Administrative Code

Creating a Report: Check the sections you'd like to appear in the report, then use the "Create Report" button at the bottom of the page to generate your report. Once the report is generated you'll then have the option to download it as a pdf, print or email the report.

Virginia Administrative Code
Title 9. Environment
Agency 25. State Water Control Board
Chapter 790. Sewage Collection and Treatment Regulations
7/8/2020

9VAC25-790-760. Bromochlorination.

A. Disinfection by bromochlorination is accomplished with bromine chloride (BrCl) in a manner similar to chlorine disinfection. Bromine chloride is an equilibrium mixture of bromine and chlorine in both the gas and liquid states. The chemical is highly soluble in water and hydrolyzes to hypobromous (HOBr) and hydrochloric (HCL) acids. Due to the rapid decay of bromine chloride in wastewater, generally there will not be any measurable bromine chloride residuals in the final sewage effluents. Pure bromine chloride is a heavy, fuming, dark, red liquid which is about 20% disassociated into molecular bromine and chlorine.

B. Design. This disinfection process can be considered for treated effluents with BOD5 and suspended solids concentrations of 30 mg/l or less. Prior documentation should be furnished which shows that adequate disinfection of a specific sewage effluent can be obtained with this process.

C. Dose control. Bromochlorination feed equipment capacity shall be based on degree of treatment, flow variations, and other uses in the treatment processes. For disinfection, the capacity shall be adequate to produce the control point residual required in the permit or certificate issued. The dosing capacity of this process for normal domestic sewage should usually be 80% of that recommended in the chlorine dosage Table 7.

1. Bromochlorination equipment and spare parts are essentially the same as similar requirements for chlorination.

2. Gas feeder systems may be used for feed rates less than 500 pounds per day. Direct liquid bromine chloride feed systems should be used for feed rates greater than 500 pounds per day.

D. Features. Where adequate heat is not provided by the vaporizer to prevent condensation, the use of auxiliary heating and insulation shall be provided as necessary.

1. Materials for piping and appurtenances shall be suitable for handling gas, pure liquid or solutions of bromine chloride as appropriate.

2. The required housing shall be the same as for chlorination, as per VOSH requirements.

3. An evaporator shall be provided for all gas feed systems. The equipment should be designed to minimize the time out of service for maintenance. A backup system shall be provided to ensure adequate disinfection for all discharges when the vaporizer is out of service for maintenance. The vaporizer system should provide superheated gas to the inlet of the vacuum-operated bromine chloride feeder.

E. Safety. The requirement for safety shall be the same as for chlorination and should be in accordance with VOSH requirements. A physical barrier shall be provided for the separation of storage areas if bromine chloride and chlorine chemical supply containers and gas cylinders are located in the same room.

F. Monitoring. Facilities shall be included for collecting samples for bromine chloride residual determinations at the five minute contact time control point and for pathogenic bacterial indicator organism determinations following the total contact period. There should be no readily detectable bromine residual within the final effluent.

1. As bromochlorination equipment represents new technology and limited performance data is available for these systems, an initial period of increased sampling frequency and testing requirements for pathogenic bacterial indicators, such as fecal coliform, may be required. The required initial testing program should take place over a period of one year or more under reasonable operating conditions with a minimum sampling frequency of at least once per week.

2. Disinfection of secondary or better quality effluent should consistently maintain a fecal coliform level below 200 per 100 milliliters of sample volume, or the allowable level contained in the certificate or permit issued, whichever is more restrictive.

3. Indicator organism test results should be correlated with other measurements at the time of sampling, including flow rate, effluent suspended solids, bromine dose rate, and residual measurements.

Statutory Authority

§ 62.1-44.19 of the Code of Virginia.

Historical Notes

Former 12VAC5-581-820 derived from Volume 18, Issue 10, eff. February 27, 2002; amended and adopted as 9VAC25-790-760, Virginia Register Volume 20, Issue 09, eff. February 12, 2004.

Website addresses provided in the Virginia Administrative Code to documents incorporated by reference are for the reader's convenience only, may not necessarily be active or current, and should not be relied upon. To ensure the information incorporated by reference is accurate, the reader is encouraged to use the source document described in the regulation.

As a service to the public, the Virginia Administrative Code is provided online by the Virginia General Assembly. We are unable to answer legal questions or respond to requests for legal advice, including application of law to specific fact. To understand and protect your legal rights, you should consult an attorney.