The biggest challenge with many packages: Weight, hygiene and durability requirements - solvable by reducing the multitude to one plastic.e biggest challenge with reusable packaging: Weight, hygiene and shelf life requirements

For many food and drugstore products, reusable packaging made of break-resistant glass or stainless steel is also available on the Frankfurt Bridges. For particularly lightweight products or those for which glass or stainless steel packaging is unsuitable, the plastic alternative bio-based polyethylene is provided: Here, the large number of plastics used is reduced to one, the combustion of which produces only water and CO2, the latter in such a pure form that it can be reused industrially – since a mixture of plastics once incinerated, produces too many combustion products, thus making the clear separation and reuse of CO2 impossible. And polyethylene fits all: It can be used to produce all forms of packaging, from films to hard shells, and it can also be made from renewable raw materials.

Content: The solution to the packaging problem must combine different approaches - unpackaged, reusable and (ecologically immaculate) disposal

1.Products that do not necessarily require end-user packaging are left unpackaged.

2.Reusable glass and wafer-thin stainless steel packaging is used for all food and drugstore products for which it is suitable.

3.Residual materials from the processing of agricultural products are used for sustainable packaging - so that no new cultivation areas have to be created, but instead existing CO2 -binding plant residues are put to good use.

4.For many products, however, plastic packaging is necessary for reasons of hygiene and durability. On the Frankfurt Bridges, therefore, there is also plastic packaging, but its variety is reduced to input materials so that even in the event of disposal by incineration, the CO2 is released in the process in such a pure form that it can be collected with a standard filter and used as a manufacturing agent for further production processes.

Only when the variety of packaging materials is limited to a few materials can each remaining packaging-form reach a scale that enables economies of scale and thus sustainability

The world of packaging is almost impossible to grasp: It is extremely diverse and confusing. So far, the easiest option has therefore been to incinerate the majority of packaging: Because re-use, recycling and disposal processes for so many different materials have a correspondingly low throughput, so that the economies of scale that would be necessary to save resources and energy cannot be achieved. The answer to the problem: The complexity of the materials must be reduced - then the individual processes, whether re-use, recycling or disposal, will result in a significantly higher throughput per process, making the system more sustainable.

However, the reduction must be differentiated and take into account that different product groups have different packaging requirements. Unfortunately, there is no single "super material" that can replace all current packaging materials in one fell swoop.

Previous approaches to solving packaging problems in supermarkets and drugstores are unsatisfactory

Most of our food and drugstore products are packaged in single-use plastic. Once used up, the plastic packaging is found in the waste garbage can.

Just under 19 million tons of packaging waste was generated in Germany in 2018 - in the year 2009 it was still 15 million tons, according to statistics from the German Federal Environment Agency. Most of the household waste is incinerated. Only 16% of it was recycled, according to a 2017 study by market research institute Conversio.

According to a 2020 statement by NABU (the German Nature and Biodiversity Conservation Union), thermal waste treatment plants in Germany emit more than nine million metric tons of CO2 equivalents.

There are good approaches, but they all have certain disadvantages:

(1) Recyclable plastics do not completely solve the problem of energy and resource consumption, because mostly true recycling is only possible in parts - the largest part is lost to downcycling.

(2) Bioplastics: Most are not biodegradable with reasonable effort or if biodegraded they shed microplastics.

One valid approach to solving this problem, which is also being promoted on the bridges, is unpackaged stores: however, their concept is not suitable for all products in terms of hygiene and shelf life.

A sustainable reusable and disposal system will therefore be created on the Frankfurt Bridges, using robust glass, enameled stainless steel, plastics that can be incinerated without leaving residues, and packaging materials that are completely biodegradable with low energy consumption. This system can be successively transferred first to the area surrounding the Frankfurt Bridges, then to all of Frankfurt, and then to other cities.

Today, resources and energy spent on disposable packaging literally end up in the garbage can - full recycling is rarely possible

Even if part of the valuable material plastic is recycled: Most plastic packaging is so heterogeneous and multi-layered that a recycling process with separation into recyclable components is far too costly or simply impossible.

