This paper summarizes the results of field studies in Tucson, Arizona, to estimate the soil aquifer treatment (SAT) effectiveness of a 5.7-ha (I4-acre) water spreading facility,the Sweetwater Underground Storage and Recovery Facility. Groundwater samples collected from the facility during 1989 to 1990 were analyzed for pathogens. A specific basin was selected during the to 1993 recharge seasons for sampling source water (tertiary effluent), poreliquid samples from the vadose zone, and groundwater during recharge. These samples were analyzed for the nitrogen species, dissolved organic carbon (DOC), and total organic halide (TaX). The results showed that the site provides effective SAT. Enteroviruses were completely removed during travel in the 37-m (120-ft) thick vadose zone. No Giardia were detected in any of the groundwater samples. The DOC and TOX were reduced by 92% and 85%, respectively. After leaching of indigenous nitrogen from the vadose zone, total nitrogen was reduced by approximately 47% during recharge. Near-surface anaerobic conditions promote denitrification. Water Environ. Res .. 67, 371 (1995).

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This paper summarizes a study to estimate the potential for dry‐well drainage of urban runoff to recharge and pollute ground water in Tucson, Arizona. We selected three candidate dry wells for study. At each site we collected samples of runoff, dry‐well sediment, vadose‐zone sediment, perched ground water, and ground water. Water content data from vadose‐zone samples suggest that dry‐well drainage has created a transmission zone for water movement at each site. Volatile organic compounds, while undetected in runoff samples, were present in dry‐well sediment, perched ground water at one site, and ground water at two sites. The concentrations of volatile organics (toluene and ethylbenzene) in the water samples were less than the corresponding EPA human health criteria. Pesticides were detected only in runoff and dry‐well sediment. Lead and chromium occurred in runoff samples at concentrations above drinking water standards. Nickel, chromium, and zinc concentrations were elevated in vadose‐zone samples at the commercial site. Of the metals, only manganese, detected at the residential site, exceeded Secondary Drinking Water Standards in ground water. It is concluded that the three dry wells examined during this study are currently not a major source of ground water pollution.