5 Colo. Code Regs. § 1002-84.21
The provisions of sections 25-8-205(1) and 25-8-308(1)(h) C.R.S., provide the specific statutory authority for the Reclaimed Domestic Wastewater Reuse Control Regulation adopted by the Commission. The Commission has also adopted, in compliance with section 24-4-203(4), C.R.S., the following statement of basis, specific statutory authority, and purpose.
BASIS AND PURPOSE
In March of 1998 the Commission requested that a subcommittee of the Water Quality Forum be convened to consider potential statutory changes to the Colorado Water Quality Control Act ("Act") to address reuse of reclaimed domestic wastewater for landscape irrigation. The joint reuse committee of the American Waterworks Association and the Water Environment Association ("AWWA/WEA") suggested this approach to the Commission in a February 1998 presentation.
In the fall of 1999 the Forum subcommittee made a recommendation that the Colorado Water Quality Control Act be amended to provide the Commission with the authority to promulgate control regulations for the oversight of reuse and to provide the Division with the authority to implement a reuse program. In March of 2000 the general assembly adopted changes to the Act consistent with the subcommittee's recommendations and those changes became effective on July 1, 2000. The subcommittee had been concurrently working on a proposed control regulation that is patterned after the Commission's Biosolids Regulation.
It is the intent of the Commission that this regulation further promote reuse of reclaimed domestic wastewater by providing a comprehensive framework which, when followed, will assure responsible management of operations and a product of a quality compatible with the state's goals of protecting the public health and the environment. The Commission concludes that the provisions of this regulation are economically reasonable considering the economic, environmental and public health costs and impacts of the program.
The Commission, in adopting these regulatory provisions, has limited the scope of the regulation to reuse of reclaimed domestic wastewater for landscape irrigation. The statutory changes do not, on their face, appear to limit the adoption of control regulations to this type of reuse. However, the Commission finds that it is appropriate to limit the scope of the regulation to this aspect of reuse based on the AWWA/WEA recommendation that landscape irrigation should be addressed first as the vast majority of reclaimed domestic wastewater in Colorado is used for this purpose. The Commission will consider regulatory proposals for other types of reuse, such as industrial and agricultural, in future rulemaking hearings where recommendations from a broad spectrum of interests are brought forward. This regulation is not intended for single family residential areas, unless the landscape irrigation areas are commonly owned or otherwise subject to reasonable controls by a neighborhood association to assure application is consistent with the "Conditions for Application" requirements.
The Commission has adopted provisions for the application of reclaimed domestic wastewater at "agronomic rates" with the intent that, once conforming changes are made to the Colorado Discharge Permit System ("CDPS") Regulations, reuse of reclaimed domestic wastewater in accordance with the provisions of this regulation will not be required to obtain a CDPS ground water discharge permit. The Commission does not intend that these regulations be used to limit flexibility to apply additional nutrients to landscaping being irrigated with reclaimed domestic wastewater. The Commission does expect that treaters will, as part of their overall program, inform applicators of the nutrient content of the reclaimed domestic wastewater.
The Commission has found that the use of an approach similar to that defined in the Biosolids Regulation will provide the appropriate level of oversight of reuse operations yet will not unduly burden the entities that are treating and applying reclaimed domestic wastewater to landscape.
The Commission expects that the amount of available information both on the health effects of reclaimed domestic wastewater and on the monitoring of pathogens will increase over the next several years. As a result, the Commission anticipates that the standards may be adjusted as new information becomes available. In the triennial review of this regulation, the Commission will consider any new information that is brought to it concerning pathogenic microorganisms and indicators of the presence or absence of such microorganisms in reclaimed domestic wastewater.
In order to facilitate the use of reclaimed domestic wastewater the "treater" is required to submit a Letter of Intent for each "applicator" to which it will be supplying reclaimed domestic wastewater. This will add a marginal burden to the treater, the entity that is most knowledgeable of the operational and regulatory requirements of the regulation, and will facilitate the responsible use of reclaimed domestic wastewater by entities that are interested in obtaining a viable product. At the same time, the Commission recognizes that the applicator must take responsibility for the proper use of reclaimed domestic wastewater by requiring the applicator to acknowledge receipt of the regulation and their intent to comply therewith. The treater must submit a description of an educational program that, in combination with a proposed plan to oversee the applicator's operation, will provide reasonable assurance of compliance.
The Commission has allowed existing treatment and land application facilities until December 31, 2001, to submit Letters of Intent as they will continue to be regulated under an existing discharge permit. This will give these systems ample time to obtain the required information from their applicators and to develop any additional information on their own facilities. New operations are required to submit Letters of Intent at least 30 days prior to the use of reclaimed domestic wastewater for landscape irrigation. This difference in timing is appropriate as existing facilities have been operating under a different set of regulatory requirements while new operators will be made aware of the requirements of these regulations through the site application approval process for domestic wastewater treatment works.
