Loading...
HomeMy WebLinkAboutNC0064726_SPECULATIVE LIMITS_19990716NPDES DOCUWEMT SCANNINO COVER : MEET NPDES Permit: NC0064726 East Bend Industrial Park WWTP Document Type: Permit Issuance Wasteload Allocation Authorization to Construct (AtC) Permit Modification Complete File - Historical r 0,§Peculative Limits Instream Assessment (67b) Environmental Assessment (EA) Permit History Document Date: July 16, 1999 This document its priaated on reaxise paper - ignore ax y conteiat on the resrerise aide CC L State of North Carolina i - Department of Environment and Natural Resources Division of Water Quality James B. Hunt, Jr., Governor Wayne McDevitt, Secretary Kerr T. Stevens, Director Mayor William G. Hardy Town of East Bend P.O. Box 189 East Bend, NC 27018 Dear Mayor Hardy: fullA,&-JF�, NCDENR NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES 16 July, 1999 Subject: Speculative Limits UT to Logan Creek, Sites I & 2 Town of East Bend Yadkin County This letter serves to transmit speculative effluent limits for a proposed W WTP discharging to two potential points on an unnamed tributary (UT) to Logan Creek. This plant would discharge 200,000 GPD of treated domestic wastewater to the UT to Logan Creek in the Yadkin River Basin in Yadkin County. The speculative limits presented here are based on our understanding of the proposal and of present environmental conditions. The Division of Water Quality (DWQ) cannot guarantee that it will issue the Town an NPDES permit to discharge treated wastewater into waters of the State. Nor can we guarantee that the effluent limitations and other requirements included in any permit will be exactly as presented here. Final decisions on these matters will be made only after the Division receives and evaluates a formal permit application for the Town's proposed discharge and provides the public an opportunity to comment on a proposed permit. Water Quality Issues in the High Rock Lake Watershed The Division has significant concerns about the level of nutrients entering the High Rock Lake watershed. The high rate of nutrient loading to High Rock Lake, as well as high levels of in -lake nutrients, have caused excessive algal growth. The nutrient enrichment problem in the watershed has been well researched and is well documented. The proposed discharge to the UT to Logan Creek would add to the current nutrients entering the High Rock Lake watershed. DWQ is concerned that additional loading to the system, especially during low flow periods, could cause water quality to decline and threaten the designated uses of High Rock Lake. DIVISION OF WATER QUALITY • NPDES UNIT • NC DENR PO BOX 29535. 1617 MAIL SERVICE CENTER • RALEIGH NC 27699-1617 Telephone 919-733-5083 FAX N 733-9919 An Equal Opportunity Affirmative Action Employer • 50 % recycled/10 % post consumer paper In order to ensure that water quality conditions do not worsen, DWQ intends to proceed with the development of a nutrient management strategy for the High Rock Lake watershed during the next basinwide planning cycle. The process may include all or part of the watershed. The long-term solution to nutrient enrichment in this watershed may require a comprehensive approach to nutrient reduction affecting both new and existing dischargers. DWQ has recommended that all dischargers in the watershed make progress toward decreasing end -of -pipe phosphorus loads. Further, DWQ strongly advises potential new dischargers to provide for biological nutrient removal in the design of their W WTP systems. Failure to adequately plan for this eventuality may cause lengthy project delays and increased costs to the Town of East Bend. Environmental Assessments of New Proiects and Expansions Please be aware that you will have to evaluate this project for environmental impacts before applying for a NPDES permit. Due to the size and placement of the potential discharge, an Environmental Assessment (EA) must be prepared. Anyone proposing to construct new or expanded waste treatment facilities using public funds or public (state) lands must first prepare an environmental assessment (EA) when wastewater Flows (1) equal or exceed 0.5 MGD or (2) exceed one-third of the 7Q 10 flow of the receiving stream. Both of the proposed sites meet the second condition of exceeding one-third of the 7Q10 flow of the receiving stream. DWQ cannot accept a NPDES permit application for a project requiring an environmental assessment until the Division has approved the EA and sent a Finding of No Significant Impact (FONSI) to the state Clearinghouse for review and comment. The Environmental Assessment should contain a clear justification for the new or expanded flow. It should also provide a comprehensive analysis of potential alternatives to the discharge, including a thorough evaluation of non -discharge alternatives. Non -discharge alternatives, such as spray irrigation, are considered to be environmentally preferable to a surface water discharge. The following