250 R.I. Code R. 250-RICR-150-10-8.40

Current through November 21, 2024

Section 250-RICR-150-10-8.40 - Technology Assessment Protocol Methodology

A. The objectives of this protocol are to characterize, with a reasonable level of statistical confidence, an emerging technology's effectiveness in removing pollutants from stormwater runoff and to compare test results with proponents' claims.

B. Primary treatment level designation is granted based on the information submitted and best professional judgment. Submitting the appropriate amount of data does not guarantee that primary treatment designation will be given. Decisions are based on system performance and other factors such as maintenance burden, operation, and integrity. Technologies not granted primary treatment will automatically be considered as pretreatment or secondary treatment.

C. Quality Assurance Plan: Before initiating testing, a QAP must be prepared based on this protocol. The QAP must be submitted for review before conducting field tests. The QAP must specify the procedures to be followed to ensure the validity of the test results and conclusions. The QAP must specify the name, address, and contact information for each organization and individual participating in the performance testing. Include project manager, test site owner/manager, field personnel, consultant oversight participants, and analytical laboratory that will perform the sample analyses. Identify each study participant's roles and responsibilities and provide key personnel resumes. In addition, provide a schedule documenting when the vendor's equipment will be installed, the expected field testing start date, projected field sampling completion, and final project report submittal.

D. Field Testing and Site Characterization: Sites must provide influent concentrations typical of stormwater for those land use types for the technology's intended applications. National median stormwater concentrations contains about 43, 49, 81, and 99 mg/L TSS for commercial, residential, industrial, and freeway land use classifications respectively (Pitt, R. E., Maestre, A., and Center for Watershed Protection. 2005. The National Stormwater Quality Database, version 1.1. USEPA Office of Water, Washington, D.C.). Include the following information about the test site:

1. Field test site catchment area, tributary land uses, (roadway, commercial, high-use site, residential, industrial, etc.) and amount of impervious cover;

2. Description of potential pollutant sources in the catchment area;

3. Baseline stormwater quality information to characterize conditions at the site. For sites that have already been developed, it is recommended that the investigator collect baseline data to provide a sizing basis for the practice, and to determine whether site conditions and runoff quality are conducive to performance testing;

4. Site map showing catchment area, drainage system layout, and treatment practice and sampling equipment locations;

5. Catchment flow rates (i.e., water quality design flow, 1-year, 10-year, and 100-year peak flow rates) at 15-minute and 1-hour time steps as provided by an approved continuous runoff model;

6. Make, model, and capacity of the treatment device, if applicable;

7. Location and description of the closest receiving water body;

8. Description of bypass flow rates and/or flow splitter designs necessary to accommodate the treatment technology;

9. Description of pretreatment system, if required by site conditions or technology operation; and

10. Description of any known adverse site conditions such as climate, tidal influence, high groundwater, rainfall pattern, steep slopes, erosion, high spill potential, illicit connections to stormwater catchment areas, industrial runoff, etc.

E. Stormwater Data Collection Requirements: The stormwater data and event requirements are provided in the table in § 8.40(F) of this Part to assist in developing the sampling plan.

F. Stormwater Data Collection Requirements

Item	Stormwater Data Collection Requirement
1	Water level in practice shall be continuously recorded throughout the field testing program, including non-sampled storms and non-rainfall days.
2	Range of recorded water levels shall extend below normal, low flow or dry weather level in practice to above treatment capacity.
3	Recorded water levels shall be plotted along with rainfall.
4	Include a description of each maintenance task performed, reason for maintenance, quantities of sediment removed, and a discussion of any anomalous, irregular, or missing maintenance data.
5	To determine practice's required maintenance interval, the minimum duration of the overall field testing program shall be 1 year beginning at installation, commissioning or the beginning of the removal rate testing, whichever is greater.
6	Storm event must have a minimum total rainfall depth of 0.1 inches.
7	Inter-event dry period between storms shall begin when runoff from prior storm ceases.
8	Minimum of 20 storms sampled, although 25 or more are recommended.
9	Storms do not need to be consecutive.
10	Peak runoff of at least 3 storms shall exceed 75% of the practice's capacity.
11	Minimum total rainfall for all storms sampled shall be 15 inches.
12	Minimum number of samples collected shall be 10 for storms lasting longer than 1 hour or more.
13	Minimum number of samples collected shall be 6 for storms lasting less than 1 hour.
14	Samples shall be taken over time to cover a minimum of 70% of total runoff volume.
15	Rainfall shall be recorded continuously during events with max time interval of 5 minutes for runoff collection based on time and max rainfall interval of 0.01 inches for runoff collection based on volume.
16	Rainfall shall be recorded throughout the sampling program.
17	Rainfall from non-sampled events can be recorded with same gauge or obtained from a nearby gauge provided that gauge has minimum recording interval of 1 hour.
18	Maximum 15 minute rainfall intensity shall be 5 inches/hour.
19	Maximum total rainfall shall be 3 inches.
20	1 storm sampled may exceed previous two requirements.

