Decew Falls Water Treatment Plant - 2020 Annual Water Quality Report

The Annual Water Quality Report summarizes the quality of drinking water from the Decew Falls Water Treatment Plant from January 1 to December 31, 2020.

The Decew Falls Water Treatment Plant Summary Report is available for inspection.

Description of Drinking Water System

A conventional surface water treatment plant incorporates the following steps in its purification process:

  • Zebra mussel control
  • Travelling screens
  • Coagulation
  • Flocculation
  • Sedimentation
  • Filtration
  • Disinfection

The plant consists of three separate treatment trains; referred to as Plant 1, Plant 2, and Plant 3, with a combined rated capacity of 227,300 m³/day. Primary disinfection is achieved utilizing Sodium Hypochlorite with Ultraviolet light as enhancement.

The Decew Falls Water Treatment Plant supplies drinking water to the City of St. Catharines, City of Thorold, Town of Niagara-on-the-Lake, and sections of the Town of Lincoln, and is located at 2700 DeCew Rd.

The water treatment chemicals used over this reporting period are:

  • Sodium Hypochlorite
  • Aluminum Sulphate

Monetary Expenses Incurred

To ensure safe and efficient operations, the following major repairs or upgrade projects took place:

  • Plant 3 upgrade design - $590,000
  • Water treatment plant pump upgrades - $53,000
  • Raw water intake - $36,000
  • UV upgrade - $24,000
  • Intake building rehabilitation - $130,000

System infrastructure

  • Virgil Elevated Tank rehabilitation - $46,000
  • Thorold South Elevated Tank rehabilitation - $405,000
  • St. David's Standpipe decommissioning - $50,000
  • Downing transmission main - $75,750
  • St. David's watermain - $18,000

Notices Submitted

Incident Date Parameter Result Unit of Measure Corrective Action Corrective Action Date
NIL          

Water Quality Test Results

Starting in 2018, reported units of measure have been updated to match the units of measure included within Ontario Regulation 169/03 - Ontario Drinking Water Quality Standards.

Reported results that are shown with a less than symbol (<) before the value indicates that the sample result is below the lowest possible detection limit for the parameter.

Microbiological

Total Coliform and E.coli bacteria tests are performed on raw, treated and distributed drinking water.

Microbiological testing done under the Schedule 10, 11 or 12 of Regulation 170/03, during this reporting period.

Test Number of Samples Range of E.Coli or Fecal Results (minimum number)-(maximum number) Range of Total Coliform Results (minimum number)-(maximum number) Number of HPC* Samples Range of HPC Results (minimum number)-(maximum number)
Raw 52 0-4 0-5,000 Not applicable Not applicable
Treated 156 0-0 0-0 156 0-11
Distribution 270 0-0 0-0 270 0-6

*HPC (heterotrophic plate count) bacteria indicate biological growth. They are not harmful to humans and do not represent poor drinking water quality.

Operational

Operational testing done under Schedule 7, 8 or 9 of Regulation 170/03 during the period covered by this Annual Report.

Test Number of Samples Range of Results (minimum number)-(maximum number)
Turbidity 8760 0.017-0.191 NTU*
Chlorine 8760 058-1.57 mg/L
Fluoride Not applicable  

*NTU (nephelometric turbidity units) is a unit that measures the lack of water clarity.

An analyzer continuously monitors the water treatment process and records results on a predetermined frequency. Continuous monitors use 8760 as the number of samples.

Summary of additional testing and sampling carried out in accordance with the requirement of an approval, order or other legal instrument.

Date of legal instrument issued Parameter Date Sampled Result Unit of Measure
Municipal Drinking Water Licence: August 2, 2019 Total Suspended Solids (to environment) Weekly Annual Average 9.0 mg/L
Municipal Drinking Water Licence: August 2, 2019 Free Chlorine Residual (to environment) Weekly 0.00-0.01 mg/L

Inorganics

Inorganic substances include heavy metals and dissolved minerals that may be present in treated drinking water. The following is a summary of inorganic parameters tested or the most recent sample results.

Parameter Sample Date Result Value Unit of Measure Exceedance
Antimony Nov. 4, 2020 <0.0005 mg/L 0
Arsenic Nov. 4, 2020 <0.001 mg/L 0
Barium Nov. 4, 2020 0.018 mg/L 0
Boron Nov. 4, 2020 0.018 mg/L 0
Cadmium Nov. 4, 2020 <0.0001 mg/L 0
Chromium Nov. 4, 2020 0.001 mg/L 0
Lead* - - - -
Mercury Nov. 4, 2020 <0.0001 mg/L 0
Selenium Nov. 4, 2020 0.0013 mg/L 0
Sodium Dec. 9, 2020 9.93 mg/L 0
Uranium Nov. 4, 2020 <0.001 mg/L 0
Fluoride Dec. 9, 2020 0.06 mg/L 0
Nitrite Dec. 9, 2020 <0.05 mg/L 0
Nitrate Dec. 9, 2020 0.28 mg/L 0

*Only for drinking water systems testing under Schedule 15.2; this includes large municipal non-residential systems, small municipal non-residential systems, non-municipal seasonal residential systems, large non-municipal non-residential systems, and small non-municipal non-residential systems.

