Wet coal is dried in a continuous rotary dryer that operates at atmospheric pressure. The chips with a water content of 40 wt% and must leave with a moisture content of less than 15%. Hot air is fed to the dryer at a rate of 11.6 m³ (STP)/kg wet coal. MOIST AIR WET COAL DRYER HOT AIR DRIED COAL To monitor the performance of the dryer by sampling the exiting coal and determining their moisture content directly would be a cumbersome procedure and almost impossible to automate. Instead, wet- and dry-bulb thermometers are mounted in both the inlet and outlet air lines, and the moisture content of the exiting chips is determined by a material balance calculator. (STP: Standard Temperature and Pressure is 0*C and 101.325 kPa)

Problem 8 Given L0,mix=12 mg/L, DO mix=DOsat=11.33 mg/L, kd=0.3 d-1, and kr =0.4 d-1, find the following: (a) Initial oxygen deficit (Do) (b) Critical time on the oxygen sag curve (tc) (c) Critical deficit (Dc)

A 2-tank Step Aeration Activated Sludge (SAAS) system has the following characteristics: V1 V2 Q Waste Recycle Oxygen demand (L) (L) (L/min) Ratio Ratio of Cells 500,000 450,000 100 0.45 0.5 1.2 Xv1 Xv2 Xd1 Xd2 SO S1 S2 Xrv Xrd (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) 1500 ☐ 14 1400 200 150 150 10 2 2000 1000 1. What is the mean cell residence time and hydraulic residence time in days? 2. Write the mass balance equation for required oxygen in tank #1. 3. What is the oxygen requirement for tank #1 in kg/day? (equation will be in units of mg/min)

Please include Equations. This is for a water and wastewater review, it is not for a grade. I just need to understand the problem.

Determined and fil-up the unknown data of the given table. Physical Properties Mix Design Specific Dry-rodded Materials Fineness Estimated Absolute gravity weight ft3 Absorption modulus Ib/yd3 Ib/yd3 (SSD) Ib/ft3 Cement 3.15 ? ? Sand 2.64 0.7 2.72 11/2 62.4 Ib/ft Gravel 2.67 0.5 100.5 Water ? Vol. of entrapped air w/C = ? GIVEN: Specification Requirements compressive strength, psi 4000 Slump, in. 3 4

Calculate the R-value of the conventional 12x8x16-in CMU unit (Kerf type) insulated with 4-cm thick layer of the XPS foam

Q- ASP is used to treat a waste water flow of 2MLD having BOD5 of 250 mg/lit. The biomass concentration in the aeration tank is 2500 mg/lit and the concentration of biomass leaving the system is 80 mg/lit, the aeration tank has a volume of 200m³. Find the hydraulic retention time HRT.

True/False questions. 1 For filtration process: when the water level rises to the point that the filter bed must be cleaned. This point is called terminal head loss ( 2 As the temperature decreases the detention time in 7 slow-mix tank decreases. ( 6 8 When CO₂ is bubbled in water with carbonate buffer system, the pH will decrease slightly and the reaction will shift to the left. ( ) 9 The lower the water turbidity, the higher the allowable ) scour velocity in sedimentation tank.( For mixed-media filter the layer of garnet is used to catch the very fine particles ( 3 The addition of polymers in coagulation process is called inter-particle bridging. ( ) ) 4 Slow-mixing can be accomplished by hydraulic As the weir lengths become shorter the scouring velocity becomes higher ( jump ( ) ) 5 Water with high turbidity requires more coagulant 10 Aluminum sulfate has a wider pH range for effective to be treated. ( coagulation than fèrric salts ( )

A complete-mix flow reactor is designed to treat an influent waste stream containing 130mg/L of casein at a flow rate of 80 liters per minute (lpm). Assume that casein removal follows first-order removal kinetics with a rate constant, k, of 0.5h-1 and that the effluent should contain 13 mg/L of casein at steady state. Determine: a. the detention time in hours b. the volume of the reactor in cubic meters

An organic matter is degrading in a steady state complete mix type reactor following the firstorder kinetics. The upstream concentration of organic matter is 20 mg/1 and downstream concentration is 4 mg/1. The treatment of water is at the rate of 58 m3/min. and volume of the tank is 580 m³. Which of the following statements is/are correct for the given reactor? Detention time of tank is 10 minutes. B Rate constant is 0.4 min¹ C Average rate of decay is 1.6 mg/1/s. D Correct Option Correct Option Detention time required to achieve 90% efficiency is 20 min.