Technologies are always evolving and present several options while making decisions. Generally, costs are given prime consideration as a selection criterion while meeting the required target of efficiency and yields. Costs include the capital and operating costs on a life time basis. We calculate the Present Worth of the two options by amortizing the operating costs and help us to make a comparison to select the technology of the least life cycle cost.
It has been now realized that costs alone may not be the sole criteria. While cost could be one of the critical and deciding factor, there could be other considerations as well, especially on the environmental and social frontiers.
One of the important environmental factors is the generation of wastes and emissions. We consider this perspective by adding the costs of pollution control and monitoring to the base costs of the technology. These costs include installation as well as operating costs. A technology may not be preferred when costs of pollution control are added to the base costs. We see this situation when comparing biological processes with those following the thermal or chemical routes.
Use of technologies that have low Material Intensities or MI (including embodied energy as well as factoring virtual forms of water) is sometimes preferred. These decisions are taken by performing Life Cycle Assessment (LCA) to helps to arrive at the estimates of MI. You may like to visit “databases” created by Wuppertal Institute in Germany. A paper on Assessment of wastewater treatment technologies: life cycle approach by Pradeep Kalbar, Subhankar Karmarkar and Sham Asolekar will be an interesting read.
Another criterion is the emissions of Greenhouse gases (GHG). While there are no emission limits legally prescribed, most would like to choose technology option that has minimum emissions of GHG. Such technologies are often called as low carbon technologies. Technologies that use more of renewable energy get preferred as compared to those which may use of fossil fuels. You may find Buyers Guide to Renewable and Low Carbon Technologies as an interesting read published in the UK.
Exclusion is another environmental criterion that could decide the choice of technology. For example, we may not like to prefer technologies that use mercury or chlorine in any form. On the other hand, there could be preferences. We may prefer technologies that can make maximum use of the locally sourced materials to avoid transportation and boost local entrepreneurs.
We also need to factor the costs of disposal of the end of life of the equipment. In some cases, because of the use of non-biodegradable or potentially hazardous materials –costs of disposal of the used or abandoned equipment could be substantial. This aspect could influence the final decision between technology options.
Environmental risk is another perspective. Some technologies may be compliant to the waste/emission standards that are legally prescribed but may pose risks of process upsets even leading to disaster during operations. These risks may arise due to process abnormalities that may occasionally arise – albeit rarely, posing certain restrictions on continuous operations or requiring on-line monitoring with process control or investments on the back-up systems. These considerations could add to the total costs.
Social considerations could also play an important role in the selection of technologies. These considerations include local employment. When one of the objectives of investment is to improve livelihoods of people, then technology options that generate local jobs may be preferred. Here low to moderate scale of technology and associated investments, especially in offering decentralized solutions get preferred. These technologies should be easy to understand and operate.
Generation of odor and noise and safety become additional considerations in the interest of workers and the neighborhood. Technologies that lead to nuisance during operations, shut down and startup operations are not preferred
When we address all the above considerations, we generally come up with design of a “system” that incorporates a “mix or combination of technologies”. In this system design, we ensure that technologies are in place for pre-treatment (that may include separation), main processing, with add on pollution control and recovery units and process control instrumentation (monitoring and interlocks) for ensuring safety during operations. This entire system then needs to be assessed based on economic, environmental and social parameters. For this purpose, quantitative or qualitative schema are used such as weighted scoring and Analytical Hierarchical Process (AHP). You may like to read paper by Tung Nguyen Nhu on Application of Analytical Hierarchical Process Method to Select a Technology Option for Water Treatment in Rural Settings.
When investments are sourced from public funds, a transparent process of technology assessment needs to be followed. I developed for the International Environment Technology Center (IETC) at the United Nations Environment Programme (UNEP), a methodology called Sustainability Assessment of Technologies (SAT). Figure below shows the steps followed.
Methodology for Sustainability Assessment of Technologies
SAT methodology operates in tiers such as screening, scoping and detailed assessment. It follows a PDCA cycle as implemented in the most management systems to ensure that feedbacks on the use of technology is factored. Importantly it involves expert and if appropriate a public consultation. Lastly, the methodology could be used to select options at both strategic and operational level e.g. whether decentralized solutions are better suited than the centralized option. More details on SAT can be accessed from the manual available online.
Applications of SAT methodology have been carried out for making choice of technologies across sectors such as water treatment, wastewater recycling, waste recovery etc. The SAT manual cited above includes a solved example that could be perused for better understanding.
I spoke to my Professor Friend about how sustainability could be factored in the technology selection. I told him that the “costs” incurred due to wrong selection of technology could be more than the apparent savings! Professor let me speak while enjoying his cigar. After I finished, he extinguished his cigar and said “Dr Modak, what you said is worth in a conference. The world would have been different or the research would have changed its course – if sustainability considerations were actually considered while making the right choice on technologies.
He then paused, smiled and said while patting my back
“Don’t forget Dr Modak, today it is the L1 that counts!”
I realized that there are hardly any choices to make!!
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