Wastewater Management – REHS Study (June 2025)

Vocabulary flashcards summarizing major laws, pollutants, treatment processes, on-site systems, soil science, and stormwater terms from the Wastewater Management lecture notes.

State Water Resources Control Board (SWRCB)

California state agency (created 1963) that allocates water resources and enforces water-quality regulations.

Regional Water Quality Control Boards (RWQCB)

Nine regional boards under SWRCB that develop basin plans and issue permits for water quality within their regions.

Porter-Cologne Water Quality Act (1969)

California law requiring preservation and enhancement of all beneficial uses of the state’s waters; considered a strong anti-pollution statute.

Uniform Plumbing Code

Model code setting minimum standards for design, installation, and maintenance of plumbing systems to protect public health and safety.

Clean Water Act (CWA) of 1972

Federal law that regulates discharges of pollutants into U.S. surface waters and sets water-quality standards.

National Pollutant Discharge Elimination System (NPDES)

Permit program under the CWA that regulates point-source discharges of pollutants to U.S. waters.

Stormwater Pollution Prevention Plan (SWPPP)

Site-specific document identifying possible stormwater pollution sources and describing best management practices to prevent unpermitted discharges.

Publicly Owned Treatment Works (POTW)

Municipal wastewater treatment facility regulated by EPA that collects and treats sewage.

Preliminary Treatment

First stage of wastewater treatment; removes large solids through screening, comminution, grit removal, and similar methods.

Primary Treatment

Settling process that removes most remaining settleable and floatable solids from wastewater.

Secondary Treatment

Biological stage (e.g., activated sludge, trickling filters) that degrades organic matter using microbes.

Tertiary Treatment

Advanced treatment (extra filtration & disinfection) that removes inorganic compounds, pathogens, and nutrients.

Comminution

Grinding wastewater solids into smaller pieces during preliminary treatment.

Coarse Screening

Use of bar racks or screens to trap large debris entering a treatment plant.

Micro-Screening

Fine screening step to remove very small suspended particles from influent.

Grit Removal

Separation of sand, gravel, and other heavy inorganic particles during preliminary treatment.

Trickling Filter

Secondary process where wastewater trickles over media coated with biofilm to oxidize organic matter.

Activated Sludge

Aerobic secondary treatment that mixes wastewater with recycled biomass while supplying oxygen.

Aeration (Wastewater)

Process of bringing air and water into contact to promote oxidation and gas removal.

Clarifier

Sedimentation tank that removes suspended solids by gravity settling.

Air Stripping

Technique that passes air through contaminated water to volatilize and remove chemicals such as VOCs.

Coagulation

Addition of chemicals to destabilize suspended particles so they can clump together.

Flocculation

Gentle mixing that promotes formation of larger flocs from coagulated particles, aiding settling.

Disinfection – Chlorine

Chemical disinfection method using chlorine to inactivate pathogens after tertiary treatment.

Disinfection – Ultraviolet (UV)

Physical disinfection method exposing effluent to UV light to damage microbial DNA.

Disinfection – Ozone

Strong oxidant used to disinfect and oxidize contaminants in tertiary treatment.

Packaged Treatment Plant

Factory-built, compact wastewater treatment unit for commercial, industrial, or small community use.

Reclaimed Water

Treated wastewater suitable for non-potable uses such as irrigation and industrial processes.

Gray Water

Untreated domestic wastewater from showers, baths, and washing machines (excludes toilet waste).

Cross-Connection

Physical link between potable and non-potable systems that may cause contamination.

Purple Pipe Standard

Color-coded piping (purple background) indicating non-potable reclaimed water per California Plumbing Code.

Nitrates

Nitrogenous compounds in wastewater that can cause groundwater contamination and methemoglobinemia.

Coliform Bacteria

Indicator group of bacteria signaling possible fecal contamination in water.

Fecal Coliform

Subset of coliforms originating from intestinal tracts of warm-blooded animals; indicates fecal pollution.

Total Dissolved Solids (TDS)

Measure of dissolved inorganic and organic substances in water (mg/L).

Total Suspended Solids (TSS)

Concentration of undissolved particles suspended in water (mg/L).

