Ultrasonic Flow Meter and V-notch Weir for Wastewater Treatment Plant (Video)

Video

Wastewater Treatment Plant Ultrasonic Flow Meter and V-notch Weir

Effluent flow measurement in wastewater treatment plants have traditionally been measured by weirs, flumes, time-transit flowmeters, partially filled pipe flow meters, insertion meters, magmeters and other flowmeter technologies. This wastewater treatment plant uses two 90 degree V-notch weirs along with an Ultrasonic Flow Meter system from Aqua Technology Group and Nivelco to accurately measure the treated waste water as it flows out of the plant into the receiving waters.

But what if you have a flow meter application like this dual 90 Degree V Notch Weir or another primary flow device? Aqua Technology Group and Nivelco have you covered with a best of breed solution for any wastewater flow application.

How Does a Ultrasonic Flowmeter with V-notch Weir Flowmeter Work?

The two v-notch weirs act as the primary flow measurement devices for the system. Primary measuring devices like these weirs provide a reliable way of producing a measurable head (or water level) above the crest elevation. The V-notch weirs are are available in various angles and we typically fabricate them out of 1/4″ or larger aluminum plate. We can even provide them as fabricated fiberglass weirs. The head 0r water level above the crest (or bottom of the V) of this 90 Degree V-notch weir is accurately measured by a Nivelco EasyTREK ultrasonic level transmitter. The integrated ultrasonic level transmitter and flow meter sends a scaled 4-20 mA + HART signal over two wires to the Nivelco MultiCONT multichannel display and process controller. The MultiCONT can act as a fully featured multichannel process controller in many applications but here it simply provides a remote display of the instantaneous level in feet along with flow in GPM (Gallons Per Minute). The MultiCONT process controller also provides the accumulated flow in both resettable and non-resettable totalizers. The 4-20 mA signal is then looped through the wastewater effluent sampler and back to the RTU and SCADA system for analysis and archiving.

weir measurement point design diagram

Weir Point of Measurement. Typical Weir Installation and Design Diagram. Hmax dimensions are critical to a good accuracy.

What’s the angle of that V-notch weir?

V-notch Weir Angles Range from 22.5 Degrees up to 120 Degrees

22.5 Degree V-notch weir

30 Degree V-notch weir

45 Degree V-notch weir

60 Degree V-notch weir

90 Degree V-notch weir

120 Degree V-notch weir

V-Notch Weir Design Considerations

  • Minimum of 2.4 inches or 0.2 feet of head (water level above the crest).
  • Maximum of 24 inches or 2.0 feet of head (higher is possible but not recommended for good accuracy).
  • The upstream weir face must be vertical – always check with a level.
  • The edges of the weir must be cut or machined straight, sharp and crisp – no burs or jagged edges.
  • The channel should have a free-fall of 6″ (152.4 mm) downstream of the crest of the weir.
  • Ice, debris, corrosion, algae and biological buildup must be removed regularly – keep the edges clean!
  • The weir nappe must be adequately aerated so the water does not cling to the outfall face of the weir.
  • The pool on the upstream side of the weir must be kept free of weeds and debris.
  • The upstream pool must be large enough and properly sized to ensure accuracy.
  • The approach velocity of weirs should normally be below 0.5 ft./s (0.1524 m/s). Above this requires calibration.

How to Size Your V-Notch Weir

What is the Minimum and Maximum Head for V-notch Weirs? Download V-notch Weir Min/Max Table

Flow may become very unstable if you regularly have low discharge head (or water level above the notch). If the minimum head of .2′ (2.4″) is not reached, you may see flow inconsistencies or even meter errors. Engineers and flow experts alike agree that heads less than 2.4 inches will not produce reliable flow meter results as the nappe tends to adhere to the crest of the weir and viscous drag is observed.

V-notch weir minimum head and maximum head

Minimum and Maximum Head for V-notch Weirs

How Do I Calculate Flow Across a V-notch Weir at a Given Head? Download V-notch Weir Discharge Table

In this 90 degree V-notch weir application, we want to know our flow in GPM (gallons per minute). We have approximately 1.0 feet of head which calculates out to about 112o GPM. We calculate this by taking 1120 times the head in Feet ^2.5 power. (1120 x 1^2.5 = 1120 GPM).

