Ala. Admin. Code r. 335-6-20-.11
Current through Register Vol. 43, No. 1, October 31, 2024
Section 335-6-20-.11 - Municipal Reclaimed Water Treatment, Limitations, and Monitoring Requirements(1) Class A reclaimed water shall be treated to the secondary treatment levels specified in paragraph (3) of this rule. In addition, the water shall be coagulated, clarified, filtered, and disinfected or treated by an alternate process acceptable to the Department. The Department may require pilot testing or demonstration, or may condition acceptance upon the successful outcome of such testing or demonstration.(2) Class B reclaimed water shall be treated to the secondary treatment levels specified in paragraph (3) of this rule. In addition, the water shall be disinfected to meet the requirements set forth in paragraph (3) of this rule. The Department may require pilot testing or demonstration, or may condition acceptance upon the successful outcome of such testing or demonstration.(3) The Department may require additional treatment, beyond the requirements of this rule, for reclaimed water to be injected through an ASR well. An ASR well shall also be subject to the requirements of chapter 335-6-8, as applicable.(4) The table below summarizes Class A and Class B reclaimed water requirements. Subparagraphs (a) and (b) of this paragraph provide further details regarding the requirements. Class A Reclaimed Water | Class B Reclaimed Water |
Chlorine | No less than 1.0 mg/L entering distribution system. No less than 0.5 mg/L chlorine residual in the distribution system prior to being transferred to storage ponds and/or distributed to customers. | No less than 1.0 mg/L entering distribution system. No less than 0.5 mg/L chlorine residual in the distribution system prior to being transferred to storage ponds and/or distributed to customers. |
E. Coli | Median of no greater than 18 col/100 mL as determined from the last seven days of results. Results of no greater than 34 col/100 mL in any one sample. | Median of no greater than 18 col/100 mL as determined from the last seven days of results. Results of no greater than 34 col/100 mL in any one sample. |
Turbidity | No greater than 3 Nephelometric Turbidity Units (NTUs). | Not applicable |
Nitrates + Nitrites | No greater than 10 mg/L monthly average. | No greater than 10 mg/L monthly average. |
pH | No less than 6.0 S.U. and no greater than 8.5 S.U. | No less than 6.0 S.U. and no greater than 8.5 S.U. |
CBOD5 | No greater than 10 mg/L monthly average. | No greater than 10 mg/L monthly average. |
TSS | Not applicable | No greater than 30 mg/L monthly average. |
Total Nitrogen | Monitoring only | Monitoring only |
Total Phosphorus | Monitoring only | Monitoring only |
(a) Acceptable primary disinfectants are chlorine, chlorine dioxide, Ultraviolet Light (UV), O-zone, or an equivalent process acceptable to the Department. Chlorine is the preferred primary disinfectant. A disinfection application rate must be provided to all Class A and Class B reclaimed water to achieve the following: 1. If chlorine is used as the primary disinfectant, a suitable contact time must be utilized to ensure that the total residual chlorine (TRC) entering the distribution system shall not be less than 1.0 mg/l. Facilities utilizing another disinfectant other than chlorine must add a disinfectant to maintain disinfectant residuals in the distribution system such that the minimum chlorine requirements are met.2. The median number of bacteria of the E. coli group does not exceed eighteen organisms per one hundred milliliters, as determined from the bacteriological results of the last seven days for which analyses have been completed. No sample shall exceed thirty-four organisms per one hundred milliliters in any one confirmed sample; and3. The point of compliance for reclaimed water for E. coli shall be at any point in the system following final treatment and disinfection contact time. It is required that a TRC of 0.5 mg/l be maintained in the distribution system prior to being transferred to storage ponds or distributed to customers.(b) Class A reclaimed water systems shall meet the following turbidity requirements:1. For filtration systems utilizing sand or other granular media, cloth media, or other filtration systems acceptable to the Department, the turbidity shall not exceed three NTU and any water exceeding three NTU shall be automatically rejected. Once diversion has begun, it must continue until the three NTU requirement is met and the operator manually overrides the reject diversion.2. One in-line continuous monitor recording turbidimeter is required for each treatment train after filtration and prior to disinfection.(5)Monitoring Requirements. (a) Reclaimed water shall be sampled and analyzed daily for E. coli unless an alternate frequency is approved or required by the Department. The factors for determining the adequacy or necessity of an alternate frequency include, but may not be limited to, the following: the volume of reclaimed water reused, the disinfection method used, the demonstrated disinfection efficiency and reliability, the point of compliance, or other factors demonstrating that the alternative frequency is protective of public health.(b) TRC shall be monitored daily after chlorination and upon entry to the distribution system. Monitoring in the distribution system shall be conducted monthly unless an alternate frequency is approved or required by the Department. Monitoring locations throughout the distribution system shall be performed at locations acceptable to the Department.(c) Turbidity shall be monitored continuously for all Class A reclaimed water on the filtered water prior to disinfection.(d) Monitoring for pH shall be daily using grab samples or continuous monitoring, and may be increased if not continuous and if deemed necessary by the Department.(e) Monitoring for CBOD5, Total Suspended Solids, Total Nitrogen, Nitrate + Nitrites and Total Phosphorus shall be weekly using composite samples and may be increased if deemed necessary by the Department.(f) Monitoring for other parameters may be required by the Department on a case-by-case basis.(6) Analytical testing on reclaimed water samples collected for the permit application and for permit compliance determinations shall adhere to 40 CFR Part 136 unless otherwise required by the Department.Ala. Admin. Code r. 335-6-20-.11
Adopted by Alabama Administrative Monthly Volume XXXIII, Issue No. 11, August 31, 2015, eff. 9/29/2015.Author: Nicholas Caraway
Statutory Authority:Code of Ala. 1975, §§ 22-22-1 to 22-22-14; §§ 22-22A-1 to 22-22A-16et seq., as amended.