The Commission has established a 30-day period during which the Division must notify the applicant if the Letter of Intent is incomplete. This period is long enough to allow the Division to complete its review of the application and will not unreasonably delay approval of new systems or the addition of new applicators to existing systems.
The Division has an additional 30 days from the time that the Letter of Intent is determined to be complete to issue the Notice of Authorization. This Commission finds this to be reasonable amount of time as the treater will have already received approval of the site application for the treatment facilities such that a substantial amount of information regarding the system will have already been provided to the Division. The Commission has required a Notice of Authorization to be issued to the treater and each applicator as a means of ensuring that the burden of compliance with the regulations is fairly distributed between the entity providing the reclaimed domestic wastewater and the entity that is putting that water to use.
The Commission has provided the opportunity for the treater, an applicator, or any other aggrieved party to appeal the Division's decision to issue or deny a Notice of Authorization in accordance with the Commission's procedural regulations.
The Commission has not limited the effective period of the Notice of Authorization since changes other than the addition or removal of applicators are expected to be relatively infrequent. This will reduce the burden that renewing Notices of Authorization would have on both the treater/applicator and the Division.
Notices of Authorization will include appropriate monitoring and reporting requirements, reclaimed domestic wastewater standards, and other necessary conditions to ensure the protection of the environment and public health.
Treatment Requirements and Technology-Based Limits
The public health risk of contracting disease from pathogenic microorganisms via exposure to reclaimed domestic water is mitigated by treating wastewater so as to minimize the number of viable pathogenic microorganisms: bacteria, viruses and protozoans. Acceptable public health risk is determined based on an absence of acute gastrointestinal disorders [the most likely type of disease manifestation] in those persons casually exposed to reclaimed domestic wastewater as it is used for surface irrigation of landscaping. Bacterial protection is ensured through the imposition of limits on E.coli , a surrogate organism for determining the potential presence of bacterial pathogens. Viral and protozoan (meaning specifically enteroviruses, and giardia/cryptosporidia parasites) protection is ensured by the imposition of limits for turbidity or total suspended solids, as appropriate.
The Commission has determined that, for unrestricted use of reclaimed domestic wastewater, which has a higher level of public contact, an additional barrier is appropriate to ensure the physical removal of pathogenic organisms that may potentially be present in the wastewater. Therefore, filtration, with associated turbidity limits to ensure the proper operation of the filtration facilities, is required for treaters practicing unrestricted use. Dilution after the filtration process will not provide a positive barrier to pathogenic organisms and is not allowed to be used as a means of complying with limits unless a variance has been obtained. Restricted use, with its much lower potential for public contact, will not require filtration; however, total suspended solids limits consistent with a well-operated secondary treatment system will be required.
Selection of turbidity as a surrogate measure of microbial purity for reclaimed domestic water is valid as an inexpensive means of determining microbial purity with regard to viruses and parasites. There is an absence of data to absolutely define a turbidity at or below which viruses will be absent. Actual turbidity vis-a-vis virus density data illustrate that, when combined with adequate disinfection, an absence of virus plaque forming units can be achieved up to turbidity levels of six NTU (nephelometric turbidity units). (D'Angelo, et al. Pilot Testing to Evaluate Virus Removal and Deactivation , Proceedings of the 1984 Specialty Conference on Environmental Engineering, ASCE/Los Angeles, California, June 25-27, 1984). Similarly, from 1984 to 1991, comprehensive virus testing by Dr. Gerba at the University of Arizona recovered only one plaque forming unit (virus) from the Tucson Water Department's recycled water facility which was operating with a five NTU limit with an actual turbidity averaging between 3.5 and 4.0 NTU. In addition, there are four turbidity levels used among several states that permit the use of reclaimed domestic wastewater for irrigation. A two NTU limit is used in California, Missouri, and Oregon, a three NTU limit is used in Nevada and Texas (30-day average in TX, only), and a five NTU limit is used in Tucson, Arizona. In some cases concomitant virus and parasite (specifically Ascaris lumbricoides) monitoring is required; in other cases virus or parasite monitoring is required with no attention paid to turbidity; and in one case total suspended solids limits are used instead of turbidity limits. There is no consensus among the several states as to the appropriate turbidity limit. Accordingly, the Commission has selected a middle ground for unrestricted use application of reclaimed domestic wastewater. For these systems, calendar-month-average and maximum limits will be set at three NTU and five NTU (not to be exceeded in more than 5% of samples), respectively. No turbidity limits are required for restricted use sites, however, a total suspended solids limit of 30 mg/l is required as a daily maximum. This is deemed a somewhat conservative health risk-based standard given the low potential for contact with reclaimed domestic wastewater in this circumstance. This standard is technologically achievable and the Commission finds it to be appropriate to maintain public confidence in reclaimed domestic wastewater.
