Bioresources chain

A bioresource can be used multibranched—to produce one main product and one or more coproducts. Furthermore, after food consumption and after substantial utilization of a biobased product, some of the components of the original product may be used again. In this way bioresources can be used in cascades. Examples are shown in Ref. 30. However, utilization never can be repeated unlimited, since losses occur in each step.The final stage in the bioresource utilization chain is either energetic utilization or disposal. 

As processing outcomes, they consist of parts from the primary bioresources. They may be mechanically removed residues from the primary bioresources during primary processing. Mechanical, but also biological, chemical, or physical processes could be used for separations in the follow-up processing chain. The main output of such processes are the primary bioresources, all others are secondary bioresources, if they met the previous noted criteria. 

As maintenance residues secondary bioresources are generated on green areas such as large parks, lawns, sport places, and dikes if harvested as genuine fractions in significant amounts under controlled conditions. For harvest and collection, the follow-up steps in the utilization chain should be considered in order to gain the maintenance residues in ample quality in terms of purity and fireshness. 

Tertiary bioresources are also parts from virgin materials, which were separated along the chain. But compared to secondary bioresources they are residues which occur rather in small amounts at the generation place and/or are mixed with undefined firactions or... 

Note Often a lot of unused food is thrown away (Chapter 7, Section 4.1.2), which should be avoided. In contrast, food preparation residues such as potato peels and vegetable trunks are considered as not avoidable. In case of meal residues avoidable fractions mainly occur in case of too big portions. The avoidable fractions should not be considered as bioresources. However, if generated, they should be included in reuse chains, but priority should be given to avoidance measures. 

The coding system shall help to define the bioresources place in the chain, to design and evaluate utilization options, as well as to work sector-comprehensive and sectorconnecting. It can be built on existing coding systems. Some sectors connected with bioresources have already terminologies and classification systems, which are adjusted to the primary goal of the respective sector. 

Interrelations Between Bioresource Categories Shown on the "Paper Chain"... 

An example for the complex interrelation between primary, secondary, tertiary, and quaternary bioresources is shown in Figure 7.5. The paper chain is a simplified visualization of the complex processes connected with the production of a paper-containing product. Figure 7.5 focuses on the main processes connected with bioresource transformations only. Processes of pulping including specific pathways for by-product utilization, e.g., valorization of tall oil, are discussed in more detail in Chapter 3. The processes involved in paper production are described in more detail in Ref 54. A good overview on aspects related to the whole cascade is to be found in Ref. 5. The paper chain was used as an example, since paper production has historical tradition and the processes are well established today, but still have room for improvements. 

Note The intermediate products (pulp and paper) and the e product (paper product) in this chain contain primary bioreources they are not a primary bioresource as a whole. 

Figure 7.5 The paper chain—bioresource utilization pathways from the primary generation over multichain and cascade utilization till final disposal or energetic utilization demonstrated on the example of paper generation with data for Germany.

To sum up, the primary bioresource for paper chain is the harvested tree respectively the tree s stem-wood. Secondary and tertiary bioresources are bark, other woody biomass, black liquor, paper production, and processing residues which are generated along the chain. If these are utilizedfor substantial or energetic purposes we have a multichain utilization. And if the quaternary postconsumer fibers from wastepapers are reused we have cascade utilization. 

Figure 7.7 Principal process chain with examples for bioresource-depending process steps in the first part of the chain.

To evaluate the efficiency of bioresource utilization chains, easy and comprehensive standardized methodologies have to be established. Since all bioresource utilization chains— the paper chain, the food chain, and others—are very complex, they have to be simplified. One simplified option is shown in Figure 7.4 for the paper chain. Although in Chapter 7, Section 2.4 a lot of data from various sources from all stages of the paper chain were provided, the data collection is stiU not comprehensive enough for a chain evaluation. To define, which data are needed and how they could be provided in an open and structured way is a challenge for the future. With progress in statistical data documentation, evaluation can improve as the accuracy of data improves. 

The various regional tertiary and quaternary bioresources generated, the actually established technical systems, and the frame conditions for upgrades as well as the demands on products lead to various very different processing chains. A principal scheme of a chain with some bioresource-depending options for technical units is shown in F re 7.7. The displayed scheme includes a process leading to an energetic product as core unit. 

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