TX Water/Wastewater Operator cheat sheet

Texas Water Code and TCEQ rules (30 TAC Chapters 290, 291, 217) govern public water systems; Chapter 217 covers wastewater collection and treatment design criteria.

Public water systems are classified by source and treatment type (e.g., C-surface water, B-groundwater under influence, G-groundwater) and by population; the classification sets the required operator grade.

A public water system must employ a licensed operator whose grade meets or exceeds the system classification; the system must have a designated responsible charge operator.

Wastewater treatment facilities are classified A, B, C, or D based on complexity and design flow; the highest grade required is A for the most complex plants.

Operator licenses are issued by TCEQ in grades D, C, B, A (and A surface water for water); each grade requires passing the corresponding exam plus minimum experience.

Continuing education is required for license renewal (30 TAC Chapter 30): TCEQ sets the CEU hours per renewal cycle by license type.

Disinfection byproduct and maximum contaminant level compliance is reported to TCEQ; public notice is required for violations under 30 TAC Chapter 290 Subchapter D.

Sanitary surveys are conducted by TCEQ; significant deficiencies must be corrected on a TCEQ-approved schedule to remain in compliance.

Surface water sources include rivers, reservoirs, and lakes; groundwater sources include wells and springs; each has distinct treatment and monitoring requirements.

Groundwater under the direct influence of surface water (GUI) is determined by a TCEQ-approved method; GUI sources require surface-water-type treatment (filtration and disinfection).

A watershed protection program identifies potential contamination sources and implements management measures to prevent source water degradation.

The hydrologic cycle: precipitation, infiltration, runoff, evaporation, transpiration, and groundwater recharge; runoff feeds surface supplies while infiltration recharges aquifers.

Wellhead protection areas are delineated around public water supply wells to control potential contaminant sources within the zone of contribution.

Safe yield of a source is the maximum withdrawal rate sustainable without unacceptable depletion or water-quality degradation.

Source water quality parameters to monitor include turbidity, pH, temperature, alkalinity, hardness, and indicator organisms; sudden changes signal upstream contamination.

Drought contingency and water conservation plans are required for many systems; triggers and demand-reduction measures are specified in the plan.

Conventional surface water treatment train: coagulation, flocculation, sedimentation, filtration, and disinfection; each unit operation has a specific removal role.

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

Flocculation is gentle mixing that promotes particle collisions and floc growth; velocity gradient (G) and detention time govern floc formation.

Sedimentation removes settleable floc; overflow rate (surface loading rate) = flow / surface area, expressed in gpm/ft² or m³/m²·d.

Filtration removes remaining turbidity; filter loading rate = flow / filter area; backwash is triggered by headloss or effluent turbidity limits.

Jar testing determines optimal coagulant dose and pH by simulating treatment on a bench scale.

Softening removes hardness (calcium and magnesium); lime-soda softening raises pH to precipitate calcium carbonate and magnesium hydroxide.

Disinfection contact time (CT) = disinfectant residual concentration × contact time; required CT depends on pH, temperature, and organism targeted.

Distribution system pressure must be maintained at a minimum (typically 20 psi) at all points under normal and fire-flow conditions; low pressure triggers public notice.

Storage facilities include elevated tanks, ground storage tanks, and standpipes; they provide equalization, fire flow, and emergency reserve.

Water age increases with low demand and oversized storage; high water age degrades disinfectant residual and promotes disinfection byproducts.

Distribution system flushing removes sediment and stale water; unidirectional flushing improves scouring velocity and water quality.

Cross-connection control uses air gaps, reduced-pressure-zone backflow preventers, and double-check valves; an air gap is the highest protection.

Distribution system monitoring includes chlorine residual, bacteriological samples, and pressure; sample sites are rotated per a written sampling plan.

Pipe flow velocity = flow / cross-sectional area; typical design velocities are 2–5 ft/s to limit headloss and maintain scouring.

