Water Source Characterization and Intake Structures

Raw Water Quality Assessment

• Comprehensive analysis of potential water sources, including rivers, lakes, reservoirs, and groundwater aquifers.
• Detailed examination of physical parameters: turbidity, color, temperature, and total solids. Understanding how each affects treatment processes and final water quality.
• In-depth chemical analysis: pH, alkalinity, hardness (calcium and magnesium), dissolved organic carbon (DOC), disinfection byproduct precursors (DBPs), nutrients (nitrogen and phosphorus), metals (iron, manganese, arsenic), and organic contaminants (pesticides, herbicides, VOCs). Mastery of analytical techniques and data interpretation to identify potential treatment challenges.
• Microbiological assessment: total coliforms, fecal coliforms, E. coli, Giardia, Cryptosporidium, and viruses. Understanding indicator organisms and their implications for waterborne disease. Application of quantitative microbial risk assessment (QMRA) to determine the required log removal/inactivation.
• Seasonal variations in water quality: analyzing long-term data to understand trends and predict changes in raw water characteristics due to rainfall, snowmelt, agricultural runoff, and other environmental factors. Development of adaptive treatment strategies to account for these variations.

Intake Structure Design and Operation

• Location considerations: evaluating factors such as water depth, flow velocity, accessibility, environmental impact, and proximity to potential sources of contamination.
• Types of intake structures: submerged intakes, infiltration galleries, intake towers, and riverbank filtration systems. Detailed understanding of the advantages and disadvantages of each type, and their suitability for different water sources and site conditions.
• Screening and debris removal: designing and operating coarse and fine screens to remove large debris and prevent clogging of downstream equipment. Selection of appropriate screen materials and mesh sizes based on the characteristics of the raw water.
• Pump station design: determining the required pumping capacity based on the plant's design flow rate and headloss characteristics. Selection of appropriate pump types (centrifugal, submersible, vertical turbine) and materials. Installation and maintenance of pump control systems.
• Intake maintenance and inspection: regular inspection and cleaning of intake structures to prevent biofouling, sedimentation, and corrosion. Underwater inspection techniques and repair methods.

Coagulation and Flocculation

Coagulant Chemistry and Selection

• Theory of coagulation: destabilization of colloidal particles through charge neutralization and bridging mechanisms. Understanding the role of zeta potential and surface charge in the coagulation process.
• Types of coagulants: aluminum-based (alum, polyaluminum chloride - PACL), iron-based (ferric chloride, ferric sulfate), and polymer-based coagulants. Detailed comparison of their effectiveness, cost, and impact on pH and alkalinity.
• Jar testing: performing jar tests to determine the optimal coagulant dosage and pH range for effective floc formation. Data analysis and interpretation to optimize treatment performance.
• Coagulant feed systems: designing and operating chemical feed systems for accurate and reliable delivery of coagulants. Calibration and maintenance of feed pumps and metering devices.
• Factors affecting coagulation: water temperature, pH, alkalinity, turbidity, and organic matter. Understanding how these factors influence the coagulation process and adjusting treatment accordingly.

Flocculation Process Optimization

• Flocculation theory: promoting particle aggregation through gentle mixing to form larger, more settleable flocs. Understanding the role of velocity gradient and detention time in the flocculation process.
• Types of flocculation equipment: mechanical mixers, hydraulic flocculators, and tapered energy flocculation systems. Detailed comparison of their advantages and disadvantages, and their suitability for different plant configurations.
• Flocculation control parameters: optimizing mixing intensity and detention time to promote effective floc formation without causing floc breakage. Monitoring floc size and settling characteristics to assess treatment performance.
• Polymer addition: using polymers as flocculant aids to enhance floc strength and settling velocity. Selection of appropriate polymer types and dosages based on the characteristics of the raw water.
• Troubleshooting flocculation problems: diagnosing and resolving issues such as poor floc formation, pin floc, and carryover of flocs to downstream processes.

