Quantifying Nutrients in Effluent from Uncovered, Intact Mature Bovine Carcass Compost Piles Subjected to Storm Events

Abstract

Effluent pollutant concentrations and volumes were collected from uncovered, intact carcass, dairy cow mortality compost piles subjected to successive simulated 10.2 cm storm events after: (1) composting one cow in fresh sawdust only; (2) turning that pile, adding fresh amendment, adding a second cow, and composting it; and (3) turning the pile again, without an animal tissue addition. Phosphorus leaving an active mortality compost pile in runoff as produced by a 10.2 cm storm simulation ranged from 4.6 grams to 0.1 grams. Total COD in runoff ranged from 94 to 888 grams. Data indicated that the majority of nutrients in effluent leaving a pile from a 10.2 cm storm event infiltrate the soil surface. Total nitrogen mass load infiltrating the soil was estimated to range between 362 and 1778 grams under various management stages. With the exception of NO₃, the nutrient concentrations in groundwater at 1.2 m soil profile depth were reduced by nine fold or more when compared to direct pile effluent, indicating that soil provided treatment of infiltrating pile effluent. No significant accumulation of soil nutrients below mortality compost piles occurred during the study. However, pile effluent nutrient characteristics indicate that soil nutrient accumulation may occur over time.