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Regulations and Operator Certification

• Operator Certification Act (Act 538 of 1972, Title 48 Section 40):

  • Establishes a state committee tasked with setting forth rules and regulations governing the requirements for obtaining and maintaining water and wastewater certification.
  • Mandates specific operational requirements for water and wastewater systems, including system classifications, minimum required levels of operator certification, operational categories, and the minimum number of certified operators required per system.

• General Operator Requirements:

  • One Hour Response Time Rule: Certified operators must be able to respond to system issues within a maximum of one hour.
  • Ownership of Certification: Water and wastewater certifications belong individually to the operator, not to the facility or water system.
  • Display of Certificates: All operator certificates must be mounted and displayed in a prominent place at the treatment facility or operating office.

Disinfection Methods and Chemistry

• Core Concepts and Definitions:

  • Disinfection: The process of killing or inactivating pathogenic organisms (disease-causing germs) in water to a safe level.
  • Sterilization: The absolute destruction or removal of all living microorganisms.
  • Purpose of Water Disinfection: Primary objective is to reduce and prevent waterborne diseases caused by pathogens. Disinfection is mandated by the State Sanitary Code.

• Primary Disinfection Methods:

  • Chlorination:
    • Most widely used disinfectant method in water treatment.
    • Advantages: Readily available, inexpensive, and leaves a measurable disinfectant residual in the distribution system.
    • Disadvantages: Extremely dangerous chemical hazard; reacts with organic matter to produce cancer-causing Disinfection By-Products (DBPs).
  • Chloramines:
    • Formed by combining chlorine with ammonia, primarily in the form of monochloramines.
    • Advantages: Significantly reduces DBP formation, maintains a highly stable and long-lasting residual throughout the distribution system, and assists in controlling taste and odor problems.
    • Disadvantages: Less effective as a disinfectant compared to free chlorine, requiring longer contact time.
  • Chlorine Dioxide ($\text{ClO}_2$):
    • Generated on-site using a chlorine dioxide generator by reacting sodium chlorite ($\text{NaClO}_2$) with chlorine gas or acid.
    • Advantages: Reduces DBP formation, highly effective for taste and odor control, and remains an effective disinfectant across a high pH range of $8.0$ to $10.0$.
    • Disadvantages: Must be generated on-site, which presents severe handling and chemical safety hazards.
  • Ultraviolet (UV) Light:
    • Disinfects by emitting electromagnetic radiation that damages the cellular genetic material (DNA/RNA) of microbes, rendering them unable to reproduce.
    • Disinfection effectiveness is completely independent of water pH.
    • Advantages: Requires no chemical additions or hazardous chemical storage.
    • Disadvantages: Leaves no disinfectant residual in the distribution system; direct exposure to UV light causes severe burns to eyes and skin.
  • Ozone ($\text{O}_3$):
    • Requires a specialized gas preparation unit and a high-voltage electrical power source.
    • Advantages: Exceptionally powerful oxidizer and disinfectant; superior at removing color, taste, and odor.
    • Disadvantages: Unstable gas that leaves no disinfectant residual and must be generated continuously on-site.

• Forms and Methods of Chlorination:

  • Chlorine Gas ($\text{Cl}_2$): Supplied in $100\text{ lb}$, $150\text{ lb}$, $1\text{ ton}$ cylinders, and bulk rail cars.
    • Advantages: Lowest chemical cost and widely available.
    • Disadvantages: Extremely dangerous toxic gas hazard.
  • Calcium Hypochlorite ($\text{Ca(ClO)}_2$): Granular or tablet chlorine, commonly known as HTH.
    • Advantages: Hazardous but safer to store and handle than compressed gas.
    • Disadvantages: Expensive operational chemical cost; subject to thermal degradation.
  • Sodium Hypochlorite ($\text{NaClO}$): Liquid bleach used in hypochlorination.
    • Operational Mandate: Hypochlorinators must be calibrated during each work shift.
    • Advantages: Safer handling than chlorine gas.
    • Disadvantages: Expensive chemical costs; degrades over time when exposed to heat and light.

