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The WTC Notification Form

WTC Notification Form - Additional Information

WTC Notification Form (PDF, 72 KB)

The preferred method of submitting the WTC Notification Form to the Department is by email (PDF version). Submission of Material Safety Data Sheets (MSDS) is discouraged unless the Department specifically requests these.

Toxicity Testing of WTCs

For surface water discharges, aquatic toxicity testing data is required to complete the WTC Notification Form. Submission of acute (48 or 96 hour LC50 or EC50) and/or chronic (7 day NOEC or IC25) test results for at least one vertebrate and one invertebrate species is required. NOECs estimated from acute 48 or 96 hr tests do not qualify as chronic test data and may not be reported as such. All reported test data must represent tests conducted in accordance with current EPA toxicity testing manuals for appropriate species, (See link in the right column of this page under "links leaving DEC's website). If the discharge is to fresh water then only fresh water species should be reported on the form. Likewise for discharges to marine waters.

Following is the list of acceptable species:

  • Freshwater Invertebrates:
    1. Ceriodaphnia dubia (daphnid water flea) - recommended
    2. Daphnia magna (daphnid water flea)
    3. Daphnia pulex (daphnid water flea)
  • Freshwater Vertebrates:
    1. Pimephales promelas (fathead minnow) - recommended
    2. Oncorhynchus mykiss (rainbow trout)
    3. Salvelinus fontinalis (brook trout)
  • Estuarine/Marine Invertebrates:
    1. Mysidopsis bahia (mysid shrimp) - recommended
  • Estuarine/Marine Vertebrates:
    1. Cyprinodon variegatus (sheepshead minnow) - recommended
    2. Menidia beryllina (inland silverside)
    3. Menidia menidia (Atlantic silverside)
    4. Menidia peninsulae (tidewater silverside)

Submitting data for non-aquatic species (e.g., mice, rats, rabbits), dermal studies, etc. is unacceptable, since we are trying to determine toxicity effects in aquatic systems.

If the discharge is to groundwater then WET test data is not necessary unless the groundwater is in close communication with surface water.

Further information concerning WET testing is contained in TOGS 1.3.2 (PDF, 202 KB)

Department Review Procedures

Following is a simplified summary of how Department staff review WTC requests.

Step 1. Completeness

A WTC Notification Form that has been submitted is first reviewed to determine if it is complete. All requested information must be provided, including exact chemical composition and toxicity information. If the form is incomplete then review stops and the applicant is notified. If the form is complete then proceed to Step 2.

Step 2. Toxicity Review

Step 2 only applies to discharges to surface water. If discharge is to groundwater then skip Step 2 and proceed to Step 3.

Toxic-in-Effluent Calculation: If only acute data is provided, the permit writer applies a safety factor of 100 to the lowest value and compares this to the effluent concentration. If acceptable chronic data is provided, the permit writer applies a safety factor of 10 to the lowest value. One purpose of the safety factor is to account for possible differences between test species and species that were not tested but might be more sensitive. If the WTC effluent concentration is less than the calculated toxicity then the WTC "passes" the toxic-in-effluent calculation and proceed to Step 3. If the WTC "fails" the toxic-in-effluent calculation then it must be further evaluated to predict if it could cause toxicity after dilution in the receiving water.

Toxic-in-Receiving-Water Calculation: If the WTC is predicted to be toxic-in-effluent, then a second toxicity evaluation is performed by considering available receiving water dilution. If the WTC "passes" the toxic-in-receiving-water calculation, then proceed to Step 3. If the WTC "fails" the toxic-in-receiving-water calculation it should not be authorized for discharge, then proceed to Step 5.

The Department may consider documentation showing actual WTC degradation/removal prior to discharge and verified using acceptable analytical methods. Such documentation could justify reducing the predicted outfall WTC concentration to a level which results in a "pass" for toxicity. Anecdotal claims of degradation/removal will not be accepted.

Following is an example of the toxicity calculations:
  • Example 1 - Chemical ABC is proposed to be continuously used at a maximum of 10 lbs/d and discharged through a 0.50 MGD (avg) outfall. The calculated effluent concentration is 2.4 mg/l. Acute and chronic toxicity data are provided for acceptable vertebrate and invertebrate species. The lowest toxicity concentration is 20 mg/l for the most sensitive species reported. Applying the safety factor of 10, the "toxic threshold" is predicted to be 2.0 mg/l and the toxic-in-effluent calculation "fails" (2.4 mg/l effluent > 2.0 mg/l toxic threshold). Further toxicity review is required. The receiving stream low flow is 0.19 MGD resulting in a calculated in-stream concentration of 1.7 mg/l. The toxic-in-receiving-water calculation "passes" since the predicted effluent concentration is less than the toxic threshold. No further toxicity review is required.

Applicants should screen WTCs for toxicity before submitting a WTC Notification Form to avoid making requests which are unlikely to be authorized. The toxic-in-effluent calculation is simple to perform. The toxic-in-receiving-water calculation is also fairly simple but it requires that receiving stream dilution be known. This dilution value can often be found in the most recent SPDES permit fact sheet.

