Water and Wastewater Operations

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Landfill Airspace Consumption and In-Place Density - Converts tonnage and in-place density into waste and cover airspace, the airspace utilisation factor.
Landfill Gas Generation (First-Order Decay) - Sums first-order decay across placement years to the peak at closure.
Leachate Generation from a Water Balance - Turns precipitation, runoff, and evapotranspiration into leachate per year, per day, and per open acre.
Landfill Daily Cover Soil Volume - Computes daily cover volume, its share of all airspace consumed.
Recycling Diversion Rate and Residual Contamination - Separates a reported diversion rate from the true one after measured inbound contamination.
Waste Settlement and Recovered Airspace - Splits settlement into primary, recoverable as airspace while the cell is open, and secondary.
Landfill Working Face Cell and Lift Volume - Daily cell volume, face advance, exposed surface, and cover for a working face.
Pounds Formula - The pounds per day of a chemical a dose and a flow add up to.
Filter Loading Rate and Backwash - Loading rate, backwash flow, and rapid-sand vs high-rate category.
RO Recovery, Concentrate Flow, and Concentration Factor - The reverse-osmosis mass balance an operator sets recovery from.
Chlorine Dose to Oxidize Iron and Manganese - The free-chlorine dose to oxidize dissolved iron and manganese ahead of a filter.
Cistern / Storage Reserve Days and Required Volume - The reserve a storage tank carries and the tank a target reserve needs, a straight mass balance.
Detention Time - Detention time = volume / flow in min, hr, days; pass/fail vs target.
Lab Dilution and Serial Dilution - The missing concentration or volume in a dilution, plus each step of a serial dilution.
Pump Wire-to-Water Efficiency - Water HP, brake HP estimate, and wire-to-water % with good/ok/degraded category.
SRT and F/M Ratio - Solids retention time and food-to-microorganism ratio with conventional-activated-sludge check.
Coagulant Dose from Jar Test - Pure equivalent + product feed (lb/day, gal/day) for alum, ferric chloride, or PAC at the jar-test optimal dose.
Sludge Volume Index (SVI) - How well activated sludge settles, as an index in mL/g, and what that index means.
Disinfection CT (USEPA SWTR) - CT achieved against the USEPA SWTR requirement for 3-log Giardia inactivation.
Pool Turnover Rate and Chlorine Demand - Required pump flow from pool volume and turnover target.
Well Drawdown and Specific Capacity - Drawdown, specific capacity (GPM per ft), and recommended pump-setting depth.
Cooling Water Makeup (Cycles of Concentration) - Evaporation, blowdown, drift, and total makeup flow from recirculation, range, and cycles of concentration.
Chlorine Residual Decay (First-Order) - First-order residual C(t) = C0 x exp(-k t), time to a target residual, and an optional booster distance.
Backflow Assembly Test Pass Criteria - Pass/fail per assembly type with the governing field-test criterion.
Weir / Flume Open-Channel Flow - Open-channel flow over a 90-degree V-notch or rectangular (Francis) weir in cfs, GPM.
Cipolletti (Trapezoidal) Weir Flow - Flow over a Cipolletti (trapezoidal) weir, whose 1H:4V side slopes make up the end-contraction loss.
Sluice-Gate (Underflow) Free-Flow Discharge - The third canal-control structure the flow set was missing.
Broad-Crested (Critical-Flow) Weir Discharge - The critical-flow weir that completes the weir family alongside the sharp-crested V-notch, rectangular.
Weir Head from a Target Flow - The head over a sharp-crested weir needed to pass a target flow.
Langelier Saturation Index - LSI and a corrosive/balanced/scaling interpretation from pH, temperature, calcium hardness, total alkalinity, and TDS.
Chemical Metering-Pump Setting - Neat chemical (lb/day), solution feed (GPD and mL/min), and pump setting (% of max) from plant flow, target dose.
Clarifier Surface, Weir, and Solids Loading - Whether a clarifier is inside its surface, weir, and solids loading limits.
BOD/TSS Mass Loading and Percent Removal - The pounds a day a plant takes in, and the percent it removes.
Design Flow from Population (Average, Peak, Minimum) - Average, peak, and minimum design flow from a service population.
Total Dissolved Solids from Conductivity - Total dissolved solids estimated from a conductivity reading.
Conductivity from Total Dissolved Solids - The inverse of the TDS estimate: EC (uS/cm at 25 C) = TDS (mg/L) / k, k commonly 0.55-0.75 (default 0.65).
Population Equivalent (Organic Load) - The population equivalent of a discharge, figured three ways.
Return Activated Sludge (RAS) Flow Rate - The return-pump rate from the solids mass balance.
Settleability-Based RAS Rate (from SVI) - The RAS number straight from the settleometer, no RAS_SS lab result needed.
WAS Rate to Hold Target SRT (Sludge Age) - The daily wasting decision: how much sludge to waste today to hold a target SRT.
Anaerobic Digester Volatile Solids Loading - The digester health metric: volatile-solids loading rate VSLR = VS_fed / volume x 1000 (lb VS/day per 1,000 ft^3).
Digester Volatile-Acid to Alkalinity Ratio - The early-warning stability index the pH meter misses.
Digester Gas and Methane Production - The payoff side of anaerobic digestion, from the volatile solids destroyed.
Activated-Sludge Oxygen and Blower Air Demand - The oxygen the aeration system must supply and the blower air to deliver it.
Mixing Velocity Gradient (G / Gt) - The Camp-Stein velocity gradient G = sqrt(P / (mu x V)) and the Gt product that set floc formation.
Tapered Flocculation G Schedule - The mixing power each stage of a tapered floc train needs.
Paddle Flocculator Power from Geometry - The mixing power a paddle-wheel flocculator delivers, from its geometry.
