Topic
Wastewater
69 guides across the knowledge base.
Sequencers
Step-based control for operations that always run in the same order: backwash, pump and valve startup, batch makeup, membrane cleans. What every step needs, three ways to implement one, handling faults and power loss mid-sequence, and what the HMI shows.
10 min readUpdated Sep 5, 2026
Control Strategies
Choosing how a loop is controlled before choosing how to program it: on-off with deadband, staging, PID, ratio and feedforward, cascade, split range, and override, with the water and wastewater applications each fits and the questions that pick between them.
11 min readUpdated Sep 5, 2026
Modicon M340
Field notes on the Schneider Electric Modicon M340, a rack-based mid-range controller common in water plants: rack and CPU layout, X80 I/O, memory card behavior, Ethernet and serial communications, programming in Control Expert, and what to check on site.
8 min readUpdated Sep 5, 2026
ControlLogix
Field notes on the Rockwell Automation ControlLogix, the chassis-based controller of larger water plants: chassis and modules, tag-based memory and tasks, EtherNet/IP and older networks, controller redundancy, version matching, and what to check on site.
9 min readUpdated Sep 5, 2026
Reporting from the Historian
Turning history into the reports a utility must produce: the monthly operating report, compliance reports for the regulator, daily operator summaries, pump run and energy reports, the calculations behind daily minimums, maximums, and totals, handling bad quality and gaps, and building reports once so they run every month without an engineer.
9 min readUpdated Sep 5, 2026
Wet Well Level Measurement
How lift station wet well level is measured, which technology suits which well, the failure modes that flood a station, and why the high level float must stay hardwired.
8 min readUpdated Sep 5, 2026
Hydrostatic Level Measurement
Measuring level from the pressure of the liquid above a sensor: submersible transducers, bubblers, and base-mounted transmitters, the density assumption behind all of them, venting, installation, and what makes them drift.
8 min readUpdated Sep 5, 2026
Ultrasonic Level Measurement
Non-contact level by time of flight: how the sensor works, the blanking zone and beam angle, temperature compensation, the surfaces and vapors that defeat it, mounting rules, and what to do when it loses its echo.
8 min readUpdated Sep 5, 2026
Float Switches
The oldest level instrument and still the one that saves a station: how tilt and stem floats work, the wiring conventions, mounting and spacing in a wet well, classified-area ratings, and how to use them alongside a continuous instrument.
7 min readUpdated Sep 5, 2026
Open Channel Flow Measurement
Flumes and weirs with a level sensor: how the head-discharge relationship works, Parshall flume and weir equations, where to put the sensor, submergence, and the errors that make a permit-reporting flow meter wrong.
11 min readUpdated Sep 5, 2026
Chlorine Residual Analyzers
Amperometric and colorimetric residual analyzers: what each measures, free versus total chlorine, pH and flow dependence, sample line design, calibration against a DPD grab sample, and using the signal for feed control.
11 min readUpdated Sep 5, 2026
pH Measurement
Glass electrodes, reference junctions, and why pH is the measurement that drifts: how the sensor works, temperature compensation, two-point buffer calibration, mounting rules, the failure modes of the reference, and using the signal for chemical feed control.
11 min readUpdated Sep 5, 2026
Dissolved Oxygen Measurement
Optical and membrane DO sensors for aeration control: how each measures, why optical has taken over, air calibration with pressure and salinity corrections, sensor placement in an aeration basin, fouling and cleaning, and the response time that limits the control loop.
11 min readUpdated Sep 5, 2026
Impulse Lines
The tubing between the process tap and the pressure or DP transmitter, and everything that goes wrong in it: slope and routing for liquid and gas, elevation head and how to correct for it, air and condensate, blocking and manifold valves, freezing, plugging on dirty service, and the diaphragm seal alternative.
9 min readUpdated Sep 5, 2026
Ultrasonic Flowmeters
Transit-time and Doppler ultrasonic flow measurement: how each works, which liquids each suits, clamp-on versus wetted transducers, the pipe data the meter needs, the accuracy to expect, and the installation details that decide whether to trust the reading.
10 min readUpdated Sep 5, 2026
Flow Troubleshooting
A method for a flow reading that is wrong, noisy, zero, or disputed: establish the truth with an independent check, separate installation from configuration from signal chain, then the specific checks for magnetic, ultrasonic, and DP meters.
10 min readUpdated Sep 5, 2026
Differential Pressure Level
Measuring level in a closed or pressurized vessel with a DP transmitter: high and low side connections, dry legs and wet legs, zero suppression and elevation, the range calculation with a worked example, remote seals, and the density dependence.
