| A | B |
|---|
| geometric mean | antilog of (sum of all logs results/number of samples) |
| %settleable solids | mls of settled sludge after 30 mins / vol. of settleometer)*100 |
| sludge volume index (SVI) | (% settleable solids * 10000) / MLSS in mg/l |
| Recirculation rate for trickling filters | recirculation flow / influent wastewater |
| surface loading (overflow rate), gpd/ft2 | flow in gpd / surface area in ft2 |
| weir overflow rate | flow in gpd / feet of weir |
| Q, quantity of flow | A, cross sectional area(width *depth), usually in ft2/V, velocity, in ft/sec |
| velocity in ft /sec | distance travelled in ft / time in seconds |
| velocity in (ft /sec) | (flow rate in ft^3/sec) / (cross sectional area in ft 2) |
| flow in ft^3/sec | cross sectional area (ft^2) x velocity (ft/sec) |
| trickling filter organic loading, lbs/day/1000ft^3 | BOD applied in lbs per day / volume of media in 1000ft^3 |
| trickling filter hydraulic loading, gpd/ft^2 | gal/day(including recirculation flow) / surface area in ft^2 |
| mean cell residence time (MCRT) in days | (MLSS in mg/l x MG (aer. tank +sec. clar. vol.)*8.34) / [(EFF SS in mg/l xMGDx8.34)+(WAS in mg/l xWAS MGD x8.34)] |
| MCRT | suspended solids in system in lbs / suspended solids leaving system in (lbs/day) |
| water horsepower (water HP) | (gpm x total head in ft) / 3960 |
| sludge age, days | (MLSS in mg/l x aerator volume in MG x 8.34) / Primary Eff SS in mg/l x MGD X 8.34) |
| BOD5 (unseeded), mg/l | DOi -DO5 / p |
| DOi | DO initial |
| DO5 | DO after 5 days |
| p | mls of sample / 300 ( mls in a BOD bottle) |
| wasting rate, gpm | [pumping rate, MGD] x [694 gpm / MGD] |
| Total suspended solids (TSS), mg/l | dry solids in grams x 1000 mg / g x 1000 ml / l) / (sample volume in mls) |
| TSS | (weight of solids in mg x 1000 mls / l) / sample volume in mls |
| Total solids (TS), mg / l | (A - B x 1000) / (sample volume in ml) |
| A | weight of dish + dried residue in ml |
| B | weight of dish in milligrams |
| Volatile solids (VS), mg/l | [ (A-B) x 1000] / sample volume in mg / l |
