Recorded Trace Organic Concentrations at Selected Soil Aquifer Treatment Sites ngL

Pesticide

Endrin

Lindane

Methoxychlor

Toxaphene

2,4,5-TP silvex

Applied Wastewater

Vineland, New Jersey

Shallow Groundwater

<0.03 453-1172 <0.01 <0.1 16.4-13.0 26.8-120

Control Groundwater

10.4 185

Applied Wastewater

Milton, Wisconsin

Shallow Groundwater

Downgradient Groundwater

23.6

38.7

Source: Data from Benham-Blair & Affiliates (1979).

rate, and presence of easily degradable organics to serve as a primary substrate (Crites, 1985b). Removals studied at Phoenix, Arizona; Ft. Devens, Massachusetts; and Whittier Narrows, California, have ranged from 10 to 96%. Levels of pesticides in applied effluent and in groundwater at two SAT sites are presented in Table 8.18.

8.4.3.6 Endocrine Disruptors

Soil aquifer treatment systems have been utilized for the removal of endocrine-disrupting chemicals found in municipal wastewaters (Conroy et al., 2001; Quan-rad et al., 2002). Endocrine disruptors originate from industrial, agricultural, and domestic sources. These include a combination of natural hormones, pharmaceutical products, and industrial chemicals such as polychlorinated biphenyls, orga-nochlorine pesticides, phenoxyacid herbicides, phthalates, and tirazines. Following conventional secondary treatment, percolation through approximately 120 ft (36 m) of unconsolidated sediments to the local aquifer reduced residual estrogenic activity by >95% (Table 8.19) (Quanrad et al., 2002). The fate of micropollutants

TABLE 8.19

Fractional Attenuation of Estrogenic Activity (Relative to Primary Effluent) During Secondary Treatment and Soil Aquifer Treatment

Sample Location Fractional Removal

Primary 0.00

Secondary unchlorinated 0.62

Secondary chlorinated 0.65

Secondary dechlorinated 0.65

Storage pond 0.68

5.2 m (17 ft) 0.83 18.3 m (60 ft) 0.93 36.6 m (120 ft) 0.99

Source: USEPA, Process Design Manual for Land Treatment of Municipal and Industrial Wastewater, Center for Environmental Research Information (CERI), U.S. Environmental Protection Agency, Cincinnati, OH, 2004.

originating from pharmaceuticals and active ingredients in personal-care products have been studied at two groundwater recharge facilities in Arizona (Drewes et al., 2001). Preliminary studies indicate that groundwater recharge offers a high potential to remove acidic drugs such as lipid regulators and analgesics. Other compounds such as antiepileptic drugs and x-ray contrast agents showed no clear indication of removal during travel times of more than 6 years.

Additional studies of long-term SAT at field sites in Mesa, Arizona, indicate that substantial removal of effluent organic matter can occur. Identified trace organics were efficiently removed as a function of travel time to very low concentrations or below detection limits. Based on the characterization techniques used, the character of bulk organics present in final SAT water resembled the character of natural organic matter present in drinking water (Drewes et al., 2001).

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