• Breakpoint Chlorination Principles:

  • Definition: The point at which chlorine demand has been fully satisfied and additional chlorine added results directly in a proportional free chlorine residual.
  • Core Mathematical Formulas:
    • $\text{Chlorine Demand} = \text{Chlorine Dose} - \text{Chlorine Residual}$
    • $\text{Chlorine Residual} = \text{Chlorine Dose} - \text{Chlorine Demand}$
    • $\text{Chlorine Dose} = \text{Chlorine Demand} + \text{Chlorine Residual}$

• pH Influence on Free Chlorine Species:

  • Low pH conditions shift chlorine balance toward Hypochlorous Acid ($\text{HOCl}$), which is a powerful and fast-acting disinfectant.
  • High pH conditions shift chlorine balance toward the Hypochlorite Ion ($\text{OCl}^-$), which is a much weaker disinfectant.

• Combined Chlorine Residual Species:

  • Monochloramine ($\text{NH}_2\text{Cl}$)
  • Dichloramine ($\text{NHCl}_2$)
  • Trichloramine / Nitrogen Trichloride ($\text{NCl}_3$)

Chlorine Gas Safety, Storage, and Equipment

• Physical and Chemical Properties:

  • Greenish-yellow color, nonflammable, and nonexplosive; however, it strongly supports combustion.
  • Gas density is $2.5\text{ times}$ heavier than air.
  • Liquid-to-gas expansion ratio is $1\text{ to }450$ (1 volume of liquid chlorine expands to form 450 volumes of chlorine gas).
  • Permissible Exposure Limit (PEL) = $0.5\text{ ppm}$.
  • Immediately Dangerous to Life or Health (IDLH) = $10\text{ ppm}$.
  • Corrosivity: Extremely corrosive when mixed with moisture or water (Chlorine Gas + Water/Moisture = Hydrochloric Acid [$\text{HCl}$]).
  • Spill Neutralization: Chlorine gas leaks or liquid spills can be absorbed using caustic soda or hydrated lime.

• Emergency First Aid & Protection:

  • If exposed to chlorine gas: Immediately flush eyes with copious amounts of water and drink milk to relieve throat irritation.
  • Always don a Self-Contained Breathing Apparatus (SCBA) prior to entering an atmosphere containing chlorine gas.
  • Chlorine disinfection efficiency increases at lower pH levels and higher water temperatures.

• Storage Room Design & Requirements (Per Fire Code):

  • Storage rooms must feature an exhaust ventilation system with an inlet located no higher than $12\text{ inches}$ above the floor surface and an exhaust fan discharging outdoors.
  • Cylinders must be stored completely separated from any heat sources.
  • $150\text{ lb}$ cylinders must always be secured in a strictly vertical, upright position.
  • Protective valve caps must remain screwed onto cylinders when not in use. All cylinders (whether empty or full) must be restrained at all times using safety chains.
  • Piping Materials: Use rigid steel piping for chlorine gas systems; NEVER use neoprene.

• Safety Plugs and Emergency Repair Kits:

  • Fusible Plugs: Designed as thermal relief safety devices that melt at temperatures between $158\text{ }^\circ\text{F}$ and $165\text{ }^\circ\text{F}$.
    • $150\text{ lb}$ cylinders contain $1$ fusible plug.
    • $1\text{ ton}$ cylinders contain $6\text{ to }8$ fusible plugs ($3\text{ to }4$ located on each container end).
  • Emergency Repair Kits:
    • Repair Kit "A": Used for $150\text{ lb}$ cylinders (Color-coded RED).
    • Repair Kit "B": Used for $1\text{ ton}$ cylinders (Color-coded YELLOW).
    • Repair Kit "C": Used for bulk rail tank cars (Color-coded GREEN).

• Equipment Operational Safety Rules:

  • Leak Detection: Use concentrated ammonia vapor (ammonia hydroxide solution) to test for leaks; contact with chlorine creates a dense white smoke cloud (ammonium chloride).
  • Cylinder Valve Operation: Open cylinder valves only ONE full turn using a proper cylinder wrench.
  • Maximum Withdrawal Rates: Do not exceed a maximum withdrawal rate of $40\text{ lbs/day}$ from a $150\text{ lb}$ cylinder to prevent gas cooling and valve freezing.
  • Gaskets: Always install a new lead gasket every time a chlorine cylinder connection is changed.
  • Prohibited Substances: NEVER use grease, oil, or petroleum lubricants on or around chlorine valves and equipment.
  • Replacement Parts: Use only original factory replacement parts and dedicated tools.

