PRETREATMENT RATIONALE FOR REISSUANCE/MODIFICATION

Waste Management of Mississippi Inc, Pecan Grove Landfill and Recycling Center and Rubbish Site
Harrison
Pass Christian, MS

MSP091891
SIC: 4953
June 2, 2011
Permit Engineer: Michelle Vinson

I.	FACILITY INFORMATION

A.	Nature of Business: Municipal Solid Waste Landfill
B.	Process Wastewater Description: Landfill leachate
C.	Proposed Flowrate: 50,000 gpd
D.	Applicable Federal Guidelines: None

II.	RECEIVING POTW INFORMATION

A.	POTW and Permit Number: Gulfport (North) MS0051756
B.	POTW Treatment Type: Activated Sludge
C.	POTW Design Flowrate: 7.75 MGD
D.	POTW Receiving Stream: Ditch to Bernard Bayou
E.	POTW Receiving Stream 7Q10 (Q7/10): NA (Estuarine)

III.	PERTINENT FLOWRATE AND LOADING DATA

A.	POTW 12-month Average Flowrate (QPOTW):

Month	Flow, MGD	
April 2011	5.52	
March 2011	6.10	
February 2011	5.17	
January 2011	4.72	
December 2010	4.23	
November 2010	4.37	
October 2010	4.01	
September 2010	4.90	
August 2010	7.07	
July 2010	6.02	
June 2010	6.05	
May 2010	6.06	
Average	5.35	

B.	
Industrial Facilities Flowrate Data:

B and J Vacuum Service		11,000gal/week	1571.4 gpd1
Pecan Grove Landfill						50,000 gpd2
Total (QInd)							0.05157 MGD

1 B and J is permitted for 11,000 gal/week but has reported no discharge to the POTW for the last 12 months.  Therefore, the maximum permitted flow rate will be used in calculations in this rationale.
2 Pecan Grove is currently permitted for a discharge flow of 30K gpd, but is proposing to increase the discharge flow to 50K gpd.  This value will be used in calculations in this rationale.

C.	Current Maximum Permitted Loads (Xta):

For the parameters of concern identified from the renewal application, there are no current maximum permitted loads from either B and J Vacuum or Pecan Grove landfill.  Neither facility is required to test for the identified parameters.  The values reported in the application for Pecan Grove will be used in the calculations in this rationale.  The parameters of concern are Chromium, Mercury, Nickel and Zinc. 

D.	Maximum 30-day Average Discharge Value (Xt) using the most recent 12 months of DMR data:

For the parameters of concern identified from the renewal application, there are no maximum 30-day average discharge values from either B and J Vacuum or Pecan Grove landfill.  Neither facility is required to test for the identified parameters.The values reported in the application for Pecan Grove will be used in the calculations in this rationale.  The parameters of concern are Chromium, Mercury, Nickel and Zinc.

IV.	BACKGROUND/DOMESTIC LOADING CALCULATIONS

Background Loading (BGL), lb/d = 8.34 x BGC(mg/L)(1) x (QPOTW - QINDUSTRIAL(2))(MGD)

Chromium
BGL, lb/d = 8.34 x 0.0025 mg/L x (5.35 MGD – 0.05157 MGD)	= 0.1105 lb/d

Mercury
BGL, lb/d = 8.34 x 0.00010856 mg/L x (5.35 MGD – 0.05157 MGD)	= 0.0048 lb/d

Nickel
BGL, lb/d = 8.34 x 0.0025 mg/L x (5.35 MGD – 0.05157 MGD)	= 0.1105 lb/d

Chromium
BGL, lb/d = 8.34 x 0.135 mg/L x (5.35 MGD – 0.05157 MGD)	= 5.9655 lb/d

1 BGC = Background concentration of domestic sewage.  Calculated from actual POTW data as shown in Appendix A or literature values from Table 3-13 of the EPA Guidance Manual on the Development and Implementation of Local Discharge Limitations Under the Pretreatment Program (December 1987) for those pollutants with insufficient data. 

2 QINDUSTRIAL = QW1 + QW2 + …
where QW is the largest average flowrate from the DMR over the last twelve months.  (Maximum daily flow data may be used when monthly average data is not available.)

