标题:
Biophysical Evaluation of the Vadose Zone at a Landfill Site in the Niger Delta, Nigeria
作者:
Akaha C. Tse, Lucky O. Odokuma
关键词:
Attenuation, Biodegradation, Biophysical, Landfill, Vadose Zone
期刊名称:
Journal of Geoscience and Environment Protection,
Vol.4 No.4,
April
22,
2016
摘要: The
vadose zone of a landfill site proposed as an integrated waste management
facility was evaluated based on geohydrological, chemical and microbiological
characteristics of the groundwater and underlying soil. These data were also
used to assess the attenuation capacity of the zone by the use of microbial
degradation test of some major constituents including fatty acids, organic
nitrogen and chloride of the leachate for a 28-day period. The main soil type
in vadose zone consisted of brownish clayey sand of low permeability. The depth
to water table which is equal to the thickness of the vadose zone varied from 8
- 13 m. Groundwater flowed with a hydraulic gradient of approximately 4.0 × 10Dž and a pore velocity of 1.6 × 10Dž cm/sec. The results of the
biodegradation tests showed that the major constituents of the leachate such as
ammonia/organic nitrogen, phosphate and organic carbon were completely degraded
within 28 days. The population of aerobic bacteria within the 6 m soil depth
was sufficient to bring about over 0.05% organic carbon removal. The soil
characteristics in the vadose zone are very favourable for the occurrence of
natural attenuation. The potential natural attenuation capacity of the vadose
zone is therefore classified as moderate to high.