LACSD's Instrumentation Lessons Learned for Control of Biological Nutrient Removal

Presentation Description: The Los Angeles County Sanitation Districts (LACSD) has used online analyzers to measure water quality parameters for research and process control for decades. Analyzers can provide continuous data collection while reducing labor costs. However, equipment can be challenging and require substantial technical knowledge to troubleshoot and maintain. What type, where, and how an analyzer is installed can substantially impact ease of use, data quality, and staff willingness to provide long-term support. With detailed techniques and methods from the perspective of testing and operations, this presentation will summarize:
1. Analyzer benefits
As grab and composite sampling can require substantial labor and processing, analyzers can offer more data points, real-time results, and provide insight for improved process performance.

2. Types
LACSD has worked with several types of analyzers intended for different applications in different parts of treatment processes. The type of analyzer used is important for what is meant to be measured and what part of the process it should be located. For example, ion selective electrode analyzers are likely to perform more favorably in higher concentrations and should be installed in locations likely to see higher concentrations.

3. Installation
Selecting a representative location for avoiding intermittent noise and dead zones is important for obtaining good results. Methods for location selection and troubleshooting from field experience will be shared. A key aspect of installation, particularly those in situ, is mounting hardware, which can improve ease of maintenance. Innovative techniques for mounting analyzers will be detailed.

4. Maintenance
Part of using any analyzer is regular maintenance, which should be considered for full-scale implementation. Detailed in this presentation will be cleaning methods (automated/manual), frequency of cleaning depending on the environmental matrix, and the importance of regular maintenance and equipment service.

5. Interpreting the results/ Calibration
Analyzer results can indicate the status of the sensor (fouled/needs maintenance) or can suggest a change is needed in the process. This presentation will also provide insights on sensor calibration and corrections. Over the years the Districts have discovered many tips and tricks that are not in the manuals, these will be discussed.