Over the last few years, the members of zero discharge communities and industries have developed a five‐step methodology for implementing Zero Emissions. Pauli’s Breakthroughs (1996) provides a far more comprehensive approach that extends well beyond the manufacturing site. The summary provided here emphasizes the use and impact of a ZD approach at the manufacturing level.
Analyze Throughput
The first step toward achieving Zero Discharge and/or Zero Emissions is an in‐depth review of the industry to see if total throughput is possible. This means determining whether all material inputs can be found in the final product – if there are no wastes, all inputs must have ended up in the product. One of the few industries where this can occur is cement manufacturing. In the Mini‐Case Study 1.1, however, only a small fraction of the nutrients in the grain ends up in beer.
If throughput is not total, the next step is to determine whether the products manufactured can be easily reintegrated into the ecosystem without additional costs for processing, energy, or transportation. However, since this is rarely possible, most industries will not achieve Zero Discharge unilaterally.
Process and product design engineers will probably find their first opportunities by meeting with their traditional clients, analyzing each client’s throughput, and looking for opportunities for pollution prevention and waste minimization that the client’s in‐house experts may not have seen. The analysis would include evaluating products and services presently being produced, processes and materials used, and management of environmental issues including energy efficiency, as well as clarifying the full scope of emissions.
1.10.2 Inventory Inputs and Outputs
Once the initial analysis has determined that total throughput is not possible, and that wastes will be generated, the next step is to assess the industry’s inputs and outputs, and to inventory all the outputs (“wastes”). A diagram of the inputs and outputs of a system like that of Figures 1.2, 1.5, and 1.6 are then used to compile basic overview of the company’s resources and needs. From this information, design engineers and process specialists can attempt to modify the manufacturing process so that it can become a Zero Emissions system.
Extracting raw materials and processing them imposes significant environmental burdens. An analysis of the industrial metabolism of the product (i.e. its input, materials use, and life cycle expectancy) will help determine the path of least environmental impact. Some materials choices will yield better throughput or by‐products that are more suited for use as an input for another industry.
Additional audits and inventories may be needed to determine manufacturing efficiency by percentage of input wasted, to quantify amounts of waste landfill by type of material, to account for amounts of materials collected for recycling, and to identify major emissions of waste heat and the site and amounts of wastewater discharges. Analysis of these outputs may reveal the most effective ways to reuse these outputs and help to determine which industries could use the wastes as raw materials. For example, at the Namibian brewery, spent grain, excess heat, and wastewater all have potential uses in producing food items.
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