G. Stormwater Field Sampling Procedures

1. Sampling methods: Collect samples using automatic samplers, except for chemical constituents that require manual grab samples. Use teflon tubing if samples will be analyzed for organic contaminants. To use automatic sampling equipment for insoluble total petroleum hydrocarbon/oil, a determination is needed that any total petroleum hydrocarbon/oil adherence to the sampling equipment is accounted for and meets QA/QC objectives. This determination requires support with appropriate data. The responsible project professional should certify that the sampling equipment and its location would likely achieve the desired sample representativeness, aliquots, frequency, and compositing at the desired influent/effluent flow conditions. The following three sampling methods have been identified for evaluating whether new treatment technologies will meet the stormwater treatment goals:

a. Automatic flow-weighted composite sampling. Collect samples over the storm event duration and composite them in proportion to flow. This sampling method generates an event mean concentration and can be used to determine whether the treatment technology meets the pollutant removal goals on an average annual basis. For this method, samples should be collected over the entire runoff period. The greater the number of aliquots and storm coverage the greater the confidence that the samples represent the event mean concentration for the entire storm.

b. Discrete flow composite sampling.

(1) For this method, program the sampler to collect discrete flow-weighted samples. Combine samples representing relatively constant inflow periods to assess performance under specific flow conditions. The monitoring approach must also address the effect of lag time within the practice that would affect the comparability of influent and effluent samples paired for purposes of evaluating a particular flow rate. One way to achieve this is to set the flow pacing so that each discrete sample bottle fills when the total runoff volume passing the sampler is equal to 8 times the treatment unit's detention volume. Other ways to account for lag time may also be considered.

(2) Proponents can use this method to determine whether the treatment technology achieves the pollutant removal goals at the design hydraulic loading rate. For this method, collect samples over a flow range that includes the manufacturer's recommended treatment system design flow rate. Sample other flow ranges if needed to characterize the efficiencies of the practice over a reasonable range of hydraulic loading rates. Distribute samples over a range of flow rates from 50-150 % of the practice's design loading rate. This technique is necessary for practices where the influent and effluent flowrate are nearly equal because the system does not control the effluent flowrate. This technique is required to verify how the practice functions at varying flowrates.

c. Combination method. For flow-through practices, proponents can use a combination of the above two methods to evaluate treatment goals. For the combination method, collect discrete flow composite samples as allowed during a single storm event and process for analysis. Composite the remaining bottles in the sampler into a single flow-weighted composite sample to capture the entire runoff event for analysis. Mathematically combine the results from the discrete flow composite samples and the single flow-weight composite sample to determine the overall event mean concentration.

2. Sampling locations

a. Provide a site map showing all monitoring/sampling station locations and identify the equipment to be installed at each site. To accurately measure system performance, samples must be collected from both the inlet and outlet from the treatment system. Sample the influent to the treatment technology as close as possible to the treatment practice inlet. To ensure that samples represent site conditions, design the test site so that influent samples can be collected from a pipe that conveys the total influent to the unit. To avoid skewing influent pollutant concentrations, sample the influent at a location unaffected by accumulated or stored pollutants in, or adjacent to, the treatment practice.

b. Influent, effluent, and bypass sampling shall be conducted upstream and downstream of any practice diversions and/or bypass so that the entire sampled storm runoff can be included in sampling. In some instances bypass sampling may not be possible.

c. Sample the effluent at a location that represents the treated effluent. If bypass occurs, measure bypass flows and calculate bypass loadings using the pollutant concentrations measured at the influent station. In addition, be aware that the settleable or floating solids, and their related bound pollutants, may become stratified across the flow column in the absence of adequate mixing. Collect samples at a location where the stormwater flow is well-mixed.

