Showing posts with label water treatment. Show all posts
Showing posts with label water treatment. Show all posts

Friday, May 4, 2018

7 Ways Thermal Mass Flow Meters Can Help Cut Wastewater Treatment Aeration Energy Costs

FCI Thermal Mass Flow Meter
One of the biggest expenses in wastewater treatment operations is the cost of energy to run the blowers and compressors that produce air for the aeration basins. The figures most often cited are that 40 to 50 percent of a wastewater plant’s total energy usage can be attributed to the aeration process.

By measuring the system’s air flows with accurate, repeatable air flow meters, the aeration process can be better controlled to optimize the process and minimize plant energy cost. Three flow sensor technologies typically have been used in aeration air flow monitoring applications in wastewater treatment plants:

Within wastewater treatment plant aeration systems, it is now generally accepted that thermal dispersion mass flow meters are the preferred, proven best solution and have the largest installed base. For plant expansions, new plants and upgrades this trend is expected to continue. The embedded document below presents seven tips that explain how thermal mass flow meters can reduce aeration plant energy costs and have become the flow meter of choice for aeration applications.

Alternatively, you can download your own copy of "7 Tips to Cut Wastewater Aeration Energy Costs with Thermal Mass Flowmeters" here.

Saturday, July 15, 2017

Solving Critical Process Applications for the Water and Wastewater Industry

Thermal Dispersion and Coriolis technology
From the early 1960s, Fluid Components International recognized the need for flow and level instrumentation which met specific customer requirements and demands for the Water and Wastewater Industry. By utilizing Thermal Dispersion and Coriolis technology exclusively in all FCI flow, level, interface, temperature switches and mass flow meters, our products solve typical Water and Wastewater Industry application challenges with standard product features such as:
  • No moving parts
  • All welded materials of construction 
  • Direct mass flow measurement
  • No pressure drop
  • Explosion-proof design
  • Wide flow range
  • Low flow capability
The document below outlines where and how Thermal Dispersion and Coriolis technology are used throughout water treatment facilities around the USA.

For more information on any water treatment process application, contact Flow-Tech at 410-666-3200 in Maryland, or 804-752-3450 in Virginia, or visit

Tuesday, September 27, 2016

Flow Meter Enhances Chlorination System Performance for Municipal Water Department

Flow Meter Chlorination System
Flow Meter Installed on Chlorination System
By Steve Cox, Senior Technical Staff,  Fluid Components International (FCI). Reprinted with permission.

The water municipality at a mid-size city in the Western region of the U.S. serving a population of about 180,000 people needed to address a chlorine disinfection system problem at one of its water treatment plants. The city’s engineers take great pride in providing their community with a safe source of drinking water and gave this issue the highest priority.

In order to provide a reliable, safe source of clean drinking water, all municipal system operators rely on a disinfection system to kill germs. There are several different methods of disinfection treatment, such as chlorine (Cl2), UV, and ozone. Chlorine remains a popular disinfectant around the world. Where chlorine is in use, accurate measurement of the gas is essential for successful disinfection and for safety purposes.


Water treatment plant chlorine tanks
Figure 1: Water treatment plant
chlorine tanks
At one of the city’s water treatment plants, the chlorinator system’s flow measurement lacked suitable turndown capability (measuring range) and was not repeatable at lower flow rates and monthly totalized chlorine usage were not consistent (Figure 1). This poor control over the amount of chlorine being dispensed resulted in either excessive, wasteful chlorine use, or potentially hazardous and expensive re-treatment. Adding too much chlorine affects water taste (swimming pool), wastes expensive chlorine gas and adds the cost of extra residual chlorine removal. With too little chlorine added, the disinfection treatment process is incomplete, and the water requires costly additional alternative treatment or re-treatment.

The city’s system had been initially designed with simple site-gauge rotameters. Later, for automated control purposes, differential pressure (dP) type orifice plate  ow meters were added into the system. The city’s engineers soon discovered the orifice plate dP meters could not be relied upon to measure accurately under  ow conditions where little pressure differential was available, and the limited  ow range could not support the changing dose rates with changes in water demand.