Even the reusable plastics usually undergo downcycling rather than recycling because they are no longer suitable for food contact. This means that no new food packaging can be made from them, but rather more undemanding products such as doormats and flower pots.

The positive core idea of recyclable packaging is therefore retained on the Frankfurt Bridges in a more sustainable way: Glass is 40% recyclable, stainless steel even completely.

Bioplastics are often deceptive, as many of them can also release microplastics

Even packaging certified as compostable is not straightforward. The label "compostable" is often misunderstood, as these products do not decompose in home garden compost, but only in industrial plants under certain circumstances.

In addition, polymers classified as compostable only have to decompose to 90% into parts smaller than 2mm (see EN 13432). So there are always small particles left over.

This 3-month process also devours energy, since the mass to be composted must be moved and certain temperatures must be maintained, which places a massive burden on the ecological rucksack.

If such "compostable" packaging ends up in nature, in landfills or in bodies of water, they decompose, if at all, releasing microplastics.

There is often a call for a return to earlier shopping processes - but the demands in supermarkets and drugstores are higher than they used to be in corner stores or markets

While take-away packaging has a life-cycle-time of a few hours, supermarket packaging in particular needs to protect food throughout the supply chain and eliminate any deterioration.

It is therefore difficult to shop as we used to in the corner store: a large part of our food still has to endure too long transport routes and is not regional.

Shopping habits and demands on food are also constantly changing: While visits to restaurants used to be the exception, today we cook much less ourselves.

Moreover, in the past, vegetables were bought and eaten when they were already a little limp or wilted, but today we want everything spotless and crisp and fresh.

Uncontrolled omission of packaging would lead to wastage of food and thus of raw materials and energy

By keeping food fresh and preventing it from spoiling, packaging plays a key role in reducing CO₂ emissions:

Agriculture accounts for almost 20% of global CO₂ emissions. This does not include the energy used to transport the food, which also has an impact.

All food that is thrown away because it no longer meets our requirements has been produced for nothing and has polluted the environment with CO₂for nothing.

Therefore, packagings are not per se a wasteful component of our modern life – in fact, adequate packaging of food can save large amounts of agricultural land, fertilizer as well as methane and CO₂ emissions.

The agricultural sector is one of the most important sources of anthropogenic greenhouse gas emissions today.

It is estimated that around one third of global greenhouse gas emissions are due to food production (IPCC 2021, Nature Food 2021). They result from land-use change through the conversion of forests to cropland and pasture, as well as from the draining of peatlands and the burning of biomass. Transportation, waste management and industrial processes also contribute.

The unpackaged stores therefore have a selected range of products that tolerate sales processes without packaging

Unpackaged stores are proliferating, expressing society's willingness to change profound patterns of convenience. But to do so, customers must be willing to bring their own containers to the store for certain products. This works for the portion of people who consciously store at unpackaged stores. But the question is: Does it also work on a large scale? If you want to switch to the system of today's unpackaged stores, you first have to plan exactly in advance, and second, you still have to go to the supermarket for all refrigerated or canned products. So you have to be willing to invest some time and say goodbye to spontaneity for a bit.

Offerings without packaging have nowadays been discovered by life style providers

In the area of drugstore products, too, there are more and more offers without packaging.

This clearly shows the interest in society and the willingness to buy unpackaged products.

To promote unpackaged products, there are market halls on the Frankfurt Bridges with stands for sellers from the region

The shorter the delivery routes, the less packaging is needed. For this reason, special market halls on the Frankfurt Bridges are reserved for products from the region or production communities from the surrounding area.

Market hall on the bridges for products from the region, urban gardening, or even allotment harvests

The next best packaging option: a reusable system in standard containers

Organic supermarkets in particular are moving towards offering environmentally friendly reusable glass packaging for typical unpackaged products - because self-filling is time-consuming for many customers or is perceived as unhygienic.

However, if the products are "packaged," you can take them right off the shelf, you don't have to fill and weigh them, and you can be sure that they have not been contaminated before reaching the shelf.

