Virginia Wastewater Treatment Examination Formula Sheet

1. Circumference, Area, Volume

 a. Circumference C = 3.1416 × Diameter b. Perimeter P = [2 × Length] + [2 × Width] c. Area Rectangle Area = Length × Width Circle Area = 0.785 × Diameter × Diameter Triangle Area = ½ × Base × Height d. Volume Rectangle Volume = Length × Width × Depth Cylinder Volume = 0.785 × Diameter × Diameter × Depth Cone Volume = 0.262 × Diameter × Diameter × Height Sphere Volume = 0.524 × Diameter × Diameter × Diameter

2. Conversion Factors

 a. ft to gallons Volume, Gallons = Volume, ft3 × 7.48 gallons/ft3 b. Gallons to pounds Pounds = Gallons × 8.34 lbs/gallon c. mg/L to pounds Pounds = Concentration, mg/L × TAnk Volume, MG × 8.34 lbs/MG/mg/L d. mg/L to pounds/day Pounds/Day = Concentration, mg/L × Flow, MGD × 8.34 lbs/MG/mg/L e. mg/L to kilograms/day Kilograms/Day = Conc., mg/L × Flow, MGD × 3.785 lbs/MG/mg/L f. mg/Kg to pounds/ton Pounds/Ton = Concentration, mg/KG × 0.002 lbs/ton/mg/KG g. Pounds to mg/L h. Pounds/Day to mg/L i. Pounds/Day to MGD

3. Flow

 a. MGD to GPD Flow, GPD = Flow, MGD × 1,000,000 gallons/MG b. MGD to GPM c. MGD to CFS Flow, cfs = Flow, MGD × 1.55 cfs/MGD

4. Chemical Weight

 Using Specific Gravity Weight/lbs/gallon = Specific gravity × 8.34 lbs/gallon

5. Population Equivalent

6. Percent to Decimal Percent

7. Percent Removal (Wastewater)

 a. Based on Concentration b. Based on Quantity (lbs, lbs/day, KG or KG/day)

8. Hydraulic Detention Time

 a. HDT, Minutes b. HDT, Hours c. HDT, Days

9. Flow Measurement

 a. Flow, (Fill and Draw), GPM b. Flow (Velocity), cfs Flow (Q), cfs = Channel Width, ft × Water Depth, ft × Velocity, fps

10. Grit Removal

 a. Velocity (float method) b. Velocity c. Settling Time* d. Required Channel Length* *The settling velocity must be given or determined experimentally.

11. Settling

12. Ponds

 a. Area in Acres b. Volume in Acre-Feet c. Flow in Acre-Feet/Day Flow, Acre Feet/Day = Flow, MGD × 3.069 Acre Feet/MG d. Flow, Acre-Inches/Day Flow, Acre Inches/Day = Flow, MGD × 36.8 Acre Inches/MG e. Hydraulic Detention Time, Days f. Hydraulic Loading g. Organic Loading h. Population Loading

13. Trickling Filter

 a. Total Flow (given flows) Total Flow, MGD = Influent Flow, MGD + Recirculation Flow, MGD b. Total Flow (given ratio) Total Flow, MGD = Influent Flow, MGD × (1.0 + Recirculation Rate) c. Hydraulic Loading Total Flow always includes recirculated flow. d. Organic Loading Organic loading does not include recirculated flows.

14. Rotating Biological Contactors

15. Activated Sludge

 a. Settled Sludge Volume b. Settled Sludge Volume c. Return Rate (By SSV) d. Return Rate (By SVI) e. Return Rate (Clarifier Mass Balance) f. Clarifier Solids (Core Sample) SolidsC, lbs = Core Sample TSS, mg/L × VolumeC MG × 8.34 lbs/ mg/L/ MG g. Clarifier Solids (MLSS) SolidsC = MLSS, mg/L × Volume C, MG × 8.34 lbs/ mg/L/ MG h. Clarifier Solids (MLSS and RASSS) C = Clarifier or Settling Tank MLSS = Mixed Liquor Suspended Solids in milligrams/Liter RASSS = Return Activated Sludge Suspended Solids in milligrams/Liter i. Sludge Volume Index j. F:M Ratio k. Desired MLVSS, (lbs) l. Desired MLVSS (mg/L) m. Waste Volatile Solids (Based on F:M) Waste, lbs = Actual MLVSS, lbs - Required MLVSS, lbs n. Waste Rate, MGD (Based on F:M) o. MCRT, Days p. Waste Solids, lbs/day (Based on MCRT) q. Waste Rate, MGD (Based on MCRT) r. Waste Rate, GPM

 a. Demand Demand, mg/L = Dose, mg/L - Residual, mg/L b. Dose, mg/L c. Required Chemical (Feed Rate, lbs/day) d. Feed Rate, gpd e. Feed Rate, gpm f. Feed Rate, mL/minute g. Supply Required h. Supply on Hand i. Increases, (price, usage, or for safety) Increase = Current Amount × [1.0 + % (decimal) Increase] j. Chemical Cost k. Chemical Makeup (dry chemical) l. Chemical Makeup (solution) m. Active Ingredient Chemical UsedActive Ingredient = Chemical Used, lbs × %Active Ingredient

17. Solids Pumping

 a. Estimated Pump Rate (gallons/minute) b. Gallon pumped GPD GPD = Pump Rate, gpm × Cycles, Cycles/day × Cycle Time, minutes/cycle c. Solids Pumped lbs/day Solids, lbs/day = Solids Volume, gpd × 8.34 lbs/gal × % (decimal) Solids d. Volatile Solids Pumped, lbs/day Volatile Solids, lbs/day = Solids Volume, gpd × 8.34 lbs/gal × %Solids × %Volatile Matter *All % values must be in decimal form.