Indicator Organism and Limits
The Commission finds that E.coli is the appropriate surrogate indicator organism for determining the potential presence of bacterial pathogens in reclaimed domestic wastewater. The use of E. coli is appropriate primarily based on contemporary research presented in EPA documents summarizing the scientific studies. The most recent scientific data is contained in EPA 440/ 5-84-002 (Ambient Water Quality Criteria for Bacteria - 1986), and Dufour's USEPA study (Dufour, A.P., 1984, Health effects criteria for fresh recreational waters: EPA 600/ 1-84-004 ). The evidence demonstrates that E.coli is the best possible indicator organism because the ratio between pathogens of fecal origin to indicator organisms is most valid for E.coli. Furthermore, E.coli does not regrow once it is released into the ambient environment, where it only survives for about 110 hours.
This is similar to pathogen survival. These criteria do not hold for the traditional indicator organisms such as total and fecal coliforms. (Cabelli, V.J., 1982, Microbial Indicator Systems for Assessing Water Quality, Antonie van Leeuwenhoek, 48:613). In August 1998 US EPA's Office of Science and Technology, on the advice of 14 experts, strongly agreed that E.coli was the only appropriate indicator of fecal contamination.
E. coli also more closely meets and fulfills the traditional and long standing requirements of a surrogate indicator organism for pathogens. These criteria are that an indicator must be a biotype that is prevalent in sewage and excreted by humans and warm blooded animals. It should be present in greater abundance than pathogenic bacteria and the indicator should not be readily capable of proliferation. Ideally the indicator will be more resistant to disinfectants than pathogenic bacteria but will otherwise have a similar ambient survival time with them; and, the indicator should be quantifiable by simple, inexpensive, and rapid laboratory procedures. (Kott, Y., Current Concepts of Indicator Bacteria, BACTERIAL INDICATORS/HEALTH HAZARDS ASSOCIATED WITH WATER, ASTM STP 635, A. W. Hoadley and B. J. Dutka, Eds. American Society for Testing and Materials, 1977, pp 3-13.) E. coli satisfies more of these than any other indicator microorganism recommended by health professionals for fresh water.
There are few epidemiological studies that evaluate the risk of contact with reclaimed domestic wastewater. The Commission has set the limits for E. coli at a level equivalent to that recommended by EPA for swimming beaches in Ambient Water Quality Criteria for Bacteria - 1996 which recently was reaffirmed by EPA in Draft Implementation Guidance for Ambient Water Quality Criteria for Bacteria 1996 (January 2000). While these uses do not directly correlate, the Commission has found this to be an acceptable level of risk particularly when considering that, in establishing the limit for swim beaches, it was assumed that 100 ml of water was ingested. It is reasonable to expect that criteria established to protect swimmers will be more protective of individuals casually exposed to irrigation spray of reclaimed domestic wastewater.
The Commission is establishing a number of conditions for the application of reclaimed domestic wastewater that are intended to provide additional assurance that the health of the public will be protected by minimizing exposure to pathogenic organisms and that runoff from reuse sites will not leave the application site or enter state waters in appreciable amounts. In response to concerns raised regarding how the restricted use conditions of the regulation may be applied to use of reclaimed domestic wastewater for irrigation of golf courses, the Commission anticipates that golf course irrigation that occurs before and after normal operating hours on golf courses that restrict public access during such times will typically satisfy the requirements of subsection 84.8(A) of the regulation.
The Commission finds that compliance oversight of the applicators should be shared by both the Division and the treater. The treater, based on its relationship with the applicator, is in a better position to oversee the operations of the applicator and can generally resolve violations without Division intervention as part of their routine program activities. If these efforts fail to return the applicator to compliance, then the Division will assume the lead role in the compliance oversight efforts.
Due to the limited part of the year during which irrigation takes place, the Commission finds that it is appropriate to limit the submittal of reported information to an annual report. The annual report must include the confirmation that the treater conducted inspections at a representative number of applicator sites as part of the treater's overall compliance assurance program.
The Commission is establishing a provision for variances from any aspect of the regulation but notes that the burden is on the treater to demonstrate that compliance with the regulations is unreasonable in light of the costs to comply.
The Commission recognizes that several reclaimed domestic wastewater systems were constructed and operated prior to the adoption of this regulation. This regulation is not intended to force existing systems to make capital improvements solely for assuring standardization if they accomplish the objectives of this regulation.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-84.21