Bacteriological and chemical (nitrogen, phosphorus) characterization of liquid wastes discharged by four dairy farms (Vendee, France)

摘要

Experimental device were set up on four dairy farms of a 23 km~2 watershed. Three farmsteads, including livestock buildings and characterized by different cattle numbers and levels of equipment, were hydrologically isolated to concentrate all liquide wastes flowing out to surface water at one single outlet. Grab and average effluent samples were collected through two winters (1995 and 1997). Fecal coliforms (FC) concentrations were close to 105-106 FC/100 ml. Those concentrations are similar from one farm to other, and do not depend on cattle numbers. Nitrogen losses (50% ammonia) reached 10 kg N/Livestock Unit (L. U.) between november and apris of the most rainy winter. Total phosphorus losses reached 4 kg P/L. U. (60% phosphates).