Little Rock, AR Projects
Evaluation of Lake Maumelle and Winona Water Quality
Ozark Point and Wilson Water Treatment Plant Performance Evaluations
Pilot Plant Studies of GAC & Alternative Disinfectants
H2O’C was commissioned to conduct a progressive series of full-scale and pilot-plant studies to evaluate the causes of and assess methods for controlling increasing levels of DBP’s in the Little Rock distribution system.
I. Source Water
- Evaluation of Source Water Quality: Review of Historical Data
- Enhancement of USGS Analytical Program: Metalimnetic Peak, Zooplankton
- Characterization of Organic Matter in Lake Winona and Lake Maumelle
- Seasonal Variations in Source Water Quality
- Effect of Release of Fish Hatchery Water: Organics and nutrient enrichment.
II. LRMWW In-House Laboratory Capability
- Purchase and Use of Epifluorescent Microscope, Gas Chromatograph, TOC Analyzer
- Training of Laboratory Staff in Biological and Chemical Methodologies
- Establishment of Plant and Distribution System Monitoring Program for TOC &THM
- Analytical Methodology for Pilot Plant Operations
III. Pilot Plant Modifications, Operations
- Design and Installation of Filter Media
- Construction of New Manometer Board
- Connection of Wilson Plant Settled Water
- Re-Piping of Ozonated Water Return Line
- Establishment of Pilot Plant Sampling Protocol
- Calculation of Chemical Dosages, Feed Rates and Storage Requirements for Continuous Pilot Plant Operation.
- Addition of GAC Post-Adsorbers: 10, 20 minute EBCT
IV. Pilot Plant Studies
- Filtration Studies: Comparison of Ozark Point, Wilson, Multi-Media and GAC-Capped Filters with respect to turbidity, aluminum, bacteria, TOC, and head loss development.
- Observation of Mud-Ball Formation in Filter Beds
- Pilot Plant Studies: Conventional and Enhanced Coagulation with Alum; Conventional and Enhanced Coagulation with Iron (Ferric Sulfate)
V. Evaluation of Ozark Point and Wilson Plant Performance
- Wilson Plant: Distribution of Coagulant, Modification of Distribution Weirs
- Wilson Plant: Settling of Alum Floc in Flocculation Basins
- Wilson Plant: Sedimentation Basin Effectiveness
- Wilson Plant: Evaluation of Passage of aluminum through Filters, Control for Reduction of aluminum in Filter Effluents
- Wilson Plant: Diurnal Variations in pH, alkalinity, chlorine in Settled and Filtered water. Effect of UV-catalyzed reduction of chlorine on night-time chlorine concentrations, pH and alkalinity; corrosion of filter boxes.
- Effect of Backwash Water Return on TOC of Water in Sedimentation Basins.
- Evaluation of Ozark Point Plant Performance Characteristics.
- Evaluation of Chemical Feed Data: Alum, KMnO4, PAC, and Polyphosphate Feed.
VI. TTHM and HAA Formation in LRMWW Water System
- Location of TTHM Formation Within System
- Effect of Water Temperature on TTHM Formation
- Effect of pH on Removal of Organic Matter
- Rate of Formation of TTHM
- Seasonality of TTHM Formation in Wilson and Ozark Point Treatment Plants
- Long-Term, Intensive Monitoring of TTHM in Distribution System
- Review of Historical Data on Distribution System TTHM
- Evaluation of Data on Haloacetic Acids in LRMWW Water System
VII. Evaluation of Techniques for Controlling D/DBP: Bench-Scale and Pilot Studies
- Source Water TOC Control
- Powdered Activated Carbon, Potassium Permanganate
- Chlorine Dioxide
- GAC Post-Adsorbers and GAC-Capped Filter
VIII. Detailed Recommendations for System Modification and Control
Mr. Gary Hum
Little Rock Municipal Water
10901 Rocky Valley Drive
Little Rock, AR 72212
- Seasonal evaluation of organic matter in Little Rock’s lake water sources
- Full-scale evaluation of performance of Ozark Point and Wilson Water Treatment Plants
- Pilot plant studies of enhanced coagulation; PAC, GAC and KMnO4
- Chlorine dioxide as an alternative disinfectant