From the consumer's point of view, however, the usually heavier reusable packaging primarily has the weight disadvantage. The need to transport them back also affects the purchasing process.

Reusable tempered glass and enameled stainless steel packaging works for many supermarket products

Supermarkets already have glass and metal packaging - but most of them are not reusable: Weight and return costs often make buyers shy away, while transport and cleaning costs also make it a costly solution for food manufacturers.

Special glass packaging is therefore used on the bridges: Chemically hardened, shatterproof glass allows glass containers to be made much thinner while retaining the same strength. This makes the jars lighter. The thinner glass also saves energy during transport, as with the take-away lightweight glass containers, and significantly reduces the weight in the shopping basket.

Metal containers are also potentially reusable. In contrast to today's classic metal cans, the Frankfurt Bridges packaging system uses standard containers made of enameled stainless steel for supermarket products, which are fitted with a screw cap. This means that the can does not have to be destroyed in order to be opened - as is the case with today's cans - but is reintroduced into the cycle. Only when it is no longer fit for use is it recycled.

If enough suppliers use the same standard containers, the transport costs for the return transport of used packaging will decrease significantly due to the possible logistics optimization.

As with all reusable concepts, a deposit system ensures that the containers are returned. Either via a Renomat garbage can, which is located like the yellow garbage can at the bridge houses, or directly at the supermarket.

The efficient reusable system on the bridges: reduction of complexity with a large selection of container sizes and shapes at the same time

Different products from different manufacturers can be filled into the same standard containers. These are available in different size gradations, so that suitable sizes are always included for the most diverse products - for example, only very small containers are suitable for ginger shots, while fruit juices are usually requested in containers of over 100ml.

This means that empty packaging can be returned flexibly and interchangeably to all manufacturers connected to this system. This enables significant logistics optimization for the return transport routes of the reusable packaging. In addition, trucks from manufacturers delivering goods can always return with empty, pre-cleaned returnable packaging.

Konstantinos Papaioannou - dreamstime.com

When it comes to packaging selection for drugstore products, ensuring hygiene and light weight is the biggest challenge

Similar to food in the supermarket, there are items in the drugstore that could do without packaging, such as brushes, hand mirrors or even bars of soap.

However, cosmetic as well as medical products require packaging, as certain hygiene standards must be met. The same applies to hygiene products such as tampons or pads.

While the more break-resistant glass packaging described in the chapter "Take-away packaging" could be provided for creams, this material would be too heavy in relation to the product weight for many other items (kitchen rolls, etc.).

Flat tinplate jars can be used for many cosmetic products such as mascara or lip gloss.

For food packaging, shelf life is the biggest challenge

In the supermarket, most food groups require packaging to maximize shelf life: Packaging protects them from germs on the one hand, and from being damaged on the other. This is important, for example, for sensitive foods such as sausage or raspberries.

But packaging also prevents foods such as lettuce, broccoli and other vegetables from drying out and wilting, or conversely, "sweating," as with mushrooms.

Sometimes packaging is also necessary to prevent the food from oxidizing. For example, meat and fish are therefore often vacuum packed or packaged in a modified atmosphere. Crispy products such as chips must also be packaged in an inert gas atmosphere. This prevents these foods from drawing water and thus losing "crispness" or flavor.

Packaging is therefore not bad per se - on the contrary: by preserving shelf life and hygiene standards, it indirectly contributes to making consumption more sustainable overall.

Especially in the case of food, many products have very specific requirements for their packaging

1.Protection against mechanical injuries (pressure marks, bruises): especially with sensitive fruits and vegetables, pressure marks result in reduced shelf life.

2.Protection from chemical processes and metabolic processes in plants:

Transpiration: In leafy plants, such as lettuces, water evaporation occurs as a result of natural processes in the plant. This occurs via specially adjustable openings on the underside of the leaves. The process is influenced by temperature as well as humidity. To prevent dehydration and thus reduce food waste, packaging is necessary that keeps the humidity around the product relatively constant and thus reduces transpiration.
Respiration and metabolicproduction: fruits whose skin (their natural protection) has been damaged start fermenting. In the case of mushrooms, anaerobic respiration occurs without packaging, which leads to changes in taste and odor and faster spoilage. More precisely, sugar, that oxidized to CO₂, consumes oxygen in the process and water is released at the same time.

