Tetrachloroethylene Biochemical Oxygen Demand problem

Info: BOD: Biochemical Oxygen Demand BOD5 is the total amount of oxygen consumed by microorganisms during the first five days of biodegradation BOD5 = (DOi – Dof)/(P) this is the five-day BOD of a diluted sample Where DOi = the initial dissolved oxygen (DO) of the diluted wastewater DOf = the final DO of the diluted wastewater, 5 days later P = the dilution fraction = (volume of wastewater)/(volume of wastewater plus dilution water) A standard BOD bottle holds 300 mL, so P is just the volume of wastewater divided by 300 mL 5.53) A cubic meter of a gravel-and-sand aquifer has been contaminated with 20 L of tetrachloroethylene. If the amount of ... click for more

Calculation of chlorine ions necessary for charge balance in surface water chemical analysis

Data: A chemical analysis of a surface water yields the following data: Ion Concentration mg/L Ca^(2+) 90 Mg^(2+) 30 Na^+ 72 K^+ 6 Cl^- 120 SO4^(2-) 225 HCO3^- 165 pH 7.5 Problem: The Cl^- concentration in the water analysis given has been questioned. What concentration of Cl^- (mg/L) would make the cations and anions balance?

Total hardness (TH), anion-cation balance

Calculation of total hardness (TH) and anion-cation balance given total anions.

A reverse osmosis plant desalinates 5x10^6 L/day of feedwater

A reverse osmosis plant desalinates 5x10^6 L/day of feedwater containing 1500mg/L of salts yielding 3x10^6 L/day of product water with 75 mg/L of salt. What would the salt concentration be in the brine?

Determining size needed for settling tank given flow rate and detention time.

6.10) A final settling tank for a 2-million-gallon-per-day (2mgd) activated-sludge treatment plant it to be designed to have an average overflow rate of 800 g/day-ft^2. the tank needs to have a minimum detention time of 2.0 hr and to allow proper settling it must be at least 11 ft deep. If the tank is circular, what should its diameter and depth be?