• Residual Measurement and Concentration Parameters:

  • DPD Reagent Method: N,N-diethyl-p-phenylenediamine is the standard field reagent; turns the sample pink if free or combined chlorine is present.
  • Amperometric Titration Method: The most precise analytical method for determining chlorine residuals.
  • Monitoring Frequency: Chlorine residual must be measured on-site and monitored daily using official standard testing procedures.
  • Flow Measurement: A rotameter measures physical gas flow rate, while the chlorinator regulates the chemical feed.
  • CT Value Definition:
    • $C$ = Disinfectant residual concentration in $\text{mg/L}$ measured at the end of contact time.
    • $T$ = Disinfectant contact time in minutes with water ($\text{CT} = C \times T$).
    • CT requirements depend on target microorganism, water pH, water temperature, and specific disinfectant type.

Disinfection By-Products (DBPs) and Control

• Chlorine Disinfection By-Products:

  • Total Trihalomethanes (TTHMs): Maximum Contaminant Level (MCL) = $0.08\text{ ppm}$ ($0.08\text{ mg/L}$ or $80\text{ ppb}$). Classified chemically as Volatile Organic Compounds (VOCs).
    • Compounds: Chloroform, Bromoform, Bromodichloromethane, Dibromochloromethane.
  • Haloacetic Acids (HAA5s): Maximum Contaminant Level (MCL) = $0.06\text{ ppm}$ ($0.06\text{ mg/L}$ or $60\text{ ppb}$).
    • Compounds: Chloroacetic Acid, Dichloroacetic Acid, Trichloroacetic Acid, Bromoacetic Acid, Dibromoacetic Acid.

• Alternative Disinfectant By-Products:

  • Chlorite: Formed as a DBP when using Chlorine Dioxide. MCL = $1.0\text{ ppm}$.
  • Bromate: Formed as a DBP when applying Ozone to bromide-containing water. MCL = $0.01\text{ ppm}$.

• Organic Precursors and DBP Formation Factors:

  • Total Organic Carbon (TOC):
    • Naturally Occurring TOCs: Derived from decaying leaves, wood, and natural vegetative organic matter. Act as the primary precursor to THM formation.
    • Synthetic Organic Chemicals (SOCs): Manmade industrial and agricultural chemicals, including pesticides, herbicides, solvents, and plastics entering source water primarily via farmland runoff.
  • Critical DBP Formation Factors: Contact time, concentration of natural organic precursors, free chlorine concentration, bromide ion concentration, water pH, and water temperature.

• Control and Removal Strategies:

  • Prevention Strategy: Switch to alternative disinfectants that generate fewer DBPs, such as chloramines or chlorine dioxide.
  • Removal Strategy: Remove formed THMs and organic precursors through aeration, activated carbon adsorption (GAC/PAC filters), or chemical oxidation.

Waterborne Diseases and Microorganisms

• Pathogenic Microorganisms Transmitted by Water:

  • Viruses: Polio, Hepatitis A.
  • Bacteria: Salmonella, Shigella (Dysentery), Salmonella typhi (Typhoid), Vibrio cholerae (Cholera).
  • Parasites / Protozoa: Cryptosporidium, Giardia lamblia.

• Pathogen Log Inactivation Standards:

  • $3\text{-log inactivation}$ = $99.9\%$ removal or destruction of target organisms.
  • $4\text{-log inactivation}$ = $99.99\%$ removal or destruction of target organisms.

Water Quality Parameters: pH and Fluoridation

• pH Fundamentals and Calculations:

  • Definition: A numerical scale ($0\text{ to }14$) measuring hydrogen ion activity to determine whether water is acidic, neutral, or basic (alkaline).
  • $\text{pH} = 7\text{ is Neutral}$; $\text{pH} < 7\text{ is Acidic}$; $\text{pH} > 7\text{ is Basic/Alkaline}$.
  • Mathematical Formula: The base-10 logarithm of the reciprocal of hydrogen ion activity:         $\text{pH} = \log_{10}\left(\frac{1}{[H^+]}\right) = -\log_{10}([H^+])$

• Operational Objectives for pH Adjustment:

