Flow measurement is critical in wastewater treatment plants. Flow measurement products, in addition to reducing water GHG emissions, ensure clean and safe waste water disposal.what is being measured.
Let’s understand the concept of flow measurement with its calculation.
Why is it necessary to measure wastewater flow?
• Determining wastewater flow rates is a critical step in the design of wastewater collection, treatment, and disposal facilities.
• When wastewater flow rate data is limited or unavailable, wastewater flow rate estimates must be developed using water consumption records and other data.
• Flow rates must be estimated to account for not only averages, but also peak flows. Peak flows of short duration may or may not have a deleterious effect, but peak flows that last for days may cause hydraulic failure.
Flow measurements are classified into two types:
1. At a specific point in time, instantaneous flow is measured.
2. Average flow is calculated by combining discrete flow measurements with flow volume measurements, taken over a long period of time.
How is wastewater flowrate calculated?
There are several methods for calculating flowrate in the field that require little or no additional equipment:
1: Individual activity flows: Average daily flow refers to the average total flow generated on a daily basis by individual wastewater-generating activities in a building. These activities include toilet flushing, showering and bathing, cloth washing and dishwashing, faucet use, and other miscellaneous activities.
2: Bucket and Stop Watch: The simplest method for determining flow rate; no special equipment is required. This procedure is only appropriate for minor discharges from pipes or other conveyance devices, where a bucket can catch the entire flow. Employees in the field should repeat the procedure at least three times and average the results.
3: Float or Dye Method: To estimate flow in a geometrically well-defined channel, use the following formula:
· AV = Flow
A = Flow's cross-sectional area, and
V = The channel's average flow velocity.
4: Stormwater Flow Estimation: Field employees are occasionally required to estimate stormwater runoff flows, without the use of costly flow-measuring instruments or complex setups. One of the most commonly used approaches is the following rational equation, which is based on rainfall intensity and frequency data
Where, 'Q' denotes the peak runoff rate in cubic feet per second (cu ft/sec), 'C' the runoff coefficient, 'I' the average rainfall intensity over the concentration period, and 'A' the drainage area.
5: Time to Fill: By measuring the time it takes to fill or empty sumps, wet wells, tanks, or any other well-defined geometric structure, field personnel can estimate the flow. The volume is also calculated by measuring the change in liquid depth, and multiplying it by the surface area. The volume is then divided by the recorded time to calculate the flow rate.
6: Pump Cycles: The pumping cycles of a wet well or a process sump can sometimes be used to approximate flow. Once an event recorder is connected to the pump's electric circuit, the on-off signals are typically captured electronically, or on a chart recorder. The flow can then be calculated in the field using the pump's rated capacity and pumping time.
How can we assist?
If you have any questions about wastewater treatment plants or effluent treatment plants, or if you would like to discuss about the calculations of wastewater flowrate, please contact the Netsol Water team right away. Our team is an expert in water treatment and can help you tailor a solution to your specific requirements.
We design, manufacture, supply, erect, and commission Wastewater Treatment Plants (WWTPs) on a turnkey basis, for various types and natures of wastewaters, effluent treatment systems that combine advanced physico-chemical treatment processes with tertiary polishing systems, for the removal of organic, inorganic, oil and grease, heavy metals, and suspended solids.