18. Thickening

19. Aerobic Digestion

 a. Volatile Solids Loading lbs/day/ft3 b. Digestion Time (based on flow) c. Digestion Time (based on solids) d. Chemical Requirement e. Volatile Matter Reduction

20. Anaerobic Digestion

 a. Seed Volume Seed, gallons = Digester Volume, gallons × Desired % Seed Volume b. Volatile Solids Loading c. Volatile Acids/Alkalinity Ratio d. Chemical Requirement e. Volatile Matter Reduction f. Gas Production ft3/Day Gas, ft3 = Volatile SolidsIn, lbs/day × % V.M. Reduction × Rate, ft3/lb V.M. Destroyed

21. Land Application

 a. Solids Production (dry tons/year) b. Solids Production (wet tons/year) c. Plant Available Nitrogen (PAN) (lbs/dry ton) [(Organic - N, mg/kg × f1) + (Ammonia - N, mg/kg × V1)] × 0.002 f1= Mineralization Rate (assume 0.20) V1 = Volatilization Rate Injected Sludge = 1.0 Incorporated Within 24 hours = 0.85 Incorporated Within 7 days = 0.70 d. Application Rate (nitrogen basis) e. Metals Loading lbs/acre Loading, lbs/Acre = Concentration, mg/kg × Application Rate, D.T./acre × 0.002 mg/kg/dry ton f. Allowable Applications (Metals Basis) g. Site LIfe (metal basis)

22. Pumping

 a. Head to Pressure b. Total Dynamic Head TDH, ft = Static Head, ft + Friction Head, ft + Velocity Head, ft c. Water Horsepower d. Brake Horsepower e. Motor Horsepower

23. Electrical Energy

 a. Hp to kilowatts (kW) Kilowatts = Horsepower × 0.746 Kw/hp b. kW to kilowatt hrs Kilowatt Hour = Kilowatts Used × Hours Operated c. Power Cost Cost = Kilowatt hours used × Cost/Kilowatt

24. Sampling

 a. Composite Sample Volume, mL T = Sample Collection Time b. Proportioning Factor (PF) c. Sample Volume (Using PF) Sample Volume, mL = FlowT × PF T = Time sample is collected

25. Alkalinity

 Conventional A = Volume of Standard Acid Used N = Normality of Standard Acid Low Level B = Volume of Standard Acid Used to reach pH 4.3 - 4.5 C = Total Volume of Standard Acid for titration N = Normality of Standard Acid

26. Hardness

 a. EDTA Standardization b. Hardness, mg/L Calcium Carbonate A = EDTA used in Titration, mL B = EDTA CaCO3 Equivalence, mL/mL

27. Ammonia Nitrogen

 a. Nesslerization A = Micrograms of N from calibration curve B = Volume of distillate collected C = Volume of distillate used for nesslerization Sample Volume = Original sample volume placed in distillation flask b. Titration A = Volume of titrant used for sample B = Volume of titrant used for blank Sample Volume = Volume of sample used for titration

28. Biochemical Oxygen Demand

 a. Unseeded Samples b. Seed Correction Factor c. Seeded Samples

29. Chemical Oxygen Demand

 a. FAS Standardization (Open Reflux) b. FAS Standardization (Closed Reflux) c. COD A = FAS Used for Blank, mL B = FAS Used for Sample, mL C = FAS Molarity

30. Total Residual Chlorine

 a. Iodometric Direct Titration b. Iodometric Back Titration (No Iodine correction) c. Iodine Correction d. Iodometric Back Titration (With Iodine correction) e. Iodometric Back Titration Iodate Titrant

31. Dissolved Oxygen

 Winkler Titration If N = 0.0250 & Sample Volume = 200 mL then: Titrant Used = D.O., mg/L

32. Fecal Coliform

 a. Multiple Tube b. Membrane Filtration

33. Nitrate Nitrogen

 a. Brucine Sulfate b. Cadmium Reduction

34. Nitrite Nitrogen

 Diazotization Diluted Sample C = NO2 - N Concentration, mg/L V = Total volume after dilution, mL S = Sample Volume in dilution, mL

35. Phosphorous

 Phosphorous

36. Total Suspended Solids

 TSS, mg/L

37. Total Kjeldahl Nitrogen

 a. Nesslerization A = Micrograms of N from calibration curve B = Volume of distillate collected C = Volume of distillate used for nesslerization Sample Volume = Original sample volume placed in distillation flask b. Titration A = Volume of titrant used for sample B = Volume of titrant used for blank Sample Volume = Volume of sample used for titration

38. Total Volatile Suspended Solids

 TVSS, mg/L A = Weight of Dried Solids & Support C = Weight of Ash & Support

39. Residual (Sludge) Solids Tests

 a. % Solids b. % Volatile Matter c. % Moisture

40. VPDES Reporting

 a. Average Monthly Concentration b. Average Weekly Concentration c. Average Daily Concentration d. Average Hourly Concentration e. Daily Quantity Daily Quantity, KG/Day = Conc., mg/L × Flow, MGD × 3.785 lbs/MG/mg/L Conc. = Individual Test Result in mg/L Flow = Flow on day sample was collected in MGD f. Average Monthly Quantity g. Average Weekly Quantity h. Geometric Mean (Xy) i. Geometric Mean (log)