ST100L Flow Meter
Figure 2: Installed ST100L
Flow Meter with Vortab
Flow Conditioner
The treatment plant needed a better gas flow meter solution that would be appropriate for service in a 1-inch diameter pipe at a flow rate of 150 lb/day to 2,000 lb/day [68 kg/day to 907 kg/day]. The operating temperature was 60°F to 100°F [16°C to 38°C] at a pressure of 0 psig to 10 psig [0 bar(g) to 0.7 bar(g)]. The flow meter would be used to measure chlorine and no other gases and would be installed in a location where inadequate straight-pipe run was present and added to the accuracy challenge for any velocity based instrument. The flow velocities also resulted in measurement required in the transitional zone where the gas flow profile was transitioning from laminar to turbulent. Mass flow provided an additional advantage of allowing a simple, direct means of reconciling monthly throughput compared against the change in weight of the chlorine gas containers that were installed on load cell technology scales.


Thermal dispersion
Figure 3: Thermal dispersion
constant power principle
of operation
After consulting with the application engineering team at Fluid Components International (FCI), the engineers at the water department selected the Model ST100L thermal dispersion gas mass flow meter with built-in Vortab® flow conditioner (Figure 2). The Model ST100L is an in-line, spool piece flow meter that combines best-in-class transmitter/electronics and superior sensor design to provide a truly state-of-the-art gas flow meter for industrial process and plant applications in line sizes up to 2 inches [50 mm].

FCI’s model ST100L constant power technology thermal flow meter (Figure 3) was installed in the water system’s chlorine gas inlet line to the chlorinator panel. To ensure maximum corrosion resistance and longest service life in the highly corrosive chlorine gas environment, the ST100L’s entire sensor assembly, including flow elements, flow body and Vortab flow conditioner elements, are fabricated entirely of Hastelloy C-276.

FCI’s gas flow meters are typically calibrated in FCI’s NIST traceable flow laboratory using the actual gas to be measured and at the installation’s actual temperature and pressure conditions. However, chlorine gas presents safety concerns during the calibration process which renders that process unfeasible. It has also been thoroughly established that air equivalency calibrations for chlorine gas are inaccurate, unrepeatable and simply, inadequate. FCI solves this problem by combining a lab-based equivalency basic calibration with an on-site, in-situ calibration adjustment against the site’s rotameters, all performed by an FCI field service technician. This achieved the highly accurate and repeatable measurement needed by the client. The on-site calibration matching proved to be the best solution because the totalized flow readings from the FCI Model ST100L and the weigh scale comparison were now consistently aligned.

The in-line configuration ST100L meter measures air/gas  ow from 0.25 SFPS to 1000 SFPS (0,07 NMPS to 305 NMPS), with turndowns of 100:1 and with accuracy of ± 0.75 percent of reading, ± 0.5 percent of full scale. To match present and future DCS, PLC or SCADA needs, users can select from multiple output options including triple 4-20 mA analog, frequency/pulse, or certified digital bus communications of HART®, FoundationTM Fieldbus, PROFIBUS PA and Modbus RS485.

The ST100L flow meter also features a best-in- class graphical, multivariable, backlit LCD readout, which provides operators with a continuous display of all process measurements, alarm status and service diagnostics. Its four-button user keyboard is activated through the glass, which means the user never needs to remove lids or open up the unit at the installation site. The instrument also includes a USB port for PC interface and an ethernet port for service needs.

The ST100L meter is designed to ensure the longest service life in even the most rugged industrial applications and installations. The enclosure is NEMA4X/IP67 rated and features four separate conduit ports to isolate all wiring. Additional pedigrees include global agency approval for hazardous environments (ATEX, IECEx, FM, FMc, Inmetro, NEPSI and EAC/TR CU) and SIL compliance. The electronics/ transmitter is available for installation as either integral with the flow element or remotable (up to 1000 feet [300 meters]).

The integral Vortab flow conditioner ensured optimal installation performance by overcoming the limited piping straight run and the flow range occurring in the transitional flow region. Vortab uniquely eliminates both swirl and velocity profile distortions produced by process equipment obstructions and/or inadequate straight run of pipe and ducting, as well as temperature and media stratification that can be present at the low flow rates where FCI meters perform and with the lowest pressure drop of all flow conditioner alternatives.


ST100L Flow Meter with Vortab Flow Conditioner
ST100L Flow Meter with
Vortab Flow Conditioner
The ST100L  ow meters have been installed in the chlorine gas inlet lines and achieving consistent accurate and repeatable  ow measurement results. The site is achieving the desired disinfection results with proper chlorine dosing at significant cost savings due to reduced chlorine use, avoiding re-treatment and lessened residual chlorine removal processes.

