By Nikolaus Fecht
Humans need two to three liters of water a day, which is consumed as drinking water from the tap, bottled mineral water or in the form of water-based bottled drinks. Added to this are the approx. 120 liters of water per person per day in Germany, which are used to cook, wash or for sanitary purposes. But that's not it yet.
Huge water footprint
Like the citizens of other industrialized nations, Germans consume most of their water indirectly - within products, as well as in the form of process and wastewater. Most people are not aware of how much water is required for industrial production.
The "thirst" of the various industrial sectors varies greatly. For the production of a bag of potato chips (200 grams), for example, food producers need 185 liters of water. A staggering 10 liters of water are hidden within every sheet of A4 paper and nearly 400,000 liters of water is used on average by the automotive industry to produce a vehicle. According to statistics, this represents a water footprint of 3,900 liters per German citizen per day. The output of public water utilities, which receive around 5 billion cubic meters of water per year in Germany, is correspondingly high. This volume is enough to fill over 50 million bathtubs over and over in almost all German households.
However, the quality of natural water resources is generally not sufficient for use in foodstuffs and in the beverage industry - with the exception of officially recognized mineral springs. This water must be processed using elaborate procedures and according to strict statutory provisions. This is where the German companies specializing in water and wastewater technology come into play.
Increasing hygiene requirements
The requirements on the hygiene of plants and processes have increased in recent years, particularly in drinking water treatment for beverage production. According to Stefan Jakubik, Head of Corporate Communications at Veolia Water Technologies Germany in Celle, these requirements are a challenge because they apply to the entire technology used, from planning to engineering and commissioning to regular operation and purification procedures.
These requirements are described in great detail in a large number of standards and regulations, such as the VDI Guideline 4066 on "Hygiene requirements for the production and aseptic filling of beverages" and the regulation on the quality of water for human consumption (German Drinking Water Ordinance - Trinkwasserverordnung, TrinkwV). The latter regulates, among other things, which treatment substances and materials may be used in combination with drinking water.
Incorporating hygiene into the life cycle
Veolia Water Technologies is meeting these growing requirements with a hygienic design concept that covers the entire life cycle of a water treatment plant for beverage production. "As early on as the planning and engineering stages, we take the relevant legal requirements, as well as the stricter customer-specific requirements into account in order to minimize microbial risks," emphasizes Jakubik. "We focus on meeting the requirements for all plant components including the materials used." It is important, for example, to avoid dead spots and to optimize flow designs in order to prevent stagnation. The largely automated and residue-free purification is also a central aspect. In addition, all the processes relevant to hygiene during operation must meet the requirements set on their documentation and verifiability. The Celle-born concept also stipulates the thorough training of the operator's employees and their subsequent support. This includes the continuous optimization of plant operation according to the customer's requirements.
Krones AG in Neutraubling produces plants for filling water and water-based beverages. The German Mineral and Table Water Ordinance (Mineral- und Tafelwasserverordnung, MTVO) and the Drinking Water Ordinance directly affects their work. Among other things, the MTVO specifies the prescribed procedures for water treatment, since they also define the subsequent designation on the label. "The specifications for water are relatively detailed and clear," explains Dirk Scheu, who is responsible for soft drinks, dairy products and water at Krones. "The MTVO, for example, stipulates the duty to provide documentation in order to retrace batches. If you start to take these aspects into account at an early stage, you can stop mistakes quickly."
From the well head to the bottler
In order to meet the multitude of varying regulations, the Bavarians decided to take their own approach. Dr. Roland Feilner, Head of Product Management at the company, says: "We apply a holistic approach for hygiene which starts at the well head and extends over the entire processing technology up to filling." As a one-stop shop supplier, Krones provides the entire plant technology from well head to the labeling of the bottles. "Process safety is also an important factor," says Scheu. "We use fully automatic quality tests to ensure that everything is correct in terms of the microbiology."
Avoiding the use of chemicals
In order to meet the high regulatory demands placed on hygiene, Krones' customers can clean most production paths automatically. This also includes the complete documentation. The piping, including the filters, are designed so they can be sterilized with hot water at 85 degrees Celsius. The company can also largely avoid using chemicals thanks to ultrafiltration.
But what role does water play as an ingredient in liquid products, such as beer or juice, which are bottled with Krones' technology? "The water for a product is produced exactly when it is needed, because we want to store as little treated water as possible," emphasizes Rudolf Fiegler, Product Manager for Block and Conveyor Technology. Krones takes this approach because treated water can become recontaminated.
According to Fiegler, the company's plants operate with very little temporary storage in order to use water as quickly as possible. Here, too, the Bavarians benefit from their one-stop shop concept with few interfaces.
Clean water worldwide
Grünbeck Wasseraufbereitung GmbH from Höchstädt has set itself the ambitious goal of supplying people all over the world with hygienically pure water using their technology. This technology usually involves highly complex processes. Armin Eisenhofer, head of beverage distribution and food industry at Grünbeck offers an example of the water used in products: "For brewing water, the focus is primarily on hydrogen carbonates, nitrates and perhaps pesticides." Reverse osmosis, a physical process that removes the substances dissolved in liquids, has proved to be successful here.