V-notch Weir Flow Formula Discharge Table

Discharge Equations for Thin-Plate Free Flow V-Notch Wier

Choosing the Right Ultrasonic Flow Meter for V-notch Weirs and Flumes

Not all flowmeters are created equal. Some consist of cheap components, low accuracy and other shortcuts to keep costs low. The units keep moving out the factory door but later end up in the trash bin!

We prefer the customer centric longer approach by providing the best mixture of price and quality. That leads to industry leading customer satisfaction and the least amount of warranty service calls. The Nivelco EasyTREK and MultiCONT in this application have been in continuous service for nearly a decade. We hope every customer can get that type of life. Nivelco keeps you covered with a industry leading 3 Year Warranty.

wastewater effluent flow meter

Nivelco EasyTREK Ultrasonic Flowmeter with MultiCONT Display / Totalizer and Process Controller

No flow meter can be the perfect fit for every V-notch weir or flume flow measurement application. Contact our team save you time and money with a matched system for years of service. Looking for a compact ultrasonic flow meter solution? Check out the EchoTREK compact ultrasonic flow meter. We can also help you meter water and collect meaningful data throughout the entire water cycle – raw water sources, wells, raw water pumping, water treatment plant, water distribution, waste water collection system, metering manholes, lift station flowmeters, wastewater treatment plant flowmeter, plant process flow meters,  wastewater treatment plant effluent flow and everything else in between.

Maybe you even have an existing V-notch and ultrasonic flow meter that needs service. Aqua Technology Group provides flow meter calibration, repair and emergency service for your water and waste water plant.

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Multipoint Temperature Measurement for Water Tanks

Measuring Multiple Temperature Points Inside Water Tanks, Reservoirs and Storage Tanks

Operators and water systems have been using different technologies and tank mixers to maintain the highest quality drinking water in water towers, reservoirs and storage tanks. Tank mixers and aeration can help with disinfection byproduct (DBP) removal and disinfectant control. You know thermal stratification exists in your tank but what if you wanted to know the realtime temperatures at several points inside your water tank or reservoir?

We wondered what affordable solution was availabe to monitor water tower temperature and we found a good water tank temperature solution from Nivelco. The Nivelco THERMOPOINT can monitor temperatures in water towers, water tanks and reservoirs up to 100′ in depth. The Nivelco THERMOPOINT is multipoint temperature measurement system with ultimate flexibility and communication options.

The THERMOPOINT from Nivelco provides:

  • Up to 15 temperature measurement points per probe
  • Up to 15 probes per system for a total of 225 measurements per loop.
  • Up to 100′ length probes
  • Rigid or Flexible Probe Configurations
  • ± 0.5 °C (± .9 °F) Accuracy
  • 2 wire transmitter for quick and easy wiring (12-30 VDC)
  • Flexible mounting locations: Thousands of feet between probes and the transmitter / outputs
  • Wireless transmitter option available – Up to 770 feet (235 meters) outdoors open air range (nominal)
  • Solar Power and Battery Power option available
  • Replaceable sensors – add and replace as required
  • 1 1/2″ NPT Connections for Flexible Cable Probes, 1″ NPT for Rigid Probes

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Nivelco Instruments – Refrigeration and Cooling

 

Nivelco Instruments Refrigeration Cooling Process

Nivelco Process Instruments for Refrigeration and Cooling Process

Nivelco and Aqua Technology Group can provide all you instrumentation needs for refrigeration, ammonia cooling and related processes.

The Nivelco Refrigeration and Cooling process diagram below illustrates a cooling technologic process commonly used in food, chemical and pharmaceutical industrial plants.

On the process diagram can be seen the cooling compressor applying ammonia, the circulating pump system and the liquid separator tank with the proposed Nivelco devices.

