NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM PERMIT FACTSHEET February 2017 Permittee Name: United States Navy Mailing Address: U.S. Navy Base Guam PSC 455 Box 152 FPO AP, GU 96540 Facility Location: U.S. Navy Fena Water Treatment Plant Route 2A, Naval Magazine Santa Rita, GU 96915 Contact Person(s): Charles (Omar) Damian, Environmental Engineer (671) 333-2583 Edward Moon, Installation EV Program Director (671) 339 – 3711 NPDES Permit No.: GU0020389 I. STATUS OF PERMIT The United States Navy (the “permittee”) has applied for the renewal of its National Pollutant Discharge Elimination System (“NPDES”) permit to authorize the discharge of filter backwash water and clarifier overflows from the Fena Water Treatment Plant (the “facility” or “WTP”) to the Namo River. A completed application was submitted on August 20, 2015. The Environmental Protection Agency (“EPA”) Region IX is reissuing this facility’s permit pursuant to the Clean Water Act (“CWA”) section 402. CWA section 402, and EPA’s implementing regulations, contain provisions that govern EPA’s authorization to require NPDES permit conditions. (40 CFR 122). The permittee currently is discharging under NPDES permit GU0020389 (previously GU0110019), which was issued February 23, 2011. Pursuant to 40 CFR 122.21, the terms of the existing permit are administratively extended until the issuance of a new permit. This permit has been classified as a minor discharger. After completing the NPDES permit rating worksheet, EPA classified the permittee as a minor discharger receiving 70 points. A total of 80 points is required for classification as a major discharger. II. GENERAL DESCRIPTION OF FACILITY The Fena WTP treats approximately 10.5 MGD of water from Fena Lake for drinking water. Under normal operating conditions, the drinking water is treated by conventional clarifiers, multi-media filters, ultraviolet disinfection, and ultimately stored in a clearwell before distribution. Solids are removed from the clarifiers and sent to a sludge conditioning tank and belt filter press before being sent to a Navy landfill. Wastewater that goes through the belt filter U.S. Navy, Fena Water Treatment Plant NPDES Permit No. GU0020389 Factsheet Page 2 of 22 press is recycled to the headworks and reprocessed. Wastewater from the sludge conditioning tank is sent to two backwash settling tanks. The supernatant from the settling tanks is recycled to the headworks while the solids are sent back to the sludge conditioning tank. Solids from the belt filter press are sent to the Navy Landfill. In the past, mechanical failures or limitations in the system have also caused upsets resulting in overflows from different parts of the treatment system. This type of discharge is not authorized in the NPDES permit. III. DESCRIPTION OF RECEIVING WATER The Guam Environmental Protection Agency (“GEPA”) adopted water quality standards (“WQS”) for different surface waterbodies, depending on the level of protection required. The WQS, revised in 2015, provides water quality criteria by surface waterbody classification. The Namo River is located within the area classified as Category S-3, low quality surface water(s). Category S-3 waters are used for commercial, agriculture, and industrial activities. (GEPA 2015). The facility discharges to the Namo River at latitude 13˚22’38” N and longitude 144˚40'51" E through outfall 002, which flows downstream for about three miles into Agat Bay. The Namo River and Agat Bay are not listed as impaired and no total maximum daily loads (“TMDLs”) exist for either receiving water. IV. DESCRIPTION OF DISCHARGE The discharge consists of overflows of clean-in-place washwater or maintenance washwater used to clean the filters used during the treatment process. During heavy storm events, typhoons, or lake inversions, decreased settling times experienced by the spent backwash tanks results in poor quality supernatant being recycled back to the plant headworks. As the quality of the recirculated water decreases, the fouling of the downstream processes increases, and a discharge occurs when the 549,000 gallon backwash tank overflows. Specifically, tank B589 is connected to the emergency outfall 002 and overflows from this tank are discharged via the outfall. A. Application Discharge Data As part of the application for permit renewal, the permittee provided estimated effluent characteristics including the following pollutants, which are believed to be present: total residual chlorine, color, fluoride, nitrate-nitrate (as N), total aluminum, and total barium. Estimated values were provided as the facility has not discharged during the last 10 years. U.S. Navy, Fena Water Treatment Plant NPDES Permit No. GU0020389 Factsheet Page 3 of 22 V. SIGNIFICANT CHANGES FROM PREVIOUS PERMIT TERM