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                TABLE 2.32                                      Cleaner Production  73
                Cost/Benefit Summary

                Factory unit  Action                      Capital/   Yearly  Payback
                                                          operating  savings  period
                                                          costs ($)  ($)     (month)
                Refinery      Use of liquid caustic soda     None     43,860  Immediate
                Steam        Upgrade system network         5,260    97,010   1
                Receiving    Recovery of broken seeds       1,580    81,270   1
                Preparation  Reuse of fines                  1,750    21,050  1
                All          Preventive maintenance program  2,630    5,260  6



                     • Material substitution: The neutralization process that involves the
                       removing of fatty acids to generate soap stock utilizes solid caustic
                       soda as a processing material which leads to corrosion. This material
                       has been changed to caustic soda solution which is less corrosive and
                       with a lower cost of $175/ton against $368/ton. In addition to this sub-
                       stantial decrease in cost in which the daily neutralization cost dropped
                       by 47%, soap stock quality has been improved and better working
                       conditions have been achieved. Annual saving for this process was
                       calculated to be $43,860.


                Cost/benefit analysis
                Cost/benefits analysis, shown in Table 2.32, is the process of weighing the
                total expected costs versus the total expected benefits of one or more actions
                in order to choose the best or most profitable option. While costs are either
                incurred once or may be on-going, benefits, on the other hand, are most often
                received over time. Therefore, the effect of time would be accounted for in the
                analysis by calculating a payback period or projected payback period. The pay-
                back period is the time it takes for the benefits of a change to repay its costs
                and it is calculated by dividing the cost over the annual benefit. Many compa-
                nies look for payback over a specified period of time, for example three years.
                     Example of calculation of the payback period for the preventive main-
                tenance program:

                      Payback period   cost/annual benefit

                      Payback period   15,000/30,000   0.5 years   12   6 months


                Wood furniture sector: Waste and pollution minimization in
                wood furniture companies
                Wood lumber is the raw material for wood manufacturing. It is usually in
                the form of logs of different lengths and thicknesses depending on the type
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