Evaluation of the slurry management strategy and the integration of the composting technology in a pig farm – Agronomical and environmental implications. (1st May 2017)

• Record Type: Journal Article
• Authors: Sáez, José A.; Clemente, Rafael; Bustamante, M. Ángeles; Yañez, David; Bernal, M. Pilar
• Is Part Of: Journal of environmental management. Volume 192(2017)
• Page Start: 57
• Page End: 67
• Publication Date: 2017-05-01
• Subjects: Compost -- Greenhouse gases -- Management system -- Pig slurry -- Solid-liquid separation; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2017.01.040
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: The changes in livestock production systems towards intensification frequently lead to an excess of manure generation with respect to the agricultural land available for its soil application. However, treatment technologies can help in the management of manures, especially in N-surplus areas. An integrated slurry treatment system based on solid-liquid separation, aerobic treatment of the liquid and composting the solid fraction was evaluated in a pig farm (sows and piglets) in the South of Spain. Solid fraction separation using a filter band connected to a screw press had low efficiency (38%), which was greatly improved incorporating a rotatory sieve (61%). The depuration system was very efficient for the liquid, with total removal of 84% total solids, 87% volatile solids, and 98% phosphorus. Two composting systems were tested through mechanical turning of: 1- a mixture of solid fraction stored for 1 month after solid-liquid separation and cereal straw; 2- recently-separated solid fraction mixed with cotton gin waste. System 2 was recommended for the farm, as it exhibited a fast temperature rise and a long thermophilic phase to ensure compost sanitisation, and high recovery of nutrients (TN 77%, P and K > 85%) and organic matter (45%). The composts obtained were mature, stable and showed a high degree of humification of their organic matter, absence of phytotoxicity and concentrations of nutrients similar to other composts from pig manure or separated slurry solids. However, the introduction of slurry from piglets into the solid-liquid separation system should be avoided in order to reduce the content of Zn in the compost, which lowers its quality. The slurry separation followed by composting of the solid fraction using a passive windrow system, and aeration of the liquid phase, was the most recommendable procedure for the reduction of GHG emissions on the farm. Graphical abstract: Highlights: Pig slurry treatment systems were studied under real farm conditions. Efficiency of solid-liquid separation and liquid depuration was evaluated. Composting technology was incorporated for solid fraction treatment. Management strategies were assessed for the reduction of GHG emissions on the farm.