V.	WATER QUALITY ANALYSIS

A.	Instream Wastewater Concentration(1)

IWC, % = QPOTW / (QPOTW + Q7/10) x 100

	IWC, % 	= [5.35 MGD/(5.35 MGD + 0.0 MGD)]*100
			= 100%

B.	Allowable Water Quality Criteria (AWQC) Headworks Loading Calculations

AWQC, lb/day = 8.34 x CCRITICAL(mg/L)(2) x (Q7/10 + QPOTW, MGD) / (1 – RPOTW(3))

Chromium
Acute:
AWQC, lb/day 	= [8.34 x 0.016 mg/L x 5.35 MGD]/[1 – 0.82]
			= 3.966 lb/day

Chronic:
AWQC, lb/day	= [8.34 x 0.011 mg/L x 5.35 MGD]/[1 - 0.82]
			= 2.727 lb/day

Human Health:
AWQC, lb/day	= [8.34 x 1.47 mg/L x 5.35 MGD]/[1 – 0.82]
			= 364.389 lb/day

Mercury
Acute:
AWQC, lb/day 	= [8.34 x 0.0021 mg/L x 5.35 MGD]/[1 – 0.834]
			= 0.5644 lb/day

Chronic:
AWQC, lb/day	= [8.34 x 0.000012 mg/L x 5.35 MGD]/[1 – 0.834]
			= 0.00322 lb/day

Nickel
Acute:
AWQC, lb/day 	= [8.34 x 0.260 mg/L x 5.35 MGD]/[1 – 0.42]
			= 20.002 lb/day

Chronic:
AWQC, lb/day	= [8.34 x 0.029 mg/L x 5.35 MGD]/[1 – 0.42]
			=2.231 lb/day

Human Health
AWQC, lb/day	= [8.34 x 4.584 mg/L x 5.35 MGD]/[1 – 0.42]
			= 352.644 lb/day

Zinc
Acute/Chronic
AWQC, lb/day	= [8.34 x 0.065 mg/L x 5.35 MGD]/[1 – 0.674]
			= 8.896 lb/day

Human Health
AWQC, lb/day	= [8.34 x 5 mg/L x 5.35 MGD]/[1 – 0.674]
			= 684.340 lb/day

1 If IWC ≤ 1%, only an acute screening is developed.  If IWC > 1%, an acute and chronic screening are developed.

2 CCRITICAL = State of Mississippi Water Quality Criteria (adopted October 24, 2002) or EPA Water Quality Criteria, if there is no state criteria.

3 RPOTW = Removal efficiency, in decimal form, from actual POTW data (Appendix B) or from MDEQ study or EPA Guidance Manual on the Development and Implementation of Local Discharge Limitations Under the Pretreatment Program for those pollutants with insufficient data. 

VI.	POTW INHIBITION ANALYSIS (HEADWORKS INHIBITION, HWI)

HWI, lb/day = 8.34 x QPOTW(MGD) x CINH(mg/L)(1)

	Chromium
	HWI, lb/day 	= 8.34 x 5.35 MGD x 1.0 mg/L 	= 44.619 lb/day

	Mercury
	HWI, lb/day	= 8.34 x 5.35 MGD x 0.1 mg/L	= 4.462 lb/day

	Nickel
	HWI, lb/day	= 8.34 x 5.35 MGD x 1.0 mg/L	= 44.619 lb/day

	Zinc
	HWI, lb/day	= 8.34 x 5.35 MGD x 0.3 mg/L	= 13.386 lb/day

1 CINH = Activated Sludge Inhibition Threshold Levels, from Appendix G – Literature Inhibition Values, Local Limits Development Guidance (EPA 833-R-04-002A)

I.	
VII.	LIMITING CASE (LC) SUMMARY TABLE

Parameter	HWI (lb/day)	Acute AWQC (lb/day)	Chronic AWQC (lb/day)	Human Health (lb/day)1	LC (lb/day)	BGL (lb/day)	Xtat (lb/day)	Xtt (lb/day)	BGL < LC (Pass/Fail)	Xtat < LC (Pass/Fail)	Xtt < LC (Pass/Fail)	
Chromium	44.619	3.966	2.727	364.389	2.727	0.1105	NA	NA	Pass	NA	NA	
Mercury	4.462	0.5644	0.00322	NA	0.00322	0.0048	NA	NA	Fail	NA	NA	
Nickel	44.619	20.002	2.231	352.644	2.231	0.1105	NA	NA	Pass	NA	NA	
Zinc	13.386	8.896	8.896	684.340	8.896	5.9655	NA	NA	Pass	NA	NA	

If the POTW has a limit for a specific parameter, industrial loading is limited to the amount the POTW can accept and still meet the limit.  If there is no specific limit, this column does not apply.  POTW LC (lb/day) = (8.34 x CPOTW(mg/L) x QPOTW (MGD)) / (1 – RPOTW), where CPOTW is the POTW concentration limit in mg/L.  
VIII.	DEVELOPMENT OF ALLOWABLE CONCENTRATIONS

The remaining industrial wasteload allocation will be used in calculating allowable acute and chronic concentrations using the “Concentration Limit Method Based on Industrial Contributory Flow” method as described in the EPA Guidance Manual on the Development and Implementation of Local Discharge Limitations Under the Pretreatment Program.