  • Elevate pH during the lime-soda ash softening process.
  • Adjust pH to render finished water non-corrosive and non-scale-forming.
  • Maintain finished water pH within the Secondary Maximum Contaminant Level (SMCL) range of 6.5\text{ to }8.5$.\n * Lower pH to optimize free chlorine disinfection efficiency.\n\n* **Chemical Additives for pH Adjustment:**\n * *To Increase pH (Alkalis):* Hydrated Lime (Calcium Hydroxide - \text{Ca(OH)}_2$), Caustic Soda (Sodium Hydroxide -$\text{NaOH}$), or Soda Ash (Sodium Carbonate -$\text{Na}_2 ext{CO}_3).\n * *To Decrease pH (Acids):* Sulfuric Acid (\text{H}_2 ext{SO}_4$) or Carbon Dioxide gas ($\text{CO}_2).\n\n* **Laboratory Protocol for pH Measurement:**\n * Electronic pH meters are the only official regulatory method for testing pH.\n * Benchtop meters must be calibrated daily using at least two standard buffer solutions flanking the target pH range. Never reuse buffers; respect manufacturer expiration dates.\n * Calibration records must be documented in a dedicated logbook and retained for 3\text{ years}.\n * Required meter accuracy must be within \pm 0.2\text{ pH units}.\n * Always rinse electrode probes with distilled water after calibration and between samples.\n\n* **Fluoridation Requirements and Standards:**\n * **Purpose:** Added to drinking water to prevent dental caries (cavities). Excessive fluoride concentrations cause fluorosis/mottled teeth (brown enamel staining).\n * **Target Concentration:** Approximately 1\text{ mg/L} total concentration (combined natural background plus added fluoride). Lower ambient temperatures require higher fluoride feed rates.\n * **Regulatory Limits:** Secondary Maximum Contaminant Level (SMCL) = 2\text{ mg/L}$; Primary Maximum Contaminant Level (PMCL) =$4\text{ mg/L}.\n\n* **Fluoridation Chemicals (Must comply with AWWA / NSF/ANSI Standard 60):**\n * **Sodium Fluoride (\text{NaF}):** Dry powder chemical. Applied using gravimetric dry feeders in high-flow water treatment plants. Gravimetric feeders (measuring by weight) provide superior accuracy compared to volumetric feeders.\n * **Sodium Fluorosilicate (\text{Na}_2 ext{SiF}_6):** Dry powder chemical. Applied using volumetric dry feeders in low-flow treatment plants. Most economical fluoridation chemical.\n * **Hydrofluosilicic Acid (\text{H}_2 ext{SiF}_6$):** Liquid chemical solution. Most widely used fluoridation chemical. Easiest to feed via chemical metering pump, but emits toxic fumes and etches glass. Standard concentrated solution pH ranges from$1.0\text{ to }1.5$(approximately$1.2).\n\n* **Fluoride Feed and Monitoring Protocols:**\n * **Application Point:** Fluoride MUST ALWAYS be fed into the filter effluent stream.\n * **Day Tank Rule:** Liquid solution day tanks must not store more than a maximum 30\text{-hour} supply of chemical.\n * **Testing Frequency:** Continuous online monitoring with high-level alarms is recommended. A minimum of one daily grab sample must be analyzed from a distribution customer tap using a spectrophotometer.\n\n# Surface Water Reservoirs and Algae Control\n\n* **Thermal Stratification Layers:**\n * **Epilimnion:** The warm, upper surface layer of a thermally stratified reservoir.\n * **Metalimnion / Thermocline:** The middle transition zone experiencing rapid temperature decline with depth.\n * **Hypolimnion:** The cold, deep bottom layer characterized by low dissolved oxygen.\n\n* **Reservoir Intake Configurations:**\n * **Single-Level Intake:** Fixed intake opening located near the reservoir bottom to allow water withdrawal during extreme drought conditions.\n * **Multilevel Intake:** Features intake gates at multiple depths, enabling operators to selectively draw water from optimal strata to avoid taste, odor, iron, and manganese issues.\n\n* **Algae Dynamics and Control:**\n * **Eutrophication Causes:** Excessive nutrient runoff containing phosphates and nitrogen (primarily from agricultural runoff) causes massive algal blooms.\n * **Water Quality Impacts:** Algae blooms disrupt Dissolved Oxygen (D.O.) cycles, alter pH, increase organic loading, and produce distinct taste and odor compounds.\n * **Taste and Odor Profiles:** Approximately 40 species of algae produce characteristic grassy, fishy, musty, septic, or pigpen tastes and odors.