Reducing Water Footprint in the Food and Beverage Industry

Due to the rapid growth in human development and population numbers, the value of water as a precious and finite resource is being increasingly recognised, particularly within the food and beverage manufacturing industry where it is heavily relied upon.

The rising scarcity of water due to an increase in global demand is impacting a number of regions and countries environmentally and socioeconomically, which in turn poses a major risk to global food and beverage production. Factors such as limited availability of freshwater and a lack of surface and groundwater due to drought has caused many shortage issues, placing high pressure on industrial activities and increasing the operational costs of plants. There is also the issue of chemical run-off, which contaminates a number of clean water sources.

In order to guarantee safe food production with a limited environmental footprint to an ever-growing population, the food and beverage industry must adopt a proper water management strategy using advanced treatment technology to achieve water savings and zero water discharge solutions. In this article, Jon Fielder, technical director within SOCOTEC’s Water Treatment & Equipment team, discusses the importance of controlling water usage and the various options available to food and beverage manufacturers to enable them to reduce their water footprint.

How does water usage impact the sustainability of the food and beverage industry?

During the food and beverage manufacturing process, water is used for production, refrigeration, steam generation and cleaning purposes, to name a few. In fact, recent research in food and beverage processing has shown that 66% of non-product water is used within Cleaning in Place (CIP) and heat exchangers such as cooling towers (Schug, 2016). The remaining third is split between manual cleaning, sanitation and miscellaneous utility demands.

For hygiene purposes, food and beverage manufacturers tend to use water once before discharge – a process which generally occurs in pre-rinsing containers, CIP systems and when washing produce. The general low cost of water has made this a viable option to minimise the risk of contamination and water usage, although there are additional ways in which water can be recycled and reused without risk. For example, sites with refrigeration plant that have relatively clean wastewater from produce washing and/or container pre-rinse, which with minimal treatment could be safely used for cooling tower make-up water, vehicle and plant washing, as well as other low risk applications.   

Increasing costs of process water and wastewater discharge tariffs, stricter environmental legislation, progressing water stress and rising social awareness are now forcing manufacturers to implement water re-use and conservation programmes, as well as closed loop water systems to achieve operational savings in both energy and water. To its credit, sections of the food and beverage manufacturing industry has adopted a number of water recycling and reuse strategies.

What technologies can food and beverage manufacturing companies use to effectively manage water usage?

The range of water treatment options available to the food and beverage industry can support organisations in reducing water consumption, with varying methods available depending on the individual objectives of the food/drink processor. Water and wastewater treatment companies are developing strategies that combine new and established technologies, together with eco-friendly chemical products to assist the industry in meeting a range of conservation and reuse measures. These technologies are required to comply with strict purification standards that guarantee potable water is free from potential bacteria and viruses that may come into contact with food and beverage products, ensuring it is safe for consumption and general use. Technologies used by the food and beverage sector to effectively control water usage includes:

Ozone disinfection

Plant and equipment cleaning has traditionally served as a major source of fresh water usage within the food and beverage industry (WRAP, 2001). Traditionally, high levels of chlorine/chlorine dioxide serve as the primary sanitising agent when water is used to wash produce and clean equipment. In fact, it is not unusual for manufacturers to use chlorine at levels up to and in excess of 50 times the level used in swimming pools, which leaves high levels of residual by-products in the water. This makes it extremely problematic to recycle and reuse the water in lower risk applications, such as general wash downs/vehicle washing.

When used as an alternative sanitising agent, Ozone allows the water to be reused with minimal treatment and no environmental damage. This is because the Ozone breaks down naturally into normal oxygen, leaving no residual chemicals or by-products in the water. As a result, water can be readily used for a wide range of secondary purposes, including make-up water for steam boilers, cooling towers, vehicle wash systems and general wash down. Due to its capability to destroy all bacteria algae and biofilms with no risk of resistance, build-up or immunity, Ozone is an ideal choice for direct use within food and drink applications and commonly used within food and beverage plants, this method provides the highest level of sanitation, as well as avoiding the use and handling of hazardous chemicals.

The use of ozone in process water systems allows systems to be sterilised with minimal disruption and without draining or flushing. Typical processes using chemical disinfectants or heat sanitisation would require 12-24 hours’ outage time, as well as complete drain down and flushing of the system. To achieve similar results using ozone requires less than two hours’ outage time, with no draining or flushing required. Using products such as Ozone as cleaning and disinfection agents provides an ideal opportunity for increased recycling and reuse of water, resulting in reduced water usage, waste discharges and environmental impact.

Usages of Ozone within the food and beverage industry include:

1. Cleansing fruit and vegetables

General practice for cleansing fresh fruits and vegetables consists of washing the produce in ozonated water, where the wash water is recaptured and treated by filtration and ozonation. The treated wash water is free of bacteria, colour and suspended solids, and can be recycled to reduce water usage. Unlike conventional chlorine-based washing systems, wastewater discharged by the ozonation process is free of chemical residuals, a growing concern that contributes to groundwater pollution.

2. Sanitising foods and preventing bacteria gaseous

Ozone is a strong sanitisation and fumigation agent, which can be used to sanitise foods in storage and during shipping to prevent bacteria, mould and yeast on the food surface, as well as to control insects. It can eliminate undesirable flavour produced by bacteria and chemically remove ethylene gas to slow down the ripening process, allowing for extended distribution.

