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C.B. Fedler

Publications and source records attributed to C.B. Fedler.

2 recordsLinked to original sources

Modeling duckweed growth in wastewater treatment systems

Species of the genera Lemnaceae, or duckweeds, are floating aquatic plants that show great promise for both wastewater treatment and livestock feed production. Research conducted in the Southern High Plains of Texas has shown that Lemna obscura grew well in cattle feedlot runoff water and produced leaf tissue with a high protein content. A model or mathematical expression derived from duckweed growth data was used to fit data from experiments conducted in a greenhouse in Lubbock, Texas. The relationship between duckweed growth and the total nitrogen concentration in the mediium follows the Mitscherlich Function and is similar to that of other plants. Empirically derived model equations have successfully predicted the growth response of Lemna obscura.

Livestock Research for Rural Development↗

Effects of sludge filtrate on the survival and reproduction of Ceriodaphnia dubia

The objective of this study was to determine if the runoff from croplands fertilized with municipal sludge was toxic to aquatic biota and, therefore, a potential threat to either public health or the environment. Seven-day bioassays with Ceriodaphnia dubia showed that the No-Observed-Effect-Concentration (NOEC) was 24 g/L and the Lowest-Observed-Effect-Concentration (LOEC) for survival was 30 g/L for soil samples treated with 35.2 metric tonnes (MT)/ha of municipal sludge. For soil samples treated with 0 and 17.6 MT/ha of sludge, the survival rates of C. dubia were not significantly affected at concentrations of 6-30 g/L of soil. Reproduction was suppressed by 25% when daphnids were exposed to 3.3 g/L concentration of soil treated with sludge at 35.2 MT/ha. A 50% suppression of reproduction occurred when daphnids were exposed to 15 g/L concentration of soil treated with sludge at 17.6MT/ha. A sludge application rate of 17.6MT/ha suppressed reproduction at a treatment concentration of 18g/L. These data indicate that the runoff from agricultural lands treated with municipal sludge has the potential to affect reproduction in daphnids and, therefore, the environment through the aquatic food chain.

Ecotoxicology↗