Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/86284
PROJECTS Case study: High Point Water Treatment Plant - Alabama Northeast Alabama Water District (NEAW) services 15,200 connections within 2,052 mile2 in a very large distribution area. Increasing populations expanded the service area and demand even more, creating the need for a larger water treatment facility. To increase capacity and bring water (5,250 km2 ), resulting treatment closer to its residents, NEAW and Constantine Engineering constructed the innovative High Point Water Treatment Plant in 2010 . High Point receives its raw water plant location. Managing DBPs within large ) storage reservoir at the WesTech's SCC has high volume internal solids recirculation and low floc shear, while using less horsepower. Through TOC removal, the High Point Water Treatment Plant has seen reduced DBP production due, in part, to the effectiveness of the SCC. Compared with a conventional clarifier, DBP Reduction DBP indirectly from the Tennessee River. River water is pumped 5 miles (8 km) and over 700 ft (213 m) in elevation to a 4.2 million gal (15,900 m3 distribution areas is difficult at best. Large distribution areas, long chlorine contact times, dead zones, and regrowth contribute to high DBPs. By removing dissolved organic carbon (DOC) in the clarified water, DBPs are minimized. EQUIPMENT SELECTION After completing a comprehensive study, the engineer selected enhanced flocculation clarifiers and membrane filtration, specifically SCCs and UF, as the best method to treat DOC and turbidity. The plant was also designed to allow for the addition of granular activated carbon or powder activated carbon in the future, if needed, for additional total organic carbon (TOC) removal and/or taste and odor reduction. WesTech was contracted to supply the majority of the process equipment for the High Point Plant, thereby maintaining equipment continuity and consolidating process responsibility. Solids Contact Clarifier Quantity Design Flow Size Motor HP Rake Arm Drive: Impeller Drive: Coagulant Dose Range: Avg: 2 units 770 gpm/unit 32 ft square Hydraulic Loading Rate 0.9 gpm/ft2 Basin Detention Time 150 min 0.5 HP 2 HP 11-37 ppm 21 ppm Turbidity UV 254 TOC Color Iron Manganese Temperature TTHM HAA5 MCL Prior Levels Present Levels (µg/L) 80 60 (µg/L) 57 44 (µg/L) 26 26 The need for chemical cleaning of the filters is decreased with the removal of TOC, in turn increasing the efficiency of the membrane filter. AltaFilter™ Membrane Filtration Quantity 2 trains Flow Design Flux Recovery CIP Frequency 60 total modules 1,475 gpm 45 GFD 95% 30 days System has a pore size of 0.01 µm, providing the highest level of pathogen and particulate matter removal available for low-pressure membrane filters. The AltaFilter also consistently produces the highest possible quality filtrate, with greater than 4 log removal of cryptosporidium and giardia. The WesTech AltaFilter UF Membrane CUSTOMER SATISFACTION The new High Point facility has been online since January 2011, and has been a Water Quality Raw Water Range: 11-585 NTU AVG: 24 NTU 0.057 cm-1 2.5 mg/L 10 Pt-Co 0.14 ppm 0.06 ppm 6-80°C After Solids Contact Clarifier 1.0 NTU 0.022 cm-1 1.6 mg/L - Non-Detect 0.01 ppm - After AltaFilter 0.014 NTU 0.018 cm-1 1.6 mg/L 0 Pt-Co Non-Detect Non-Detect - May-June 2012 | Desalination & Water Reuse | 23 | The UF membrane system at High Point WTP The SCC at High Point WTP. great improvement to the NEAW. As seen in Table 4, turbidity and TOC have been reduced to meet or exceed required levels. Water quality has increased and operations and maintenance has been simplified. The community and NEAW alike are pleased with the installation of this new equipment. Operators were especially pleased with the extra level of training provided by WesTech. n Project Location: Henager, Alabama Owner: Northeast Alabama Water District Engineer: Constantine Engineering Contractor: Lambert Inc