FOR REISSUANCE WITH MODIFCATION
Canton Municipal Utilities, Beatties Bluff Wastewater Treatment Facility
Madison County
Canton, Mississippi
Water NPDES No. MS0057517
September 2025

CLASSIFICATION

Municipal Major

DESCRIPTION OF WASTEWATER

Municipal/Domestic Wastewater

PURPOSE OF MODIFICATION

The Permittee is proposing to build a new 4.0 MGD mechanical treatment plant to accommodate the rapid growth of population in the general area. The existing 8 MGD treatment system will also be upgraded. 

DESCRIPTION OF WASTWATER TREATMENT 

Currently wastewater is biologically treated by means of an 8 MGD oxidation ditch treatment facility followed by UV disinfection prior to discharge. The proposed system will be a new 4 MGD oxidation ditch system. The effluents from both systems will be combined prior to UV disinfection. The system will continue to have one effluent discharge point into the Big Black River. The total design flow for the expanded system will be 12 MGD. See Attachment #2 for process schematic. An antidegradation report was submitted for the proposed expansion. 

RECEIVING WATER

Big Black River.  The 7Q10 of the receiving stream is 86.5 cfs. The Big Black River is not listed on the 2024 adopted 303d list for impaired water bodies. The Big Black River currently has Total Maximum Daily Loads (TMDLs) for pH, Sediment, DDP, and Toxaphene. The discharge as permitted complies with the conditions of the TMDLs and will not further contribute to the impairment. The current this along with the facility’s expanded design flow of 12.0 MGD (18.58 cfs) results in an Instream Waste Concentration (IWC) of 17.68%. 

The instream wastewater concentration (IWC) is based on the low flow 7Q10 at the point of discharge and determined by the following calculation:

Qw = Design flow of the wastewater treatment facility = 8 MGD or 12.4 cfs 
Qr = Receiving stream 7Q10 = 86.5
IWC = (Qw/ (Qw + Qr)) * 100 =  (12.4/ (12.4 + 86.5)) = 16.56 %

Qw = Design flow of the proposed wastewater treatment facility = 12MGD or 18.58cfs
Qr = Receiving stream 7Q10 = 86.5 cfs
IWC = (Qw/ (Qw + Qr)) * 100 =  (18.58/ (18.58 + 86.5) = 17.68%

See Attachment #1 for site map included with application. 

APPLICABLE GUIDELINES

State of Mississippi Water Quality Criteria (MSWQS), Wastewater Regulations for National Pollutant Discharge Elimination System Permits, Underground Injection Control Permits, State Permits, Water Quality Based Effluent Limitations (11 MS Admin Code (11MSAC)), 40 CFR Part 133 (Technology), Wasteload Allocation (WLA), Total Maximum Daily Load (TMDL)

PROPOSED FINAL LIMITATIONS

Upon permit issuance the Permittee shall operate under the Effluent Limitations and Monitoring Requirements for Outfall 001. Effluent Limitations and Monitoring Requirements for Outfalls 002, 102, and 202 shall not apply. Upon completion and operation of the new 4 mgd treatment system the Permittee shall operate under the Effluent Limitations and Monitoring Requirements for Outfalls 002, 102, and 202. Effluent Limitations and Monitoring Requirements for Outfall 001 shall not apply at that time.

	External Outfall 001 Current System Outfall into the Big Black River

	Parameter				Value				Basis
Flow					8.0 MGD (Mo. Avg.)		Design
CBOD5 				11 mg/l (Mo. Avg.)		Previous Permit
	TSS					30 mg/l (Mo. Avg.)		Technology
	Ammonia Nitrogen			2 mg/l (Mo. Avg.)		Previous Permit
pH  					6.0 to 9.0 S.U.			MSWQS
Chlorine				0.066 mg/l			IWC, MSWQS 
	E. Coli 	 			126 Col/100mL 		MSWQS
Dissolved Oxygen			6.0 mg/l, Minimum		MSWQS
	CBOD5, % Removal			85%, Minimum		Technology
TSS, % Removal 			85%, Minimum		Technology 
Total Phosphorus			Report				Previous Permit
Total Nitrogen				Report				Previous Permit
	Ceriodaphnia dubia					    16.56%			IWC, 11MSAC
	Pimephale promelas			         	16.56%			IWC, 11MSAC
	Zinc						0.392 mg/l			IWC, MSWQS							

The minimum and maximum values for dissolved oxygen and 30 – minute sludge settleability in the aeration unit must be reported.

External Outfall 002 Proposed Combined System Outfall  

	Parameter				Value				Basis
Flow					12.0 MGD (Mo. Avg.)	Design
CBOD5 				2502 lbs/day (Mo. Avg.)	Technology
	TSS					3002 lbs/day (Mo. Avg.)	Technology
	Ammonia Nitrogen			700 lbs/day (Mo. Avg.)	WLA
pH  					6.0 to 9.0 S.U.			MSWQS
Chlorine				0.062 mg/l			IWC, MSWQS 
	E. Coli 	 			126 Col/100mL 		MSWQS
Dissolved Oxygen			6.0 mg/l, Minimum		MSWQS
	CBOD5, % Removal			85%, Minimum		Technology
TSS, % Removal 			85%, Minimum		Technology 
Total Phosphorus			Report				Previous Permit
Total Nitrogen				Report				Previous Permit
	Ceriodaphnia dubia					    16.56%			IWC, 11MSAC
	Pimephale promelas			         	16.56%			IWC, 11MSAC
	Zinc					0.367 mg/l			IWC, MSWQS
	