3. Sampler installation, operation, and maintenance. Provide a detailed sampling equipment description (make and model) as well as equipment installation, operation, and maintenance procedures. Discuss sampler installation, automatic sampler programming, and equipment maintenance procedures. Install and maintain samplers in accordance with manufacturer's recommendations. Indicate any deviations from manufacturer's recommendations. Provide a sampling equipment maintenance schedule. When developing the field plan, pay particular attention to managing the equipment power supply to minimize the potential for equipment failure during a sampling event.

4. Flow monitoring. Measure and record flow into and out of the treatment practice on a continuous basis over the sampling event duration. The appropriate flow measurement method depends on the nature of the test site and the conveyance system. Depth-measurement practices and area/velocity measurement practices are the most commonly used flow measurement equipment. For offline systems or those with bypasses, measure flow at the bypass as well as at the inlet and outlet. Describe the flow monitoring equipment (manufacturer and model number), maintenance frequency and methods, and expected flow conditions at the test site. For offline flow, describe the flow splitter that will be used and specify the bypass flow set point. Identify site conditions, such as tidal influence or backwater conditions that could affect sample collection or flow measurement accuracy. Flow is typically logged at a 5-minute or shorter interval, depending on site conditions.

5. Rainfall monitoring. Measure and record rainfall at 15-minute intervals or less during each storm event from a representative site. Indicate the type of rain gauge used, provide a map showing the rain gauge location in relation to the test site, and describe rain gauge inspection and calibration procedures and schedule. Install and calibrate equipment in accordance with manufacturer's instructions. At a minimum, inspect the rain gauge after each storm and if necessary, maintain it. In addition, calibrate the gauge at least twice during the field test period. If the onsite rainfall monitoring equipment fails during a storm sampling event, use data from the next-closest, representative monitoring station to determine whether the event meets the defined storm guidelines. Clearly identify any deviations in the Technical Evaluation Report, required pursuant to § 8.40(I) of this Part. Nearby third party rain gauges may only be used in the event of individual rain gauge failure and only for the period of failure. If third party rain gauges are used to fill in data gaps, establish a regression relationship between site and third party gauges and use the regression equation to adjust the third-party data to represent site rainfall when needed.

6. Sampling for TSS, Suspended Sediment Concentration, Nutrients, and Bacteria

a. Standardized test methods should be used.

b. This protocol defines TSS as matter suspended in stormwater, excluding litter, debris, and other gross solids.

c. Sampling for nutrients will include dissolved inorganic nitrogen, total Kjeldahl Nitrogen, total nitrogen (TN), soluble reactive phosphate (orthophosphate), and total phosphorous.

d. Sampling for bacteria will include Total Coliform, Enterococci, and Escherichia coli.

e. It is understood that sampling and analyses for nutrients and bacteria can be problematic for 6-hour holding times with anything other than grab samples. Automated samplers will need to maintain sample storage at 1-4 °C.

f. To determine percent reduction, the samples must represent the vertical cross section (be a homogeneous or well-mixed sample) of the sampled water at the influent and the effluent of the practice. Select the sampling location and place and size the sampler tubing with care to ensure the desired representativeness of the sample and the stormwater stream. Performance goals apply on an average annual basis to the entire annual discharge volume (treated plus bypassed).

g. Accumulated Sediment Sampling Procedures

(1) Measure the sediment accumulation rate to help demonstrate facility performance and design a maintenance plan. Practical measurement methods would suffice, such as measuring sediment depth, immediately before sediment cleaning and following test completion. Particle size distribution analyses are determined using wet sieving and hydrometer.

(2) Use several grab samples (at least four) collected from various locations within the treatment system to create a composite sample. For QA/QC purposes, collect a field duplicate sample. Keep the sediment sample at 4 degrees centigrade during transport and storage prior to analysis. If possible, remove and weigh (or otherwise quantify) the sediment deposited in the system. Quantify or otherwise document gross solids (debris, litter, and other particles). Use volumetric sediment measurements and analyses to help determine maintenance requirements, calculate a total sediment mass balance, and determine if the sediment quality and quantity are typical for the application.

