Economic profit valuation- capital

stands for in CFA institute L2 Curriculum Vol2, page 23 stand for in Schweser L2 Notes book1, page 34 table 32, capital has annual depreciation 30,000. Capital is $$ from creditor and shareholder invested in the project . I do not understand why it has depreciation like equipment. Except company return the capital 30,000 to bond holder and shareholder yearly. there is a similar example