Nivelco Product Used

Instrumentation of the compressor:

  • The measurement of the pressure on the suction and pressure side is accomplished by NIPRESS DRC-3xxx type pressure transmitter
  • The measurement of the temperature is completed by THERMOCONT TTJ-Sxxx temperature transmitters
  • The suction side pressure transmitter performs the power control or the compressor, while the pressure side transmitter controls the condenser

Instrumentation of the liquid-separator:

  • The continuous level measurement is executed by NIVOCAP CTR-2xxx type capacitive level transmitter
  • This device controls the feeding valve applying me UNICONT PMM-311 type controller
  • The upper and lower failsafe switching is executed by NIVOMAG MKA-210 type level switches,
  • As high level is reached, the compressor shuts off, while at low level the ammonium pump is stopped.

Instrumentation of the liquid tank:

  • The instruments and procedure is similar to the separator but a NIVOTRACK MRC-5xxx type level transmitter is recommended due to the high pressure (16 bar)

Instrumentation of the cooling water:

  • A continuous level measurement is accomplished with EchoTREK SGA-3xxx type ultrasonic level transmitter, the level in the tank is kept constant by the help of a UNICONT PMM-311 type controller by actuating a supplementary water valve
  • The continuous conductance measurement is executed with an ANACONT LGK-2xxx type device,
  • The conductivity or cooling water is permanently increasing due to the evaporation in the condenser, so at a predetermined value, the PMM-311 controller opens the emptying as well as the supplementary valve
  • The low and high failsafe NIVOSWITCH RFM-401 type switches protect the pump and issue the alarm signals.

Instrumentation of the condenser:

  • The level control of the water tank under the condenser is accomplished by a NIVOCONT KKH-222-5 type level switch.

 

Nivelco Instruments for Wastewater Treatment

Nivelco Process Instruments for Wastewater Treatment.

Nivelco and Aqua Technology Group can provide all your instrumentation and control needs for collection systems, liftstations and pumps, package plants and wastewater treatment plant. This diagram of the wastewater treatment process details two separate sections: wastewater treatment processes and slurry treatment processes.

COLLECTION SYSTEM / LIFTSTATIONS / SUMPS / PITS

The sewage is collected in lifstations, underground sumps or pits, also known as wetwells, and is pumped to the sewage treatment plant.

Measurement and control tasks:
Reliable level measurement is necessary to provide pump start and stop signals with fail safe switch-off points to avoid dry running.

RECOMMENDED INSTRUMENTS

The  EasyTREK SP type non-contact ultrasonic level transmitter models with IP68 ingress protection is Nivelco’s recommendation for this measurement task.

Another popular choice for liftstations or deep sumps is the flush mounted  NIVOPRESS NC  type
hydrostatic borehole transmitter or the NIVOPRESS NP  series with recessed membrane equipped with a sewage adaptor working on the principal of the diving bell.

Nivelco NIVOPRESS N NIVOPRESS D transmitter

A  PLC  or our  MultiCONT  process controller unit is ideal to process the analogue 4…20 mA signals and to control the switching points. For fail-safe protection, the robust NIVOFLOAT NWP float level switches are recommended.

Nivelco Nivofloat and Nivocont

WASTEWATER TREATMENT PLANT

The sewage pumped in from the network contains a lot of organic and non-organic materials in suspended form as well as in solution. This pollution has to be removed. The particles are filtered with a mechanical screen. The dissolved pollution can be reduced by adding coagulant materials. The reduced slurry is then separated from the water in the sedimentation tank.
The purified sewage can be streamed to any natural water after chemical inspection and yield measurement.

RECOMMENDED INSTRUMENTS

  • Ultrasonic level transmitters for level measurement (2-wire integrated  (blind) or compact versions), EchoTREK or EasyTREK
  • For the control of the mechanical screen a differential system with 2 ultrasonic level transmitters is recommended
  • The  AnaCONT  range of analytical measurement devices is ideal for the chemical analysis of the cleaned water
  • Open channel flow metering can be done using our  Parshall flume, and  EasyTREK level transmitter.
  • Nivelco EasyTREK Echo-TREK ultrasonic transducers
  • For the calculation and data logging a MULTICONT PEW controller can be used.
  • High and low level switching will be performedwith NIVOSWITCH vibrating fork sensors

 

WASTEWATER TREATMENT PLANT,SLURRY TREATMENT PROCESS

The slurry separated in the sedimentation tank istransferred to the digester tank. The emitted biogas is stored in a biogas tank and then fed to a biogas generator. The biogas section of the plant is classified as a hazardous environment. The slurry retained in the digester is transported from the plant after dewatering (dehydration)

