PERMIT RATIONALE FOR REISSUANCE
Pinecrest Sewer Company, Forest Hill Subdivision
Desoto County
Olive Branch, Mississippi
Water NPDES No. MS0048038

I.	CLASSIFICATION – Commercial NPDES 

II.	DESCRIPTION OF WASTEWATER – Domestic Wastewater

III.	DESCRIPTION OF WASTEWATER TREATMENT – Domestic wastewater is collected and treated biologically by means of an aerated lagoon followed by chlorine disinfection prior to discharge.  No increase in treatment capacity is proposed within the application.  

IV.	RECEIVING WATER – Unnamed tributary of Coldwater River.  The point of discharge is located within the Yazoo River Basin and is classified as Fish and Wildlife.  At the point of discharge the receiving stream does not appear on the most recent State of Mississippi 303(d) list of evaluated or impaired waterbodies. The discharge does appear on a completed Total Maximum Daily Load (TMDL) for Fecal Coliform in the Coldwater River (December 2003). The facility utilizes chlorine disinfection, which complies with the conditions of the TMDL.

The 7-day, 10 year minimum flow, 7Q10, for Coldwater River at the point of 	discharge is 0.15 cfs.  The instream wastewater concentration at the point of discharge is 	determined using the following calculation:

IWC = {(Qw)/ (Qw + QR)}*100
	Where:
	QW = Design flow of the wastewater treatment facility, 0.26 MGD or 0.402 cfs.
	QR = Receiving stream 7Q10, 0.15 cfs

IWC = {(0.402 cfs)/(0.402 cfs + 0.15 cfs)}*100 = 72.8 %

V.	APPLICABLE GUIDELINES – 11 Mississippi Admin Code pt. 6, Commercial Facility Guidelines (Technology), Mississippi Water Quality Standards (MSWQS), Wasteload Allocation (WLA) 

VI.	SUMMARY OF LIMITATIONS –
	Parameter						Value		Basis
	Flow							0.26 MGD		Design
	BOD5							30 mg/l 		Technology
	TSS							90 mg/l 		Technology
	Ammonia Nitrogen	(Phase I) 		3.4 mg/l 		WLA
	Ammonia Nitrogen	(Phase I) 		1.5 mg/l 		WLA
	Dissolved Oxygen 					> 6.0 mg/l 		WLA
	E. coli						   126 Col./100 ml		MSWQS
	Chlorine, Total Residual			0.015 mg/l 		MSWQS
	pH							6.0 – 9.0 pH		MSWQS

VII.	CHANGES FROM PREVIOUS PERMIT – 

Phase II Ammonia Nitrogen limitations were added to the proposed draft permit, due to the updated ammonia toxicity standard. 

The schedule of compliance states:

Phase II limitations shall apply as soon as the treatment system has demonstrated compliance with the Phase II limitations, but no longer than three (3) years after the issuance of the permit.

The permittee shall notify our office orally at least 24 hours prior to start-up and in writing no later than 48 hours after start-up.”

Also, the permit requires the following:

The Permittee shall Submit engineering report: Due once within 6 months (180 days) after effective date. Said report shall outline the improvement activities needed to upgrade the wastewater treatment facility to comply with the site's Phase II limitations and shall include a proposed schedule for those improvement activities. 

The Permittee shall Submit progress report: Due annually - every 1 year after effective date. Said report shall update the Permittee's progress in addressing needed upgrades to the wastewater treatment facility in order to meet the site's Phase II limitations. Said report should also include an updated schedule for completing these activities.