Acommunity is utilizing 2 trickling filters, each 15 ft deep with an area of 1250 ft2 . the biodegradation rate constant (k) for these filters is 0.45 (ft·d)-0.5. the influent to the filters has a bod concentration of 325 mg/l and flow to the system has been averaging 100,000 gal/d. however, a new development is being planned which will increase the flow to 125,000 gal/d. the discharge permit for the plant requires that discharge bod be 25 mg/l or less. a. determine the effluent bod concentration at the plant’s current flow rate. has the plant been meeting the discharge requirement at this flow? b. determine the effluent bod concentration at the increased flow when the new development is added. will they be able to meet the discharge requirement?

Steam at a pressure of 100 kpa and a quality of 50% initially fills a rigid vessel having a volume of 0.5 m^3. the steam is then heated, causing the pressure in the vessel to rise to 150 kpa. determine: i. the mass of the steam in the vessel. ii. the temperature and quality of the steam after the heating process. ii the mass of the vapour, mg and liquid, m in the vessel after the heating process. if the steam in the vessel is now further heated, what would the pressure and temperature in the vessel be when all steam has turned into saturated vapour? b. sketch the processes in part (a) and part (b) on p-v and t-v diagrams, indicating clearly the temperatures, pressures and the paths. c. (0.59kg, 111.4°c, 73%, 0.4307kg, 0.1 593kg, 2.11 bar, 121.84°c)