3. Disinfecting bottled water

For decades, Ozone has served as an effective disinfectant of food products and is now also commonly used in the disinfection of bottled drinking water. Ozone is particularly soluble in water, as it is effective in killing microorganisms through the oxidisation of their cell membranes. It also has a unique property of autodecomposition and will leave no toxic residues. This provides bottling plants with the opportunity to disinfect the drinking water and extend shelf life without chemically adding to the process water.

Rainwater conservation

The food and beverage supply chain incorporates large cold storage and distribution centres to store and manage logistics to supermarkets. By necessity, these centres have an extensive roof area and hard standing for vehicles, which serves as an ideal solution to catch rainwater. Some organisations have taken the initiative of capturing rainwater for use in secondary low risk applications, such as Evaporative Cooling systems on refrigeration plant, vehicle washing and toilet flushing. In most cases, it is a planning requirement during the building of these sites to incorporate underground consolidation tanks to prevent flooding in heavy rain, meaning that upgrading to water recycling is not complex. Ozone can be applied as a primary source of disinfection, providing a simple, environmentally-friendly option for the supply chain’s water hygiene requirements.

CIP systems

Industries that rely heavily on CIP systems are those requiring high levels of hygiene, including the food and beverage industry. CIP systems have been reliably used to remove solids/bacteria and clean inside the surfaces of tanks and pipelines in liquid process equipment, helping to avoid the costly downtime associated with lengthy dismantling and cleaning tasks. Many existing and older CIP systems can be time intensive and waste large amounts of energy, water and chemicals, so manufacturers must aim to optimise them or upgrade the technology where possible. For example, when using a CIP set that washes different sizes of vessels, adding alternative programmes for smaller units can save the plant time and water.

Root Vegetable Washing and Hydrocoolers

Developments in Cyclone Dirt Separation filtration technology has allowed for a greater re-use of water during produce washing thanks to the maintained cleanliness of the water systems. This reduces the risk of high energy and water consumption, while also improving the handling of waste material. For example, the use of Cobra Cyclone units during the primary washing of root vegetables not only allows for increased recycling of wash water, as well as the simple separation of soil sediment for disposal. Similarly, when Ozone is used to sanitise the water in conjunction with Cyclone Dirt Separators, it allows the final discharge water to be used safely for irrigation purposes.

The hydrocooling process sprays or submerges fresh produce with either ice or cold water (at 0.5 degrees Celsius or 31 degrees Fahrenheit), which suppresses enzymatic degradation and respiratory activity. This is a fast and effective way to prevent rapid decay, slow down microbial growth and improve the overall shelf life of the produce. In terms of its ability to reduce water usage, hydrocooling ensures that no water is removed from the produce itself, keeping it fresher for longer, while also helping food manufacturers to more effectively manage their water consumption. The use of ozone in place of chlorine in hydrocoolers achieves equal or better microbiological control whilst allowing extended recycling and secondary use of the water.  

Recycling Waste Water from CIP, Processing & Cooling Towers

Reverse Osmosis & Membrane Filtration

Both ultrafiltration and Reverse Osmosis allow for water to be recycled within clean applications in food and beverage manufacturing, providing a positive barrier to prevent suspended solids, bacteria, viruses, endotoxins and other pathogens from contaminating the water. In particular, Reverse Osmosis systems are frequently used to purify the water used within the production of flavoured beverages.

Greater understanding in the design of Reverse Osmosis systems can improve a plant’s water footprint by allowing for a significant reduction in wastewater and increased membrane life. In the majority of cases, Reverse Osmosis systems discharge 25-40% of the water to waste within the purifying process. However, by carefully selecting the pre-treatment of the water prior to the Reverse Osmosis system in conjunction with a secondary unit on the waste stream, the wastage level will be reduced to less than 10%.  

Electro-deionisation

New developments in electro-deionisation target the desalination or purification of impaired water or water with elevated salt levels. This technology increases energy efficiency and reduces the water footprint of the traditional purification process, enabling its use across a wider range of applications. Ideally suited to water recycling in the food and beverage industry, the process uses electricity, ion exchange membranes and resin to deionise water and separate dissolved impurities from the water. Electro-deionisation equipment only consumes electricity and can operate continuously, producing high purity water of a consistent quality with no chemical waste.

How can SOCOTEC help?

SOCOTEC’s Water Treatment & Equipment team is best placed to advise those within the food and beverage manufacturing industries on a range of water treatment and hygiene requirements. For more information, click here or get in touch via this link.

References

• Save the Water (2019) Education Resources, Water Facts [accessed 29 May 2019] http://savethewater.org/education-resources/water-facts/
• Schug, D. (2016). Reducing water usage in food and beverage processing.
• Szyplinska, P. Food and beverage industry focuses on water footprint and greater sustainability Industry Analyst for Environment (Water) Markets at Frost & Sullivan
• WRAP (2001) Case Study: UK Drinks Sector, Water efficiency
• WRAP (2001) Case Study: UK Drinks Sector, Resource efficiency in the UK brewing sector.