Fats, Oils & Grease (FOG)

Lipids in wastewater that can clog sewers and interfere with treatment processes.

Foaming Agents

Surfactants that create stable foams in wastewater, hindering treatment efficiency.

Biological Oxygen Demand (BOD)

Amount of dissolved oxygen needed by microbes to decompose organic matter over 5 days.

Dissolved Oxygen (DO)

Quantity of oxygen dissolved in water; essential for aquatic life and treatment processes.

Chemical Oxygen Demand (COD)

Measure of oxygen equivalent required to chemically oxidize organic & inorganic matter in water.

Pharmaceuticals (in Wastewater)

Medicinal compounds entering sewage that may persist through treatment and impact ecosystems.

Vibrio

Genus of bacteria in wastewater; some species cause cholera and gastrointestinal illness.

Shigella

Pathogenic bacteria transmitted via fecally contaminated water causing shigellosis.

Giardia

Protozoan parasite causing giardiasis; cysts survive in contaminated water.

Cryptosporidium

Chlorine-resistant protozoan parasite causing cryptosporidiosis; notable waterborne pathogen.

Hepatitis A Virus

Enteric virus that can spread through sewage-contaminated water and cause liver disease.

Norovirus

Highly contagious virus causing acute gastroenteritis; present in fecally contaminated water.

Septic System

On-site wastewater treatment consisting of a septic tank and soil absorption (leach) field.

Septic Tank

Watertight tank providing 24–72 h retention for solids settling and scum separation.

Distribution Box (D-box)

Device that evenly splits effluent flow to multiple drain-field lines.

Drain Field (Leach Field)

Network of perforated pipes or chambers that disperse effluent into soil for treatment.

Seepage Pit

Deep excavation lined with perforated walls that allows wastewater percolation where space is limited.

Mound System

Elevated sand and gravel bed used when shallow soils or high water tables prevent standard leach fields.

Pressure Dosing System

Timed, pressurized effluent distribution ensuring uniform loading to the absorption area.

Intermittent Sand Filter

Media filter that intermittently doses effluent through sand for further treatment.

Aerobic Treatment Unit (ATU)

On-site system that introduces air to promote aerobic digestion before soil disposal.

Packed-Bed System (e.g., Advantex)

Fixed-media treatment units that filter effluent through textile or other media for polishing.

Evapotranspiration System

On-site disposal relying on evaporation and plant uptake rather than percolation to soil.

Chamber System

Plastic arch chambers replacing gravel trenches in drain fields to promote soil infiltration.

Drip Irrigation (Wastewater)

Slow, pressurized effluent application through tubing at shallow soil depths.

Contour Trench

Shallow trenches along land contours used for effluent distribution in sloped sites.

Soil Texture

Proportion of sand, silt, and clay particles that influences permeability and suitability for leach fields.

Loam

Ideal soil mixture (~40 % sand, 40 % silt, 20 % clay) with good drainage and nutrient capacity.

Permeability (Soils)

Rate at which water moves through soil; critical for absorption field performance.

Restrictive Layer

Soil horizon (e.g., clay, fragipan, rock) that limits vertical or lateral effluent movement.

Seasonal High-Water Table

Highest level that groundwater rises seasonally; limits depth of on-site systems.

Mottling (Redoximorphic Features)

Blotches of different soil colors indicating periodic saturation and fluctuating water table.

Fragipan

Dense, brittle subsoil layer that restricts root growth and water movement.

Percolation Test (Perc Test)

Field test measuring the rate (minutes per inch) at which water infiltrates soil for system sizing.

Minutes Per Inch (MPI)

Unit expressing soil percolation rate; values

Pre-Soaking (Perc Test)

Initial saturation of test holes for several hours to mimic field moisture conditions.

Stormwater

Rain- or snow-melt runoff that can carry pollutants into watercourses if uncontrolled.

Straw Wattle

Fiber roll used on slopes to filter stormwater runoff and control erosion.

Dry Well

Class V injection well that infiltrates uncontaminated stormwater; not suitable for sewage disposal.

Class V Injection Well

EPA category for shallow wells that inject non-hazardous fluids, including dry wells.

Storm Drain

Conveyance system designed to carry stormwater (not wastewater) to a water body.