Sedimentation and Clarification

Sedimentation Basin Design and Operation

• Sedimentation theory: gravity settling of suspended solids in a quiescent environment. Understanding the relationship between particle size, density, settling velocity, and detention time.
• Types of sedimentation basins: horizontal-flow, upflow, and inclined plate/tube settlers. Detailed comparison of their advantages and disadvantages, and their suitability for different plant configurations.
• Design parameters: surface overflow rate, detention time, and weir loading rate. Calculating these parameters to ensure adequate settling capacity and prevent short-circuiting.
• Sludge removal systems: designing and operating mechanical sludge collectors to remove accumulated sludge from the bottom of the basin. Selecting appropriate sludge disposal methods.
• Maintenance and inspection: regular inspection and cleaning of sedimentation basins to prevent sludge buildup, corrosion, and other problems.

Clarifier Operation and Optimization

• Clarifier types: conventional clarifiers, solids-contact clarifiers, and ballasted sedimentation systems. Understanding the principles of operation of each type and their suitability for different water quality conditions.
• Solids-contact clarification: promoting rapid floc formation and settling by recycling sludge and mixing it with incoming raw water. Optimizing sludge blanket depth and recycle rate to enhance treatment performance.
• Ballasted sedimentation: using micro-sand or other ballast materials to increase the settling velocity of flocs. Optimizing ballast dosage and mixing intensity to achieve high solids removal efficiency.
• Clarifier performance monitoring: measuring turbidity, suspended solids, and particle counts in the effluent to assess treatment performance. Adjusting operating parameters to optimize solids removal.
• Troubleshooting clarifier problems: diagnosing and resolving issues such as poor effluent quality, excessive sludge production, and clarifier upsets.

Filtration

Filtration Principles and Media Selection

• Filtration mechanisms: straining, interception, impaction, and adsorption. Understanding how these mechanisms contribute to the removal of suspended solids and pathogens.
• Types of filter media: sand, gravel, anthracite, granular activated carbon (GAC), and membranes. Detailed comparison of their properties, performance, and suitability for different applications.
• Filter bed design: optimizing filter bed depth, media size, and porosity to achieve high solids removal efficiency and prevent excessive headloss.
• Pretreatment requirements: optimizing coagulation and sedimentation processes to reduce the solids loading on the filters and extend filter run times.
• Filter performance monitoring: measuring turbidity, particle counts, and headloss in the filter effluent to assess treatment performance.

Filter Operation and Backwashing

• Types of filters: rapid sand filters, slow sand filters, pressure filters, and membrane filters. Detailed comparison of their advantages and disadvantages, and their suitability for different plant configurations.
• Filter backwashing: removing accumulated solids from the filter bed by reversing the flow of water and air. Optimizing backwash frequency, duration, and flow rate to effectively clean the filter bed without losing excessive media.
• Surface washing: using surface washers to break up the filter bed and remove accumulated solids before backwashing.
• Air scouring: using compressed air to agitate the filter bed and enhance the removal of solids during backwashing.
• Filter ripening: allowing the filter to operate for a short period of time after backwashing to establish a stable biological layer and improve treatment performance.

Disinfection

Disinfection Chemistry and Byproduct Formation

• Disinfection mechanisms: inactivation of pathogens through oxidation, damage to cell membranes, and interference with cellular processes.
• Types of disinfectants: chlorine, chloramine, chlorine dioxide, ozone, and ultraviolet (UV) light. Detailed comparison of their effectiveness, cost, and potential for byproduct formation.
• Chlorination: understanding the chemistry of chlorine disinfection, including the formation of hypochlorous acid (HOCl) and hypochlorite ion (OCl-). Optimizing chlorine dosage and contact time to achieve effective disinfection without forming excessive disinfection byproducts (DBPs).
• Chloramination: using chloramine to provide a longer-lasting residual disinfectant and reduce the formation of DBPs. Understanding the chemistry of chloramination and the factors that affect chloramine stability.
• Disinfection byproduct formation: understanding the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) during chlorination, and strategies to minimize their formation, such as enhanced coagulation and alternative disinfectants.