Table 1. Changes from previous permit term Permit Previous Permit Re-issued permit Reason for change Condition (2010 – 2015) (2016 – 2021) Effluent Contains effluent Removes effluent The permittee has not discharge during the last Limitations limits for arsenic, lead, limits for arsenic, 10 years. No reasonable potential exists for and manganese. lead, and arsenic and lead. Previous limits were based on manganese. the 401 water quality certification from GEPA. For manganese, the previous permit incorrectly used a marine water quality standard for manganese. There is no freshwater standard. Contains a 2.0 mg/L Revises the The revised aluminum limitation is based on aluminum effluent aluminum effluent GEPA’s water quality standard of 1.00 mg/L limit, as a daily limitation to be 1.0 because there is reasonable potential for a maximum. mg/L, as a daily discharge to exceed this standard. maximum. Contains a 2.0 ug/L Revises the GEPA’s water quality standard includes a mercury effluent limit, mercury effluent standard of 0.051 ug/L for organisms only. Per as a daily maximum. limit to be 0.051 GEPA’s water quality standards, the organisms ug/L, as a daily only standard applies to S-3 waters. There is maximum. reasonable potential to exceed this standard. Contains a 100 ug/L Revises the zinc The revised zinc limitation is based on GEPA’s zinc effluent limit, as a effluent limit to be water quality standard, acute aquatic life, of 120 daily maximum. 120 ug/L, as a daily ug/L because there is reasonable potential for a maximum. discharge to exceed this standard. Contained narrative Revised narrative The receiving water, the Namo River, is an S-3 effluent limitations effluent limitations water, per GEPA’s water quality standards. based on S-2 waters. to be based on S-3 waters. Contained annual Revised all The discharge is intermittent and monitoring monitoring monitoring to be should be conducted during the discharge to requirements for TDS, once per discharge. ensure data is available to assess compliance nitrate-nitrate (as N), with effluent limitations. fluoride, cadmium, chromium VI, selenium, and silver. Discharge N/A. Clarifies the only The previous permit called any unauthorized Prohibitions authorized discharge, such as overflows from other parts of discharge is for the treatment plant, as an upset. However, upset outfall 002, which is defined in 40 CFR 122.41(n). The reissued consists of permit clarifies that discharges from other parts overflows from the of the treatment plant are not authorized. backwash settling tank(s). The permit also contains electronic reporting requirements for discharge monitoring (DMRs), which are consistent with EPA’s final rule, NPDES Electronic Reporting Rule, effective U.S. Navy, Fena Water Treatment Plant NPDES Permit No. GU0020389 Factsheet Page 4 of 22 December 2015, as well as EPA’s final rule, Use of Sufficiently Sensitive Test Methods for Permit Applications and Reporting, effective September 2014. VI. DETERMINATION OF NUMERICAL EFFLUENT LIMITATIONS EPA developed effluent limitations and monitoring requirements in the permit based on an evaluation of the technology used to treat the pollutant (e.g., “technology-based effluent limits”) and the water quality standards applicable to the receiving water (e.g., “water quality-based effluent limits”). EPA established, in the permit, the most stringent of the applicable technology- based or water quality-based standards, as described below. A. Applicable Technology-Based Effluent Limitations There are no applicable national or Guam criteria for drinking water treatment plants. There are, however, NPDES general permits for the water treatment industry in other states that contain technology-based effluent limits (TBELs) based on best professional judgement. The previous permit compared such TBELs for drinking water treatment plants in 4 states (Mississippi, South Carolina, South Dakota, and Washington). The table below contains an updated comparison of these 4 states and includes an additional 5 general permits (for Alabama, Arkansas, Massachusetts and New Hampshire, Ohio, and Oklahoma)1. The additional general permits were considered during this renewal because the permits included an aluminum effluent limit and were recently issued. Table 2. Maximum Daily Limits from State General Permit Examples State2 Settleable TRC Aluminum TDS TSS Solids (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) Alabama -- 0.019 -- -- 45.00 Arkansas -- <0.100 2.00 -- 30.00 instant max Massachusetts and -- <0.100 -- -- 50.00 New Hampshire Mississippi -- 0.019 -- -- 45.00 1 Many general permits included effluent limits for other types of metals, like iron, manganese or arsenic, dependent on the type of source water and type of treatment process. Since this facility