7. Sampling for Particle Size Distribution

a. To meet the solids removal goals, treatment technologies must be capable of removing TSS across the size fraction range typically found in urban runoff. Field data show most TSS particles are silt sized particles. Particle size distribution analyses must be performed for 3 paired events per year for influent, effluent, and accumulated residual sediments at the end of the monitoring period. Comparisons of particle size distribution in the influent and effluent and the accumulated residual sediments will demonstrate the particle range of sediments removed and un-removed. Particle size distribution data can also provide information regarding total solids transport during a storm.

b. Of the analytical procedures available, the Coulter Counter (Model 3) and the laser-diffraction method are used for samples obtained by auto-sampler and for measuring smaller particles. Sieving can only be used to quantify large volume samples with sediment volumes typically in excess of 500 grams. Due to the potential differences in precision among analytical procedures, use the same analytical apparatus and procedure for each evaluation test program. A recommended particle size distribution analytical procedure using laser diffraction instrumentation and sieve analysis is included. It must be recognized that particle size distributions obtained by optical measure (laser diffraction and Coulter Counter) will have limited direct comparison with sieving and hydrometer analysis.

H. Field Quality Assurance and Quality Control. Field QA/QC should include the elements listed below:

1. Equipment calibration: Describe the field equipment calibration schedule and methods, including automatic samplers, flow monitors, and rainfall monitors.

2. Recordkeeping: Maintain a field logbook to record any relevant information noted at the collection time or during site visits. Include notations about any activities or issues that could affect the sample quality. At a minimum, the field notebook should include the date and time, field staff names, weather conditions, number of samples collected, sample description and label information, field measurements, field QC sample identification, and sampling equipment condition. Also, record measurements tracking sediment accumulation. In particular, note any conditions in the tributary basin that could affect sample quality. Provide a sample field data form in the QAP.

3. Laboratory Quality Assurance Procedures: Laboratories performing stormwater sample analysis must be certified by a national or state agency regulating laboratory certification or accreditation programs. Report results in the Technical Evaluation Report or use level designation application. Include a table with the following:

a. Analyte;

b. Sample matrix;

c. Laboratory performing the analysis;

d. Number of samples;

e. Analytical method (include preparation procedures as well as specific methods especially when multiple options are listed in a method); and

f. Reporting limits for each given analytical method (include the associated units).

4. Data Management Procedures: Include a quality assurance summary with a detailed case narrative that discusses problems with the analyses, corrective actions if applicable, deviations from analytical methods, QC results, and a complete definitions list for each qualifier used. Specify field/laboratory electronic data transfer protocols (state the percent of data that will undergo QC review) and describe corrective procedures. Indicate where and how the data will be stored.

5. Data Review, Verification, and Validation

a. Describe procedures for reviewing the collection and handling of the field samples.

b. Establish the approach that will be used to determine whether samples meet all flow sampling and rainfall criteria.

c. Validation requires thoroughly examining data quality for errors and omissions. Establish the process for determining whether data quality objectives have been met. Include a table indicating percent recovery and relative standard deviation for all QC samples. Determine whether precision and bias goals have been met. Establish a procedure to review reporting limits to determine whether non-detected values exceed reporting limit requirements.

d. Analyze all data for statistical significance.

I. Technical Evaluation Report

1. After testing has been completed, submit a Technical Evaluation Report to DEM or CRMC. The Technical Evaluation Report supports the technologies ability to obtain a primary treatment level designation. The Technical Evaluation Report must contain performance data from a minimum of 1 test site, and a statement of the QAP objectives including the vendor's performance claims for specific land uses and applications. A prescriptive reporting approach is provided to insure completeness of reporting and to facilitate an effective and rapid review. The framework is listed below.

a. Summary: Executive Summary with rated performance rating, Study Summary, Data Collection Summary;

b. Definitions;

c. Site Conditions: longitude, latitude, land cover type, land use activities, site conditions, site elevations and slopes, location of sampling equipment, location of on-site stormwater collection system, and a description of any upstream BMPs;

d. Technology Description:

(1) The specific device used (model number, size, operating rate or volumetric flow rate);

(2) Functionality of treatment mechanisms including pretreatment and bypass requirements;

(3) Physical description: engineering plans, site installation requirements;

(4) Sizing methodology used for test: either manufacturers sizing methodology or approving agency specific sizing requirements (flows, volumes, runoff depth, etc.); and

