Wastewater operator vocab

Sanitary Sewer Overflow (SSO)

a release of wastewater from a sewage collection system or an intercepter sewer directly into a water or on land. MUST be repolrted to the DNR within 24 hours

Common types of industrial discharge in wisconsin

dairy operations, food industry, breweries, metal finishing, cleaning products, and FOGs

Wet well lift station

A temporary storage container that collects wastewater from a lower elevation is often used to move wastewater to a higher point so gravity continues to move it to a treatment plant.

Inverted siphons

a pipe that carries waste/stormwater under an obstruction like a river or a road. A U shaped pipe where the pressue of oncoming water forces it through and up.

Lift (pump) stations

a component of a sewer system that uses pumps to lift wastewater from a collection area (wet well) and force it into a pressure pipeline (force main) to convey it to a treatment plant

Force mains

sewer pipes, where wastewater is pumped under pressure, to a specific location, are used when gravity isn't an option.

Mainline sewer

a utility pipe that conveys wastewater from buildings/homes via gravity to a treatment plant

Infiltration

groundwater that seeps into sewer pipes through holes, cracks, joint failures, etc. This can affect the treatment quality and increase the amount of water that needs to be treated. Also, it increases treatment costs and can cause backups

Inflow

Refers to stormwater entering the sanitary sewer system through improper connections such as sump pumps, roof drains, manholes, and foundation drains. Particularly an issue during periods of heavy rainfall. This increases wastewater flow, leading to higher treatment costs, inefficiency, and sewer backups/overflows. Effective management is essentail for maintaining sewer capacity.

Clean Water Act (1972)

The Act that created water quality standards to control pollution, including the elimination of point source discharge of pollutants. Also regulates dumping of pollutants into water and wetlands.

Confined space

a space large enough for an operator but with limited means for entry and exit. Isn't designed for continuous occupation.

Waste Activated Sludge (WAS)

the activated sludge (excess biomass) that is removed from the secondary treatment process. Typically a portion of the RAS flow stream.

Treatment unit

an individual structure or component within a collection system or treatment facility that is a part of the treatment process.

Treatment process

the biological and chemical action that is applied to wastewater to clean it up.

Tertiary treatment

a part of the treatment process that removes suspended solids and nutrients that the secondary treatment process couldn't. Typically focusing on eliminating non-biodegradable pollutants.

Side streams

the byproduct water generated by various treatment processes in a facility. It is set aside for later disposal.

Selector

a mixing basin where the water treatment process that comes before the aeration basin, where specific conditions are created for favorable bacteria. This improves the quality of water treatment and its effeciency.

Secondary treatment

a stage of the treatment process that utilizes bacteria to remove pollutants

Screenings

materials in wastewater that are removed with screens at the headworks of a plant (sticks, stones, plastics, etc)

Return activated sludge (RAS)

The settled activated sludge that is collected in a final clarifier is returned to the secondary treatment process to mix with incoming wastewater. The return of a super concentrated batch of microorganisms to the aeration basin.

Process control

the tools and methods used to optimize treatment plant operations. EX: monitoring, equipment, chemical dosing, adjusting pumps/filters.

Primary treatment

the stage of treatment that is mostly focused on clarification and removal of suspended/floating matter. Well-designed and operated primary facilities can expect removal efficiencies of 40% to 60% for suspended solids and 20% to 35% for BOD.

microorganism

a living organism that cant be seen with the naked eye and needs a microscope. Includes bacteria, fungi, viruses, and protozoa

Headworks

the beginning of a treatment plant where influent flow is measured and sampled. Also where primary treatment occurs.

Grit

the fine abrasive material removed from wastewater. Made up of stuff like sand and eggshells.

Disinfection

a process used to destroy most pathogens to a safe level in effluent, this doesn't destroy all microorganisms.

Clarifier

a cricular/rectangular tank that is used to remove floatable and settleable solids in wastewater

Biosolids

organic matter recycled from sewage, especially for use in agriculture.

anoxic

a condition where oxygen is only available in a combined form

(nitrate, nitrites, sulfate, etc) in an anoxic environment

Anerobic (septic)

a condition where free, dissolved, and combined oxygen are unavailable in an aqueous environment

Aerobic (oxic, O2)

the conditions under which free and dissolved oxygen are available in an aqueous environment.