10 min readUpdated Sep 5, 2026
Level Troubleshooting
A method for a level reading that is wrong, frozen, jumping, or lost: establish the true level, check the signal chain and configuration, then the checks for ultrasonic, radar, hydrostatic, DP, and float instruments, and the failure behavior to design in.
10 min readUpdated Sep 5, 2026
Differential Pressure
The differential pressure transmitter as an instrument: what it measures, static and overrange ratings, the three-valve manifold and the order of operations that protects the cell, and the applications from filter head loss to membrane TMP, flow, and level.
9 min readUpdated Sep 5, 2026
Ammonia Analyzers
Online ammonia measurement in water and wastewater: ion-selective probes, gas-sensing electrodes, and wet-chemistry analyzers, what each is good for, the interferences that decide accuracy, and the maintenance and calibration it demands.
9 min readUpdated Sep 5, 2026
Nitrate Analyzers
Online nitrate measurement: ultraviolet absorbance probes and analyzers, ion-selective electrodes, and wet chemistry, the interferences from organics, turbidity, and chloride, the uses in denitrification and source monitoring, and maintenance.
8 min readUpdated Sep 5, 2026
ORP
Oxidation-reduction potential: what the millivolt reading means and does not, the platinum and reference pair, uses in dechlorination control, disinfection indication, anoxic monitoring, and chemical treatment, checking with standards, and electrode drift.
7 min readUpdated Sep 5, 2026
UL 698A
Industrial control panels for hazardous locations: what UL 698A adds to UL 508A, a panel in a classified area or a safe-area panel with intrinsically safe circuits, barriers and isolators, the control drawing, and where utilities meet classified areas.
8 min readUpdated Sep 5, 2026
Duplex Pump Panels
The duplex control panel: two pumps on one wet well and the sections every duplex panel contains, from power and starters through level control, alternation, hand-off-auto, alarms, and the backup float circuit to telemetry, with the failure responses.
9 min readUpdated Sep 5, 2026
Triplex Pump Panels
The triplex control panel: three pumps on one wet well, the alternation schemes that keep three pumps evenly used, staging levels and standby logic, power, drives and their coordination, the backup circuit for three pumps, and what a duplex never decides.
8 min readUpdated Sep 5, 2026
Lift Station Lead/Lag Control
How a duplex or triplex station decides when one pump is enough and when it is not: the setpoint ladder, cycle volume, the lag call, parallel pumping, and what to do when the lead pump fails.
12 min readUpdated Sep 5, 2026
Lift Station Pump Alternation
Which pump leads, how the lead role rotates, what an alternator relay does, and why equal run hours are not always the goal. Includes the logic rules that keep alternation from causing trouble.
10 min readUpdated Sep 5, 2026
Lift Station High Level
The alarm that stands between a lift station and an overflow: where the high-level float goes, what it must do on its own, how much response time the well provides, and how to diagnose a high level that should not be happening.
11 min readUpdated Sep 5, 2026
Lift Station Backup Control
How a lift station keeps pumping when the transmitter, the PLC, or the SCADA link is gone: float backup logic, the control transfer relay, redundant-off protection, and how to test it with the controller actually dead.
12 min readUpdated Sep 5, 2026
Wet Well Level PID Control
Holding a wet well level with a variable speed pump instead of bang-bang control: the loop structure, the minimum speed floor, the stop and restart logic at low inflow, tuning for a slow integrating process, and where level PID is the wrong idea.
11 min readUpdated Sep 5, 2026
VFD Pump Control in Wastewater
The control modes for a variable speed wastewater pump: level control, flow pacing, fixed speed with soft start, and drawdown modes, plus the wastewater-specific rules: minimum speed, ragging at low speed, force main velocity, and the periodic full-speed run.
10 min readUpdated Sep 5, 2026
Triplex Lift Station Controls
What changes when a station has three pumps: the lead, lag, and standby roles, rotation with three positions, the diminishing return of the third pump on the system curve, availability logic, and the power and panel arrangements that three pumps require.
10 min readUpdated Sep 5, 2026
Lift Station Generator Operation
Standby power at a lift station: what the transfer switch does, how the controls ride through the transfer, staggered pump restarts, what SCADA should see, load testing, and the portable generator connection.
10 min readUpdated Sep 5, 2026
Aeration Control
Controlling the largest energy user at a wastewater plant: the DO cascade to airflow, blower staging and turndown, most-open-valve pressure control across basins, ammonia-based aeration control, the instruments each strategy depends on, and the interlocks that keep blowers out of surge.