(5) Maintenance procedures.

e. Test Methods and Procedures:

(1) Particle size for influent, effluent, and residuals, mass based, concentration based;

(2) Water quality parameters monitored;

(3) Data Quality Objectives, QA methods, and measurement accuracy for the observations;

(4) Measuring instruments, sampling frequency, and sampling program information; and

(5) Sampling Locations and Peak Concentration Timing.

f. Testing and Sampling Event Characteristics:

(1) Storm date, depth, antecedent dry period, intensity, duration, season, type of runoff (precipitation, snowmelt, groundwater, etc.);

(2) Number of influent and effluent aliquots; storm volume, % storm treated influent, effluent, peak flow rate, calculation of peak reduction and lag coefficients, number of storms exceeding design criteria;

(3) Comparisons with Data Quality Objectives;

(4) System timeline (start and completion, sample events, rainfall events, maintenance occurrence); and

(5) Water level within system and rainfall for testing duration.

g. Performance Results and Discussion:

(1) Event mean concentrations for influent and effluent with summary statistics (N, mean, median, coefficient of variation, standard deviation, one - tailed sign t-test);

(2) Detection limits and confidence intervals;

(3) Performance metrics: removal efficiency for event mean concentration and mass loads, efficiency ratio;

(4) Statistical Evaluation: time series plot, box and whisker with confidence intervals, effluent probability method, linear regression;

(5) Solids characterization: influent, effluent, residuals particle size analysis;

(6) Accumulated mass reductions;

(7) Individual Storm Reports with event characteristics (§§ 8.40(I)(1)(f) ((1)) and ((2)) of this Part), combination event hydrograph and hyetograph with sample times; system performance characteristics (§§ 8.40(I)(1)(g) ((1)) through ((3)) of this Part), monitoring details;

(8) Quality Assurance, rejection criteria and rejection summary; and

(9) Maintenance findings: discussion on recommended maintenance schedules.

h. Conclusions, performance claims, and limitations;

i. Appendices: raw data and credentials; and

j. Third Party Review. The testing and reporting, if not performed by an independent professional third party, must be reviewed.

2. Confidential Information Submitted by the Applicant

a. Certain records or other information furnished in the Technical Evaluation Report may be deemed confidential. In order for such records or information to be considered confidential, the proponent of such technology must certify that the records or information relate to the processes of production unique to the manufacturer, or would adversely affect the competitive position of such manufacturer if released to the public or to a competitor. The proponent must request that such records or information be made available only for the confidential use.

b. To make a request for confidentiality, clearly mark only those pages that contain confidential material with the words "confidential." Include a letter of explanation as to why these pages are confidential. A notice will be sent granting or denying the confidentiality request.

3. Treatment Efficiency Calculation Methods

a. Calculate several efficiencies, as applicable. Consider lag time and steady-state conditions to calculate loads or concentrations of effluents that represent the same hydraulic mass as the influent. State the applicable performance standard on the table or graph.

b. For technologies sized for long residence times (hours versus minutes), the proponent must consider cumulative event mean performance of several storms, wet season or annual time periods. For short residence times (several minutes), event mean comparisons are recommended.

c. Method #1: Individual storm reduction in pollutant concentration. The reduction in pollutant concentration during each individual storm calculated as:

Click here to view

Where

A = flow-weighted influent concentration

B = flow-weighted effluent concentration

d. Method #2: Aggregate pollutant loading reduction. Calculate the aggregate pollutant loading removal for all storms sampled as follows:

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Where

A = (Storm 1 influent concentration) * (Storm 1 volume) + (Storm 2 influent concentration) * (Storm 2 volume) +. (Storm N influent concentration) * (Storm N volume)

B = (Storm 1 Effluent concentration) * (Storm 1 volume) + (Storm 2 effluent concentration) +.(Storm N effluent concentration) * ( Storm N volume)

Concentrations are flow-weighted and flow = average storm flow or total storm volume (vendor's choice)

e. Method #3: Individual storm reduction in pollutant loading. Calculate the individual storm reduction in pollutant loading as follows:

Click here to view

Where

A = (Storm 1 influent concentration) * (Storm 1 volume)

B = (Storm 1 effluent concentration) * (Storm 1 volume)

250 R.I. Code R. 250-RICR-150-10-8.40

Amended effective 11/13/2018