In a plant that processes water for the production of fruit juice, on the other hand, the Höchstädt-based company's task is to reduce the oxygen. Fruit juice is produced from fruit juice concentrate, which is diluted with what is known as mixing water. "According to the old German Fruit Juice Ordinance, this water had to be extremely low in salt," explains Eisenhofer. The new pan-European Fruit Juice Ordinance is a little less strict on limit values. The water must now comply with the German Drinking Water Ordinance and must not contain any chlorine, as free chlorine can affect the taste.
Slowing down the aging process
The mixing water complied with these specifications. "However, a customer of the fruit juice manufacturer demanded to reduce the residual oxygen content in the mixing water from 7 to 8 to less than half a milligram per liter in order to delay the aging process for as long as possible and to prevent any changes to the taste," says Eisenhofer. This is also a requirement in the production of beer. The Höchstädt-based company solved the problem with a membrane degassing plant which can process 40,000 liters per hour.
At EnviroChemie GmbH in Rossdorf, process water is an important resource in various processes. For Dr. Gerd Sagawe, member of the management team, wastewater is also important because other substances like phosphor or energy in the form of biogas or heat can be extracted from it. "It is therefore always a case of taking a holistic view of the cycles to determine whether and how the process waters can be used and reused," says Sagawe. "If they are to be used for irrigation, however, they must comply with the purity laws."
Close customer orientation
Because the requirements on process water can vary significantly, EnviroChemie always coordinates closely with the customer. "We discuss the process that the customer's water will go through in a detailed and solution-oriented manner," explains Sagawe. "After that, we take a look at how the process water can be used," he adds. This involves, for example, whether the user wants to use the water for irrigation or recycle it in order to clean the plants. A further possibility is to check whether the customer can recover other substances from the process water.
Keeping an eye on life cycle costs
A closer look at the life cycle costs in this process is also key. Plant manufacturers and users are looking at the entire usage period from the commissioning to the dismantling of the plant. This is very important because only about 20 percent of the total costs are attributable to the investment in the plant, while the remaining 80 percent comes from operation. Sagawe speaks from his experience when he says that customers are placing increased value on determining and optimizing operating costs. The new services therefore include the optimization of plants and individual plant components, especially in the field of wastewater treatment.
Modular construction appeals to global players
This holistic view is also reflected in the way in which the South Hessians develop and build their plants. "We have been modularizing and standardizing plants and components for ten years now," says Sagawe. For this purpose, EnviroChemie divides the entire plant into sub-procedures and their corresponding components in order to reduce complexity. At the Rossdorf site, entire large plants including water technology are created from the standardized components, which are later disassembled into individual modules for the container transport.
The plants can thus be expanded flexibly in a modular manner. "This concept particularly appeals to global players who build standardized plants around the world. The standardized components and procedures are an essential prerequisite for Industrie 4.0 because they reduce complexity," says Sagawe.
Draining wastewater at night
Plants that clean wastewater, for example in beer or mineral water production, are among the specialties of Invent Umwelt- und Verfahrenstechnik AG from Erlangen. The legal requirements vary by country and location. "If a brewery is located in the middle of the city, it can often direct its wastewater directly into the municipal sewage system," explains Dr. Marcus Höfken, Chair of the Board at Invent and Chair of the VDMA Water and Wastewater Technology Group. "The brewery must then follow the rules for an indirect discharger, which means that it drains water into the sewage system and must be able to store the wastewater temporarily." The wastewater is generally drained at night, because the sewage treatment plant can then better absorb the easily degradable industrial wastewater due to its low degree of capacity.
In contrast to this, breweries or beverage bottlers outside of cities have to discharge large amounts of wastewater directly into a receiving water course. They must operate their own sewage treatment plants, which are subject to very high hygiene requirements.
Thorough ventilation of wastewater
"Indirect dischargers often use cleaning agents that can damage the biological process of sewage treatment plants," adds Dr. Peter Huber, the global process expert at Invent. "In order to dilute the cleaning agent or other substances, the plant technology harmonizes the various streams." Moreover, there is the risk of acidic wastewater, which attacks the sewage system due to its low pH value or develops unpleasant odors. This is where plant technology is used to ventilate the wastewater.
Direct dischargers are fail-proof
The situation is different in the case of direct dischargers, which often clean their contaminated wastewater using great quantities of atmospheric oxygen. In an ideal scenario, these sewage treatment plants are efficient and consume very little energy. They are very robust and fail-proof because a standstill would mean an immediate halt in production. Recycling is also central, since a large part of the wastewater - 40 percent in breweries - is used again in processing.
"As a general rule, the requirements for wastewater treatment can vary from case to case," explains Höfken. Currently, the priority on saving and reusing water, he adds. In addition, there is high demand for competitive technology that can be operated with little effort and minimum personnel resources while at the same time being representative and innovative. Therefore, almost no plant is like the other. Each is tailormade using the modular system.
Using simulation to create the tailor-made plant
The system supplier adapts the underlying gradual process to the respective production conditions and according to requirements. This ranges from collecting the water to the final discharge. Simulation technology plays an important role in the development of such complex plants. "Virtual engineering helps to save on costs, increase operational safety and optimize the process," says Höfken in praise of the company's approach.