\n * **Operational Problems:** Algae clogs intake screens, increases chemical coagulant demand, and severely shortens filter run times.\n * **Chemical Control:** Copper Sulfate (\text{CuSO}_4 \cdot 5\text{H}_2 ext{O}$, known as Bluestone). Copper application levels must be carefully controlled not to exceed regulatory limits ($0.5\text{ mg/L to }1.0\text{ mg/L}).\n\n* **Diurnal D.O. and pH Fluctuations:**\n * Dissolved oxygen and pH levels decrease significantly at night due to the cessation of photosynthesis and continuous cellular respiration by biological organisms.\n\n* **Reservoir Turnover:**\n * Occurs in spring and autumn when surface and deep water temperatures equalize, destroying thermal stratification. The reservoir flips (bottom water rises to top), causing sudden taste, odor, color, and turbidity problems.\n\n# Water Treatment Processes and Plant Operations\n\n* **Core Water Treatment Definitions:**\n * **Aeration:** The process of introducing air into water to oxidize dissolved minerals (such as iron and manganese), release dissolved gases (such as hydrogen sulfide), and strip volatile organic compounds and tastes/odors.\n * **Coagulation:** The rapid mixing of chemicals to neutralize electrical charges on colloidal particles, causing fine suspended solids to clump together into microscopic micro-floc. Water with low alkalinity will not coagulate properly.\n * **Flocculation:** The gentle, slow mixing phase that promotes collisions between micro-floc particles, forming large, visible, settleable macro-floc.\n * **Sedimentation:** The physical clarification process where heavy floc particles settle to the bottom of a basin or clarifier by gravity.\n * **Zeolite:** A natural or synthetic ion exchange resin used for water softening.\n * **Ion Exchange:** A reversible chemical process exchanging unwanted dissolved ions in water with target ions bound to a solid resin bed.\n * **Potassium Permanganate (\text{KMnO}_4):** A powerful chemical oxidant used in conjunction with manganese greensand filters to remove dissolved iron and manganese.\n * **Manganese Greensand:** A green mineral filter medium (glauconite) treated with potassium permanganate used to strip iron and manganese from water.\n * **Lime Types:** Hydrated Lime (Calcium Hydroxide - \text{Ca(OH)}_2$) and Quicklime (Calcium Oxide -$\text{CaO}). Quicklime must be slaked with water before application. Lime increases pH and alkalinity, removes hardness, and reduces corrosivity.\n * **SCADA:** Supervisory Control and Data Acquisition system; a computer network designed to monitor, alarm, log data, and automatically control plant processes.\n * **Jar Testing:** A bench-scale laboratory procedure simulating plant coagulation and flocculation processes to optimize chemical dose. Objective: produce dense, rapidly settleable floc leaving clear water between particles.\n * **Launder:** An overhead collection trough with V-notch weirs used to evenly collect clarified water effluent from sedimentation basins.\n * **Tube Settlers:** Inclined parallel tubes installed in a settling basin that shorten settling distance and enhance sedimentation efficiency.\n * **Aluminum Sulfate (Alum - \text{Al}_2(\text{SO}_4)_3 \cdot 14\text{H}_2\text{O}):** The most common primary coagulant used in water treatment.\n * **Hardness:** Water quality characteristic caused predominantly by dissolved calcium (\text{Ca}^{2+}$) and magnesium ($\text{Mg}^{2+}) cations.\n * **Anthracite:** A durable granular filter material produced from crushed hard coal.\n * **Activated Carbon:** High-surface-area carbon media (PAC or GAC) used to adsorb dissolved organic compounds, tastes, and odors.\n * **Alkalinity:** The quantitative capacity of water to neutralize acids, primarily composed of bicarbonate (\text{HCO}_3^-$), carbonate ($\text{CO}_3^{2-}$), and hydroxide ($\text{OH}^-) ions.\n\n# Filtration Technologies\n\n* **Conventional Rapid Sand Filtration Process Train:**\n 1. *Influent:* Raw water enters.\n 2. *Coagulation:* Coagulant chemical injected into flash/fast mix zone (dosage determined by jar testing).\n 3. *Flocculation:* Gentle slow-mix zone (flocculator speed adjusted for optimal floc growth; floc settles faster in warmer water).