple in its nature, the prob- lem is owned by a composite community of stakeholders with different drivers and despite the growing urgency, research on FOG remains relatively scarce. The 3rd International FOG Confer- ence was held last month at Cranfield University, co-organised with British