3. shelf life through vacuuming

Removing air not only reduces reactive gases on the food, but also preserves nutrients. Fresh meat, for example, is increasingly being vacuumed. It contains the purple pigment myoglobin. This would oxidize to oxymyoglobin (bright red dye) by an increased concentration of atmospheric oxygen.

By oxidizing the iron II ion to the iron III ion, metmyoglobin is formed. As a result, the meat then exhibits a gray-brown color. (DLG.org) This process can be prevented by vacuuming or a protective atmosphere.

4. simply keeping contaminants out of the environment

There are many influences in the environment that cause food to spoil more quickly, for example germs that cause a cold cut to spoil. Tight packing or vacuuming can provide a remedy.

5. shelf life through protective gas atmospheres

Here, the gas inside the food packaging consists of various gas components such as carbon dioxide, nitrogen and oxygen. These have various functions such as inhibiting oxidation processes and the growth of aerobic bacteria (CO₂ and N₂) and inhibiting growth for anaerobic microorganisms (O₂). A distinction is made here between different compositions.

Controlled Atmosphere: Enrichment with nitrogen and displacement of oxygen. Not used in sales, but mainly for long storage of fruit or vegetables.
Modified Atmosphere: Different gas mixtures depending on the product. For example, to keep baked-on rolls as long as possible and prevent mold, an inert gas atmosphere is introduced into the packaging. Nuts, on the other hand, require an inert gas atmosphere of nitrogen, otherwise they quickly go rancid due to their high fat content. In the case of dairy products such as cheese or yogurt, nitrogen or carbon dioxide is also added to the product as an atmosphere.
Equilibrium Modified Atmosphere (EMA): Atmosphere in which gas exchange is possible. This is mainly used for fruit and vegetables, as the product's own respiration must be taken into account. Therefore, the packaging film is micro-perforated, which allows gas exchange between CO₂ and O₂ and thus better shelf life and longer freshness. Strawberries or mushrooms are an example of this.

Plastic is required for the packaging of some products due to shelf life requirements, weight reasons or due to the product shape

Reusable jars and cans are suitable for all foods that adapt their shape, such as jam or yogurt, rice, beans or even butter. However, glass jars and metal cans are not ideal for everything: Cold cuts or cheese as well as fruits and vegetables cannot be packed in them.

They are also not suitable for frozen products, nor for finished products prepared in their packaging (e.g. in oven or microwaves), as extreme temperatures can have a negative effect on the extremely thin glass or metal.

Other products, on the other hand, require plastic to be vacuumed or to ensure gas exchange through special microperforations.

For bulky drugstore products such as toilet paper, correspondingly large packaging made of glass or metal would be too heavy in proportion: for some such products, uncoated, and thus easily recyclable, paper packaging is the solution, but for all moisture-containing products in the drugstore, this option is also eliminated.

Conclusion: To meet all the requirements of a modern food and drugstore market, there is indeed still a need for a packaging material other than metal or glas – a material with the properties of plastic.

The plastic of choice: bio-based polyethylene (PE)

To minimize the damage potential of plastics, they should:

1.not be produced from scarce or regionally limited resources (i.e. not from petroleum, for example), but should preferably be able to be produced from renewable raw materials.

2.be recyclable or at least suitable for downcycling.

3.emit neither microplastics nor pollutants nor unfilterable (i.e. contaminated with residues) CO2 during disposal.

In addition

1.combustion does not produce any substance that cannot be easily filtered out.

2.the plastic must be suitable for food, ideally also for acidic products.

3.the plastic must be approved for food contact under German food law.

Polyethylene (PE) is one such plastic. It is already used as a packaging material in the food industry for both robust hard plastic packaging and film packaging.

