Unit 1 — Wastewater Foundations: Lesson 2 — Where Does Wastewater Come From?

Vocabulary flashcards covering the major sources and classifications of wastewater, infiltration and inflow (I/I), sewer collection system types, and operational influent parameters from Unit 1, Lesson 2.

Domestic Wastewater

Wastewater originating from normal human residential activities (such as toilets, showers, bathtubs, sinks, washing machines, and dishwashers), containing human waste, soaps, synthetic detergents, food particles, organic matter, and nutrients (nitrogen and phosphorus).

Commercial Wastewater

Wastewater generated by non-manufacturing commercial establishments and service institutions, such as restaurants, hotels, laundromats, office complexes, and schools.

Industrial Wastewater

Wastewater produced by manufacturing or chemical production processes, which often contains manufacturing byproducts, synthetic chemicals, heavy metals, extreme pH levels, or high organic loads.

Infiltration

Groundwater entering the sewer system through subterranean defects, such as cracks in pipes, leaking pipe joints, and deteriorated manhole walls.

Inflow

Surface water or stormwater runoff entering the sewer network through direct pathways or connections during wet weather (such as roof leaders, yard drains, catch basins, and unsealed manhole covers).

Infiltration and Inflow (I/I)

Unwanted, unpolluted extraneous environmental water (groundwater or stormwater) that enters the collection system and adds hydraulic load.

Sanitary Sewer System

A sewer network designed exclusively to carry domestic, commercial, and industrial wastewater, intended to receive only minimal, unintended infiltration and inflow.

Combined Sewer System

A single pipe network designed to collect and transport both sanitary sewage and stormwater runoff together.

Pre-treatment Permit

A regulatory requirement often mandated for industrial facilities before discharging process wastewater into municipal sewers to manage extreme variability in strength, pH, chemical composition, and volume.

Fats, Oils, and Grease (FOG)

High organic load constituents commonly present in commercial kitchen and restaurant discharges alongside detergents and food waste.

Hydraulic Flow Rate

The volume rate of wastewater moving through a treatment facility; rapid spikes from rainstorms or infiltration/inflow increase plant velocity and reduce detention time.

Organic Loading (BOD/COD)

The concentration and volume of organic matter entering a wastewater plant that dictates the amount of oxygen and aeration required for biological treatment.