On-line microwave total solids sensoring in sewage characterization

Area of Science:

• Environmental Engineering
• Water Treatment Technology
• Sensor Technology

Background:

• Municipal wastewater treatment plants (WWTPs) face challenges in monitoring influent streams, particularly those from sources like slaughterhouses.
• These streams exhibit high and variable organic loads, including nitrogen, phosphorus, and microorganisms, complicating accurate measurement.
• Traditional laboratory analyses for parameters like total solids (TS) can be time-consuming and may not reflect real-time influent conditions.

Purpose of the Study:

• To introduce and evaluate a novel microwave on-line sensor for measuring total solids (TS) load in complex wastewater influent.
• To assess the reliability and correlation of the microwave sensor's measurements against established laboratory analyses.
• To investigate the relationship between TS measurements and other key wastewater parameters (e.g., conductivity, nitrogen, BOD7, phosphorus, pH, temperature).

Main Methods:

• Deployment of a microwave on-line sensor to continuously measure the total solids (TS) load in slaughterhouse and sanitary wastewater influent.
• Validation of the sensor's performance through direct comparison with standard laboratory analyses for TS.
• Statistical analysis to determine the correlation between on-line TS measurements and other monitored wastewater parameters.

Main Results:

• The on-line microwave sensor provided measurements comparable to laboratory reference analyses, demonstrating good correlation between the two techniques.
• Total solids (TS) values measured by the microwave sensor showed significant correlation with conductivity, total nitrogen, and biochemical oxygen demand after 7 days (BOD7).
• No significant correlation was found between TS values and phosphorus concentration, pH, or temperature in the studied wastewater streams.

Conclusions:

• On-line microwave sensoring is a reliable and effective method for monitoring total solids (TS) in challenging wastewater influent.
• This technology can provide valuable real-time data for optimizing the operation of municipal wastewater treatment plants (WWTPs).
• The established correlations between TS and other parameters (conductivity, nitrogen, BOD7) can aid in comprehensive wastewater process monitoring and control.