\n 4. *Sedimentation:* Clarifier/settling basin containing smooth zone, settling zone, and sludge zone. Clarified water collected in launders.\n 5. *Filtration:* Water passes through rapid sand filter (filtration rate typically 3\text{ to }5\text{ gpm/sq. ft.}). Removes turbidity, color, taste, odor, and pathogens.\n 6. *Disinfection & Stabilization:* Disinfectant and calcium carbonate added.\n 7. *Effluent:* Finished water flows to clearwell.\n\n* **Filter Operational Details and Auxiliaries:**\n * **Media Configurations:** Single-media, dual-media (anthracite and sand), or mixed-media (anthracite, sand, and garnet). If anthracite is present, its lower density keeps it on top.\n * **Polymers:** Non-ionic polymers are added as filter aids to prevent breakthrough.\n * **Backwashing & Mudballs:** Inadequate or improper backwashing causes mudball formation within the bed. Use auxiliary air wash or mechanical surface wash jets to prevent mudballs.\n * **Backwash Expansion:** Backwash flow rate must expand the filter bed depth by 50\% during washing.\n * **Short-Circuiting:** Cracks or structural breaks in the filter bed cause short-circuiting, allowing unfiltered water to pass.\n * **Flow Control:** Rate-of-flow controllers maintain a constant filtration rate despite increasing head loss across the run.\n * **Recycle Stream:** Plants are encouraged to settle and recycle spent backwash water back to the head of the plant to conserve water resources.\n * **Effluent Quality:** The quality of individual filter effluent determines overall water quality entering the distribution system.\n\n* **Alternative Filtration Processes:**\n * **Direct Filtration:** Sequence: Coagulation \rightarrow$Flocculation$\rightarrow Filtration. Eliminates the sedimentation stage completely (and in some cases eliminates flocculation).\n * **Pressure Filtration:** Enclosed steel pressure vessel forcing water under pressure through sand and underdrains.\n * **Slow Sand Filtration:** Gravity-fed system operating at very low loading rates. Does not use chemical coagulation. The active biological layer on top of the sand is called the *schmutzdecke*. Requires vast physical surface area.\n * **Diatomaceous Earth (DE) Filtration:** Uses fine silica media composed of fossilized skeletal remains of diatoms. Common in food/beverage industries requiring extreme clarity.\n\n* **Solids-Contact Units (Upflow Clarifiers):**\n * Integrates chemical coagulation, flocculation, and sedimentation into a single compact tank.\n * Water flows vertically upward through a suspended sludge blanket.\n * Extremely sensitive to sudden changes in flow rate, water temperature, and raw turbidity.\n * Controlling the precise volume of the sludge blanket provides operational stability.\n\n# Softening, Iron and Manganese Removal, and Membrane Processes\n\n* **Lime Softening Process:**\n * Chemical Additions: Hydrated lime is added to remove carbonate hardness. Hydrated lime PLUS soda ash is added to remove non-carbonate hardness.\n * Process Chain: Influent \rightarrow$Aeration$\rightarrow$Coagulation$\rightarrow$Flocculation$\rightarrow$Sedimentation$\rightarrow$Recarbonation ($\text{CO}_2$injection to lower pH and stabilize water)$\rightarrow$Filtration$\rightarrow$Disinfection$\rightarrow Effluent.\n * Removes hardness along with turbidity, color, taste, odor, and pathogens.\n\n* **Zeolite Softening (Ion Exchange):**\n * Unit construction: Contains zeolite resin, gravel bed, and underdrains.\n * Operational Cycles: 1) Service cycle, 2) Backwash cycle, 3) Brine cycle (regeneration using concentrated \text{NaCl} solution), 4) Rinse cycle.\n * Softened water exiting unit must read 0\text{ mg/L} hardness. Hardness breakthrough indicates immediate need for brine regeneration.\n\n* **Iron and Manganese Removal:**\n * Chemical Sequence: Adjust pH upward \rightarrow$Oxidize water by injecting Potassium Permanganate ($\text{KMnO}_4$) or Chlorine (water should show a faint pink tint prior to filter)$\rightarrow$Pass through Manganese Greensand filter bed$\rightarrow$Gravel support$\rightarrow$Underdrain$\rightarrow Finished Effluent.