Part II. Reclaimed Water Treatment, Standards, Monitoring Requirements and Reuses
9VAC25-740-70. Treatment and standards for reclaimed water.
A. Treatment and standards for reclaimed water are provided in Table 70-A.
Table 70-A Treatment and Standards for Reclaimed Water | |||
1. Level 1 | |||
a. Treatment | Secondary treatment with filtration and higher-level disinfection. | ||
b. Bacterial Standards | (1) Fecal coliform1: monthly geometric mean2 less than or equal to 14 colonies/100ml; corrective action threshold at greater than 49 colonies/100 ml; or | ||
(2) E. coli1: monthly geometric mean2 less than or equal to 11 colonies/100 ml; corrective action threshold at greater than 35 colonies/100 ml; or | |||
(3) Enterococci1: monthly geometric mean2 less than or equal to 11 colonies/100 ml; corrective action threshold at greater than 24 colonies/100 ml. | |||
c. Total Residual Chlorine (TRC)3 | Corrective action threshold at less than 1.0 mg/l4 after a minimum contact time of 30 minutes at average flow or 20 minutes at peak flow. | ||
d. pH | 6.0 – 9.0 standard units | ||
e. Five-day Biochemical Oxygen Demand (BOD5) | (1) BOD5: monthly average less than or equal to 10 mg/l; or (2) Carbonaceous Biochemical Oxygen Demand (CBOD5)5: monthly average less than or equal to 8 mg/l. | ||
f. Turbidity6 | Daily average of discrete measurements recorded over a 24-hour period less than or equal to 2.0 nephelometric turbidity units (NTU); corrective action threshold at greater than 5.0 NTU. | ||
2. Level 2 | |||
a. Treatment | Secondary treatment and standard disinfection. | ||
b. Bacterial Standards | (1) Fecal coliform1: monthly geometric mean2 less than or equal to 200 colonies/100ml; corrective action threshold at greater than 800 colonies/100 ml; or | ||
(2) E. coli1: monthly geometric mean2 less than or equal to 126 colonies/100 ml; corrective action threshold at greater than 235 colonies/100 ml; or | |||
(3) Enterococci1: monthly geometric mean2 less than or equal to 35 colonies/100 ml; corrective action threshold at greater than 104 colonies/100 ml. | |||
c. Total Residual Chlorine (TRC)3 | Corrective action threshold at less than 1.0 mg/l4 after a minimum contact time of 30 minutes at average flow or 20 minutes at peak flow. | ||
d. pH | 6.0 – 9.0 standard units | ||
e. Five-day Biochemical Oxygen Demand (BOD5) | (1) BOD5: monthly average less than or equal to 30 mg/l; maximum weekly average 45 mg/l; or (2) Carbonaceous Biochemical Oxygen Demand (CBOD5)5: monthly average less than or equal to 25 mg/l; maximum weekly average 40 mg/l. | ||
f. Total Suspended Solids (TSS) | Monthly average less than or equal to 30 mg/l; maximum weekly average 45 mg/l. | ||
1After disinfection. 2For the purpose of calculating the geometric mean, bacterial analytical results below the detection level of the analytical method used shall be reported as values equal to the detection level. 3Applies only if chlorine is used for disinfection. 4TRC less than 1.0 mg/l may be authorized by the department if demonstrated to provide comparable disinfection through a chlorine reduction program in accordance with the Sewage Collection and Treatment Regulations (9VAC25-790). 5Applies only if CBOD5 is used in lieu of BOD5. 6Where ultraviolet radiation will be used for disinfection of Level 1 reclaimed water, other turbidity standards may apply in accordance with 9VAC25-740-110 A 2 a. | |||
B. Point of compliance (POC).
1. Reclaimed water produced by reclamation systems and SRSs for reuse shall meet all applicable standards in accordance with this chapter, excluding the turbidity standard for Level 1 treatment, at the POC. The POC for Level 1 and Level 2 treatment shall be after all reclaimed water treatment and prior to discharge to a reclaimed water distribution system. Where chlorination is used for disinfection of the reclaimed water, the POC for the TRC standard shall be the monitoring location specified in 9VAC25-740-80 A 2. The POC for the turbidity standard of Level 1 treatment shall be just upstream of disinfection.
