A battery manufacturing plant has been ordered to cease discharging acidic waste liquids containing mercury into the city sewer system. As a result the firm must now adjust the pH and remove the mercury from its waste lioquids. Quotations from three firms are included in the following table of costs. If the instalation will last 15 years and money is worth 12%, which equiment should be purchased?

Annual Income Annual from Installed Operating Mercury Salvage Cost Cost Recovery Value Bidder $ 70,000 $5000 $6500 $10,000 Foxhill Instrument Quicksilver Almaden 50,000 90,000 5000 5000 2500 7800 0 10,000