$$ \mathrm CAPEX =\mathrm Preliminary \ \mathrm financial investment +\sum \mathrm RI _ \mathrm biofilter +\sum \mathrm RI _ \mathrm PSA +\sum \mathrm RI _ \mathrm comp +\sum \mathrm RI _ \mathrm v \_\mathrm pump $$ In the biotrickling filter, aerobic bacteria decompose H2S, and to help keep these bacteria inside the reactor, an enlarged surface a