items should be thoroughly investigated and documented: • Population data, growth, and flow justifications • Participation in a regional system The EA should address effluent reuse, wastewater reduction efforts, land use restrictions, Infiltration and Inflow (1/I) reduction, urban run off reductions, and wetlands restoration initiatives. In accordance with North Carolina General Statutes, the preferred alternative must be the practicable waste treatment and disposal alternative with the least adverse impact on the environment. If the EA demonstrates that the project may result in a significant adverse impact on the quality of the environment, you must then prepare an Environmental Impact Statement (EIS). The Water Quality Planning Branch can provide additional information regarding the requirements of the N.C. Environmental Policy Act. Please contact our EA coordinator, Ms. Gloria Putnam, directly at (919) 733-5083, ext. 567 for more information. Ammonia Toxicity Our analysis of the proposed discharge at Site #1 (1.6 miles above the confluence with Logan Creek) indicates that ammonia toxicity in the receiving stream is a very serious concern. Because of the smaller -1 drainage area and lower flows at Site #1, NH3-N limits of 2.0/4.0 mg/l (summer/winter) may not protect aquatic life against ammonia toxicity in the receiving stream at low flow. For this reason, DWQ strongly discourages developing the discharge at Site #1 and recommends Site #2 instead. Further, approval of a NPDES permit for a new discharge at Site #1 may be problematic. Speculative Effluent Limits Based on the available information, tentative limits for the proposed discharge to the UT to Logan Creek at 0.2 MGD are attached in a draft effluent limits page format. The speculative limits are explained below. Site #1 (1.6 miles above confluence with Logan Creek) DWQ strongly discourages the development of the discharge at this site. Flow Limits. The flow will be limited to 0.2 MGD, as requested. Detailed justification for this level of flow must be provided. BOD, 5 day. Minimum treatment required by federal regulations. Nutrients: Total Phosphorus. Although specific limits have yet to be developed for dischargers in the High Rock Lake watershed, it is likely that Total Phosphorus limits of 2 mg/l or lower will be required. NH3-N. The 2.0/4.0 mg/I (summer/winter) limits were developed to protect aquatic life against ammonia toxicity in the receiving stream at low flow. TSS. The limits for total suspended solids are standard for secondary treatment of municipal wastewater. Total Residual Chlorine. To protect the receiving stream from high concentrations of chlorine, a TRC limit of 28 ug/l would be required at this site. Fecal Coliform, pH. The limits for fecal coliform bacteria and pH are derived to protect water quality in the receiving stream. Site #2 (1.2 miles above confluence with Logan Creek) DWQ recommends the development of the discharge at this site. Flow Limits. The flow will be limited to 0.2 MGD, as requested. Detailed justification for this level of flow must be provided. BOD, 5 day. Minimum treatment required by federal regulations. Nutrients: Total Phosphorus. Although specific limits have yet to be developed for dischargers in the High Rock Lake watershed, it is likely that Total Phosphorus limits of 2 mg/l or lower will be required. NH3-N. The 2.0/5.0 mg/I (summer/winter) limits were developed to protect aquatic life against ammonia toxicity in the receiving stream at low flow. TSS. The limits for total suspended solids are standard for secondary treatment of municipal wastewater. Total Residual Chlorine. To protect the receiving stream from high concentrations of chlorine, a TRC limit of 28 ug/I would be required at this site. Fecal Coliform, pH. The limits for fecal coliform bacteria and pH are derived to protect water quality in the receiving stream. I trust this response offers sufficient guidance for the Town's proposed treatment plant construction. If you have any additional questions about these limits, feel free to contact Mark McIntire at (919) 733- 5083, extension 553. Sincerely, David A. Goodrich Supervisor, NPDES Unit Water Quality Section cc: Winston-Salem Regional Office Point Source Branch Central Files cNPUES_Unit Files A (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS speculative limits SPEC SITE #1 �4` During the period after construction to 0.2 MGD and lasting until expiration, the Permittee is authorized to discharge from outfall(s) serial numbej001. Sd ch' discharges shall be limited and monitored by the Permittee as specified below: V '� EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTSI Monthly Average Weekly Average Daily Maximum Measurement Fre uenc `� Sample U n,=T`y eJ Sample Location' Flow 0.2 MGD ContiriuousPl 1—Aqbdordinq I or E BOD, 5 day, 20°C (April 1 — October 31 2 30.0 m /I 45.0 m /I Weekly I ! Composite E, I BOD, 5 day, 20°C November 1 - March 31 z 30.0 m /I 45.0 m /I Weekl" Composite E, I Total Suspended Residuez 30 m /I 45.0 m /I Weekly Composite E, I NH3 as N (April 1 - October 31) 2.0 mg/I `•, j r �i Weekly Composite E NH3 as N (November 1 — March 31) 4.0 mg/I A, Weekly Composite E Dissolved Oxygen Aril 1 - October 31 5.0 rr '/I i I Weekly Grab E Dissolved Oxygen November 1 — March 31 f i :1 Weekly Grab U, D' H4 Weekly Grab E Fecal Coliform(geometric mean 200 /.100 ml i l 400 / 100 ml Weekly Grab E Fecal Coliform(geometric mean r200 /i100 ml%' 400 / 100 ml Weekly Grab U, D' Temperature 'C ( I i Daily Grab E Temperature °C i > I' - rJ Daily Grab U, DI Total Nitrogen (NO2+NO3+TKN)' '( 7 ° Weekly5 Composite E Total Nitrogen (NO2+140;`t';TKN)",:% Weekly5 Grab U, D Total Phosphorus- , (:'` ram" Weekly5 Composite E Total Phos hornsN 'I Weekly5 Grab U, D Total,Residual Chlbrinee 28,u/I 2/Week Grab E Coriductivit i. C` Weekly Grab E Notes:-'- rj Sample locations: E - Effluent, I - Influent, U - Upstream in the pool formed immediately upstream of the instream flow weir, D - Downstream on the existing dam structure in a location so as to avoid contact between the ground and the sample bottle. Upstream and Downstream samples of Dissolved Oxygen, Temperature, Fecal Coliform, and Conductivity shall be collected three times per week during the months of June through September and once per week during the remaining months of the year. 2 The monthly average effluent BOD5 and Total Suspended Residue concentrations shall not exceed 15% of the respective influent value (85% removal). 4 The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units. 5 Effluent and Instream monitoring for Total Nitrogen and Total Phosphorous shall be conducted on the same day. - 6 Chronic Toxicity (Ceriodaphnia) P/F at 90%; February, May, August, and November, See Part III, Condition F. Chlorophyll -a shall be monitored weekly during the months June through September, during the remaining months of the year, no monitoring is required. 8 Total Residual Chlorine shall be monitored only if chlorine is added to the effluent. There shall be no discharge of floating solids or visible foam in other than trace amounts. A (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS speculative limits SPEC SITE #2 During the period after construction to 0.2 MGD and lasting until expiration, the Permittee is authorized to discharge from outfall(s) serial number 001. Such, discharges shall be limited and monitored by the Permittee as specified below: Q rJ EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTS Monthly Average Weekly Average Daily Maximum Measurement-1 Fre uencj��5 ✓Sample I, t1, T' 'e Sample Location' Flow 0.2 MGD Contiriuousi, l I 1Re6ordin I or E BOD, 5 day, 20°C (April 1 — October 31 2 30.0 m /I 45.0 m /I Weekl' ! J Composite E, I BOD, 5 day, 20°C November 1 - March 31 2 30.0 mg/1 45.0 m /I Wedkl' Composite E, I Total Suspended Residue2 30 m /I 45.0 m /I J.fj:J Weekly Composite E, I NH3 as N (April 1 - October 31) 2.0 mg/I Weekly Composite E NH3 as N (November 1 — March 31) 5.0 mg/I A � I Weekly Composite E Dissolved Oxygen Aril 1 - October 31 5.0 m'/I t,i I Weekly Grab E Dissolved Oxygen November 1 — March 31 ut"'il 1`` 1 Weekly Grab E H41 ,%:�.;I 1<:) Weekly Grab E Fecal Coliform(geometric mean 200 /,,l00 ml;- 400 / 100 ml Weekly Grab E Fecal Coliform(geometric mean (200 /1100 in15 400 / 100 ml Weekly Grab U, D' Temperature °C i I i LJ Daily Grab E Temperature °C Daily Grab U, D' Total Nitrogen (NO2+NO3+TKN)' (,—i ` Weekly5 Composite E Total Nitrogen (NO2+NO_'3tTKN),' / Weeklys Grab U,D Total Phos horus—� l:.% Weekl s Composite E Total Phos hor6s\ Weekl 5 Grab U, D Total.Residu6l;Chlorine8 28p /I 2/Week Grab E Coriductivi I 7" Weekly Grab E Notes` V Sample locations: E - Effluent, I - Influent, U - Upstream in the pool formed immediately upstream of the instream flow weir, D - Downstream on the existing dam structure in a location so as to avoid contact between the ground and the sample bottle. r Upstream and Downstream samples of Dissolved Oxygen, Temperature; Fecal Coliform, and Conductivity shall be collected three times per week during the months of June through September and once per week during the remaining months of the year. 2 The monthly average effluent BOD5 and Total Suspended Residue concentrations shall not exceed 15% of the respective influent value (85% removal). 4 The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units. 5 Effluent and Instream monitoring for Total Nitrogen and Total Phosphorous shall be conducted on the same day. 6 Chronic Toxicity (Ceriodaphnia) P/F at 90%; February, May, August, and November, See Part III, Condition F. 7 Chlorophyll -a shall be monitored weekly during the months June through September; during the remaining months of the year, no monitoring is required. 8 Total Residual Chlorine shall be monitored only if chlorine is added to the effluent. There shall be no discharge of floating solids or visible foam in other than trace amounts.