Select Water Treatment Additives Discharge Application Instructions

Select Water Treatment Additives Discharge Application Instructions

Select Water Treatment Additives (WTAs) are those commonly used chemical products that are added as conditioners to improve the water quality for use in a system or process, condition and treat the water to make it suitable for discharge, are considered to not adversely affect aquatic life, are a single chemical (i.e., not a mixture of chemicals), and can be regulated through a facility’s National Pollutant Discharge Elimination System (NPDES) permit with a chemical specific water quality-based effluent limit (WQBEL), using a parameter that mitigates the WTA toxicity (i.e., pH limits that mitigate a pH adjusting WTA).

The following chemicals are considered to be Select WTAs and are commonly used disinfectants and dechlorinating agents, flocculants, pH adjusters, water softeners, and oxygen scavengers.

The process to receive approval to use and subsequently discharge Select WTAs to a surface water of the state from a NPDES permitted outfall includes the following:

  1. Connect to MiWaters, our new web-based permitting and compliance database.  Go to your facility site in MiWaters, click on Apps, Requests and Reports, Start New Form, in the search box under form name enter additive, and click begin submission for the Service Request - Select Water Treatment Additive Request Form.  Please note that the permittee or other authorized user/editor must submit forms directly through the facility’s MiWaters page.  A request will not be processed if submitted on an unaffiliated page.
  2. Upon submittal of your request, you will be notified via email that your Select Water Treatment Additive Request has been received and this notification will be your approval.  The Department will review your submission and contact you only if additional information is required. 
  3. Only those Select WTAs included on the Select Water Treatment Additives List are authorized under this process.  The process to receive approval to discharge any WTA not included on the Select Water Treatment Additives List must follow the process outlined under Water Treatment Additive Discharge Application Instructions (Non-Select WTAs).
  4. The facility must already possess a NPDES permit, and the outfall from which the Select WTA will be discharged must already be permitted under the NPDES permit.
  5. The corresponding NPDES limit for the Select WTA must already be included in the NPDES permit for the outfall from which the WTA will be discharged.  Corresponding NPDES limits are included on the Select Water Treatment Additives List.
  6. Required sampling to fulfill NPDES permit requirements must be conducted on effluent discharged from the outfall during a representative time period of Select WTA usage and discharge.

Select Water Treatment Additives List

NOTE: Approval to discharge additives on this list must be obtained by the Water Resources Division prior to use and discharge of the additive.  The corresponding NPDES limit must already be included in the permit for the outfall from which the Select WTA will be discharged.  Additives that contain the following chemicals as a single constituent in the product (plus water) are considered to be Select WTAs.

Table 1: Select Water Treatment Additives - Disinfectants and Dechlorinating Agents

Constituent

Product Type

Corresponding NPDES Limited Parameter

Calcium hypochlorite

Disinfectant

TRC and pH

Sodium hypochlorite

Disinfectant

TRC and pH

Chlorine gas

Disinfectant

TRC and pH

Sodium thiosulfate

Dechlorinating Agent

TRC and pH

Sodium sulfite

Dechlorinating Agent

TRC and pH

Sodium bisulfite

Dechlorinating Agent

TRC and pH

Sodium metabisulfite

Dechlorinating Agent

TRC and pH

 

Table 2: Select Water Treatment Additives - Flocculants

Constituent

Product Type

Corresponding NPDES Limited Parameter

Ferric chloride

Flocculant

pH

Aluminum sulfate (alum)

Flocculant

pH

 

Table 3: Select Water Treatment Additives – pH Adjusters and Water Softeners

Constituent

Product Type

Corresponding NPDES Limited Parameter

Hydrochloric acid (muriatic acid, hydrogen chloride)

pH Adjuster and Water Softener

pH

Phosphoric acid

pH Adjuster and Water Softener

Phosphorus and pH

Carbon Dioxide

pH Adjuster

pH

Sodium Bicarbonate

pH Adjuster

pH

Sodium Carbonate

pH adjuster

pH

Sodium hydroxide

pH Adjuster and Water Softener

pH

Sulfuric acid

pH Adjuster

pH

Nitric acid

pH Adjuster

pH

Citric acid

pH Adjuster

pH

Lime

pH Adjuster

pH

 

Table 4: Select Water Treatment Additives – Oxygen Scavengers

Constituent

Product Type

Corresponding NPDES Limited Parameter

Sodium bisulfite

Oxygen Scavenger

pH and DO

 

If you have questions, please contact:

Jack Farrelly, Aquatic Biologist, Water Quality and Aquatic Nuisance Control Permits Unit, farrellyj1@michigan.gov or 517-599-9943

Darrin McCullough, Aquatic Biologist, Water Quality and Aquatic Nuisance Control Permits Unit, mcculloughd@michigan.gov or 517-242-8647.