AL Water Operator cheat sheet

A public water system provides water for human consumption through pipes to at least 15 service connections or regularly serves at least 25 people for at least 60 days per year.

Surface water sources require filtration and disinfection; groundwater under the direct influence of surface water (GWUDI) is generally treated and monitored as surface water.

Turbidity measures suspended particles that scatter light; high turbidity can shield pathogens from disinfection and increases chlorine demand.

Federal MCLs include nitrate 10 mg/L as N, nitrite 1 mg/L as N, arsenic 0.010 mg/L, lead action level 0.015 mg/L, and copper action level 1.3 mg/L.

Alkalinity and pH affect coagulation and corrosion control; low pH and high chloride-to-sulfate ratio can increase lead and copper release.

Watershed and wellhead protection programs reduce source contamination; source water assessments identify susceptibility to contamination.

Reservoir stratification and turnover can bring low-oxygen water with elevated iron, manganese, and taste-and-odor compounds to intakes.

E. coli in source water indicates fecal contamination; total coliforms are used as indicator organisms for treatment and distribution integrity.

Coagulation destabilizes particles by neutralizing negative surface charge; common coagulants include alum, ferric chloride, ferric sulfate, and polyaluminum chloride.

Alum reacts with natural alkalinity and lowers pH; if alkalinity is insufficient, add lime or soda ash to maintain effective coagulation.

Jar tests determine the optimum coagulant dose and pH by simulating coagulation, flocculation, and settling at bench scale.

Flocculation is gentle, tapered mixing that grows small particles into settleable floc; typical detention is about 15 to 45 minutes.

Sedimentation design uses surface overflow rate (flow divided by surface area), commonly about 0.3 to 1.0 gpm/ft², with detention often 2 to 4 hours.

Tube and plate settlers increase effective settling area and improve particle removal in sedimentation basins.

Conventional rapid sand filters commonly operate at about 2 to 4 gpm/ft²; backwash typically uses 15 to 20 gpm/ft² with sufficient bed expansion.

Filter turbidity limits: combined filter effluent must be 0.3 NTU or less in at least 95% of monthly measurements, and no individual filter may exceed 1.0 NTU.

Backwash recycle can return solids and pathogens to the plant; manage recycle flow and turbidity to avoid treatment spikes.

CT is disinfectant concentration in mg/L multiplied by contact time in minutes; required CT depends on disinfectant, target pathogen, pH, and temperature.

Chlorine demand equals applied dose minus residual after contact; free chlorine reacts with organics, ammonia, iron, and manganese.

Breakpoint chlorination occurs when chlorine addition exceeds demand and converts ammonia to chloramines before free chlorine persists; the breakpoint is roughly 7.6 lb Cl2 per lb ammonia-N.

Free chlorine is a stronger disinfectant; combined chlorine (chloramine) is weaker but more persistent and typically forms fewer regulated disinfection byproducts.

The MRDL for chlorine and chloramine is 4.0 mg/L as Cl2 in the distribution system; minimum entry-point residuals commonly are 0.2 mg/L free or 0.5 mg/L combined.

Maintain a detectable disinfectant residual throughout distribution; record the lowest residual and investigate areas with low residual or high water age.

UV disinfection credit depends on validated dose in mJ/cm²; UV inactivates pathogens but leaves no persistent residual.

Ozone is a powerful oxidant and disinfectant; in bromide-containing water it can form bromate, a regulated disinfection byproduct.

Chlorine dioxide is an effective disinfectant but forms chlorite and chlorate; the chlorite MCL is 1.0 mg/L.

Total dynamic head (TDH) equals static head plus friction and minor losses plus velocity head, expressed in feet of water.

Water horsepower = gpm × head (ft) ÷ 3960; brake horsepower = water horsepower ÷ pump efficiency.

Affinity laws for a centrifugal pump at constant impeller diameter: flow varies with speed, head with speed squared, and power with speed cubed.

Cavitation occurs when local pressure falls below vapor pressure; prevent it by keeping NPSH available above NPSH required.

Distribution systems commonly maintain at least 20 psi under normal conditions to prevent backflow and contamination; fire flow may require higher pressure.

Storage tanks provide equalization, fire flow, and emergency supply; poor turnover increases water age and can reduce chlorine residual.

An air gap is a physical separation between the potable water outlet and the flood level of a receiving vessel and is the highest level of backflow protection.

Reduced-pressure-zone (RPZ) assemblies protect against high-hazard backflow and must be tested and maintained according to the primacy agency's requirements.

Water hammer from sudden valve closure is controlled with slow-closing valves, surge tanks, air valves, and proper pipeline design.

The Alabama Department of Environmental Management administers the Safe Drinking Water Act in Alabama and enforces public water system regulations in Alabama Administrative Code Chapter 335-7.

Federal MCLs include nitrate 10 mg/L, nitrite 1 mg/L, arsenic 0.010 mg/L, TTHM 80 µg/L, and HAA5 60 µg/L.

A positive E. coli result in distribution is an acute risk: notify the primacy agency promptly, issue Tier 1 public notice, and complete corrective actions.

Community water systems must deliver a Consumer Confidence Report to customers by July 1 each year covering the previous calendar year.

Public notification tiers: Tier 1 is immediate (24 hours) for acute health risk, Tier 2 is within 30 days, and Tier 3 is within 90 days.

Alabama operator certification has grades I through IV; higher grades are required for larger or more complex systems, and continuing education is required for renewal.

Chlorine gas safety requires gas detection, respiratory protection, emergency shutdown, and trained personnel; sodium hypochlorite degrades with heat and light and can off-gas.

Confined space entry requires a permit, atmospheric testing for oxygen, flammables, hydrogen sulfide, and carbon monoxide, plus ventilation, an attendant, and retrieval equipment.

Calculations: lb/day = mg/L × 8.34 × MGD; MGD = gpm × 0.00144; dose (mg/L) = lb/day ÷ (8.34 × MGD); detention time = volume ÷ flow using matching units.