PAI, lb/day = (LC, lb/day – BGL, lb/day) (QI, MGD / QT, MGD)

CALLOW, mg/L = (PAI, lb/day) / (8.34 x QI, MGD)

Where,
PAI 	=	Permit allocation for indirect discharger
CALLOW=	Allowable concentration for indirect discharger
QI	=	Applicant’s permitted process discharge 
QT	=	Total industrial contributory flow for pertinent pollutants
LC	=	Limiting case loading
BGL	=	Background/domestic loading

Chromium
PAI, lb/day = (2.727 lb/day – 0.1105 lb/day) x (0.05 MGD/0.05 MGD) = 2.617 lb/day

CAllow, mg/L = (2.617 lb/day)/(8.34 x 0.05 MGD) = 6.276 mg/L

Mercury
The background loading, BGL, is greater than the limiting case of 0.00322 lb/day developed from calculation of the Chronic Allowable Water Criteria.

Nickel
PAI, lb/day = (2.231 lb/day – 0.1105 lb/day) x (0.05 MGD/0.05 MGD) = 2.617 lb/day

CAllow, mg/L = (2.617 lb/day)/(8.34 x 0.05 MGD) = 6.276 mg/L

Zinc
PAI, lb/day = (8.896 lb/day – 5.9655 lb/day) x (0.05 MGD/0.05 MGD) = 2.931 lb/day

CAllow, mg/L = (2.931 lb/day)/(8.34 x 0.05 MGD) = 7.029 mg/L

I.	
IX.	PROPOSED PERMIT LIMITATIONS

Parameter	Reported Max. Conc. (mg/L)	Allowable Concentration 	Categorical Limits	Current Permit Limits	Proposed Permit Limits	Sampling Frequency 	Sample Type	Basis of Decision1	
		Acute (mg/L)	Chronic (mg/L)	Max (mg/L)	Avg. (mg/L)	Max. (mg/L)	Avg. (mg/L)	Max. (mg/L)	Avg. (mg/L)				
Chromium	0.014	3.966	2.727	None	None	None	None	None	None	NA	NA	Rationale	
Mercury	0.00046	0.5644	0.0032	None	None	None	None	Report	Report	Quarterly	Grab	Rationale	
Nickel	0.20	20.002	2.231	None	None	None	None	None	None	NA	NA	Rationale	
Zinc	1.03	8.896	8.896	None	None	None	None	None	None	NA	NA	Rationale	
													
Flow	0.025 MGD							0.05 MGD	0.05 MGD	Upon Each Occurrence	Batch	Application	
Ammonia Nitrogen, Total (as N)	1500					Report	Report	Report	Report	Twice per month	Grab	POTW	
Kjeldahl Nitrogen, Total						Report	Report	Report	Report	Twice per month	Grab	POTW	
Oil and Grease	29.0					Report	Report	Report	Report	Twice per month	Grab	POTW	
BOD (5 day)	10200					Report	Report	Report	Report	Twice per month	Grab	POTW	
pH	8.13 SU					8.5 SU	5.0 SU (min.)	8.5 SU	5.0 SU (min.)	Twice per month	Grab	POTW	
Total Suspended Solids (total annual)	6100					Report	Report	Report	Report	Twice per month	Grab	POTW	

1 Basis of Decision: WQC = Water Quality Criteria; TBEL = Technology-Based Effluent Limitation; BPJ = Best Professional Judgment; etc.

X.	

STATEMENT OF BASIS (narrative)

The renewal application submitted proposed an increase in the flow to the POTW from 30,000 gallons per day (gpd) to 50,000 gpd.  The calculations contained herein include this proposed flow increase.  Based on the available data, the POTW can accept the increased flow rate.  Further calculations of the allowable concentrations for the parameters of concern indicate only one parameter, Mercury, would require monitoring from the facility.  The background loading at the POTW is greater than the allowable water quality criteria for chronic concentrations.  A numerical is not proposed for the facility given that the maximum concentration level from the facility is an order of magnitude below the allowable concentration.  Therefore, a report only limit is being proposed with quarterly sampling for the parameter.  The draft permit will be developed based on the information contained herein in addition to the historical data from the facility and current permit conditions applied to the POTW.  Therefore, conditions and limitations contained in the draft pretreatment permit will be protective of human health and the environment.

