Infiltration mechanism controls nitrification and denitrification processes under dairy waste lagoon

S. Baram, S. Arnon, Z. Ronen, D. Kurtzman, O. Dahan

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Earthen waste lagoons are commonly used to store liquid wastes from concentrated animal feeding operations. The fate of ammonium (NH+ 4) and nitrate (NO- 3) was studied in the vadose zone below earthen-clay dairy farm waste lagoons using three independent vadose zone monitoring systems. Th e vadose zone was monitored from 0.5 to 30 m below land surface through direct sampling of the sediment porewater and continuous measurement of the sediment profile's water content variations. Four years of monitoring revealed that wastewater infiltration from the lagoon is controlled by two mechanisms: slow (mm d-1), constant infiltration from the lagoon bed; and rapid (m h-1) infiltration of wastewater and rainwater via preferential flow in desiccation cracks formed in the unsaturated clay sediment surrounding the lagoon banks. The preferential flow mechanism is active mainly during wastewater-level fluctuations and intensive rain events. The vadose zone below the waste sources remained unsaturated throughout the monitoring period,and all infiltrating NH+ 4 was oxidized in the upper 0.5 m. The NH+ 4 oxidation (nitrification) was coupled with NO- 3 reduction(denitrification) and depended on the sediment water content,which was controlled by the infiltration mechanism. Coupled nitrification-denitrification (CND) resulted in 90 to 100% reduction in the total nitrogen mass in the vadose zone, with higher removal under high water content (~0.55 m3 m-3). Mass balance of nitrogen and isotopic composition of NO- 3 indicated that CND,rather than cation exchangecapacity, is the key factor regulating nitrogen's fate in the vadose zone underlyingearthen waste lagoons.

Original languageEnglish
Pages (from-to)1623-1632
Number of pages10
JournalJournal of Environmental Quality
Volume41
Issue number5
DOIs
StatePublished - 1 Sep 2012

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Management, Monitoring, Policy and Law

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