Step 3. Technology-Based Requirements

As with any other wastewater discharge, the Department may develop technology based effluent limits, best management practices, or other monitoring requirements for chemicals. If so, the SPDES permit may require modification. In practice, technology-based effluent limits for WTCs are unnecessary in many cases (chlorine is a notable exception). Proceed to Step 4.

Step 4. Water Quality Criteria Evaluation

The WTC ingredients are compared to the criteria in TOGS 1.1.1 to determine if water quality based effluent limits may be necessary. Additionally, any applicable TMDLs or water quality problems are considered during this review. Effluent limits may be established depending on discharge levels and the availability of acceptable analytical methods. If acceptable analytical methods do not exist and an exceedance of water quality criteria is predicted the Department may not be able to authorize the WTC. Proceed to Step 5.

Step 5. Review Decision

The review decision is normally communicated back to the applicant using the WTC Notification Form. Item 18 of the form indicates what the decision is.

If a WTC "fails" due to toxicity the applicant may be able to reduce the dosage to a level which is acceptable for both toxicity and their treatment needs, and modify their request. Otherwise, the applicant can work with the WTC supplier to identify an alternative chemical which is less toxic to use.

Special Case WTC Ingredients

Biocides - Many WTCs are also biocides and must be registered for use in New York State. Otherwise they may not be authorized for use and discharge.

Bromine - This includes bromine chloride, sodium bromide, and brominated hydantoins. These compounds have toxicity comparable to chlorine and their use will typically require a SPDES permit modification to include effluent limits.

Chlorine - Chlorine is very toxic to aquatic life and its use will typically require a SPDES permit modification to include effluent limits.

Dimethyldithiocarbamates - These compounds have been used as precipitation aids and possibly for other purposes. Dimethyldithiocarbamates are very toxic to aquatic life and can combine to form, or break down into, a number of other very toxic chemicals. Analytical methods do not exist to sufficiently assess these discharges. Permittees should seek less toxic alternatives.

Microorganisms - Microorganisms may be added to assist the function of biological treatment systems and for other purposes. The Department does not routinely review the acceptability of discharging microorganisms other than pathogens. The use of pathogenic, dangerous, or genetically engineered organisms is prohibited. Otherwise, a proposed use may proceed without Department review so long as it will not cause or contribute to noncompliance.

Nutrients - Nitrogen (N) and phosphorus (P) compounds may be added to biological wastewater treatment systems which are deficient in nutrients to maintain proper function. Such use may proceed without Department review as the need for nutrients limits would have normally have been evaluated for a biological treatment system discharge in the past. Discretionary use of such WTCs in other systems is generally discouraged tributary to waters with N or P TMDLs, impairments, or related water quality concerns. A permittee may be required to demonstrate that the use and discharge of such WTCs to waters with an N or P problem is necessary and that no acceptable alternatives exist. In some cases, permits should be modified to incorporate appropriate requirements to control these substances. Of course, if the permit already adequately regulates this pollutant then further review is unnecessary and revised use may proceed.

Use of Multiple WTCs

Some permittees use several WTCs at a time. It is possible that the WTCs may be considered to have acceptable toxicity when considered individually but when considered together there may be sufficient justification to require a SPDES permit modification to add whole effluent toxicity testing.

Do all WTC uses require submission of a WTC Notification Form?

WTC use does not require Department review when the chemical is used in a "closed system" where it will not be discharged to waters of the State.

Some WTCs are used by facilities which discharge to municipal sewage collection systems. While Department authorization of such discharges is not required, the facility should follow the authorization requirements of their sewer authority.

As noted above, use and discharge of certain microorganisms and nutrients may not require submission of a WTC Notification Form. If the existing SPDES permit has a limit for the chemical ingredients and no limit modification is sought by the permittee then use can proceed without submission of a form.

  • Example 2 - A facility uses chlorine and has determined that it should increase the chlorine dose to meet anti-fouling requirements. If the facility has an existing chlorine limit in its SPDES permit and can achieve this limit at the higher chlorine dose then a form need not be submitted.

  • Example 3 - A facility uses H2SO4 to adjust the pH of its wastewater and would like to switch to HCl for this purpose. If the facility has an existing pH limit in its SPDES permit and can achieve this limit using the other acid then a form need not be submitted.

This example extends to other simple acids/bases/salts where there is no chemical-specific water quality concern and existing limits are adequate.

  • Example 4 - A facility wishes to switch from one manufacturer of ferric chloride to another. If the WTC composition is the same and the dosage will not increase then a form need not be submitted.

Note that there is no list of "approved" WTCs that are exempt from Department review. Other than the exceptions noted above, WTC discharges require case-by-case review and authorization because of the unique combination of variables at each facility (e.g., usage rate, outfall flow, receiving waterbody flow and classification, presence of other discharges, etc.). Note also that there is no "library" of characteristics for each WTC that would obviate the need for case-by-case submission of ingredient and toxicity information. WTC manufacturers change product names and formulations from time-to-time which makes it impractical to maintain an accurate library.

Trade Secret Information

Some WTC manufacturers may be reluctant to reveal product formulations to the permittee. The WTC Notification Form has been designed so that this can be accomplished by the permittee and manufacturer separately completing sections of the form. Upon request, the Department will maintain confidentiality in accordance with 6 NYCRR Part 750-1.22. Failure to disclose the exact chemical composition to the Department will prevent authorization of a WTC.