Food waste and dirty dishes are a fact of life in restaurants. While they may be the least glamourous aspect of foodservice operations, the right warewashing equipment and disposal systems can go a long way towards boosting efficiency and labour savings.
At the heart of the issue is the need to tackle the challenge of energy and water usage. And there’s no better place to start with the area that accounts for the most hot-water consumption.
Up to 75 per cent of hot water used in dining facilities is consumed in the dish room, and accounts for a large portion of energy costs, says David Zabrowski, vice-president, Frontier Energy, Inc. in San Ramon, Calif. “Half of that hot water usage is the warewashing machine. The rest is the pre-rinse and pot sink.”
Over the past few years, warewashing vendors have been pulling out all the stops in developing an array of technologies that not only reduce water consumption, but eliminate the need for external hot-water heaters. The two main drivers for water consumption are the amount that is needed to fill the main wash tank, and the water used in the fresh final rinse. So, the more water that can be filtered and re-cycled, the better.
According to Gabriele Forneris, sales development manager, Warewash and Food Machines for Hobart in Toronto, today’s machines use up to five times less water than 10 years ago. “Less water means less hot water, energy, and chemicals. While the government is not telling us the maximum water machines can use, we expect this will be mandatory within the next five years.”
Frontier studies show that the energy consumption for warewashers is as much as the cook line, says Zabrowski. “If you focus on things like hand sinks, you won’t go far. But if you focus on pre-rinse and dish-washing operations, that’s where you will get the biggest potential gains. However, the performance very much depends on how machines are installed, commissioned, maintained, and operated.”
“The technology we are most excited about is [ventless] heat recovery,” he adds. “Dishwashers operate using heat to break down food soil and oils. Hot-water sanitizing machines use even more heat for the final sanitizing. Rather than using a vent hood, the heat is captured on a heat exchanger and transferred to incoming cold water.”
While ventless heat recovery has been a relatively common technology on flight machines, over time it has been scaled down to conveyor, door types and even on some undercounter style machines, notes Zabrowski. “Although with smaller machines there is a slight trade off in that it slows down throughput as it takes 15 to 30 seconds longer to capture the heat and transfer it to the cold water.”
Another energy-saving option is drain water energy recovery — a technology that transfers the heat generated during the cycle to the incoming cold water, resulting in an up to 20 per cent energy savings and reducing water tempering by up to 90 per cent, explains Forneris.
Other features helping the cause include active soil removal or ASR (a process that pumps food soil from the wash tank rather than allowing it to fall), improved water filtration, Energy Star certification, adjustable wash cycles, and intelligent controls that allows data to be transmitted to a central computer to monitor usage and performance.
“Hobart [has recently] introduced its Advansys system that enables ASR, drain water heat recovery, automatic cleaning and de-liming, and smart connections to Wi-Fi,” says Gary Lummis of Gary Lummis Food Service Design in Fredericton, N.B. “They now offer Advansys into their smaller machines including uprights. Champion has introduced the Prodigy Controller communications systems on its bigger machines, while Meiko’s GreenEye Technology is included in the M-iQ flight machine.”
Beyond the heat capture and water-savings features, there’s an equally important focus on managing food waste. Food-waste systems are typically deployed closest to the source, that is, in warewashing and food-prep areas.
Depending on the size of the operations and space, operations may go with pulpers or bio digesters. Pulpers can reduce foodservice waste volume by up to 85 per cent and can be coupled at the waste-collection source. Foodservice waste sent to the pulper is mixed with water to create a slurry that is transported via a pipeline to an extractor for removing the water. The extracted water is recovered and returned to the pulping tank for re-use.
“It’s much like a trash compacter,” says Forneris. “Separating the water from the solid means you have much lower waste volumes.”
There can be a labour-savings component as well, he adds. “Some businesses clean dishes before going to the dish room, creating a lot of waste and labour. With the right systems, servers can bring everything straight to the dish room for separation to the pulper. When you compress waste there is much less risk of bacteria, less space requirements, and less water usage.”
Another area of interest is reducing food waste to water by chemical processes, says Lummis. “It’s a very efficient way to handle your waste, but there are also disadvantages in terms of cost and concerns over pollutants.”
Depending on the model, bio-digesters use an anaerobic digestion process in which the waste is put into three chambers (a grease interceptor, a biological digester, and a soak pit) and processed using gas and bacteria. However, the process can be lengthy and the systems require a great deal of space, and in some cases output is not suitable for discharge to the sewer.
“Most bio-systems occupy a lot of space, so they don’t suit facilities such as hospitals,” explains Forneris. “They might suit environments that have a lot of space, such as a military base.”
Some large-scale Canadian food operations are looking at technologies such as the Power Knot, which has various sizes of units, and generates grey water that can be safely discharged, notes Lummis.
“Because the world situation is becoming more critical,” says Lummis, “everyone is putting more effort into delivery energy efficient systems that can collect waste and run more efficiently.”
BY DANIELLE SCHALK