2. Where the department determines that reclaimed water monitoring is required for a system storage facility or a reclaimed water distribution system, the number and location of POCs for these facilities shall be determined on a case-by-case basis and shall be described in the following documents for approval by the department:
a. For system storage facilities other than those considered part of reclaimed water distribution systems, in the operations and maintenance manual of the reclamation system or SRS where the storage facility is located; and
b. For reclaimed water distribution systems, including system storage facilities considered part of these systems, in the reclaimed water management plan pursuant to 9VAC25-740-100 C 1 h.
C. Reclaimed water that fails to comply with the standards shall be managed as follows:
1. Should reclaimed water reach the corrective action threshold (CAT) for turbidity in the standard for Level 1, or for TRC in the standards for Level 1 or 2, whichever applies, the operator of the reclamation system shall immediately initiate a review of treatment operations and data to identify the cause of the CAT monitoring results to bring the reclaimed water back into compliance with the standards. Resampling or diversion shall occur within one hour of first reaching the CAT. Procedures for resampling, operational review and diversion shall be as described in an approved operations and maintenance manual for the reclamation system. If subsequent monitoring results of the resamples collected within one hour of the first CAT monitoring results for turbidity or TRC continue to reach the CAT of the standards, the reclaimed water shall be considered substandard or reject water and shall be diverted to either storage for subsequent additional treatment or retreatment, or discharged to another permitted reuse system requiring a lower level of treatment not less than Level 2 or to a VPDES permitted effluent disposal system provided the reject water meets the effluent limits of the permit. If the reclamation system is unattended, the diversion of reject water shall be initiated and performed with automatic equipment. There shall be no automatic restarts of distribution to reuse until the treatment problem is corrected. Failure to divert the substandard or reject water after one hour of CAT monitoring results shall be considered a violation of this chapter. Upon resuming discharge of reclaimed water to the reclaimed water distribution system for which the CAT was reached, resampling for turbidity or TRC shall occur within one hour to verify proper treatment.
2. Should reclaimed water reach the CAT for bacteria (i.e., fecal coliform, E. coli or enterococci) in the standards for Level 1 or 2, whichever applies, the operator of the reclamation system shall immediately initiate a review of treatment operations and data to identify the cause of the CAT monitoring results to bring the reclaimed water back into compliance with the standards. Procedures for operational review shall be as described in an approved operations and maintenance manual for the reclamation system. Two consecutive bacterial monitoring results that reach the CAT of the standards shall be considered a violation of this chapter.
3. Repeated, although temporary, failure to comply with all other standards by the reclamation system may be considered a violation of this chapter determined by the frequency and magnitude of the noncompliant monitoring results and other relevant factors. Failure to resample after determination that monitoring results are not in compliance with the standards, to make adjustments to the treatment process to bring the reclaimed water back into compliance with the standards, or to divert substandard or reject water in accordance with subdivision 1 of this subsection shall be considered a violation of this chapter.
D. Treatment or standards other than or in addition to the treatment and standards in subsection A of this section may be necessary based on the quality and character of the wastewater to be reclaimed or the intended reuse or reuses of the reclaimed water. Such alternative or additional treatment or standards may be exempt from this chapter unless required by the department to protect public health and the environment.
E. Standards for the reclamation of industrial wastewater shall be determined on a case-by-case basis relative to the proposed reuse or reuses of the reclaimed water and for the purpose of protecting public health and the environment. Industrial wastewater may also be subject to disinfection requirements of Level 1 or Level 2 if the industrial wastewater contains sewage or is expected to contain organisms pathogenic to humans, such as, but not limited to, wastewater from the production and processing of livestock and poultry. The point of compliance for reclamation standards of industrial wastewater shall also be determined on a case-by-case basis.
Statutory Authority
§ 62.1-44.15 of the Code of Virginia.
Historical Notes
Derived from Virginia Register Volume 24, Issue 26, eff. October 1, 2008; amended, Virginia Register Volume 30, Issue 9, eff. January 29, 2014; Errata 30:11 VA.R. 1615 January 27, 2014; amended, Virginia Register Volume 39, Issue 5, eff. November 23, 2022.
9VAC25-740-80. Reclaimed water monitoring requirements for reuse.