11 min readUpdated Sep 5, 2026
Headworks Control
The first stop for raw wastewater: influent flow measurement, mechanical screens and their differential level control, grit removal, influent pumping where the plant needs it, the odor and hazardous atmosphere considerations that shape the electrical design, and what SCADA needs from the headworks.
10 min readUpdated Sep 5, 2026
Clarifier Control
Primary and secondary clarifiers from the control room: the mechanism drive and its torque protection, sludge blanket measurement and sludge withdrawal control, scum removal, the weir and the effluent turbidity, and the sludge blanket as the early warning for a secondary process losing its footing.
9 min readUpdated Sep 5, 2026
RAS and WAS Control
Return and waste activated sludge: what each flow does for the process, RAS control by influent flow ratio or by blanket level, WAS control to a target sludge age or a target mixed liquor concentration, the flow and solids measurements each needs, and the pump and valve arrangements that make the setpoints achievable.
10 min readUpdated Sep 5, 2026
Lift Station SCADA
Getting a remote station onto the SCADA system and keeping it there: which signals to bring back and which controls to allow, the telemetry path from licensed radio to cellular to fiber, and the maintenance that keeps the link up.
9 min readUpdated Sep 5, 2026
Biological Treatment
The biological process from the controls side: activated sludge and its common forms, conventional, extended aeration, oxidation ditch, sequencing batch reactor, and membrane bioreactor, and the alarms that give an operator time.
9 min readUpdated Sep 5, 2026
Chemical Systems in Wastewater Treatment
The chemical feeds of a wastewater plant and their controls: coagulants for phosphorus, polymer for thickening and dewatering, hypochlorite and sulfite for disinfection and dechlorination, and the alarms that keep the plant in its permit.
9 min readUpdated Sep 5, 2026
Effluent Disinfection
Disinfecting the effluent and proving it: chlorination with contact time and residual control, dechlorination with sulfite controlled by ORP or a residual analyzer, ultraviolet systems with dose control from flow, and the records the discharge report needs.
9 min readUpdated Sep 5, 2026
Effluent
Effluent from the controls side: the flow measurement the permit is built on, the composite samplers it paces, the parameters measured online, flow, pH, dissolved oxygen, residual, turbidity, and the data integrity that makes the record defensible.
8 min readUpdated Sep 5, 2026
Residuals
Solids handling from the controls side: thickening by gravity, flotation, or drum, aerobic and anaerobic digestion with their temperature, mixing, and gas systems, dewatering by belt press, centrifuge, and the records that biosolids regulation requires.
9 min readUpdated Sep 5, 2026
Constant Speed Pump Control
On and off pumping with constant speed pumps: why it remains the right answer at most lift stations, the level bands and the wet well volume that set the cycle, starts per hour and motor limits, and the cases where variable speed is worth its cost.
8 min readUpdated Sep 5, 2026
Station Flow Control
Controlling the flow a lift station sends downstream: why a station would limit or match its flow, the plant hydraulic limit, the force main capacity, equalization, and wet weather, and the alarms.
8 min readUpdated Sep 5, 2026
Pump Sequencing Strategies
The strategies for sequencing wastewater pumps: level bands with alternation, lead and lag and standby with runtime balancing, a drive lead with constant speed lag, pump-down against steady-flow operation, and how each strategy fails and recovers.
9 min readUpdated Sep 5, 2026
Small Utility Cybersecurity Priorities
What a utility with a few operators and no IT department should do first: the ten measures that remove most of the risk for the least money and time, in the order to do them, with what each one costs, what it prevents, and how to know it is done.
10 min readUpdated Sep 5, 2026
OT Incident Response Plan
The plan for the day the control system is not trusted: who decides, the triggers, the first hour, isolating without stopping treatment, running by hand, preserving evidence, who to notify and when, recovery from backups, and the exercise that makes it real.
10 min readUpdated Sep 5, 2026
Security Program Basics
What a control system security program is for a utility that has never had one: a named owner, an inventory, a risk assessment, a few policies, baseline controls, training, vendor rules, an exercised incident plan, and a first-year plan for a small staff.
10 min readUpdated Sep 5, 2026
Manual Operation Procedures
Written procedures for running the plant and the remote sites without the SCADA or the controllers: what to read and set by hand, how often to check, what to log, chemical dosing from a flow reading, when to stop, staffing, and the drill that proves them.
9 min readUpdated Sep 5, 2026
Reporting Requirements
Who a water or wastewater utility must tell about a cyber incident, how fast, and what to say: the federal critical infrastructure reporting rule, state laws, the drinking water regulator, public notification, law enforcement, the sector center, and insurers.
