Optimizing Water Reclamation Systems by Automation using Continuous Water Quality Analysis

Transcription

1 Optimizing Water Reclamation Systems by Automation using Continuous Water Quality Analysis Standards Certification Education & Training Publishing Conferences & Exhibits Speakers: Vickie G. Olson, Honeywell Process Solutions 2014 ISA Water / Wastewater and Automatic Controls Symposium August 5-7, 2014 Orlando, Florida, USA

2 Presenter Vickie G. Olson Liquid Analytical Product Consultant Responsible for eastern US, Europe, Asia/Pacific and Africa More than 20 years experience with Water and Wastewater Analysis BS Textile Chemistry, Georgia Tech MBA, Georgia State University 2

3 Presentation Outline Introduction Municipal plant overview and analytical requirements Industrial wastewater plant processes and analytical applications Probe selection considerations Location Maintenance Summary 3

4 Water Reclamation System Analytical Automation Why Important? Meet regulatory requirements Reduce energy consumption Keep bugs alive (if using biological treatment) Optimize chemical use Demand for high quality effluent for downstream use Fewer operators are available for manual testing

5 Reducing Costs through Improved Aeration Efficiency BENEFITS TO WASTEWATER UTILITIES Aeration Costs need management Aeration accounts for 50% to 70% energy usage at WWTPs No other individual component > 15% Many plants have oversized aeration systems due poor design or underflow to plant due to population shift Energy Savings due to Advanced Controls Up to 30-35% typical on blower electrical Typical Case turn down blower hp (e.g., 740 to 550 hp) At $0.07 per kwh At $0.10 per kwh -- save $160,000 per year -- save $230,000 per year

6 Analytical Parameters for WWT Process Control ph ORP TSS MLSS SL DO TOC TDS CL2 ph Oxidation Reduction Potential Total Suspended Solids Mixed Liquor Suspended Solids Sludge Level Dissolved Oxygen Total Organic Carbon Total Dissolved Solids Chlorine Halogens Halogens O3 Ozone 6

7 Municipal Wastewater Treatment Plant Primary and Secondary Treatment ph ph. Effluent or Tertiary Treatment Influent Primary Clarifier Aeration Basin Secondary Clarifier ph, DO Effluent ph ph DO ph ph TSS ORP MLSS ORP TOC TSS TSS TSS/Turbidity ph. ph SL SL Nitrate TDS Phosphate

8 Municipal Wastewater Treatment Plant Tertiary Treatment Options Sand Filters Lagoons Denitrification Dephosphatization Disinfection Turbidity ph DO DO Chlorine/Halogen TSS/Turbidity ORP ORP Ozone Ammonia Phosphate ORP Nitrate TOC for UV 8

9 Industrial Wastewater Treatment Food & Beverage Chemical Pulp & Paper Metals Processing Pharmaceutical Refinery Any Plants with Processes that require wastewater discharge to municipalities or have federal or state permits

10 Industrial Wastewater Treatment: Inlet Inlet & API Separator a c i d b a s e a c i d b a s e Influent 1.pH 1. Confirm wastewater will not have negative impact on equipment API Separator (refining) 1. ph 1. Inlet optimize separation

11 Equalization Tanks a c i d b a s e a c i d b a s e Equalization Tanks -Raw Wastewater 1.DO 2.Conductivity Control homogenization of different flows Control homogenization of different flows -Outlet 3.pH Control quality of equalized wastewater for further treatment

12 Neutralization Units a c i d b a s e a c i d b a s e Neutralization Units 1.pH 2.ORP 1. To control the process & protect biological step from poisoning 2. Cyanide destruct control (metal finishing)

13 Bioreactor Modular fixed-film technology with mixed-media support for immobilized bio-catalysts. Removes higher levels of organics and metal removal from wastewater. ph and TOC

14 Commercial Laundry Bioreactor Treatment Challenge: Limited fresh water supply for industrial laundry drove the need for treatment & recycling wash water to enable production of finished garments UOP

15 Parameters to Consider in Selecting Sensors Range - average operating and extremes Sample temperature and pressure Sample composition Past experience Distance between sensor and analyzer Cleaning requirements

16 Location Locate sensors in representative site cantilevered at least 2 feet from the tank wall. If tank is over 6 feet above ground, a safe system should be set up. If auto-clean/auto-calibration system is installed, locate near pressurized air or water source For remote locations such as lagoons, wireless communication and solar power make process analytical systems easier to monitor.

17 Installation Considerations Sensors should be readily accessible for cleaning, calibration and replacement. Hanging sensors by cables will cause eventual leakage. Plan for communications and power connections 17

18 Auto-Clean/Auto-Cal Installation Drive Unit Analyzer / Transmitter Probe D.O. Analyzer / Transmitter Place ware

19 Keep Wet Store new probes wet that arrive wet, i.e. ph and ORP Set up installation to keep wet If process is intermittent: Remove probe and place in solution Switch sample line to service water, etc.

20 Maintenance - Calibration Calibration frequency is dependent on many factors. Newer technologies may require less frequent calibration or have automatic calibration. Run sample checks with a calibrated portable to detect cleaning requirements. Sample calibrations for ph should be run routinely to give more accurate response in operating conditions. 20

21 Maintenance - Cleaning Soapy water Hot water Acidic solution Alkaline solutions Scrubbing

22 Cleaning Any Solution That Will Not Damage Sensor In Low ph Applications Weak Caustic Solution In High ph Applications Weak Acid Solution

23 Cleaning After cleaning with harsh chemicals the sensor should be completely rinsed. It is a good idea to put it back in the process to equilibrate before attempting either a process or buffer calibration

24 Summary There are multiple factors driving the need to control plant processes with on-line analytical instrumentation Considerations for successful implementation are: Analyzer selection Location Installation Cleaning and Calibration 24