Gas Chlorine Cylinder Withdrawal Rate - Whether a gas chlorine container can physically deliver the feed rate.
Pool Waterline Tile and Coping Perimeter Takeoff - Waterline tile and coping around a pool perimeter.
Pool Gunite Shell and Plaster Volume - Gunite shell and plaster for a pool, both driven by the interior surface area.
Gravity Oil/Water Separator Surface Area (API 421) - The minimum horizontal (plan) area of a gravity oil/water separator per API 421.
Discrete-Particle Settling Velocity (Stokes' Law) - The terminal settling velocity of a discrete spherical particle in still water by Stokes' law.
Pool Water Volume by Shape - Pool gallonage, the input every pool dose and heater calculation needs.
Pool Total Alkalinity Adjustment - Sodium bicarbonate to raise or muriatic acid to lower total alkalinity, by pool volume and the ppm change.
Pool Cyanuric Acid Dose - Cyanuric acid to raise stabilizer, or -- since CYA leaves only by dilution.
Pool Salt Dose - Pool salt to add for a salt-chlorine generator, or the water to replace to lower an over-salted pool.
Pool Calcium Hardness Increase (Calcium Chloride) - Calcium chloride to raise a pool's calcium hardness.
Pool Free-Chlorine Dose by Product - Free-chlorine dose = ppm x (gal/1e6) x 8.34 lb, divided by the product available-chlorine fraction.
Pool Heater Sizing and Heat-Up Time - The heater a pool needs, and how long it takes to come up to temperature.
Pool Heater Output for a Target Heat-Up Time - The heater input rating (the nameplate Btu/h) needed to warm a pool by a rise in a target time.
Breakpoint Chlorination Dose - The combined chlorine in the water, and the shock dose that burns it off.
Chlorine Demand and Dose for a Target Residual - Chlorine the water consumes, and the dose needed to hold a target residual.
Dechlorination Chemical Dose - The sulfur-based chemical to neutralize a chlorine residual before an NPDES discharge or a fish-bearing stream.
Float-Method (Velocity-Area) Open-Channel Flow - A field estimate of open-channel flow (ditch, canal, outfall) with a float, a tape, and a stopwatch.
Flow-Weighted Two-Source Water Blend - The concentration of two water sources blended together and the split to meet a target.
Fluoride Feed Dose (Available Fluoride Ion) - The pounds-per-day of a fluoridation chemical to hit a target fluoride level.
Chlorine Decay Constant from a Bottle Test - The first-order decay constant k from an initial and a measured residual over an elapsed time.
UV Dose and Target Check - Delivered UV dose, checked against a validated target.
UV Required Intensity or Contact Time - Solves a target UV dose for whichever you are missing: intensity or contact time.
Well Sustainable Yield from Specific Capacity - The sustainable pumping rate a well gives up without pulling the water below the pump.
Detention Basin Volume for a Target Time - The basin volume required to hold flow for a target detention time.
Filter Area for a Target Loading Rate - The filter area needed for a target loading rate at the design flow.
Clarifier Surface Area for a Target SOR - The clarifier surface area a target surface overflow rate needs at the design flow.
Step-Drawdown Test and Well Efficiency - What a single-rate test cannot tell you: how much of a well's drawdown is the aquifer, and how much is the well itself.
Well Casing Storage, Purge Volume, and Disinfection - How much water stands in a well casing, how long purging it takes, and what disinfecting it costs in chlorine.
Constant-Pressure Well VFD Setpoint and Speed - What speed a constant-pressure well pump really runs at when demand falls, and why the energy saving is small.
Lift Station Wet-Well Volume and Cycle Time - The active volume a lift station wet well needs so its pump does not start more often than the motor allows.
Water Main Flushing Volume, Duration, and Velocity - How much water a main flush takes, how long it runs, and whether it reaches a scouring velocity at all.
Water Pressure Zone HGL and Service Pressure - What pressure a service sees, and which elevations one pressure zone can serve.
Pool Cover Evaporation and Heat Loss Savings - What evaporation costs a pool and what a cover saves.
Pool Evaporation Rate (ASHRAE / Carrier) - How fast a pool loses water to evaporation from the water temperature, the air temperature and humidity.
Pool Pump Speed Reduction at Constant Turnover - What slowing a pool pump actually saves, once the pool still has to be turned over.
Pool Heat Pump Capacity vs Air, Water, and Humidity - What a pool heat pump delivers at the conditions it runs in, rather than the ones it was rated at.
Spa Drain Interval and Refill Volume - How often a residential spa needs draining: the volume in gallons over three times the daily bathers.
Emergency Drinking Water Bleach Dose - The EPA's emergency bleach table is the most-printed water number in any disaster.
Boil-Water Time and Boiling Point at Altitude - A rolling boil is the standard emergency disinfection, and altitude lowers the temperature it happens at.
Disinfection Contact Time from a Baffling Factor - The CT a disinfection step earns depends on T, the time by which only 10% of the water has passed through.
Total Coliform Routine and Repeat Sample Count - Restoring a water system after a flood or a main break ends in sampling.
Solar Water Pump Array Sizing - A solar pump is sized from the water, not from the load.
Rainwater First-Flush Diversion Volume and Standpipe Length - The first rain off a roof washes it, carrying dust, pollen, bird droppings, and after a storm or a fire, debris and ash.
Lift Station Outage: Time to Overflow and Pump-and-Haul Loads - When a storm takes out power to a sewage lift station.

Water and Wastewater Operations

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