Virginia Law

A. Water analyses and tests performed at waterworks are conducted for four main purposes: (i) to ensure compliance; (ii) to control water treatment plant operation; (iii) to record water treatment plant performance; and (iv) to provide information for improving water treatment plant performance. Tests designed to control operation shall present evidence that:

1. Each key process, such as mixing, coagulation, sedimentation, filtration, softening, iron and manganese removal, disinfection, and taste and odor control, is effective; and

2. The finished product is clean, is free from objectionable taste and odor, is free from undesirable chemical characteristics, and is safe for human consumption.

B. Testing for regulatory compliance purposes shall use an EPA-approved analytical method found in 40 CFR Parts 141 and 143. Instruments used for operational control purposes must be calibrated in accordance with manufacturer instructions. Calibrations shall be documented in a manner acceptable to the department.

C. Ample laboratory space shall be provided for all required laboratory analyses as specified in 12VAC5-590-760.

D. Required waterworks onsite laboratory analyses. The analyses listed in this subsection are the minimum required. Additional testing may be required by the department.

1. The owner of a waterworks employing chemical coagulation or lime softening in combination with any filtration treatment for turbidity removal or TOC reduction shall provide equipment for the analysis of pH, alkalinity, hardness, turbidity, water temperature, and coagulant dosage. A calibrated electric pH meter must be provided; however, a color comparator may be used as a backup unit. Turbidities must be determined by the use of a calibrated turbidimeter.

2. The owner of a waterworks employing membrane filtration without chemical coagulation or lime softening shall provide equipment for the analysis of turbidity and temperature. Turbidities shall be determined by the use of a calibrated turbidimeter.

3. The owner of a waterworks employing softening only and utilizing chemical precipitation shall provide equipment for the analysis of pH utilizing a calibrated electric pH meter, alkalinity, hardness, water temperature, and chemical dosage for precipitation utilizing a multiple jar stirring machine.

4. The owner of a waterworks employing iron and manganese removal by chemical precipitation shall provide equipment for the analysis of pH, alkalinity, iron, manganese, and water temperature.

5. The owner of a waterworks employing fluoridation shall provide equipment for the analysis of the fluoride ion concentration and water temperature.

6. The owner of a waterworks employing chlorination, rechlorination, chloramination, or rechloramination shall provide equipment for the analysis of the appropriate chlorine residual measurement and temperature.

7. The owner of a waterworks employing iron and manganese removal by ion exchange or softening by ion exchange shall provide equipment for the analysis of iron and manganese.

E. Process control instruments, monitors, gauges, and controllers, including reading, recording, and alarm features, required in Part III, Manual of Practice (12VAC5-590-640 et seq.), shall be maintained fully operational and calibrated in accordance with the manufacturer instructions.

1. The owner of a waterworks employing UV for inactivation credit shall perform UV sensor calibration checks. Calibrations and instrument checks shall be documented in a manner acceptable to the department. All UV sensors shall be calibrated with a reference UV sensor at least monthly. It is also recommended that offline and standby sensors be calibrated at the same time. At least one reference sensor for calibration of online sensors shall be provided. The reference UV sensor shall be calibrated at least yearly at a qualified facility, usually the manufacturer. Ultraviolet transmittance (UVT) analyzer calibration is required when used as a control instrument. The UVT analyzer shall be calibrated at least weekly by comparing online measurements to a benchtop spectrophotometer that is calibrated in accordance with manufacturer instructions. Instead of an online UVT analyzer, a benchtop spectrophotometer may be utilized to determine UV transmittance at least every four hours.

2. The owner of a waterworks employing ozone for inactivation credit shall perform calibration checks on continuous, online ozone residual monitors at least weekly. Inactivation credits for a multiple chamber contactor shall be based on only the chambers that have a measured ozone residual greater than 0.02 mg/L or higher, depending on residual analysis instrumentation.