A. The monitoring requirements for the standards provided under 9VAC25-740-70 A, are as follows:
1. Turbidity analysis:
a. Analysis shall be performed by a continuous, on-line turbidity meter equipped with an automated data logging or recording device and an alarm to notify the operator when the CAT for turbidity in the standard for Level 1 has been reached. Compliance with the average turbidity standard shall be determined daily, based on the arithmetic mean of hourly or more frequent discrete measurements recorded during a 24-hour period. Monitoring for the turbidity CAT shall be continuous.
b. Should the on-line turbidity meter go out of service for either planned or unplanned repair, the permittee shall be allowed to manually collect samples for turbidity analysis at four-hour intervals up to a maximum of five days. Following the five-day period of repair, continuous, on-line monitoring with a turbidity meter shall resume.
2. Sampling and analysis for residual concentrations of disinfectants, including total residual chlorine (TRC):
a. For Level 1:
(1) Shall be continuous on-line monitoring, equipped with an automated data logging or recording device and an alarm to notify the operator when the CAT for the disinfectant has been reached. For disinfectants other than chlorine, continuous on-line monitoring shall be provided at the point of compliance monitoring. For TRC, continuous on-line monitoring shall be provided at the end of the contact tank or contact period. Monitoring for the TRC CAT shall be continuous.
(2) Should the on-line disinfectant monitoring equipment go out of service for either planned or unplanned repair, the permittee shall be allowed to manually collect samples for disinfectant analysis at four-hour intervals up to a maximum of five days. Following the five-day period of repair, continuous, on-line disinfectant monitoring shall resume.
b. For Level 2, shall be based on the designated design flow of the reclamation system and be the same sampling type and frequency as specified for sewage treatment works in the Sewage Collection and Treatment Regulations (9VAC25-790). For chemical disinfectants other than TRC, monitoring shall be provided at the point of compliance in accordance with 9VAC25-740-70 B. For TRC, monitoring shall be provided at the end of the contact tank or contact period.
3. Sampling for TSS and BOD5 or CBOD5 shall be at least weekly or more frequently based on the designated design flow of the reclamation system, and shall be the same sampling type and frequency as specified for sewage treatment works in the Sewage Collection and Treatment Regulations (9VAC25-790). Compliance with the monthly average TSS and BOD5 or CBOD5 standards shall be determined monthly, based on the arithmetic mean of all samples collected during the month. Compliance with the maximum weekly average TSS and BOD5 or CBOD5 standards shall be determined monthly, using the same procedures applied in the VPDES permit program for point source discharges.
4. Sampling for fecal coliform, E. coli or enterococci:
a. Shall for Level 1, be grab samples collected at a time when wastewater characteristics are most representative of the treatment facilities and disinfection processes for water reuse, and at the frequencies provided in Table 80-A. Compliance with the geometric mean standards for fecal coliform, E. coli, or enterococci shall be determined monthly, based on all bacteriological monitoring results for that month. Monitoring of the CAT for fecal coliform, E. coli, or enterococci shall be based on the bacteriological monitoring results determined for each day a sample is collected.
Table 80-A | |
Reclamation System Designated Design Flow (MGD)(1) | Bacterial Sampling Frequency(2) |
>0.500 | Daily with the ability to reduce to no less than four days per week(3) |
0.050 to 0.500 | Four days per week with the ability to reduce to no less than three days per week(3) |
<0.050 | Three days per week with no reduction allowed |
(1)MGD means million gallons per day. (2)For reclamation systems treating municipal wastewater, bacterial samples shall be collected between 10 a.m. and 4 p.m. to coincide with peak flows to the reclamation system. An exception to this requirement may be approved upon demonstration to the department that peak flows to the reclamation system occur outside this period. (3)Monitoring frequency may be reduced after demonstrating compliance with bacterial standards for Level 1 and adequate correlation between bacterial monitoring results and measurements for surrogate disinfection parameters, such as TRC and turbidity. | |
b. Shall for Level 2, be based on the designated design flow of the reclamation system and be the same sampling type and frequency as specified for sewage treatment works in the Sewage Collection and Treatment Regulations (9VAC25-790). Compliance with the geometric mean standard and monitoring of the CAT for fecal coliform, E. coli or enterococci shall be in accordance with the same procedures specified for Level 1 in subdivision 4 a of this subsection.
5. Samples for pH shall be grab samples collected at least daily. Compliance with the range of the pH standard shall be determined daily based on the pH of the samples.
