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NORTH COLLIER REGIONAL WATER TREATMENT PLANT

PLANT NAME AND ADDRESS

North Collier Regional Water Treatment Plant
8005 Vanderbilt Beach Road Extension
Postal Address:
3301 E. Tamiami Tr., Bldg H
Naples, Fl 33104
TEL: 941- 352-7001
FAX: 941- 352-7020 Contact Person: Randy Garay, Production Superintendent
Plant's Web Page: http://www.co.collier.fl.us/CollierWater/serv02.htm
EMAIL:breeder@mediaone.net

CONSULTANT
Boyle Engineering Corporation
California Corporate Offices
1501 Quail St.
Newport Beach, CA 92660
TEL: 949- 476-3300
Contact Person: Dan Boyd or Tom Maddock
WEB PAGE: http://www.boyleengineering.com/

EQUIPMENT AND MEMBRANE SUPPLIER

Hydranautics
401 Jones Road
Oceanside, CA 922054
TEL: 760-901-2500
FAX: 760-901-2578
1-800-CPA-PURE
Contact Person: Mark Wilf, PhD
Technical Market Support Director
EMAIL: mwilf@hydranautics.com
WEB PAGE: http://www.hydranautics.com

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SUMMARY DATA
Startup Year1993
ProcessNF/RO
Capacity (MGD)12; 8MGD BWRO being added
Recovery Rate (%)90
Pretreatmentsulfuric acid, anti-scalant, cartridge filtration
Post-Treatmentdegasification
Feed Water Compositionsignificant hydrogen sulfide
Product Water CompositionTDS = 196 mg/L; ph = 8.05
Concentrate Compositionprecipitated sulfides
Concentrate Disposalinjection well



COSTS*
CAPITAL COST ($000)O & M COSTS ($000)
  
Building Electric Power 307
Plant Equipment Steam 
Wells or feed intake O&M Personnel 575
Product tanks  Parts, Chemicals 600
Brine Disposal  Replacement Membranes    5
Other costs  Not specified 
TOTAL26,000TOTAL1487

*Source: Leitner & Associates, Survey of U. S. Costs and Water Rates for Desalination and Membrane Softening Plants, Water Treatment Technology Program Report No. 24, July 1997: U. S. Bureau of Reclamation Water Treatment Engineering & Research Group


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TREATMENT PROCESS*

*from http://www.co.collier.fl.us/CollierWater/membrane.htm







The North Regional Water Treatment Plant has been designed to utilize a membrane softening process to remove undesirable constituents from raw water supply. As designed the facility is capable of treating 13.3 M.G.D with a 90% recovery rate, producing12 MGD of high quality treated water. Raw water is pretreated with sulfuric acid and scale inhibitor are fed into an inline static mixer upstream of the Facility's 5 micron cartridge prefilters. The pretreated water is then piped to the indiviual membrane trains. High pressure pumps located at each train boosts the raw feedwater supply pressure from and average of 20 p.s.i to approximately 150 psi providing the driving force to overcome the osmotic pressure. Water that has passed through the membrane is referred to as permeate. Permeate is collected and piped to the degasifiers for further treatment. The minerals removed by the membranes are contained in a concentrated solution called concentrate or reject. The solution is pumped into one of the Department's two deep injection wells to a depth of approximately 3,100 feet.




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DEGASIFICATION

As gases are not removed by the membrane process, they remain in the permeate and must be removed by degasification or air-stripping. The Collier County deeper ground water contains significant hydrogen sulfide. Permeate flow from the membrane trains is split and fed into 3 degasifiers. The flow enters each structure near the top into a head box. From there the permeate is distributed, through spray nozzles, uniformly across the top of a packed media, reduing the flow into droplet form increasing the surface area in contact with the air. Simultaneously, the large air volume from the blower system enter the bottom of each degasifier and flows upward through the permeate droplets, further increasing the turbulence. This action exposes the droplet surface to the air flow, allowing the entrapped gases to transfer to the air stream at a transfer rate according to their respective partial pressures. The degasified permeate from each unit collects in a common clear well. Chlorine solution is introduced to the degasified permeate as it enters the clear well at each degasifier. Fluoride solution is also introduced at this point





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STORAGE CAPACITY

Degasified water is collected in the transfer clear well and pumped via installed piping through a static mixer where final treatment chemicals are added to the ground storage tank. The storage tank is used as a reservoir to facilitate smooth plant operation during fluctuating demands on the usage. Sodium hydroxide is added to raise the pH to a non-corrosive level. Poly-phosphate delays the scale formation and ammonia reacts with the Chlorine added to the water to form chloramines which act as a disinfectant. High service pumps move the water through the distribution system to the consumer.

ODOR CONTROL

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The odor control system is a dual-train 2-stage wet process system. The process involves odorous air from the facilities degasifiers entering the first stage scrubber from the bottom, where it is drawn upward through the system's synthetic media exiting from the top into ducting where it is carried to the bottom and enters the bottom of the second stage, again flowing upward through the similar media to the first stage and exiting through a tall stack to atmosphere. The concentration of hydrogen sulfide in the odorous gas is reduced more than 99%. Additionally, chemically treated water is recirculated from the lower sump and sprayed out above the media which acts to increase the air to water interface and causes the hydrogen sulfide to be adsorbed into the water. Sodium hydroxide in the first and second stages. While sodium hypochlorite is added only to the second stage. A continuous overflow of makeup water carries away the precipitated sulfides formed during the chemical reaction and is disposed of directly into the County wastewater system.


INJECTION WELLS


Concentrate or reject from the membrane process is collected in a sump and pumped from there into deep injection wells. There are two wells #1 is 3330 feet deep, #2 in 3200 feet deep.A hydropneumatic tank supplies air pressurized water to packing which interfaces with the deep well aquifer this prevents flow up through the annulus space between the well casing and the discharge piping.



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INJECTION WELL ANALYSIS

The North Collier Regional Water Treatment Plant is a membrane softening plant. In membrane softening treatment the water is separated into two streams, a finished water product called a permeate and a waste stream called the concentrate. The waste stream is disposed by a method called deep well injection. The waste or concentrate stream and its effect on the ground water surrounding the injection well is closely monitored by laboratory personnel. Samples are collected from two monitoring wells located near the injection well. The following analysis is performed on the monitoring wells; as well as, the concentrate stream: pH, temperature, Conductivity, Chloride, Sulfate, Total Dissolved Solids, Total Kjeldahl Nitrogen, Sodium, Fluoride, Gross Alpha, Radium 226 &228. The analysis results are reported to the Florida Department of Environmental Protection.





















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