Polyethylene can be made from renewable raw materials such as sugar, starch or cellulose, or even from waste products such as food scraps or peels. If it is burned in a single-variety process, only CO2 and water are produced. The CO2 can be captured and taken out of the cycle or even used for other chemical manufacturing processes.

Polyethylene made from renewable raw materials is therefore primarily used for films and plastic packaging on the Frankfurt Bridges. By limiting the packaging of all items requiring plastic in the bridge stores primarily to the one plastic PE, it is possible to incinerate it by type - unlike the large number of plastics that end up in the yellow garbage can today.

PE can be produced from renewable raw materials

Polyethylene can be produced from renewable raw materials such as sugar, starch and cellulose, or from waste products, such as peels, which are produced during the production of food.

However, this also applies to polypropylene, the second widely used plastic for food packaging, although it has other disadvantages (see below).

The combustion of pure PE produces only water (H2O) and carbon dioxide (CO2)

The emphasis is on "pure", because polyethylene is not the same as polyethylene: Rather, the same PE must always be taken so that CO₂ and pollutants (mostly due to additives) can be tapped schematically and thus without gaps during managed combustion. Only then will only CO₂ and H₂ O be produced. In very small quantities, the combustion products of additives are also released, which must be added to all plastic packaging. But here, too, the number can be significantly reduced through standardization.

If CO₂ is filtered out in (almost) pure form using standardized processes, it can be used for other biological-chemical processes, for example algae farming (but requires large "lakes") or for the production of other plastics such as polyhydroxybutyric acid (PHB) or artificial photosynthesis.

In addition to PE, only those plastics are included in the bridges' packaging range that can also be produced from renewable raw materials, can be incinerated with low CO2 emissions or for which a miroplastic-free disposal can be guaranteed

The range of plastic packaging must be reduced to those plastics that can be incinerated without releasing CO₂ emissions: However, this is only possible if pure CO₂ is produced during incineration, because only this can subsequently be used in other chemical processes or bound in a standardized manner.

In addition, there are plastics that can be degraded without leaving residues, i.e. can be disposed of in the organic waste garbage can. It is important here (1) that they are really degradable without leaving residues and not only under laboratory conditions, i.e. they decompose completely without leaving microplastic residues. Furthermore, it must be ensured (2) that their biodegradation process is not energy-intensive or that they decompose in a composting plant within a reasonable period of time without the need for costly microcultures to be grown, tempered and continuously renewed etc.

The recycling of PE can be seamlessly integrated into the circulation system on the bridges

After the PE packaging is separated from other packaging materials, it is incinerated. As long as the PE was produced cleanly, only CO₂ and H₂O (water) are produced during this process. The energy produced during the incineration process can be further utilized. The CO₂ is captured with special filters so that it does not enter the atmosphere. It can be recycled in various ways, e.g. in the protective atmosphere of certain products, but also in the chemical industry.

The process has to follow stirct rules: Because if the PE were to be stored in open landfills - as many plastics are today - the gas methane would be produced, which stores 25 times more heat in the atmosphere than CO₂.

Schematic illustration of packaging disposal or recycling

The three types of packaging (made of glass, metal or PE) are collected from the houses on the bridges, transported to the municipal waste disposal company, where they are either incinerated in a managed manner (PE) or cleaned and returned to the producer to be refilled and returned to the supermarket (Glas & Steel).

Conclusion: Reducing complexity is the goal of packaging material selection with regard to the disposal process

We have to find the right shape for all products:

Unpackaged wherever possible, and standard glass and standard metal containers as a reusable solution when it suits the product.

All products that do not fall under this , but are made significantly more durable with plastic packaging, should actually be packaged with plastic for sustainability reasons to avoid throwing away food.

The single-use disposal of plastic is less problematic if it has been produced from renewable raw materials (i.e. CO2-neutral) and can either be disposed of in the organic waste garbage can without the risk of microplastics or, like bio-based PE, produces such pure CO2 when incinerated that it can be used in downstream processes to manufacture other products and is not emitted into the air.

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