Hydrants must be inspected and flushed; hydrant maintenance records support fire-flow verification and system reliability.

Collection system components include gravity sewers, force mains, lift stations, manholes, and service connections.

Minimum gravity sewer slope is set by pipe diameter to maintain self-cleansing velocity (typically 2 ft/s); flatter slopes risk solids deposition.

Infiltration is groundwater entering the system; inflow is stormwater entering through manholes and illegal connections; both increase hydraulic loading.

Lift stations use pumps to raise wastewater to a higher elevation; wet well sizing balances pump cycling to limit wear and odor.

Pump cycling time depends on wet well volume and pump capacity; short cycling indicates oversized pumps or undersized wet well.

Grease, roots, and debris cause sanitary sewer overflows (SSOs); SSOs must be reported to TCEQ and the public per regulatory timelines.

Confined space entry in manholes requires atmospheric testing, ventilation, and a permit; hydrogen sulfide and oxygen deficiency are key hazards.

Sewer cleaning methods include high-velocity jetting, rodding, and mechanical root cutting; CCTV inspection documents pipe condition.

Preliminary treatment removes grit and screenings; primary treatment settles solids; secondary treatment removes dissolved organics via biological action; tertiary treatment polishes effluent.

BOD (biochemical oxygen demand) measures oxygen consumed by microorganisms degrading organics; it is the primary indicator of organic strength.

TSS (total suspended solids) measures particulate matter; effluent limits for BOD and TSS are set by permit.

Activated sludge process: aeration basin, mixed liquor, secondary clarifier, and return activated sludge (RAS); waste activated sludge (WAS) controls solids inventory.

Sludge age (mean cell residence time, MCRT) = mass of solids in system / mass of solids leaving per day; it governs process stability.

F/M ratio = food (BOD load) / microorganism mass (MLVSS); high F/M risks poor settling, low F/M risks bulking and nutrient deficiency.

Nitrification converts ammonia to nitrate by nitrifying bacteria; denitrification converts nitrate to nitrogen gas in anoxic conditions.

Sludge treatment includes thickening, digestion (aerobic or anaerobic), dewatering, and disposal; anaerobic digestion produces methane and stabilizes solids.

Chlorine residual is measured as free chlorine (HOCl/OCl⁻) and total chlorine (free plus combined); free residual is the active disinfectant.

HOCl dominates at lower pH (below ~7.5) and is a stronger disinfectant than OCl⁻; pH control optimizes disinfection.

Chlorine demand = applied dose − residual after contact time; demand reflects oxidizable matter in the water.

Bacteriological monitoring uses coliform testing; total coliform presence triggers repeat sampling and public notice if confirmed with fecal indicators.

Laboratory quality control includes blanks, duplicates, and calibration; chain of custody documents sample integrity.

Chemical safety: chlorine gas is heavier than air and highly toxic; sodium hypochlorite releases chlorine gas when acidified; store separately from acids.

Confined space, lockout/tagout, and personal protective equipment are required for treatment facility work; hydrogen sulfide causes rapid unconsciousness at high concentrations.

Turbidity is measured in NTU; it is a key treatment performance indicator and must meet regulatory limits in filtered water.

Flow: Q = A × V; area of a circular pipe = π × r² = 0.785 × D².

Detention time = volume / flow; keep units consistent (e.g., gallons / gpm = minutes).

Dose (mg/L) = (pounds of chemical × 1,000,000) / (8.34 × gallons); pounds = mg/L × 8.34 × MG.

Loading rate = flow / surface area; hydraulic loading in gpm/ft² or m³/m²·d; organic loading in lb BOD/day.

Filter or clarifier overflow rate = Q / surface area; convert units before dividing.

Chlorine dose and residual: demand = dose − residual; CT = residual (mg/L) × contact time (min).

Percent removal = [(influent − effluent) / influent] × 100.

Recordkeeping: daily logs of flow, dose, residuals, and lab results are required; data must be retained per TCEQ rules and available for inspection.