Watsewater Flow Measurement

We provide full range measurement of water velocity, depth (pressure), and conductivity of water flowing in sewerage pipes. The type of flow meter we used are an ultra-sonic technology which delivers significant advantages for watsewater measuring and monitoring

What are the advantages to using ultrasonic flow meters for wastewater?

  • Able to measure the velocity, depth and conductivity simultaneously.
  • Velocity Range: 0.02mm/s to 12m/s bi-directional
  • Pressure Depth Range: 0 to 10m
  • Utlrasonic Depth Range:0.02-5m
  • With barometric pressure compensation function


Sewerage Flow Monitoring at Existing Manhole Located at Jalan Satu and Jalan Dua Connected to Jalan Sungai Besi, Kuala Lumpur


Project Background

As the sewage generated by this new development is to be channel to STP for treatment, an existing public sewer reticulation nearby will be use to connect this sewage.This project is to analyse the current capacity of sewage flow through one existing manhole located at the Jalan Satu and another
one located at Jalan Dua, both that will discharge the final sewage to Pantai 2 RSTP and LowerKerayong STP respectively.

The study will determine the current flow rate of the sewage at flowing through the manhole toevaluate the current Population Equivalent (PE) that flow at the specific point of the manhole. This study has been set the duration of 1 day each with flow rate date that been captured at interval of 10 minutes. This report shall discuss the findings and data analysis in regard to the actual flow rate and equivalent PE. The location of manhole taken the measurement can be refer to diagram below (figure 1).


Scope of Work

The above study requires supply, installing and monitoring a flow measurement of two manhole at respective location using flow meters. The location of manhole are located 1m and 150m respectively from the proposed development. (Refer figure 1).The flow will be analyse and the maximum flow rate will be recorded for calculation of equivalent PE.


Flow Meter

The type of flow meter used during the monitoring are an ultra sonic flow meter called Doppler Ultrasonic Area Velocity Flow Meter(figure 2) . The flowmeter is design by using Doppler ultrasonic area velocity technology to measure open channel or partially filled pipe flow rate. The transmitter able to calculate flow rate and total flow of channel from the measure velocity and water level.



Based on the data collection that has been done, the summary of the findings is show table below.
Location Measurement Peak Minimum Average
Manhole 1 Flow Rate (m3/hr) 2007.822 0 1259.830
Velocity (m/s) 0.343 0 0.215
Manhole 2 Flow Rate (m3/hr) 1282.816 0 371.558
Velocity (m/s) 0.213 0 0.0617
Table 1. Summary of finding for Manhole 1 and Manhole 2

The full data collections from the finding are shown at the graphs on Appendix A and raw data on Appendix B.


PE Calculation

For discharge flow obtained from Flow meter, using Standard formula for PE and Discharge flow (as per Malaysian Sewerage Industries Guidelines), the computation to find actual PE can obtained. The flow rate are considering the maximum flow rate obtain from the flow meter measurement denotedby Qpeak.

Measured Peak flow rate, MQpeak
                   =2007.82 m3/hr
                   = 33.46m3/min
                   = 0.5578 m3/s

Peak flow factor,PF
                   = 4.7 x (PE/1000)-0.11

Average Flow Rate ,Qavg
                  = PE x 225 litre/day
                  = 0.225 PEm3/day
                  = 0.009375 PE m3/hr
 Peak Flow, Qpeak
                 = Qavg x PF
         2007.82 = 0.009375 PE x 4.7 x (PE/1000)-0.11

Population equivalent, PE
                 = 73,034 PE

Manhole 2
Measured Peak flow rate, MQpeak
                = 1282.816 m3/hr
                = 21.38m3/min
                = 0.3563m3/s

Peak flow factor,PF
                 = 4.7 x (PE/1000)-0.11

Average Flow Rate ,Qavg
               = PE x 225 litre/day
               = 0.225 PEm3/day
               = 0.009375 PE m3/hr
 Peak Flow, Qpeak
                 = Qavg x PF
         1282.82 = 0.009375 PE x 4.7 x (PE/1000)-0.11

Population equivalent, PE
                 = 44,162 PE

Raw Data



Based on the findings obtained from the data collection, it can be conclude that the flow rate of
sewage at the manhole 1 and manhole 2 are 2007.82 m3/hr, 1282.816 m3/hr respectively.

Appendix 1 - Graphs

                                               Manhole 1                                                                                                           Manhole 2


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