ABC Wastewater Collection Class IV flashcards
ABC Wastewater Collection Class IV · Build recall with a focused review session.
36 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Minimum self-cleansing velocity
- About 2 ft/s in a gravity sanitary sewer keeps solids moving and limits deposition; lower velocities allow grit and grease to settle and cause blockages.
- Manning's equation
- Q = (1.486/n) A R^(2/3) S^(1/2) predicts gravity pipe flow, where n is roughness, A is cross-sectional area, R is hydraulic radius, and S is slope.
- Hydrogen sulfide corrosion
- H2S generated in pressurized or slow-flowing sewage is oxidized to sulfuric acid on concrete above the waterline, corroding pipe crowns and manholes.
- Sanitary sewer overflow reporting
- SSOs must be reported to the state agency within the permit's timeframe, with public notice when discharge reaches waters of the state, and a follow-up written report.
- Drop manhole
- A manhole with an outside or inside drop pipe that carries a high-elevation incoming sewer down the wall, reducing turbulence, scour, and H2S release.
- Inverted siphon
- A pipe that carries sewage under an obstruction such as a stream; it flows full under pressure and needs flushing and bypass provisions for maintenance.
- Force main air valve
- An air release and vacuum relief valve on a force main prevents surge, column separation, and air binding by admitting or releasing air at high points.
- Manhole spacing
- Manholes are placed about 300–500 ft apart on straight runs and at changes in grade, alignment, or pipe size to allow inspection and cleaning access.
- Affinity laws
- For a centrifugal pump, flow varies with speed, head with speed squared, and power with speed cubed, so small speed changes greatly affect power draw.
- Total dynamic head
- The sum of static lift, friction losses in suction and discharge piping, and velocity head that a pump must overcome to move a given flow.
- Best efficiency point
- The flow and head at which a pump operates most efficiently; running far from it causes recirculation, cavitation, vibration, or motor overload.
- Wet well cycling limit
- Wet well operating volume is sized so pump starts per hour do not exceed the motor manufacturer's limit, preventing overheating and check valve wear.
- Permit-required confined space
- A space with a hazardous atmosphere, engulfment potential, trapping configuration, or other serious hazard that requires a written entry permit and controls.
- Atmospheric testing order
- Test oxygen first, then flammable gas, then toxic gases; entry is barred below 19.5% O2, at 10% LEL or above, or at the permit's H2S limit.
- Confined space attendant
- A trained person stationed outside the space who maintains communication, monitors conditions, and summons rescue without entering the space.
- Confined space rescue
- Rescue must use trained personnel with supplied-air respiratory protection; untrained would-be rescuers account for many confined space fatalities.
- Infiltration versus inflow
- Infiltration is groundwater entering through pipe and joint defects; inflow is direct stormwater entering through manholes, roof drains, and illegal connections.
- Smoke testing
- Blowing non-toxic smoke into a sewer reveals inflow sources and illegal connections where smoke escapes from manholes, drains, or service connections.
- Rainfall-dependent infiltration
- The portion of wet-weather flow that responds to rainfall, quantified by comparing dry-weather and storm-period flow monitoring data.
- CIPP lining
- Cured-in-place pipe lining installs a resin-impregnated liner inside an existing pipe and cures it in place to seal defects and restore structure.
- Peaking factor
- A multiplier applied to average dry-weather flow to estimate peak flow for sizing pipes, pumps, and capacity analysis.
- Area-velocity flow meter
- A meter that measures flow depth and velocity in a pipe and computes flow as Q = A × V, used for capacity and I/I monitoring.
- Surcharge
- Condition where flow exceeds downstream capacity and the hydraulic grade line rises above the pipe crown, risking backups and overflows.
- Partially full pipe flow
- Maximum velocity occurs near 0.8 depth ratio and maximum flow near 0.94 depth ratio; full-flow Manning's equation overstates capacity near full.
- PACP defect grading
- CCTV defect codes grade severity from 1 to 5; grade 4 and 5 structural or operational defects drive rehabilitation, while lower grades may be monitored.
- CCTV inspection
- A camera survey of sewer interiors that records structural and maintenance defects, infiltration, and root intrusion for condition assessment and rehabilitation planning.
- Dye testing
- Introducing dye into a fixture or storm drain to confirm whether it connects to the sanitary sewer, verifying cross-connections and illegal connections.
- Risk-based inspection
- Inspection frequency set by weighing pipe age, material, soil, flow, and failure history rather than fixed intervals.
- NPDES permit
- A Clean Water Act permit that regulates discharges to waters of the state and sets reporting, monitoring, and notification requirements for SSOs and bypasses.
- CMOM program
- A capacity, management, operations, and maintenance program that documents how a collection system is operated, maintained, and kept in compliance.
- OSHA confined space standard
- 29 CFR 1910.146 sets permit-required confined space entry requirements, including testing, ventilation, attendant, and rescue provisions.
- Asset management record
- Inventory, condition, work order history, and remaining useful life data used to prioritize maintenance and capital spending on collection system assets.
- CMMS
- A computerized maintenance management system that tracks work orders, labor, parts, and failure history to support preventive and corrective maintenance decisions.
- SSO rate KPI
- A key performance indicator counting sanitary sewer overflows per 100 miles of pipe, used to benchmark collection system performance.
- Emergency response plan
- A written plan covering SSOs, pump station failures, power outages, and hazardous releases, with call-out lists, notifications, and incident command roles.
- Operator certification
- State-issued credential requiring education, experience, and continuing education; Class IV operators must maintain certification through approved training.