Outfall 102 (Internal outfall after final treatment by 8 MGD System)
	
	Parameter						Value				Basis
	Flow						8 MGD				Design
	CBOD5						25 mg/l (Monthly Avg.)			WLA
	CBOD5 (Percent Removal)			85% Minimum				Technology
	TSS						30 mg/l (Monthly Avg.)			Technology
	TSS (Percent Removal)			85% Minimum				Technology
	NH3-N						7 mg/l (Monthly Avg.)			WLA
	
The minimum and maximum values for Dissolved Oxygen in aeration unit and 30-Minute Sludge Settleability in aeration unit must be reported

Outfall 202 (Internal outfall after final treatment by 4 MGD System)
	
	Parameter						Value				Basis
	Flow						4 MGD				Design
	CBOD5						25 mg/l (Monthly Avg.)			WLA
	CBOD5 (Percent Removal)			85% Minimum				Technology
	TSS						30 mg/l (Monthly Avg.)			Technology
	TSS (Percent Removal)			85% Minimum				Technology
	NH3-N						7 mg/l (Monthly Avg.)			WLA
	
The minimum and maximum values for Dissolved Oxygen in aeration unit and 30-Minute Sludge Settleability in aeration unit must be reported

The monthly and weekly average flow must be monitored at the mag meter located in the water transfer pipe from the treated water pump station. The records must be maintained as required by the permit

TOXICITY SCREENING

Chemical Specific Analysis for Metals and Results

No testing was submitted to perform a reasonable potential analysis. The facility is currently in significant non-compliance with the current permitted effluent standards. The existing 8 mgd must be upgraded to return to compliance. The facility has entered an Agreed Order with MDEQ to bring the facility back into compliance. The permit contains conditions that require all application testing be completed with 30 days of demonstrating compliance with the Agreed Order. 
Results for Volatile Organics Compounds, Acid-Extractable Compounds, and Base-Neutral Compounds and Results 

No testing was submitted. See above.

Bioassay Results
In accordance to State Regulation 11 Mississippi Admin Code pt. 6, Chp.1,VI.B.2b., a whole effluent toxicity evaluation was performed as part of the renewal application.  The applicant was to have tested in accordance with Short – Term Methods for estimating the chronic toxicity of Effluents and Receiving Water to Freshwater organisms.  Short – term chronic WET test were performed on ceriodaphnia dubia (invertebrate) and pimephales promelas (vertebrate).  

The previous permit required WET testing. The facility has demonstrated a reasonable potential to violate WET toxicity. WET limitations will remain in the permit. 

CHANGES FROM PREVIOUS PERMIT

The following conditions were added to the proposed draft permit:

•	“The Permittee shall perform monitoring of and submit for all pollutants in order to complete Table C. Effluent Parameters for Selected POTWs, of the Form 2A application. Monitoring shall initiated no later than 30 days after the facility has been discharging for one year, and performed monthly until three (3) samples have been obtained from the effluent of each parameter. Sampling shall be initiated no later than 30 days after the Permittee has demonstrated compliance with Agreed Order No. and results shall be compiled and submitted to Mississippi Environmental Quality Board, POSTMARKED NO LATER THAN THE 28TH DAY OF THE MONTH FOLLOWING THE COMPLETION OF THIS MONITORING.

•	“Mississippi Wastewater Regulations require that the influent to and the effluent from the wastewater treatment facility must be analyzed twice per month for a 6 month period for the chemicals listed below. 
o	Total Recoverable Antimony 
o	Total Recoverable Arsenic 
o	Total Recoverable Beryllium 
o	Total Recoverable Cadmium 
o	Total Recoverable Chromium 
o	Chromium (Hex) 
o	Total Recoverable Copper 
o	Total Recoverable Lead 
o	Total Recoverable Mercury 
o	Total Recoverable Nickel (Freshwater) 
o	Total Recoverable Selenium 
o	Total Recoverable Silver 
o	Total Recoverable Thallium 
o	Total Recoverable Zinc 
o	Free Cyanide 
o	Phenol 
o	Pentachlorophenol 
o	Hardness (in mg/l as CaCO3)

Please be aware that the chemical specific analysis must be performed by a method listed in 40 CFR 136 and with a Method Minimum Level (ML) at or below the level of the applicable water criterion for the measured pollutant parameter or the method has the lowest ML of the EPA approved analytically for the measured pollutant parameter.   

Sampling shall be initiated no later than 30 days after the Permittee has demonstrated compliance with Agreed Order No. and results shall be compiled and submitted to Mississippi Environmental Quality Board, POSTMARKED NO LATER THAN THE 28TH DAY OF THE MONTH FOLLOWING THE COMPLETION OF THIS MONITORING.”

•	Chlorination may be utilized by facility in the event the ultraviolet (UV) system is not available for disinfection. When chlorine is used as the method for disinfection, the facility must comply with the Chlorine, Total Residual limitations provided in the permit.  If chlorination is not being utilized, the permittee shall report NODI_CODE 9 (Conditional Monitoring - Not Required This Period) in the monthly Discharge Monitoring Report (DMR).”

Attachments

Attachment No. 1 – Discharge Location Map 
Attachment No. 2 – Plant Schematics
Attachment No. 3 – Waste Load Allocation

Attachment #1 –Discharge Location

Attachment #2 – Plant Schematics

									
Attachment #3 – Waste Load Allocation