Environmental characteristics and water quality of hydrologic benchmark network stations in the midwestern United States, 1963-95 /

Mode of access: Internet.

Methods for comparing water-quality conditions among National Water-Quality Assessment Study Units, 1992-1995 /

Mode of access: Internet.

Geohydrology of the Antelope Valley Area, California and design for a ground-water-quality monitoring network /

Mode of access: Internet.

Ground-water-quality appraisal of sand-plain aquifers in Hubbard, Morrison, Otter Tail, and Wadena Counties, Minnesota /

Mode of access: Internet.

Nonpoint-source discharges and water quality of the Elk Creek basin, west-central Wisconsin /

Mode of access: Internet.

An overview of ground-water quality data in Wisconsin /

"February 1984."

Effects of irrigating with wastewater on ground-water quality at Fort Carson Military Reservation golf course near Colorado Springs, Colorado /

Bibliography: p. 24-25.

Ground-water quality in Wyoming /

Bibliography: p. 71.

Rainfall-runoff relationships and water-quality assessment of Coon Creek watershed, Anoka County, Minnesota /

Bibliography: p. 71-73.

Runoff and water-quality characteristics of surface-mined lands in Illinois /

Mode of access: Internet.

The problems of water quality management,

"Presented at the Water quality management training course conducted by the Water Supply and Pollution Control Training Program, Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio, March 4, 1963."

Plankton diatom species-numbers as indicators of water quality,

Caption title.

Water-quality study of the Cheney Reservoir watershed, south-central Kansas /

Mode of access: Internet.

Use of duckweed, bentonite and acid to improve water quality of effluent discharge from abattoirs

Intensive animal industries create large volumes of nutrient rich effluent, which, if untreated, has the potential for substantial environmental degradation. Aquatic plants in aerobic lagoon systems have the potential to achieve inexpensive and efficient remediation of effluent, and to recover valuable nutrients that would otherwise be lost. Members of the family Lemnaceae (duckweeds) are widely used in lagoon systems, but despite their widespread use in the cleansing of sewage, only limited research has been conducted into their growth in highly eutrophic media, and little has been done to systematically distinguish between different types of media. This study examined the growth characteristics of duckweed in abattoir effluent, and explored possible ways of ameliorating the inhibitory factors to growth on this medium. A series of pot trials was conducted to test the tolerance of duckweed to abattoir effluent partially remediated by a sojourn in anaerobic fermentation ponds, both in its unmodified form, and after the addition of acid to manipulate pH, and the addition of bentonite. Unmodified abattoir effluent was highly toxic to duckweed, although duckweed remained viable and grew sub optimally in media with total ammonia nitrogen (TAN) concentrations of up to 100 mg/l. Duckweed also grew vigorously in effluent diluted 1:4 v/v, containing 56 mg TAN/L and also modified by addition of acid to decrease pH to 7 and by adding bentonite (0.5%).