B. Samples collected for TSS, BOD5 or CBOD5, and fecal coliform, E. coli or enterococci analyses, shall be analyzed by laboratory methods accepted by the department.
C. A reclamation system that produces reclaimed water intermittently or seasonally shall monitor only when the reclamation system discharges to a reclaimed water distribution system, a nonsystem storage facility, or directly to a reuse.
D. Monitoring of reclaimed water held in system storage for a period greater than 24 hours at a reclamation system or SRS may be required by the department where (i) the system storage facility discharges to a reclaimed water distribution system, a nonsystem storage facility, or directly to a reuse; and (ii) conditions exist at the facility to degrade the reclaimed water to a quality failing to comply with applicable minimum reclaimed water standards for the intended reuses of that water. When monitoring of reclaimed water in or from system storage is required, monitoring parameters and frequencies shall be determined by the department on a case-by-case basis.
E. Monitoring other than or in addition to that described under subsection A of this section may be required for treatment of reclaimed water that is provided pursuant to 9VAC25-740-70 D and 9VAC25-740-70 E.
Statutory Authority
§ 62.1-44.15 of the Code of Virginia.
Historical Notes
Derived from Virginia Register Volume 24, Issue 26, eff. October 1, 2008; amended, Virginia Register Volume 30, Issue 9, eff. January 29, 2014; Volume 39, Issue 5, eff. November 23, 2022.
9VAC25-740-90. Minimum standard requirements for reuses of reclaimed water.
A. Minimum standard requirements for reclaimed water shall be determined, in part, by the reuse or reuses of that water. For specific reuses, the minimum standard requirements of reclaimed water are provided in Table 90-A.
Table 90-A Minimum Standard Requirements for Reuses of Reclaimed Water | |||
Reuse Category | Reuse | Minimum Standard Requirements a | |
1. Urban – Unrestricted Access | All types of landscape irrigation in public access areas (i.e., golf courses, cemeteries, public parks, school yards and athletic fields) Toilet flushing b Firefighting or protection and fire suppression b Outdoor reuse (i.e., lawn watering and noncommercial car washing) b Commercial car washes Commercial air conditioning systems | Level 1 | |
2. Irrigation – Unrestricted Access c | Irrigation for any food crops not commercially processed, including crops eaten raw | Level 1 | |
3. Irrigation – Restricted Access c, d, e | Irrigation for any food crops commercially processed | Level 2 | |
Irrigation for nonfood crops and turf, including fodder, fiber and seed crops; pasture for foraging livestock; sod farms; ornamental nurseries; and silviculture | |||
4. Landscape Impoundments f | Potential for public access or contact | Level 1 | |
No potential for public access or contact | Level 2 | ||
5. Construction e | Soil compaction Dust control Washing aggregate Making concrete Irrigation to establish vegetative erosion control g | Level 2 | |
6. Industrial e | Commercial laundries Ship ballast h | Level 1 | |
Livestock watering i Aquaculture j Stack scrubbing Street washing Boiler feed Once-through cooling k Recirculating cooling towers k | Level 2 | ||
aFor reclaimed industrial wastewater, minimum standards required shall be determined on a case-by-case basis relative to the proposed reuse or reuses. bThese reuses of reclaimed water are prohibited in accordance with 9VAC25-740-50 B 2 where they would involve the distribution of reclaimed water to a one-family or two-family dwelling in order to occur. cReclaimed water treated to Level 1 or 2 may be used for surface irrigation, including spray irrigation. Reclaimed water treated to Level 2 may be used for spray irrigation if the area to be irrigated restricts access to the public and has appropriate setbacks in accordance with 9VAC25-740-170. Reclaimed water treated to Level 1 or 2 may be used for irrigation of food crops eaten raw, excluding root crops, only when there will be no direct contact (or indirect contact via aerosol carry) between the reclaimed water and edible portions of the crop. dFor irrigation with reclaimed water treated to Level 2, the following shall be prohibited unless Level 1 disinfection is provided: 1. Grazing by milking animals on the irrigation reuse site for 15 days after irrigation with reclaimed water ceases, and 2. Harvesting, retail sale or allowing access by the general public to ornamental nursery stock or sod farms for 14 days after irrigation with reclaimed water ceases. eWorker contact with reclaimed water treated to Level 2 shall be minimized. Level 1 disinfection shall be provided when worker contact with reclaimed water is likely. fLandscape impoundments may also be used to store reclaimed water for other subsequent reuses of that