APPENDIX A

BACKGROUND CONCENTRATION OF DOMESTIC SEWAGE

Chromium*
Date	Concentration	
06/08/06	0.0025	
06/22/096	0.0025	
07/11/06	0.0025	
07/13/06	0.0025	
08/18/06	0.0025	
08/29/06	0.0025	
09/14/06	0.0025	
09/28/06	0.0025	
10/03/06	0.0025	
10/15/06	0.0025	
11/17/06	0.0025	
11/30/06	0.0025	
Average	0.0025	

Mercury (ng/L)
Date	Concentration	
06/08/06	134.0	
06/22/096	29.0	
07/11/06	18.6	
07/13/06	96.6	
08/18/06	24.8	
08/29/06	48.6	
09/14/06	150.0	
09/28/06	49.1	
10/03/06	550.0	
10/15/06	80.8	
11/17/06	48.3	
11/30/06	72.9	
Average	108.56	

Nickel*
Date	Concentration	
06/08/06	0.0025	
06/22/096	0.0025	
07/11/06	0.0025	
07/13/06	0.0025	
08/18/06	0.0025	
08/29/06	0.0025	
09/14/06	0.0025	
09/28/06	0.0025	
10/03/06	0.0025	
10/15/06	0.0025	
11/17/06	0.0025	
11/30/06	0.0025	
Average	0.0025	

Zinc
Date	Concentration	
06/08/06	0.162	
06/22/096	0.088	
07/11/06	0.118	
07/13/06	0.164	
08/18/06	0.067	
08/29/06	0.097	
09/14/06	0.237	
09/28/06	0.100	
10/03/06	0.400	
10/15/06	0.082	
11/17/06	0.046	
11/30/06	0.056	
Average	0.135	

All concentrations are reported in units of mg/L except as noted.

*Where a non-detect was reported by the laboratory, one-half (1/2) of the method detection limit is reported as the influent concentration.

APPENDIX B

REMOVAL EFFICIENCIESA

Chromium
Date	Inf. Con.	Eff. Con.	Change	
06/08/06	0.0025	0.0025	0.00	
06/22/096	0.0025	0.0025	0.00	
07/11/06	0.0025	0.0025	0.00	
07/13/06	0.0025	0.0025	0.00	
08/18/06	0.0025	0.0025	0.00	
08/29/06	0.0025	0.0025	0.00	
09/14/06	0.0025	0.0025	0.00	
09/28/06	0.0025	0.0025	0.00	
10/03/06	0.0025	0.0025	0.00	
10/15/06	0.0025	0.0025	0.00	
11/17/06	0.0025	0.0025	0.00	
11/30/06	0.0025	0.0025	0.00	

The analytical data does not support the individual calculation of a removal efficiency for this parameter.  Therefore, the removal efficiency will be obtained from Appendix R – Priority Pollutant Removal Efficiencies of the Local Limits Development Guidance (EPA 833-R-04-002A) for Activated Sludge Treatment.

R,% = 82% (Chromium)

Mercury (ng/L)
Date	Inf. Con.	Eff. Con.	Change	
06/08/06	134.0	2.8	131.2	
06/22/096	29.0	9.7	19.3	
07/11/06	18.6	12.3	6.3	
07/13/06	96.6	47.4	49.2	
08/18/06	24.8	3.7	21.1	
08/29/06	48.6	2.1	46.5	
09/14/06	150.0	120.0	30.0	
09/28/06	49.1	8.3	40.8	
10/03/06	550.0	2.7	547.3	
10/15/06	80.8	0.7	80.1	
11/17/06	48.3	5.5	42.8	
11/30/06	72.9	1.4	71.5	
	108.56		90.51	

R, % = (90.51/108.56) x 100 = 83.4%

Nickel
Date	Inf. Con.	Eff. Con.	Change	
06/08/06	0.0025	0.0025	0.00	
06/22/096	0.0025	0.0025	0.00	
07/11/06	0.0025	0.0025	0.00	
07/13/06	0.0025	0.0025	0.00	
08/18/06	0.0025	0.0025	0.00	
08/29/06	0.0025	0.0025	0.00	
09/14/06	0.0025	0.0025	0.00	
09/28/06	0.0025	0.0025	0.00	
10/03/06	0.0025	0.0025	0.00	
10/15/06	0.0025	0.0025	0.00	
11/17/06	0.0025	0.0025	0.00	
11/30/06	0.0025	0.0025	0.00	

The analytical data does not support the individual calculation of a removal efficiency for this parameter.  Therefore, the removal efficiency will be obtained from Appendix R – Priority Pollutant Removal Efficiencies of the Local Limits Development Guidance (EPA 833-R-04-002A) for Activated Sludge Treatment.

R,% = 42% (Nickel)

Zinc
Date	Inf. Con.	Eff. Con.	Change	
06/08/06	0.162	0.055	0.107	
06/22/096	0.088	0.077	0.011	
07/11/06	0.118	0.076	0.042	
07/13/06	0.164	0.067	0.097	
08/18/06	0.067	0.038	0.029	
08/29/06	0.097	0.064	0.033	
09/14/06	0.237	0.050	0.187	
09/28/06	0.100	0.046	0.054	
10/03/06	0.400	0.021	0.379	
10/15/06	0.082	0.020	0.062	
11/17/06	0.046	0.014	0.032	
11/30/06	0.056	0.001	0.055	
	0.135		0.091	

R, % = (0.091/0.135) x 100 = 67.4%