Aeration basin

a tank where wastewater is aerated to achieve biological treatment

Treatment facility overflow (TFO)

A release of wastewater, other than through permitted outfalls, from a wastewater facility into a water of the state or the land surface. MUST be reported to the DNR within 24 hours

Storm sewer

an underground pipe system that collects rainwater from the streets and conveys it to a treatment plant

Collection system (sanitary sewer)

an underground pipe system is used to convey wastewater to a treatment facility

Manhole

a structure that provides access to a water collection system

lift station

an underground chamber with pumps that is used to elevate wastewater to a higher level

Combined sewer

Combining the municipal sewer systems with storm drainage. Risks overpowering the system in large rain events. The benefit is that pollutants from storm drainage get treated,

weir

a low dam barrier that is used to control and measure water flow

Total suspended solids (TSS)

The measure of solid particles suspended in water expressed in mg/L

Mixed lliquor volatile suspended solids (MLVSS)

the organic portion of the solids in the mixed liquor. they're microorganisms that are actively breaking down the organic matter in the wastewater. This level is measured by drying and burning a sample of the ML in a furnance and measuring the weight loss.

Mixed Liquor Suspended Solids (MLSS)

The amount (mg/L) of suspended solids in the mixed liquor of an aeration tank. If its too low the water isnt being properly treated, if its too high there isnt enough oxygen in the system.

SLudge Age

The theoretical length of time a particle of activated sludge stays in the treatment plant, measured in days.

Septage

A high strength waste pumped out of septic tanks, sometimes disposed at WWTPs.

pH

a measurement of the acidity or alkalinity of a sample on a scale of 0-14. Neutral is 7

million gallons per day (MGD)

Common wastewater flow measurement in a treatment plant

Milligrams per liter (mg/L)

the measurement of a concentration of a substance in a liquid expresssed as a weight in mg. This is the same as parts per million.

Influent

the raw untreated wastewater entering a treatment process

Hydraulic retention time (HRT)

the period of time that wastewater remains in a tank (dentention time)

Grab sample

a single sample representing a particular time and place, and represents its current conditions. used to measure pH, DO, turbidity, etc. Not reflective of the water quality overall.

Gallons per minute (GPM)

a flow measurement that is expressed as the number of gallons flowing each minute

Gallons per hour (GPH)

a term that expresses the number of gallons flowing each hour

Gallons per day (GPD)

is a common wastewater flow measurement expressed as the number of gallons flowing each day.

Food to Microorganism Ratio (F/M)

A measure of food provided to bacteria in an aeration tank.

FLume

a narrow channel to measure flow

Eutrophication

the excessive growth of plant and algae in receiving waters due to dissolved nutrients and their decomposition

Effluent

treated wastewater that is discharged from a plant back into its environment

Dissolved oxygen (DO)

the amount of oxygen dissolved in water and is expressed in mg/L

Composite sample

A sample prepared by combining a number of grab samples, typically over a 24 hour period.

Biochemical Oxygen Demand (BOD)

a measurement of organic strength of a sample aka the amount of oxygen it consumes over a given period of time. Expressed in mg/L

Drain line

lines located in homes and buildings that drain to a mainline

Conveyance

Transporting water, usually through a canal, ditch, pipeline, etc

FOGs

waste products of cooking. Fats, oils, and grease. Commonly causes SSOs. These also0 feed organisms that cause scum.

Volatile organics

substances like gases or solvents that can cause an explosive atmosphere in a collection system/ treatment plant

Open channel flow

an open channel where water flows (like a weir or flume). This is often where flow rates are measured.

Parshall flume

an open channel flow metering device that was developed to measure flow of surface water and irrgiation flow

Wisconsin Pollution Discharge Elimination System (WPDES)

this program regulates the discharge of pollutants to waters. these permits contain all monitoring requirements, special reports, and compliance schedules appropriate to the facility. Permits are usually issued for a five-year term.

Time-proportional composite sample

collecting samples over time usually every few minutes

Flow-proportional composite sample

samples co llected per unit of flow. the frequency is directly proportional to the flow. More samples are taken when the flow is higher, fewer samples are taken when the flow is lower. Automatic flow proportional composite samplers are required for almost all wastewater treatment plants, as they are most representative

aerated-grit chamber

Injected air creates a spiral flow of wastewater as it moves through the chamber, and as the velocity diminishes as it moves, heavier grit particles gradually settle from the water. The settled solids are typically gathered at the bottom with a rake mechanism and is removed by pumping.

Vortex-type grit chamber

raw wastewater is introduced along the side of a cylindrical tank designed for vortex flow. The water and grit combination rotates slowly around the vertical axis of the tank. THe flow spirals graqdually down the tank perimeter, allowing heavier solids to settle down.

Dissolved Air flotation

The process of injecting bubbles into wastewater which attach to sludge particles and bring them to the surface. This scum is then scraped off the top.

