DISINFECTANT MONITORING PLAN FOR

___________________________

_________________________________________

_____________, ________, ____________

PWSID #: ______________

Counties Served: ______________

Contact Person: __________________________

Telephone #: _________________________________

System Type: _____________________________

Population Served: _____________________

Source Water Type: _________________________________

Disinfectant: ______________

Treatment Plant Description: ___________________________________________________________________________________________________________________________________________________________________________

Distribution System Description: ___________________________________________________________________________________________________________________________________________________

MONITORING PLAN FOR DISINFECTANTS, DISINFECTION BY-PRODUCTS AND DISINFECTION BY-PRODUCT PRECURSORS

To meet the Maximum Residual Disinfectant Level (MRDL) for Chlorine, the system:

Measures chlorine ___________ daily at the entry point with _________________________ to monitor the finished water. The free chlorine reading is recorded each day on the MOR.

Measures free chlorine in the distribution system each month at the same time as total coliforms are sampled and the results are recorded.

Locations of sampling sites can be found in our Bacteriological Sampling Plan, with monthly distribution samples recorded on the MOR and MRDL is calculated based on an annual average of monthly averages.

The system will calculate compliance with the MCL, MRDL’s and treatment techniques by:

Measuring the free chlorine residual for each routine distribution and, if applicable, each repeat total coliform sample taken during the month.

Determine the monthly average free chlorine disinfectant residual by dividing the sum of the monthly distribution chlorine residuals by the total number of distribution chlorine residual samples taken.

After determining monthly chlorine residual averages for 12 months, divide the sum of the monthly chlorine residual averages by 12 to determine the running annual average. This gives the annual average MRDL value.

If the MRDL value is 4.0 mg/l or less the system is in compliance.

This process must be repeated every quarter after the first year by dropping the first three months of chlorine residual averages and using the past three months. MRDL compliance will be determined every quarter on the past 12 monthly chlorine residual averages.

To meet compliance for disinfection byproducts (DBP), the following locations have been identified as collection sites for TTHMs and HAA5s:

______________________________________ Maximum Residence

This sample represents the makeup of the ___________________________, being identified as having the maximum residence time. The maximum residence time site was selected by evaluation of historical data for free chlorine residual and by estimating the time of travel in the distribution main and tanks

Other locations are not required, but the following average residence sites may be used if needed:

____________________________________

____________________________________

____________________________________

The system will calculate compliance for TTHMs and HAA5s by:

For TTHMs and HAA5s, the system is required to, and will monitor, once per year. The samples will be collected beginning August 2004.

We will take the sum of the total values of the annual TTHM compliance samples and divide by the number of compliance samples to determine the average results for the year.

For annual compliance calculation, add the quarterly results and divide by the number of quarterly TTHM samples.

The same procedure will be used for calculating HAA5 compliance.

If the annual arithmetic TTHM average is 0.080 mg/l or less, and the HAA5 average is 0.060 mg/l or less, the system is in compliance.

TOTAL ORGANIC CARBON (TOC)

To determine if additional treatment is needed, paired TOC samples (raw and treated water) will be taken each month. In addition to the paired TOC samples, the alkalinity of the raw water will be determined at the same time.

To meet compliance for TOC sampling, the following procedures will be incorporated:

TOC samples will be collected from raw and finished water taps only during normal operating conditions, and will not be collected after major storm events, during times while filter backwash recycling is occurring or after any major accidents, spills or bypass events upstream of the raw water intake.

Samples will be collected only in laboratory-prepared TOC sample bottles.

All paperwork that accompanies TOC samples will be properly filled out.

The raw water TOC and alkalinity samples will be collected first.

The residence time (the amount of time that it takes for the raw water to go through the entire treatment process, from raw water to finished water, will be determined. Four hours is normal.

The treated water TOC sample will then be collected next.

TOC samples and completed paperwork will be packaged and sent to the proper laboratory for analysis.

The water system will report the alkalinity of the raw water sample and instruct the laboratory to conduct SUVA analysis on the TOC samples if the required TOC reduction or alternative compliance criteria is not met to determine if the TOC is amendable to coagulation.

Alternate Compliance Criteria

The water system may assign a monthly value of 1.0 when calculating compliance when:

In any month that the system’s treated or source water TOC level is less than 2.0 mg/l.

In any month that a system practicing softening removes at least 10 mg/l of magnesium hardness (as CaCO3).

In any month that the system’s source water SUVA is less than or equal to 2.0 L/mg-m.

In any month that the system’s finished water SUVA is less than or equal to 2.0 L/mg-m.

In any month that a system that is practicing enhanced softening lowers the alkalinity below 60 mg/l (as CaCO3).

TOC removal compliance is based on the following table:

Required Percentage of TOC Removal

Source Water

TOC (mg/L)	Source Water Alkalinity, mg/L as CaCO3
0-60 mg/L	>60-120 mg/L	>120 mg/L *
>2.0 - 4.0	35.0%	25.0%	15.0%
>4.0 - 8.0	45.0%	35.0%	25.0%
>8.0	50.0%	40.0%	30.0%

TOC removal compliance is determined by the running annual average of TOC removals based on the monthly paired samples. Average removals are calculated monthly and these monthly results are averaged after 12 months to determine the running annual average.

The System will Determine Calculations for TOC Removal by using the following formula:

1 – (TOC finished / TOC raw) X 100 = % TOC Removal

Calculation of TOC Compliance:

Refer to TOC Required Percentage Removal table.

Calculate the ratio by dividing the actual percent TOC removal by the required percent TOC removal based on the TOC concentration and alkalinity of the raw water. If the ratio is greater than 1, the compliance is met for the month.

After 12 months of data have been gathered, divide the sum of the monthly ratios by 12 to get the running annual average.

The running annual average MUST be 1.0 or greater to demonstrate compliance.

If the running annual average is less than 1.0, the system will check to see if it can use alternate criteria for compliance.

If the system meets the alternate criteria, it will record the ratio as 1.0 and identify the criteria used on the report form.

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THM Monitoring Plan template

TAUD

2004-01-29

Tony Wyatt

TAUD