ABC Wastewater Collection Class IV key terms

Groundwater or stormwater that enters a collection system through defective pipes, joints, manholes, or connections. It is a major source of clear water that adds unnecessary flow to treatment facilities.

Stormwater or surface water that enters a sanitary sewer directly through improper connections such as roof drains, sump pumps, or manhole covers. It is distinct from infiltration because it enters quickly during rain events.

A release of untreated wastewater from a sanitary sewer system before reaching treatment. SSOs can occur from blockages, capacity exceedance, or structural failures and typically require reporting to regulators.

A discharge of mixed stormwater and wastewater from a combined sewer system during heavy rain, when flow exceeds capacity. CSOs are regulated under permits and often addressed through long-term control plans.

A pipe that carries wastewater downhill by the force of gravity alone, designed with a minimum slope to maintain self-cleansing velocity. It requires no pumps but must follow terrain and depth constraints.

A pressurized pipe that carries wastewater pumped from a lift station to a higher point or treatment facility. Unlike gravity sewers, it flows under pressure and may experience air binding or surge.

The minimum flow velocity needed to keep solids suspended and prevent deposition in a sewer. For gravity sanitary sewers it is commonly about 2 feet per second at design flow.

A vertical access structure that lets workers inspect, clean, and test underground sewers. It typically includes a frame and cover, a cone or chimney, and a benched channel at the bottom.

The lowest interior elevation of a pipe or manhole channel where flow travels. Invert elevations are used to calculate slope, direction of flow, and hydraulic capacity.

A facility with pumps and controls that raises wastewater to a higher elevation so it can continue by gravity or enter a force main. It may include wet wells, screens, and emergency power.

A chamber that receives and temporarily stores wastewater before pumps move it onward. Its volume and pump cycling must be managed to prevent short cycling and overflows.

A planned method of diverting flow around a lift station using temporary pumps or hoses during maintenance or power failure. Bypass plans are prepared in advance to prevent overflows.

A device installed at high points on a force main to automatically vent trapped air. Removing air prevents flow restriction, reduces surge, and protects pumps from damage.

A pressure wave or sudden spike in a pipeline caused by rapid changes in flow, such as pump start or stop. Surge can damage pipes, valves, and fittings if not controlled.

A condition where wastewater rises above the normal pipe crown, often because downstream capacity is exceeded or a blockage exists. Sustained surcharge can lead to overflows and property damage.

An area large enough for a worker to enter, with limited entry or exit, and not designed for continuous occupancy. Sewer manholes, wet wells, and vaults are common examples requiring special precautions.

The process of measuring oxygen, combustible gas, hydrogen sulfide, and other hazards before and during confined space entry. Testing must be done at multiple levels because gases can stratify.

A toxic, corrosive, and flammable gas produced by anaerobic decomposition of wastewater. It can deaden the sense of smell at higher concentrations and is a leading hazard in collection system work.

A written authorization that documents the hazards, controls, entrants, attendants, and rescue plan for a confined space entry. It must be completed and signed before entry begins.

Methods used to reduce nuisance and corrosive odors from collection systems, such as chemical dosing, ventilation, and covers. Control also protects concrete structures from sulfide corrosion.

A technique that blows non-toxic smoke into a sewer section to reveal illegal connections, broken pipes, and defects where smoke escapes. It is a primary tool for locating inflow and infiltration sources.

The use of a closed-circuit television camera to record the interior condition of sewer pipes. Operators use the footage to identify cracks, roots, offsets, and other defects for repair planning.

A structured examination of collection system assets to assess condition, function, and compliance. It may include visual, CCTV, smoke, dye, and flow monitoring methods.

Repair or renewal of deteriorated collection system assets to restore structural integrity and hydraulic capacity. Methods include lining, replacement, grouting, and manhole restoration.

A trenchless rehabilitation method in which a resin-saturated liner is inserted into a host pipe and cured to form a new structural wall. It reduces excavation and restores pipe integrity.

The planning and operational practice of ensuring a collection system can convey design flows without overflows. It includes flow monitoring, hydraulic modeling, and capital improvement planning.

The measurement of wastewater flow and depth at selected points to understand system performance, identify infiltration, and support capacity planning. Data may be collected with weirs, flumes, or area-velocity meters.

A systematic approach to tracking the condition, value, and lifecycle of collection system assets to guide maintenance, repair, and replacement decisions. It supports budgeting and risk reduction.

The organized maintenance of operational data such as inspections, work orders, spills, and training. Accurate records support regulatory reporting, liability defense, and informed decisions.

A federal permit issued under the Clean Water Act that regulates discharges to surface waters, including some collection system overflows and treatment plant effluent. It sets limits and reporting requirements.

Adherence to laws, permits, and regulations that protect public health and the environment. For collection systems this includes spill reporting, discharge limits, and pollution prevention practices.

A prepared document that outlines actions, roles, and resources for responding to incidents such as overflows, pump failures, or injuries. It is practiced through drills and reviewed regularly.

The direction and oversight of collection system staff to ensure safe, efficient, and compliant work. It includes assigning tasks, verifying quality, and developing employee skills.

Planned instruction that builds the knowledge and skills workers need for safe and effective job performance. It includes safety, equipment operation, and emergency procedures.

The growth of tree roots into sewer pipes through joints and cracks, which can block flow and cause overflows. It is managed through chemical treatment, cutting, and pipe repair.

A clog formed when fats, oils, and grease accumulate and harden in a sewer, restricting flow. Prevention relies on grease trap programs, public education, and routine cleaning.

A maintenance method that uses high-pressure water to scour grease, sediment, and debris from sewer lines. It is often paired with vacuum removal of the loosened material.