RECOMMENDED INSTRUMENTS

  • ATEX certified ultrasonic level transmitters(EchoTREK  or  EasyTREK) or ATEX certified guided microwave level transmitter (Micro-TREK) can be used for level measurement.
  • Nivelco’s choice for measuring the temperature of biogas is the ATEX certified temperature transmitter THERMOCONT TTJ Ex.
  • Nivelco recommends an ATEX certified pressure transmitter for measuring the biogas pressure the NIVOPRESS DT Ex

Nivelco Water Wastewater Instrument Selection

Nivelco Field Instruments In Measurement Systems

Nivelco Instruments for Potable Water Production

Nivelco Instruments for Potable Water

Nivelco Process Instruments for Potable Water Production.

Nivelco and Aqua Technology Group can provide all your instrumentation needs for production wells, purification, treatment, and distribution system.

PRODUCTION WELLS

The production wells are drilled in ground layers rich in water, the pumps are lowered into the wells to pump the raw water to the central water treatment facilities.

  • Measuring tasks:
  • Continuous level measurement of the well
  • Temperature measurement of the water
  • Hydrostatic pressure (water level) of the production well
  • Flow of the produced water
  • Dry-run protection of the pumps

RECOMMENDED INSTRUMENTS

  • Hydrostatic level transmitters that combine level and temperature measurement: the NIVOPRESS N transmitter family.
  • Piezoresistive pressure transmitters: NIVOPRESS NZK types
  • Water input measurement: ISOMAG electro-magnetic flow meters

WATER TREATMENT PLANT

The raw water pumped from the production wells contains different organic and inorganic materials. These materials have to be removed from the water. Removal is done either by mechanical filters or by adding coagulant materials to the water to help precipitate the contaminating materials. The resulting slurry is separated in settling tanks. The clean water is often passed through sand or other final filtration stages.

RECOMMENDED INSTRUMENTS

WATER DISTRIBUTION SYSTEM

To move water out to the distribution system and to the customers, the pressure in the system has to be increased. This is done by booster pumps, water towers or air charged pressure vessels with compressed-air pumps.

RECOMMENDED INSTRUMENTS

Nivelco Field Instruments In Measurement Systems

Nivelco

Aqua Technology Group is proud to offer quality Nivelco process instruments.

NIVELCO Product MATRIX

LEVEL TRANSMITTERS
Non-contact Microwave PiloTREK
Guided Microwave MicroTREK
Ultrasonic Compact EchoTREK for liquids
EchoTREK for solids
Ultrasonic Integrated EasyTREK for liquids
EasyTREK for solids
Capacitive NIVOCAP
Magnetostrictive NIVOTRACK
Hydrostatic pressure NIVOPRESS D
NIVOPRESS N – borehole transmitter
LEVEL SWITCHES
Float NIVOFLOAT
Conductive NIVOCONT K
Magnetic Coupling NIVOMAG
Magnetic Tracking NIVOPOINT
Vibrating NIVOCONT R – vibrating rod
NIVOSWITCH – vibrating fork
Rotary Paddle NIVOROTA
LIQUID ANALYSIS
pH and ORP transmitters AnaCONT LE
Conductivity transmitter AnaCONT LEK / LCK
DISPLAYS AND CONTROLLERS
Loop indicator UNICONT PDF
Controller/Indicator UNICONT PMM
UNICONT PMG
Controller / Programmer / Indicator MULTICONT
PRESSURE
Pressure transmitter NIPRESS
Hydrostatic pressure NIVOPRESS D
TEMPERATURE
Thermometers THERMOCONT TT
Temperature sensor THERMOCONT TN
SENSORS AND ACCESSORIES
Current Controlled Switch UNICONT PKK
Ultrasonic Proximity Sensor MICROSONAR
Accesory HART MODEM
Universal Interface Module UNICONT PJK-100
Power supply NIPOWER
SOFTWARE
Process visualization software NIVISION
OLDER PRODUCTS
Ultrasonic Two-part System NIVOSONAR