BEFORE. AFTER. New Effluent Limitation Guidelines.
An Image/Link below is provided (as is) to download presentation
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
On November 28th, 2008, the EPA issued a proposed regulation which strengthened the existing National Pollutant Discharge Eliminations System (NPDES) permit program that currently regulates stormwater discharges from construction and development (C&D) sites.
The new ELG has been successfully challenged by the national builders association as flawed. As it turns out, the number the EPA derived were erroneous via the method used. However, the EPA is reformatting their procedure to come back with the same resultant under new testing. So eventually, the ELG will be back to very low limits, though those limits are TBD.
Almost Half of Rivers/Streams Affected in US
According to EPA’s draft ELG, “45% of assessed river and stream miles, 47% of assessed lake acres and 32% of assessed square miles of estuaries show impairments from a wide range of pollutant sources”. The EPA has identified sediment-laden stormwater runoff from construction sites as one of the major remaining water quality problems throughout the United States.
Sediment is a primary pollutant of concern because it can have tremendous impact to downstream aquatic resources, such as fish, because it can smother spawned eggs, it reduces visibility which decreases feeding capability, and can even raise water temperature due to the absorption of UV radiation. In addition, other pollutants such as metals, nutrients and petroleum products are preferentially adhered to suspended sediment or turbidity and carried to receiving waters in construction stormwater runoff. Like sediment, these pollutants can cause an array of physical chemical and biological impacts on aquatic systems. According to the EPA proposed ELG, turbidity and suspended solids impair almost 700,000 miles of streams and almost 380,000 acres of lakes and reservoirs nation-wide.
EPA based their technical and economic analysis on BAT on the performance of ATS, specifically CESF technology. Although other ATS technologies such as electro-coagulation, batch treatment (first proposed by Ron Devitt of Washington State DOE), and other methods are utilized for construction stormwater clarification, CESF is the leading technology utilized in the C&D industry to achieve stormwater discharge limits of less than 10 NTU EPA has evaluated more than 6,000 data points and cost information from many projects which have utilized ATS and has determined that “Option 2 is technologically available, economically achievable and has acceptable non-water quality environmental impacts”. This means that construction projects over 30 acres in size will need to consider ATS and in most cases will have to implement these systems to achieve the proposed 13 NTU numeric effluent limit.
CESF Only Requires 6 Components
Stormwater retention basin
CESF system pump
Chitosan delivery system
Water quality monitoring system
Industrial sand filtration unit
Interconnection pipes and hoses
EPA’s proposed ELGs were published in the Federal Register in November, 2008 and will be finalized no later than December 1, 2009. (this has been placed on hold for the foreseable future however it will be replaced after a new study is completed) The proposed ELGs are a shift from a non-numeric or narrative approach to regulating construction stormwater to a water quality based numeric effluent limit. If implemented as they are currently proposed, the ELGs would have some impact on all municipal and construction NPDES permit holders. The requirements will depend on project size and may include improved use of BMPs, installation of engineered sediment basins, routine stormwater discharge monitoring and the implementation of ATS.
Once the ELGs are finalized, they will be incorporated into new NPDES construction permits. These permits are issued by EPA regional offices or NPDES authorized stated and tribal agencies. The primary pathway for implementation of the new ELGs will be through state-wide NPDES construction general permits, since EPA only has Catalogue Government Publications (CGP) authority in five states (AK, ID, MS, NH, and NM), the District of Columbia, most U.S. Territories and most Native-American lands. NPDES authorized states may choose to adopt the new ELGs immediately into their CGP or wait until the permit renewal date.
Monthly Cost Example
Monthly rates for renting:
Sand Filter system: $3,465Generator for the system: $2,1004 pod sand filter: $2,00035 HP pump: $1,100Metering Pump: $ 100Float Dock for 35 HP pump:$ 66Enclosed Container: $ 2001 Container of Chitosan: $3,000 - Used 1/4 of it during the first month.
The implications of the ELGs will therefore differ from state to state depending on the existing regulations with the specific state’s CGP. For instance, states such as Washington, Oregon and California have relatively stringent construction stormwater requirements which means that small (<10 acres) and medium (>10 acres and <30 acres) may not see a tremendous difference in requirements. Projects greater than 30 acres in these areas would likely see significant impacts associated with meeting the 13 NTU numeric effluent limitations. Other states such as Alaska and Idaho, which fall under EPA NPDES authority, typically have less stringent requirements and will likely see more significant impacts for sizes of sites.