A small wastewater treatmentplant is using a subsurface areration system for his sludge aeration.The operational cost for this system $477 a year.The plant is considering purchasing a new system that cost $1400 with an operational cost of $239 a year.

1-Find the time to recover the investment, assuming zero percent interest. 2-Should the plant purchase the new aeration system? Discuss. 3-Find the time to recover the investment, assuming 5.5% interest, financed over 3 years, monthly payments, and discuss.