Glossary of Terms

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BMP - Best Management Practice
BNR - Biological Nitrogen Removal
Ballast - Heavy material used to enhance stability and settling.
Ballasted Flocculation -Physical/chemical process utilizing a ballast to induce faster rates of settling or clarification. This technology is capable of settling solids using a significantly smaller space than traditional clarification. Ballasted flocculation is used interchangeably with HRC
Biochemical Oxygen Demand (BOD) - The amount of oxygen used in the metabolism of biodegradable organic compounds.
CAC - Citizens Advisory Committee
CAO - Chief Administrative Officer
CD - Conceptual Design
CDE - Conceptual Design Engineer
CDR - Conceptual Design Report
CEO - Chief Executive Officer
CEPT - Chemically Enhanced Primary Treatment
CMOM - Capacity, Management, Operation and Maintenance
CRI - Connecticut River Interceptor
CRRA - Connecticut Resources Recovery Authority
CRRI - Connecticut River Relief Interceptor
CSO Control Policy - Published by EPA in 1994 to provide guidance in developing appropriate, site-specific NPDES permit requirements for all combined sewer systems that overflow due to wet weather events.
Chlorination - Disinfection using chlorine solution or gas.
Clarification - The separation from water, by gravitational settling, of suspended particles that are heavier than water. The terms sedimentation, settling, and clarification are used interchangeably.
Clean Water Act (CWA) - Enacted in 1972 to protect surface water quality in the United States by reducing direct discharge of pollutants to waterways, financing municipal wastewater treatment facilities, and managing polluted runoff
Combined Sewer Overflow (CSO) - A relief point in the combined sewer system that is designed to discharge during periods of precipitation or snowmelt, when the total volume of combined wastewater and storm water exceeds pipe or treatment facility capacity.
Combined Sewer System (CSS) - Wastewater collection systems designed to carry sanitary sewage and storm water in a single pipe to a treatment facility.
Connecticut Department of Environmental Protection (CT DEP) - State regulatory agency formed to conserve, improve, and protect natural resources and the environment in Connecticut. CT DEP also serves as a permit-issuing authority for EPA in the state.
Consent Order - A legal document, issued by a permitting authority to an individual or a group, which provides written directive that the subject is required to comply with or else be punished by penalties listed in the Connecticut General Statutes, Chapters 439, and 445 or 446k.
Consolidation Conduit - Large pipeline used to capture (or consolidate) CSO discharges for conveyance to a treatment or storage facility,

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DAF - Dissolved Air Flotation
Dechlorination - Removal of residual chlorine remaining in chlorinated wastewater by addition of chemical.
Disinfection - The selective destruction of disease-causing organisms, such as bacteria and viruses. Chlorination and UV radiation are two common methods of disinfection.
Dry Weather Overflow (DWO) - A CSO that occurs when there is no precipitation or snowmelt typically due to a blockage somewhere in the pipe or other unanticipated system malfunction.
E Coli - Bacteria normally found in the human gastrointestinal tract that may live as harmless inhabitants, or may produce a toxin causing internal illness. In terms of water quality standards in Connecticut, E. coli is the indicator bacteria used to determine if freshwater bodies are safe for recreational uses.
Effluent - Outflow from a sewer (untreated) or wastewater treatment facility (treated).
Enterococci - A usually nonpathogenic streptococcus that inhabits the intestine. In terms of water quality standards in Connecticut, enterococci is the indicator bacteria used to determine if saltwater bodies are safe for recreational uses.
Environmental Protection Agency (EPA) - Federal regulatory agency dedicated to protect human health and the environment. EPA develops regulations that implement environmental laws enacted by Congress, then enforces them. Connecticut is a part of EPA Region 1 (New England).
FAA - Federal Aviation Administration
FDE - Final Design Engineer
FST - Final Settling Tanks
Fecal Coliform - Bacteria that commonly inhabits the intestines and colon of humans and other vertebrae. In terms of water quality standards in Connecticut, fecal coliforms the indicator bacteria used to determine if shellfishing (in saltwater bodies) is safe for harvesting and consumption.
Floatables - Buoyant material in CSO flow. Floatables tend to be larger items (such as soda cans, sanitary products, cigarette butts, Styrofoam containers, plastic wrappers, leaves, paper products, etc.).
Flocculation - The process by which small particles aggregate into larger lumps, or "flocs." Flocculation in wastewater can be induced through mechanical or air agitation and chemical addition.

