mm 12-14. A rural community of 20,000 persons generates solid waste at an average rate of 7 lbs per person per day. A 20-acre landfill site (fill area) is available. The average depth of fill is limited to 40 ft. 12. Assume: Compacted density of refuse: 1,200 lb/yd Uncompacted density of refuse: 400 lb/yd Cover-to-waste ratio: 1 to 4 What is the compaction ratio of the waste? 13. 14. What is the air space available is (yd) (assume the landfill will be a pyramid with height of 40 ft) (area of pyramid = base are x height/3) What is the estimated useful life of landfill (in years)?