Monday, June 13, 2016

Choose Insertion Mass Flowmeters for Wastewater Activated Sludge Process

Insertion Mass Flowmeters for Wastewater
Insertion Mass Flowmeters in Wastewater Treatment
In wastewater treatment facilities, a variety of biological and chemical processes are employed to remove organic pollutants from water to ensure its reusability. One very common process is referred to as “the activated sludge method”. This process biologically treats the wastewater through the use of natural micro-organisms combined with the wastewater in large aeration basins.

The activated sludge method requires the pumping of compressed air into the aeration basins where a diffuser system ensures the air is distributed evenly for optimum treatment. Tiny micro-organisms in the aeration basins decompose biologically degradable organics in the wastewater. These micro-organisms rely on the aeration system to provide air for survival, but also by controlling the proper amount of air, the micro-organisms can thrive and optimally consume the organics in the wastewater. After a period of time, a flocculate forms with the non-biodegradable solids settling to the bottom of the basin.

Large amounts of compressed air is used to ensure the activated sludge method treats the water effectively before it can be moved along to the next stages, namely the clarifying basins, filtering, disinfection and other treatment processes. A very important step in this process is the accurate control of air released into the aeration basins. This is essential because, as stated above, the air flow controls the growth of micro-organisms that treat the wastewater.
Insertion Mass Flow Meter
Insertion Mass Flow Meter
(courtesy of FCI)

Flowmeters are typically installed in the aeration system piping to measure the amount of air flow and the flowmeters’ analog or digital outputs run to the wastewater treatment plant’s control system.

A highly accurate and reliable flowmeter is critical because the one of the largest energy costs in a wastewater facility is the air compressor operation. Energy management and efficiency continue to drive plant maintenance, and the compressed air system is a prime system component where considerable savings can be found. A well designed air flow metering, controlling, and reporting system for the aeration process is an excellent way to achieve measurable efficiency gains and provide a significant reduction in energy costs.

When choosing a flow meter, here are the important criteria to consider:
  • Flow Sensor Technology
  • Range and Accuracy
  • Operating Environment
  • Ease of Installation
  • Maintenance and Life
An excellent choice for these applications are insertion mass flowmeters. They provide an accurate, easy to install, no moving parts mass flow meter solution commonly used for compressed air and nitrogen flow. Their proven thermal dispersion technology provides direct mass flow measurement that results in higher performance at a lower cost than orifice plates, DP, Vortex shedding and other thermal devices. When combined with microprocessor electronics and precision calibration, they achieve excellent accuracy, fast response and virtually maintenance free operation.

For more information, contact:

Flow-Tech, Inc.

Maryland Headquarters
10940 Beaver Dam Rd
Hunt Valley, MD 21030
Ph: 410-666-3200

Central VA Office
10993 Richardson Rd#13
Ashland, VA 23005
Ph: 804-752-3450

Thursday, December 31, 2015

pH Control Loops - An Introduction

Yokogawa pH transmiter
Yokogawa pH transmiter
Analytical measurement and control a pH within a system is necessary for many processes common applications include food processing, wastewater treatment, pulp & paper production, HVAC, power generation, and chemical industries.

To maintain the desired pH level in a solution a sensor is used to measure the pH value. If the pH is not at the desired set point, a reagent is applied to the solution. When a high alkaline level is detected in the solution, an acid is added to decrease the pH level. When a low alkaline level is detected in the solution a base is added to increase the pH level. In both cases the corrective ingredients are called reagents.

Accurately applying the correct amount of reagent to an acid or base solution can be challenging due to the logarithmic characteristics a pH reaction in a solution. Implementing a closed-loop control system maintains the pH level within a certain range and minimizes the degree to which the solution becomes acidic or alkaline.

An example of an automatic pH level control system is a water treatment process where lime softened water is maintained at a pH of 9 using carbon dioxide as a reagent. As the untreated water (or influent) enters the tank, the pH is continuously monitored by the pH sensor. The sensor is the feedback device to the controller where the setpoint is compared to the control value. If the values are not equal, the controller sends a signal to the control valve that applies carbon dioxide to the tank. The reagent is applied to the tank at varying rates to precisely control the pH level. With the pH level at 11 detected by the sensor, the controller commands the control valve to open and introduce more carbon dioxide. As the increased carbon dioxide mixes with the influent, the pH is lowered in a controlled manner. Reaching the setpoint, the carbon dioxide flow is minimized and the process is continually monitored for variation. The effluent is the treated water that is discharged out of the tank. The process continues to provide the lime softened water at the desired pH level.