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Hartford Water Pollution Control Facility (HWPCF) - Regional wastewater treatment facility, located on Brainard Road in Hartford, which provides primary and secondary treatment for sewage from Hartford, West Hartford, and portions of Windsor, Bloomfield, Newington, and Wethersfield. The facility also processes sludge from the East Hartford and Rocky Hill Wastewater Treatment Facilities. Treated
effluent from HWPCF discharges to the Connecticut River.
High Rate Clarification (HRC) - Physical/chemical process utilizing a ballast to induce faster rates of settling or clarification. This technology is capable of settling solids using a significantly smaller space than traditional clarification. Ballasted flocculation is used interchangeably with HRC
Hydraulic Grade Line (HGL) - The level of a water surface or the level to which the water would rise if in a pressurized conduit.
Infiltration and Inflow (I/I) - Generally clean groundwater and surface water that enters the sewer system and uses up hydraulic capacity of the pipe network and wastewater treatment facility. III limits the capacity of the sewer system to effectively convey sewage to the treatment facility, particularly during wet weather conditions, and can cause CSOs to occur more frequently. In addition, III reduces the hydraulic capacity of the treatment facility. In other words, III takes up space that should be used to treat sewage, and the taxpayers spend money to treat water that does not require treatment.
Infiltration - Penetration of ground water into sewer pipes through defective joints, cracks, or connections at manholes. Ground water can also seep through manhole walls and enter the sewer system. Tree roots and aging pipes are two reasons for cracks to develop.
Inflow - Water discharged directly to the combined sewer system that typically does
not need treatment. Inflow sources include roof leader drains, sump pump discharges, street/parking lot drainage and stream flow.
Influent - Flow entering a sewer or wastewater treatment facility (untreated).
Interceptor - A major sewer pipe, typically large in diameter, which collects flow from smaller sewer pipes and conveys it across long distances to a wastewater treatment facility.
LPHO - Low Pressure High Output
LTPM - Long-Term Preventative Maintenance
Long-Term (CSO) Control Plan (LTCP) - A long-term plan to control CSOs, required under the 1994 CSO Control Policy. Generally LTCPs are developed for a 20 year planning horizon. The purpose of the LTCP is to evaluate alternatives for achieving compliance with the Clean Water Act, including compliance with water quality standards and protection of designated uses. Once an LTCP is completed, EPA requires the plan to be implemented as soon as practicable.
MBE - Minority Business Enterprise
MLSS - Mixed Liquor Suspended Solids
MOR - Monthly Operating Report
MOU - Memorandum of Understanding
Metropolitan District Commission (District/MDC) - A non-profit municipal corporation, chartered in 1929 by the Connecticut General Assembly, to provide potable water supply and sewerage services on a regional basis. It serves eight member municipalities: Bloomfield, East Hartford, Hartford, Newington, Rocky Hill, West Hartford, Wethersfield, and Windsor.
Million Gallons per Day (MGD) - A flow rate used to express volume over a given time period. Commonly used in reference to the size of a wastewater treatment facility.

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NRZ - Neighborhood Revitalization Zone
National Pollution Discharge Elimination System (NPDES) - Permit program that monitors pollution to waterways by regulating point-source discharges (such as a CSO outfall or a wastewater treatment facility outfall).
Nine Minimum Controls (NMC) - The EPA established nine controls that sewer and wastewater treatment facility owners can implement to reduce CSOs without requiring significant engineering studies or major construction. NMCs generally represent low-cost, technology-based actions that can be implemented in a relatively short time frame by operation and maintenance of CSO systems. Developing an NMC Plan is among the first steps in EPA's CSO Control Policy, and is intended to provide some level of control while Long-Term Control Plans are being developed and implemented.
Non-point source - Discharge that is not at a specific location, such as runoff from land surface into a water body.
 Operations and Maintenance (O&M) - Work and upkeep required to keep a system running effectively.
Organic Matter - Solids derived from the animal and plant kingdoms and the activities of man, as related to the synthesis of organic compounds. Organic compounds are normally composed of a combination of carbon, hydrogen, and oxygen, together with nitrogen in some cases.
Outfall - The point, location, or structure where wastewater or drainage discharges from a sewer pipe, ditch, or other conveyance to a receiving water body.
Overflow Alarm System (OAS) - Computerized system that the District uses to monitor CSO activity in Hartford. The system consists of sensors, located in CSO regulators, which measure flow elevation and overflow volume. Telephone and radio communications transmit measurements to a database at the District Operations Facility, where the data is recorded and alarms are generated.
PDE - Preliminary Design Engineer
PCT - Physical/Chemical Treatment
PMC - Program Management Consultant
PMU - Program Management Unit
POTW - Publicly Owned Treatment Works
PRAC - Park River Auxiliary Conduit
PS - Pump Station
PST - Primary Settling Tank
Point source - A discrete discharge location, such as the end of a pipe or a man-made ditch.
Primary treatment - The first stage of wastewater treatment designed to remove large settleable solids, as well as smaller floatables. Primary treatment is generally a physical process that captures and removes wastewater debris on screens or bars, settles out sand and grit, skims floating materials (scum/ grease) out of the flow, and removes solids that have settled to the bottom of a tank. Effluent from primary treatment usually contains considerable amounts of organic material.
RAS - Return Activated Sludge
RFP - Request for Proposal
RFQ - Request for Qualifications
RII - Rainfall Induced Infiltration
Real-Time Control - Automated control of regulating devices to maximize storage and conveyance capacity of the combined sewer system.
Receiving water - The water body (e.g. river, stream, pond, lake, ocean) into which an outfall discharges.
Regulator - A weir or other regulating device set at a specific elevation or setting to control the direction in which flow travels. When liquid levels exceed the elevation of the weir or setting of the regulating device, an overflow event occurs. When liquid levels are lower than the elevation of the weir or setting of the regulating device, flow maintains it's normal path through the system to the wastewater treatment facility.
Relief Interceptor - A major sewer pipe designed to provide extra capacity to an existing interceptor, which collects flow from smaller sewer pipes and conveys it across long distances.
Roof Leaders - Drain pipes that collect rainwater from roofs for discharge onto the ground or into combined sewer pipes and storm drain pipes.
Runoff - Precipitation or snowmelt that is not absorbed by the ground. Since it is not absorbed, it travels across the ground surface until it ponds at a low elevation, is collected by a catch basin, or reaches a water body.

