Chemical digestion begins in the _______.

A WWTP utilizing the complete-mix modification of the activated sludge process is located at 1,000 FMSL. The oxygen demand for the facility is 9,625 lb O2/day during the summer months when the maximum wastewater temperature is 84.2 ° Four mechanical aeration devices are to be used and the aerator manufacturer has determined the oxygen transfer to be 2.3 lb O2/hp-hr. Determine the theoretical aerator power (hp) per aerator if the operating DO is 1.8 mg/L. Assume α and β values of 0.75 and 0.95, respectively.   (5 pts) Determine saturation dissolved oxygen concentration of the wastewater (Cw) (unit: mg/L) (5 pts) If Cw is 7.12 mg/L, determine rate of oxygen mass transferred (N) (unit: lb O2/hp-hr) (5 pts) If the rate of oxygen mass transferred is 1.196 lb O2/hp-hr, determine aerator horsepower required (each)? (unit: hp)

A local municipality has contracted with your firm to design an induced-draft, counter-current, ammonia stripping tower at their water reclamation facility that has a permitted capacity of 5.0 MGD. Pertinent design data as follows: Average air and water temperature: 20 °C Wastewater pH: 11.0 Local atmospheric pressure: 725 mmHg Design hydraulic loading: 2.5 gpm/ft2 Design/theoretical air flow: 1.70 From the table, the partial pressure of ammonia at 20 °C is 0.03 mmHg and the ammonia concentration in the wastewater at 20 °C is 50×10-6 gNH3/gH2O.   (5 pts) Determine the equilibrium mass of ammonia in the air (Y2) (5 pts) Determine the air to water ratio (lb Air/lb H2O). (5 pts) If the G/L=2.0613 lb Air/lb H2O, determine the theoretical air required (Gtheor) (unit: lb Air/ft2·hr). Hint: determine the mass flow rate of water (L) first. (5 pts) If the theoretical air required (Gtheor) is 2,580 lb Air/ft2·hr, determine the “design” air required (lb Air/ft2·hr).  (5 pts) If the design air flow required is determined to be 750 cfm/ft2, what is the design air flow required (Air/Gallon)? (unit: ft3/gallon)

Blowers are rated at “standard” conditions. What are the temperature and pressure at standard conditions?

Which of the following statements about calcium is false?

Daily Values are _______.

Every amino acid has ________ in its chemical structure.

For nitrification, the operating dissolved oxygen (DO) concentration should be at least 2.0 mg/L. Below level, the rate of nitrification can be inhibited.

Calcareous ooze is an example of which of the following sediment types?

Which of the following conditions is not one of the 5 leading causes of death in the United States?