Suspended growth sludge (activated sludge)

the suspension of wastewater and microorganisms in an aeration basin. the mix is called MLSS. The aeration equipment supplies dissolved oxygen to promote the growth of microorganisms that remove organic materials.

aeration tank

The tank where raw or settled wastewater is mixed with return sludge and aerated. The same as aeration bay, aerator, or reactor.

Blowers

machines that blow air into aeration tanks

diffusers

these devices disperse air into the aeration tanks

positive displacement

a device that forces air to move by trapping a fixed amount then displacing that trapped volume in the discharge pipe.

fine bubble difussers

pumps that pump super fine bubbles which introduce DO into the liquid. Normally disks are tuybes to create the bubbles and cause gentle mixing.

coarse bubble diffusers

air is pumped through and divided into large bubbles. Normally discharge air at a high rate.

mechanical aerators

utilizes paddles/discs/spray turbine. by agitating wastewater from the environment is introduced.

process probes and analyzers

a device that tests pH, total suspended solids, DO, turbidity, and temp. Usually wired to an analyzer that sends data to a computer.

Supervisory control and data acquisition (SCADA)

a computer program that is used solely for gathering the plant's operational data. thr program shows the different parts of the plant and what is happening in real time. Very important for an operator to monitor.

Programmable Logic Controller (PLC)

a programmable electronic device that inputs and outputs and is usually found as part of a control panel. It could control the liquid level of a tank by turning a pump on and off. It allows for automation of processes by executing pre-defined directions.

Flow meters

used to measure liquid flow. Some areas of measurement include influent, effluent, recycle streams, sludge pumping, septic stations, lift stations, chemical feed systems, usually wired into a SCADA system that displays and stores flow data. Operators monitor this regulary.

Routine lubrication

the most important preventative maintance task at a treatment plant

drawdown distance

the vertical distance between the static water level and the pumping water level, indicating the amount of groundwater depletion during pumping.

refill distance

the vertical distance indicating how much the water level has risen after pumping ceases, which helps assess the recovery rate of the groundwater.

Calibrating lift station pumps

Helps to determine actual flow rates of lift stations (and indicates if infiltration/plugging is happening). One must first find the drawdown distance/time and the refill distance/time and then use the pump rate formula to calculate it. This process ensures that lift station pumps operate efficiently and accurately measure wastewater flow, helping to maintain optimal performance.

content of O&M manual

Refers to the guidelines and procedures outlined in the Operations and Maintenance manual that provide essential information for the proper management and maintenance of wastewater systems. Contains general info, staffing, records system, labs, safety, security and emergencies, utilities, appendiecies, etc.

Cavitation

The formation and collapse of vapor bubbles in a fluid, which can lead to damage in pumps and hydraulic machinery. This process occurs when the local pressure in the fluid drops below its vapor pressure, often resulting in noise and reduced efficiency.

Replacement fund

a reserve of money set aside to replace things such as pumps, motors, and other essential tools

Debt retirement

the debt that is taken out by the community to finance capital improvements and is gradually paid off over time, typically through scheduled payments.

Primary biosolids/sludge

solids that settle out of raw wastewater in primary clarifiers. These particles are heavier than water allowing for rapid settling. Typically contains 60-80% voltalie solids and organic material, and is often subject to further treatment or disposal methods.

Volatile solids

solid materials in wastewater that can decompose or be transformed by microorganisms, typically measured to assess organic content.

Secondary biosolids/sludge

solids are generated as a part of the secondary treatment process and settle out in the final clarifiers. These sludges are made of microorganisms that are settled out in the secondary treatment. These excess sludges must be removed in order to keep the secondary system in balance. These typically have a gravity closer to water, which makes them harder to settle out. These sludges are 75-80% volatile solids and contain bound water in the cells, making them difficult to dewater/thicken.

Thickening

The process of removing water from the sludge stream to concentrate it. This minimizes the volume of sludge being handled. This helps reduce the time and cost of treatment

Gravity settling thickener

consists of a circular tank that is fitted with collectors/scrapers at the bottom. Primary/secondary solids are fed into the tank through a center well that releases the solids at a low velocity near the surface of the tank. The solids settle to the bottom via gravity, and the scrapers slowly move the thickened solids to a discharge pipe at the bottom of the tank.

DAF (Dissolved Air Flotation)

A process where dissolved air under pressure is released into the tank. The air bubbles then attach to the sludge particles and bring them to the surface, where they are skimmed.

sludge stabilization

the process of sludge treatment to reduce the pathogens in the sludge and the attraction of vectors.