9 min readUpdated Sep 5, 2026
EPA Guidance
What the federal environmental agency provides to water and wastewater utilities on cybersecurity and what it expects: the free assessment, the checklist aligned with federal goals, joint incident response guidance, the enforcement position, and how to use it.
8 min readUpdated Sep 5, 2026
CISA Resources
What the federal cybersecurity agency provides to utilities without charge: the performance goals, regional advisors, external vulnerability scanning, control system advisories, the exploited catalog, a self-assessment tool, exercises, and incident reporting.
8 min readUpdated Sep 5, 2026
Pump Runs But No Flow
The motor turns and nothing moves. How to tell a clogged impeller from an air-bound pump, a closed valve, a stuck check, a broken coupling, or reverse rotation, using motor current and discharge pressure before pulling anything.
10 min readUpdated Sep 5, 2026
Seal Failure Alarm
The moisture probe in a submersible pump has tripped its relay: a seal that is leaking, or moisture in the cable, the junction box, or the probe circuit, a relay that does not match the pump, or a failed relay. What the alarm should do and what to check.
8 min readUpdated Sep 5, 2026
Both Pumps Running Constantly
A duplex station where lead and lag run together and never catch up: inflow beyond one pump, pumps that lost capacity to wear or rags, a force main partly blocked, a pump that runs but does not pump, a level stuck high, or bad setpoints. The drawdown test.
8 min readUpdated Sep 5, 2026
NFPA Standards for Controls
The National Fire Protection Association documents that reach into a control system: NFPA 70, the National Electrical Code, and the articles that govern panels, motors, and instrumentation; NFPA 70E for electrical safety at work; NFPA 79 for industrial machinery; NFPA 820 for wastewater plant hazardous area classification; and NFPA 110 where standby power meets the controls.
9 min readUpdated Sep 5, 2026
CISA Guidance as a Reference
How the federal cybersecurity agency publications serve as reference standards for a utility: the performance goals as a baseline for policy and procurement, the water sector goals, secure-by-design principles for vendors, and the advisories.
8 min readUpdated Sep 5, 2026
EPA Rules and Their Control System Implications
The federal environmental agency rules that shape what a water or wastewater control system must measure, record, and report: the surface water rules, residual and byproduct rules, groundwater and lead rules, discharge permits, and record retention.
10 min readUpdated Sep 5, 2026
The Lift Station That Overflowed With Everything Working
A composite of overflows that happen at well-built stations: every pump ran, every alarm fired, every device did what it was designed to do, and the handful of changes that break the chain.
9 min readUpdated Sep 5, 2026
The Knowledge That Leaves With the Retiring Technician
Water and wastewater utilities are losing the people who know how their control systems actually work, and a practical program for capturing it while there is still someone to ask.
8 min readUpdated Sep 5, 2026
Inflow and Infiltration Shows Up in the Pump Runtime
Most small collection systems have no flow meters at the lift stations, but every station reports pump runtime and starts to SCADA. How to turn those two numbers into a station flow estimate, and rank where the money for pipe work should go.
9 min readUpdated Sep 5, 2026
Wet Well Level Control
The measurement that runs a lift station: choosing setpoints, protecting the pumps, validating the signal, and the failures that flood a station.
9 min readUpdated Aug 30, 2026
Water and Wastewater Utility Threat Landscape
What has actually happened at water utilities, what those incidents had in common, and the small number of controls that would have prevented most of them.
8 min readUpdated Aug 28, 2026
Duplex Lift Station Controls
The two-pump station that makes up most of a collection system: what is in the panel, how the sequence works, what is monitored, and where these stations actually fail.
11 min readUpdated Aug 27, 2026
How to Program Lead/Lag Pump Control
Build duplex pump control with alternation, failure detection, minimum run and off timers, and an operator override that survives a restart.
10 min readUpdated Aug 24, 2026
Lead/Lag Pump Control
Which pump runs first, when the second joins, how they trade places, and the design decisions that determine whether a duplex station wears evenly.
9 min readUpdated Aug 18, 2026
Magnetic Flowmeters
Faraday's law applied to a pipe: how a mag meter works, the conductivity and full-pipe requirements, and why grounding decides whether it reads.
8 min readUpdated Aug 1, 2026
Radar Level Measurement
Non-contact and guided wave radar, why it handles a wet well better than most alternatives, and the installation details that decide whether it works.
9 min readUpdated Jul 9, 2026
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