An environmental engineer wants to evaluate three different methods for disposing of a non-hazardous chemical waste: land application, fluidized-bed incineration, and private disposal contract. Use the estimates below to help him determine which has the least cost at i = 10% per year, on the basis of an

(a) Annual worth,

(b) Present worth evaluation.

Land Incineration Contract First cost, $ AOC, $/year Salvage value, $ -900,000 - 150,000 -95,000 25,000 4 -140,000 -60,000 300,000 6. Life, years