\n\n* **Demineralization & Membrane Filtration:**\n * **Reverse Osmosis (RO):** Uses high-pressure pumps to force water through semi-permeable membrane sheets, removing dissolved minerals, salts, and contaminants to produce pure water.\n\n# Public Water System Classifications and Sanitary Code\n\n* **Identification:** All public water systems are assigned a unique Public Water Supply Identification Number (PWSID).\n\n* **Public Water System Categories:**\n * **Community Water Supply:** A public water system that serves at least 15\text{ service connections}$used by year-round residents or regularly serves at least$25\text{ year-round residents}.\n * **Non-Community Water Supply:** A public water system that does not meet community criteria and serves at least 25\text{ people}$(combination of residents and transients) at least$60\text{ days per year}. Divided into two subcategories:\n * *Non-Transient Non-Community (NTNC):* Regularly serves at least 25\text{ of the same non-resident persons}$over$6\text{ months per year}. *Example:* Schools, factories, daycare centers.\n * *Transient Non-Community (TNC):* Does not regularly serve at least 25\text{ of the same persons}$over$6\text{ months per year}. *Example:* Highway rest stops, gas stations, campgrounds.\n\n# Backflow, Cross-Connection, and Infrastructure Rules\n\n* **Backflow Dynamics and Prevention:**\n * **Backflow:** Unwanted reverse flow of water/contaminants into the potable water distribution system caused by backpressure or backsiphonage.\n * **Testing Requirement:** All backflow prevention assemblies must be field-tested at least ANNUALLY.\n * **Backflow Assemblies:** Reduced Pressure Zone (RP) assemblies, Double Check Valve Assemblies (DCVA), and Air Gaps.\n * **Air Gap Rules:** An Air Gap offers the highest level of backflow protection. The air gap separation distance must be at least TWO TIMES the inner diameter of the supply pipe, and never less than 2\text{ inches}.\n * **Backsiphonage:** Reverse flow caused specifically by negative or sub-atmospheric pressure created within the distribution piping network. Prevented using vacuum breakers, RP devices, or air gaps.\n * **Cross-Connection:** Any physical, unprotected connection between a potable water piping system and any source containing water of unknown or unapproved quality.\n\n* **State Sanitary Code (Part XII) Operational Mandates:**\n * **Minimum Distribution Pressure:** Minimum normal pressure is 20\text{ psi}$. A mandatory Boil Water Advisory or Boil Water Notice must be issued if pressure drops below$20\text{ psi}.\n * *Boil Notice:* Issued and officially lifted strictly by the State Health Department.\n * *Boil Advisory:* Issued and managed internally by the water utility.\n * **Utility Line Separation Distances:** Water mains and sanitary sewers must be laid in separate trenches, maintaining at least 6\text{ feet}$horizontal separation. When crossing, water mains must be placed$18\text{ inches} vertically above sewer lines. (Exceptions granted solely by the State Health Officer).\n\n* **Well Location Minimum Separation Distances:**\n * Septic Tanks = 50\text{ feet}\n * Storm Sewers = 50\text{ feet}\n * Sanitary Sewers = 50\text{ feet}\n * Oxidation Ponds / Sewage Treatment Plants = 100\text{ feet}\n * Solid Waste Landfills = 100\text{ feet}\n * Another Water Well = 25\text{ feet}\n\n* **Disinfection Protocol for New Infrastructure:**\n * **New Mains and Wells:** Must be disinfected with a chlorine solution of 50\text{ ppm}$($\text{mg/L}$) maintained for a minimum of$3\text{ hours}$. At the end of 3 hours, a minimum residual of$5\text{ ppm} free chlorine must remain.\n * **Water Storage Tanks:** Can be disinfected by spraying interior surfaces with a 200\text{ ppm} chlorine solution.\n * **Coliform Testing:** Must test negative for coliform bacteria prior to placing new mains, wells, or tanks into service.\n\n* **Mandatory Groundwater Disinfection Residuals:**\n * Minimum disinfectant contact time = 30\text{ minutes} prior to reaching the first customer connection.\n * Minimum free chlorine residual leaving groundwater treatment plant (based on finished pH):\n * \text{pH up to } 7.0 \rightarrow 0.5\text{ ppm}\n * \text{pH } 7.0\text{ to } 8.0 \rightarrow 0.6\text{ ppm}\n * \text{pH } 8.0\text{ to } 9.0 \rightarrow 0.8\text{ ppm}\n * \text{pH over } 9.0 \rightarrow