Info

Estimated Load

Load

Concentration

Figure 10-11 Long-term trends of effluent BOD5 for the R. M. Clayton wastewater treatment plant. Data for estimated BOD5 based on effluent flow data (Figure 10-7), 200 mg/L influent BOD5, and removal rates of 35 percent (primary), 85 percent (secondary), and 95 percent (tertiary). Sources: ARC, 1984; USEPA, 1971; USPHS, 1963; Woodward, 1949, Richards, 1999.

the state agency and the presiding judge subsequently determined that the effluent from the CSO treatment facilities failed to meet current state and federal water quality standards. A consent decree signed in July 1998 required the City of Atlanta to develop a CSO remedial measures plan that would bring all the CSO control facilities into compliance by July 2007. In July 2001, the U.S. Environmental Protection Agency and the Georgia EPD authorized the City of Atlanta to proceed with the remedial measures plan developed for the following seven CSO treatment facilities: Clear Creek, Tanyard Creek, North Avenue, Greensferry, McDaniel, Custer and In-trenchment Creek. The plan includes: separation of additional areas of the existing combined sewer system, upgrade the Intrenchment Creek facility, dechlorination of disinfected discharges at existing CSO facilities, consolidate storage in deep tunnel sewer systems, treatment of stored combined wastewater at dedicated CSO facilities and develop site-specific permit limits. Implementation of the $950 million plan adopted by the city is expected to be completed by July 2007 and will result in the complete separation of all combined sewers within 25 years (see Mynhier et al., 2001).

Recreational and Living Resources Trends

Historical records of fish population in the Chattahoochee River below Atlanta are very limited. Conditions downstream of Atlanta's wastewater discharge were unsuitable for fish survival during the 1970s, and no fish surveys could be collected (Mauldin and McCollum, 1992). Shelton and Davies (1975) conducted a preimpoundment survey of the area to be flooded by the West Point Dam. The survey lasted from January 1972 to May 1974. The station closest to Atlanta on the Chattahoochee was at Franklin, Georgia. During the early 1970s study period, the Chattahoochee River was described as carrying a high organic load from municipal wastes, a high suspended solids load from agricultural and construction practices, and high chemical concentrations from industrial effluents. The relatively poor water quality in the Chattahoochee River affected the distribution and abundance of fish species sampled in the main stem versus the tributaries. Seventeen species of fish were collected in the Chattahoochee River at Franklin, which is less than half the number of species expected for Georgia rivers of similar size.

A fish survey of the Chattahoochee River conducted between July 1990 and June 1992 revealed the return of fish in great numbers to the portion of the river below the city of Atlanta. The number of species collected ranged from 14 or 15 at the sites in the direct vicinity of the wastewater treatment plant to 18 to 22 at the sampling sites located 63 and 23 km downstream, respectively. The diverse species collected represented a considerable improvement from conditions in the early 1970s, when only 17 species were sampled at Franklin, about 100 km downstream from the wastewater treatment plant, and no fish were present downstream of Atlanta's water supply intake (Mauldin and McCollum, 1992). The recent survey collected 12 gamefish species, compared to 8 collected by Shelton and Davies (1975); the most abundant of game species by weight were largemouth bass, bluegill, and channel catfish. Samples were analyzed using the Index of Biotic Integrity (IBI) (Karr, 1981; Karr et al., 1986). IBI scores for the four sampling sites (located 1 km upstream of the discharge, 1 km downstream of the discharge, 23 km downstream, and 63 km downstream) ranged from 22 to 32, which is 37 percent to 53 percent of the maximum score of 60. Scores in the 21 to 30 range indicated poor stream quality for fish and a population dominated by omnivorous, pollutant-tolerant forms. The Chattahoochee River below Atlanta's wastewater treatment plant discharge had a disproportionate segment of carp (75 percent), a higher proportion of bluegill to redbreast sunfish than is common in Georgia streams, and fewer gamefish than expected. A score of 32 measured 23 km downstream from the discharge indicated fair stream quality for fish. Overall, the fish sampled appeared to be healthy. Neoplasms were not observed in bluegill specimens, nor were gross external abnormalities observed in catfish.

The results of the 1990 to 1992 sampling show that water quality has improved immensely since 1972 when the river below Atlanta was described as "in near septic condition for a reach of 35 miles" (GADNR, 1991). The improvement is due to enhanced wastewater treatment (Mauldin and McCollum, 1992). Combined efforts of the state, communities, and industries, along with USEPA grants for municipal wastewater treatment systems, have put the Upper Chattahoochee River on the road to recovery. Fish kills have not been commonplace since 1976, except for one caused by an unidentified agent in 1988 (Mauldin and McCollum, 1992) (Table 10-3). Bloodworm-infested sludge beds no longer float in the shallows below Atlanta, sportfish populations are recovering, there is more DO in the water, macroinvertebrate fauna is more diverse, and fecal coliform bacteria levels dropped 82 percent in only 4 years (USEPA, 1980). The number of water quality violations has dropped dramatically since the 1970s even though standards have increased. Water-based and contact recreation are now fully supported along the Chattahoochee River reach from Buford Dam to Peachtree Creek. Fishing is generally supported along the entire river (GADNR,

TABLE 10-3 Fish Kills Due to Municipal Waste Discharges in the Greater Atlanta Region

Location

Date of Occurrence

Duration

Severity

Length of Stream Affected (miles)

Game

Species (%)

Chattahoochee River,

0 0

Post a comment