reclaimed water, such as irrigation, if included in an inventory of reclaimed water storage facilities submitted to the department pursuant to 9VAC25-740-110 C 15. gIrrigation with reclaimed water to establish vegetative cover at a construction site shall be subject to requirements for irrigation reuse specified in 9VAC25-740-100 C. Continued irrigation of the same site following construction completion shall be subject to the minimum standard requirements of reuse category 1, 2, or 3 contained in this table, determined by the intended reuse of the irrigated site. hReuse of reclaimed water for ship ballast shall also comply with applicable federal regulations and standards governing the use and discharge of ship ballast. iLevel 1 disinfection shall be provided when the reclaimed water is consumed by milking livestock. jLevel 1 disinfection shall be provided for aquaculture production of fish to be consumed raw, such as sushi. kWindblown spray generated by once-through cooling or recirculating cooling towers using reclaimed water treated to Level 2, shall not reach areas accessible to workers or the public unless Level 1 disinfection is provided. See also setback requirements in 9VAC25-740-170 for open cooling towers. | |||
B. For any type of reuse not listed in subsection A of this section, including, but not limited to, indirect potable reuse and below-ground drip irrigation reuse that is newly proposed after October 1, 2008, indirect nonpotable reuse that is newly proposed after January 29, 2014, or any reuse of reclaimed industrial water, including reuses listed in subsection A of this section, the department may prescribe specific reclaimed water standards and monitoring requirements needed to protect public health and the environment. When establishing these requirements for the proposed reuse, the department shall consider the following factors:
1. The risk of the proposed reuse to public health with specific input from the Virginia Department of Health;
2. The degree of public access and human exposure to reclaimed water by the proposed reuse;
3. The reclaimed water treatment necessary to prevent nuisance conditions by the proposed reuse;
4. The reclaimed water treatment necessary for the proposed reuse to comply with this and other applicable regulations of the board;
5. The potential for improper or unintended use of the reclaimed water;
6. Other federal or state laws, regulations and guidelines that would apply to the proposed reuse;
7. The similarity of the proposed reuse to reuses listed in this chapter with regard to potential impact to public health and the environment;
8. Whether the proposed reuse may be excluded or prohibited by 9VAC25-740-50; and
9. For new indirect potable reuse proposals, residence or transport time, mixing ratios, and other relevant information deemed necessary by the department.
C. For any indirect potable reuse (IPR) project that is newly proposed after January 29, 2014, the following are required:
1. A multiple barrier approach shall be used in the planning, design, and operation of the project. Multiple barriers to be employed for the project shall be described in the application for a permit in accordance with 9VAC25-740-100 D.
2. All reclaimed water generated by a reclamation system for IPR shall meet, at a minimum, Level 1 reclaimed water standards, reclaimed water standards developed pursuant to subsection B of this section, and any other standards that may apply, including but not limited to, the Water Quality Standards (9VAC25-260) and total maximum daily loads (TMDLs). Where there is more than one standard for the same pollutant, the more stringent standard shall apply.
3. The public health risks of and the need to impose new or more stringent reclaimed water standards for an IPR project shall be reevaluated with specific input from the Virginia Department of Health upon each renewal of the permit issued to the reclamation system that produces reclaimed water for the project. Factors to be considered in the reevaluation shall include, at a minimum, applicable factors contained in subsection B of this section.
4. All reclamation systems identified as a component of an IPR project in accordance with 9VAC25-740-100 D 1, including pump stations that are part of the reclamation systems, shall meet reliability requirements specified in 9VAC25-740-130 C.
5. VPDES permitted treatment works that have SIUs and provide source water for reclamation and subsequent IPR shall, if required, have a pretreatment program or a program equivalent to a pretreatment program in accordance with 9VAC25-740-150 E.
Statutory Authority
§ 62.1-44.15 of the Code of Virginia.
Historical Notes
Derived from Virginia Register Volume 24, Issue 26, eff. October 1, 2008; amended, Virginia Register Volume 30, Issue 9, eff. January 29, 2014; Volume 39, Issue 5, eff. November 23, 2022.