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SCADA - Supervisory Control and Data Acquisition
SLR - Solids Loading Rate
SOR - Surface Overflow Rate
SOW - Scope of Work
SSES - Sewer Separation Evaluation Survey
SSO - Sanitary Sewer Overflow
SVI - Sludge Volume Index
Satellite Facility - Remote treatment or storage facility designed to capture and/ or treat CSOs at the point of discharge.
Screening - A physical process where screens (also called bar racks) are used to capture and remove debris from wastewater flow. There are coarse screens with wide openings to removes large debris, and fine screens to remove smaller objects. Objects are detained on the screens as the flow passes through the openings.
Secondary treatment - The stage of wastewater treatment following primary treatment, designed to remove organic matter and suspended material remaining after primary treatment. Secondary treatment is a biological process that uses< microorganisms to digest organic matter.
Sedimentation - The separation from water, by gravitational settling, of suspended particles that are heavier than water. The terms sedimentation, settling, and
clarification are used interchangeably.
Separation - Removing sanitary sewer flow from storm water flow. This term is typically used to describe the process of installing a new pipeline in a combined sewer service area, so that sanitary sewage travels in one pipeline and the storm water travels in a separate pipeline.
Sludge - A mixture of settled solids and liquid removed from sedimentation
processes.
Solids - Dense material in a waste stream, including sewage and CSO flow, that may settle out easily. Solids carried in CSO flow tend to be small or fine dense particles, such as sand or grit.
Storage -In terms of CSO abatement, storage describes a tank, large pipe, or tunnel built to store a specific volume of CSO. The overflow volume is contained (instead of discharged untreated to a receiving water body) until dry weather conditions are restored, at which time it is slowly discharged back to the sanitary sewer, where the CSO volume is conveyed to the WPCF for treatment.
Total Coliform - The sum of all types of coliform bacteria. In terms of water quality standards in Connecticut, total coliform is the indicator used to determine whether freshwater bodies are safe to use as drinking water supply.
Total Suspended Solids (TSS) - The sum of settleable and non-settleable solids
suspended in a liquid, typically expressed as a concentration (such as milligrams per liter). Typically, non-settleable suspended solids cannot be removed from a waste stream using conventional gravity settling.
Treatment - Removal of pollutants from wastewater.
Ultraviolet (UV) Disinfection - Dosing wastewater with UV light to kill bacteria, viruses and other disease-causing organisms.
WBE - Women Business Enterprise
WWPS - Wet Weather Pump Station
WWSB - Wet Weather Storage Basin
Water Pollution Control Facility (WPCF) - A facility permitted by an environmental regulating agency to provide treatment for wastewater (sewage), and to discharge the treated waste to a receiving water. In order to prevent water quality degradation in a receiving water, effluent from a WPCF must meet the water quality criteria specified in the permit.
Water Quality Standards (WQS) - State-adopted policy that classifies water bodies according to their desired uses, and the criteria that need to be met in order to protect those uses.
Weir - A dam placed across a river, canal, or sewer to raise, divert, or regulate flow.

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