8th August 2008
Drains and sewers are under severe strain as a result of our 21st century lifestyle. They are increasingly becoming blocked by fats, oils and grease and Thames Water reports about 65,000 stoppages a year.
The health gains of our drainage system and public water supplies were hard won but are now being eroded by the competing requirements of today’s society. We eat too much fat, with adverse consequences for our life expectancy. We are also obsessed about hygiene and use too many chemicals, often without regard to their long-term effects.
The trend towards fast food and eating out is leading to more drainage problems. Every year there are about 200,000 sewer blockages in the UK, three quarters of them caused by FOG.
Putting everything down the drain "out of sight, out of mind" has been the easy option for caterers for decades, but the consequences are becoming more apparent, especially with the recent flooding in towns and cities across the UK. Exactly how much FOG contributed to the problem is not known, but the sewers and drains could not cope, and the results were the public health risks that affected Sheffield and Tewksbury in particular.
The catering industry is being pressured to become more environmentally friendly and sustainable while providing the public with what it wants. Many business proprietors are struggling to keep up with the pace of change in food safety, health and safety, fire safety, planning, employment and now environmental and climate change laws. Each new law imposes more cost and, as food costs rise, profits are eroded and it becomes harder to stay in business.
The technology for dealing with FOG in catering premises includes solutions such as installing grease traps, the treatment of effluent with microbes that digest grease and stopping it going down the drains in the first place.
False security
Experience shows that grease traps offer a false sense of security to the caterer, who sometimes forget what is involved in using them. Given their objectionable nature, they are the last place a kitchen porter would want to clean regularly.
It does not take long for a trap to become rancid and foul smelling. The smell can be overpowering, penetrating every corner of the catering environment once the cover is removed – it is effectively an internal septic tank. In fact, grease traps should only be emptied and cleaned out by licensed waste contractors with the correct equipment. Their contents are hazardous waste as defined by the Hazardous Waste Regulation 2005 and must be dealt with accordingly.
Besides the operational difficulties, grease traps are often undersized, badly located and rarely installed to intercept all the waste from grease-producing equipment. Under-sizing is often the result of cost and space constraints in modern kitchen design. There is rarely cold water in the trap to cause the FOG to solidify and rise to the surface. Much of the FOG remains in solution, passing straight through the inefficient trap to solidify in the cold sewer.
Often, grease traps are installed in the kitchen under the sink because there is no suitable outside area. Then the hygiene nightmare begins. The Building Regulations 2000 requires that any "hot food operation should fit a grease separator, or other means of grease removal". But grease traps are regularly installed inside the catering premises as designers claim it cannot be installed outside due to lack of space or cost implications. That designer leaves a public health legacy that will cause untold risk into the future.
How can the cleaning and maintenance of these septic tanks be safely and regularly carried out without closing the kitchen, which the proprietor is unwilling to do? So the trap is not emptied and becomes useless within a few weeks.
Some companies remove and replace the trap and clean it off-site. This seems a realistic alternative to the use of fixed traps and offers the possibility of recovery for biofuel production, which could help firms be more sustainable.
In a modest-sized high street catering business, such as a Chinese takeaway, the annual cost of recovery is about £700-£800 a year, which is reasonable compared with the cost of a properly sized trap plus a maintenance contract. The replaceable traps will normally remain sealed until they have left the premises, making under-sink traps an acceptable option.
Fixed traps, however, tend to act as a "sump" for all kitchen waste and effluent discharge to collect and putrefy. They are likely to become the focus of infestation and environmental contamination. Cockroaches welcome the warm, moist environment with the ready supply of food. Various types of fly will be attracted by the aroma, promise of rich pickings and a place for their offspring to complete their lifecycle.
A sure sign that it is going wrong is when maggots are seen scurrying away from the trap to find a place to pupate. Before long such traps have the potential to become a menagerie of competing wildlife, which will cause panic in the kitchen, should they descend on the even richer pickings of diners’ lunches. If the lid is regularly removed for cleaning and maintenance, it invariably never quite goes back the same, so the seal is never truly gas- and water-tight. This has the potential for adverse odours and the potential for ready access and egress of pests. Grease traps are a serious source of potential contamination and pest breeding – in the heart of the kitchen.
Many grease traps in kitchens could be illegal – the British Standard on drainage systems demands that no odours or fetid air should be released inside buildings. How can a grease trap with its foul waste content fitted inside a kitchen, or inside any part of a building, possibly comply with this?
European regulations have many references that would make grease traps an unsatisfactory design feature in any food-service operation. Surely there is not an EHP or technical officer in the land who would readily advocate the installation of grease traps in kitchens given the legacy of issues and potential legislative non-compliance they are likely to cause?
Outside traps
So is it back to the drawing board? Possibly not. Traps do work if they are correctly sized, and correctly located. This would point to having traps that are fitted externally and underground, to provide the necessary volume and operating temperature to allow the system to work properly. But to start digging up high streets up and down the country to install such devices is going to take some considerable encouragement and funding and is probably a non-starter.
A practical alternative is the use of bacteria or enzymes to break down FOGs permanently. It would seem sensible to aid the first stage of natural bio-remediation. Sewage treatment plants rely on bacteria to digest sewage, breaking down the long molecular chains of fats, oils and greases and producing sludge. The sewage sludge cake is said to be almost innocuous and odourless. These treatment systems are becoming more readily available, are easy to use and clean, and should take up no floor space. However, the effectiveness of the bio-remediation process depends on a number of factors, including the dwell time in drainage, the make up and quality of the fluid that is being introduced to the drainage system and the volume and types of bacteria/enzymes.
The real answer to catering FOG is not to let it into the drains in the first place. It is yet another management system in the kitchen but it is achievable with commonsense and training.
It is illegal under the Water Industry Act "…to put anything down into the sewer which might impede its flow". Therefore all FOG should be collected and regularly taken away by a licensed contractor. All plates, utensils and equipment should be scraped prior to washing and any fat residues also collected from roasting trays and grill pans. It is a matter of staff awareness. This issue is not going to go away and if the industry does not get its act together, it is an area the legislators could really get their teeth into, increasing the regulatory burden further.
We cannot allow the public health infrastructure to be damaged and so increase the risk of flooding and risk to health. We cannot allow catering operations, through bad design and installation of equipment, to contribute to food safety risks. n
Geoff Ward is part time consultant with National Britannia Group