Summary of lead testing under Schedule 15.1 during this reporting period
(applicable to the following drinking water systems; large municipal residential systems, small municipal residential systems, and non-municipal year-round residential systems)

Location Type Number of Samples Range of Lead Results (min to max) Unit of Measure Exceedance
Plumbing 4 <0.0001 mg/L 0
Distribution 4 <0.0001 mg/L 0

Organics

Trace organic test parameters include: volatile organic substances, pesticides, solvents, dioxins, PCB's, and disinfection by-products. The following is a summary of organic parameters tested or the most recent sample results.

Parameter Sample Date Result Value Unit of Measure Exceedance
Alachlor Nov. 4, 2020 <0.000228 mg/L 0
Atrazine + N-dealkylated metobolites Nov. 4, 2020 <0.0005 mg/L 0
Azinphos-methyl Nov. 4, 2020 <0.000171 mg/L 0
Benzene Nov. 4, 2020 <0.0001 mg/L 0
Benzo(a)pyrene Nov. 4, 2020 <0.00001 mg/L 0
Bromoxynil Nov. 4, 2020 <0.0000195 mg/L 0
Carbaryl Nov. 4, 2020 <0.001 mg/L 0
Carbofuran Nov. 4, 2020 <0.002 mg/L 0
Carbon Tetrachloride Nov. 4, 2020 <0.0002 mg/L 0
Chlorpyrifos Nov. 4, 2020 <0.000171 mg/L 0
Diazinon Nov. 4, 2020 <0.000171 mg/L 0
Dicamba Nov. 4, 2020 <0.000195 mg/L 0
1,2-Dichlorobenzene Nov. 4, 2020 <0.0003 mg/L 0
1,4-Dichlorobenzene Nov. 4, 2020 <0.0003 mg/L 0
1,2-Dichloroethane Nov. 4, 2020 <0.0003 mg/L 0
1,1-Dichloroethylene (vinylidene chloride) Nov. 4, 2020 <0.0003 mg/L 0
Dichloromethane Nov. 4, 2020 <0.001 mg/L 0
2-4 Dichlorophenol Nov. 4, 2020 <0.0002 mg/L 0
2,4-Dichlorophenoxy acetic acid (2,4-D) Nov. 4, 2020 <0.00065 mg/L 0
Diclofop-methyl Nov. 4, 2020 <0.00013 mg/L 0
Dimethoate Nov. 4, 2020 <0.000171 mg/L 0
Diquat Nov. 4, 2020 <0.0002 mg/L 0
Diuron Nov. 4, 2020 <0.006 mg/L 0
Glyphosate Nov. 4, 2020 <0.02 mg/L 0
HAA Running annual average 0.013    
Malathion Nov. 4, 2020 <0.000171 mg/L 0
2-Methyl-4-chlorophenoxyacetic acid (MPCA) Nov. 4, 2020 <0.0065 mg/L 0
Metolachlor Nov. 4, 2020 <0.000114 mg/L 0
Metribuzin Nov. 4, 2020 <0.000114 mg/L 0
Chlorobenzene Nov. 4, 2020 <0.0005 mg/L 0
Paraquat Nov. 4, 2020 <0.0002 mg/L 0
Pentachlorophenol Nov. 4, 2020 <0.0003 mg/L 0
Phorate Nov. 4, 2020 <0.000114 mg/L 0
Picloram Nov. 4, 2020 <0.000091 mg/L 0
Polychlorinated Biphenyls(PCB) Nov. 4, 2020 <0.00006 mg/L 0
Prometryne Nov. 4, 2020 <0.000057 mg/L 0
Simazine Nov. 4, 2020 <0.000171 mg/L 0
THM Running annual average 0.022    
Terbufos Nov. 4, 2020 <0.000114 mg/L 0
Tetrachloroethylene Nov. 4, 2020 <0.0003 mg/L 0
2,3,4,6-Tetrachlorophenol Nov. 4, 2020 <0.0002 mg/L 0
Triallate Nov. 6, 2019 <0.000114 mg/L 0
Trichloroethylene Nov. 4, 2020 <0.0002 mg/L 0
2,4,6-Trichlorophenol Nov. 4, 2020 <0.0002 mg/L 0
Trifluralin Nov. 4, 2020 <0.00014 mg/L 0
Vinyl Chloride Nov. 4, 2020 0.0001 mg/L 0

Any Inorganic or Organic parameter(s) that exceeded half the standard prescribed in Schedule 2 of Ontario Drinking Water Quality Standards.

Parameter Result Value Unit of Measure Date of Sample
Sodium 9.9-16.2 mg/L

Jan. 15, 2020, Feb. 12, 2020, Feb. 26, 2020, March 13, 2020, April 7, 2020, May 6, 2020, May 13, 2020, June 3, 2020, Julu 8, 2020, Aug. 5, 2020, Aug. 19, 2020, Sept. 23, 2020, Oct. 28, 2020, Nov. 4, 2020, Dec. 9, 2020*
*Sample result below half the standard prescribed in Schedule 2 of Ontario Drinking Water Quality Standards

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