Disinfection System Design and Operation

• Chlorine gas feed systems: designing and operating safe and reliable chlorine gas feed systems, including gas feeders, chlorinators, and safety equipment.
• Hypochlorite feed systems: designing and operating hypochlorite feed systems, including storage tanks, metering pumps, and safety equipment.
• Ozone generation systems: understanding the principles of ozone generation and the design and operation of ozone generators.
• UV disinfection systems: understanding the principles of UV disinfection and the design and operation of UV reactors.
• Contact time optimization: optimizing contact time to ensure adequate disinfection. Using baffling and other techniques to prevent short-circuiting.
• Disinfection monitoring: measuring disinfectant residual and monitoring microbial indicators to verify disinfection effectiveness.

Corrosion Control

Corrosion Mechanisms and Materials

• Electrochemical corrosion: understanding the principles of electrochemical corrosion, including the role of anodes, cathodes, electrolytes, and redox reactions.
• Types of corrosion: uniform corrosion, pitting corrosion, crevice corrosion, galvanic corrosion, and microbiologically influenced corrosion (MIC). Understanding the mechanisms and prevention of each type of corrosion.
• Materials selection: selecting corrosion-resistant materials for pipes, tanks, and other water treatment equipment. Understanding the properties and limitations of different materials, such as steel, stainless steel, copper, and plastics.
• Protective coatings: using protective coatings to prevent corrosion. Understanding the different types of coatings, such as epoxy coatings, polyurethane coatings, and cement mortar linings.

Corrosion Control Strategies

• pH adjustment: adjusting pH to reduce the corrosivity of water. Understanding the relationship between pH, alkalinity, and corrosion rate.
• Alkalinity adjustment: adding alkalinity to buffer pH and reduce the corrosivity of water. Understanding the different types of alkalinity, such as bicarbonate, carbonate, and hydroxide.
• Corrosion inhibitors: adding corrosion inhibitors to form a protective film on pipe surfaces. Understanding the different types of corrosion inhibitors, such as orthophosphates, polyphosphates, and zinc orthophosphates.
• Cathodic protection: using cathodic protection to prevent corrosion by making the metal structure the cathode in an electrochemical cell. Understanding the different types of cathodic protection systems, such as impressed current cathodic protection and sacrificial anode cathodic protection.
• Lead and copper rule: understanding the requirements of the Lead and Copper Rule and implementing strategies to minimize lead and copper levels in drinking water.

Residuals Management

Sludge Handling and Thickening

• Sludge characteristics: understanding the physical and chemical characteristics of sludge produced during water treatment, including solids content, volatile solids content, and nutrient content.
• Sludge thickening: increasing the solids content of sludge to reduce its volume and improve its handling characteristics. Understanding the different types of sludge thickeners, such as gravity thickeners, dissolved air flotation (DAF) thickeners, and rotary drum thickeners.
• Sludge dewatering: removing water from sludge to further reduce its volume and prepare it for disposal. Understanding the different types of sludge dewatering equipment, such as belt filter presses, centrifuges, and plate and frame presses.
• Sludge stabilization: reducing the odor and pathogen content of sludge to make it suitable for land application or disposal. Understanding the different types of sludge stabilization processes, such as aerobic digestion, anaerobic digestion, and lime stabilization.

Disposal Methods and Regulations

• Land application: applying sludge to land as a fertilizer and soil amendment. Understanding the regulations governing land application of sludge, including limits on heavy metals and pathogens.
• Landfilling: disposing of sludge in a landfill. Understanding the regulations governing landfilling of sludge, including requirements for leachate collection and methane gas control.
• Incineration: burning sludge in an incinerator to reduce its volume and destroy pathogens. Understanding the regulations governing incineration of sludge, including limits on air emissions.
• Beneficial reuse: using sludge for other beneficial purposes, such as composting and energy production.
• Regulatory compliance: understanding and complying with all applicable federal, state, and local regulations governing sludge management.