The jambalaya shrimp processing plant generates 0.012 푚3/푠of wastewater each day. the wastewater is treated in an activated sludge plant. the average 퐵푂퐷5of the raw wastewater before primary settling is 1,400 mg/l. the aeration tank has effective liquid dimensions of 8.0 m wide by 8.0 m long by 5.0 m deep. the plant operating parameters are as follows: soluble 퐵푂퐷5after primary settling = 966 mg/lmlvss = 2,000 mg/lmlss = 1.25 (mlvss)settled sludge volume after 30 min = 225.0 ml/laeration tank liquid temperature = 15 degrees celsius determine the following: aeration period, f/m ratio, svi, solids concentration in the return sludge.

is the best method of analyzing mutually exclusive projects

Explanation:

Net present value is the present value of after-tax cash flows from an investment less the amount invested.  

Only projects with a positive NPV should be accepted. A project with a negative NPV should not be chosen because it isn't profitable.  

When choosing between positive NPV projects, choose the project with the highest NPV first because it is the most profitable.

Internal rate of return is the discount rate that equates the after-tax cash flows from an investment to the amount invested

Accounting rate of return = Average net income / Average book value  

Average book value = (cost of equipment - salvage value) / 2

NPV is more preferred to IRR for projects with multiple negative cash flows during the project live .