Original scientific paper
https://doi.org/10.13044/j.sdewes.d8.0361
The Nitrogen Fertilizer Value of Selected South African Biosolids as Affected by Drying Depth on Beds
Eyob H. Tesfamariam
; Department of Plant and Soil Sciences, University of Pretoria, Lynnwood Rd, Hatfield, Pretoria, South Africa
Elvis M. Malobane
; Department of Plant and Soil Sciences, University of Pretoria, Lynnwood Rd, Hatfield, Pretoria, South Africa
Craig G. Cogger
; Department of Crop and Soil Sciences, Washington State University, Puyallup, Washington, United States of America
Ikenna Mbakwe
; Department of Plant and Soil Sciences, University of Pretoria, Lynnwood Rd, Hatfield, Pretoria, South Africa
Abstract
Wastewater treatment and post-treatment drying techniques play a crucial role on the fertilizer value of biosolids. The aim of this study was to investigate: the nitrogen fertilizer value of biosolids from selected biosolid treatment and post treatment dewatering techniques (a) and the effect of drying depth and time on the nitrogen content of biosolid (b). To achieve the first aim, laboratory nitrogen mineralization study was conducted using thermally-hydrolysed-biosolid, activated-biosolid, and anaerobically-digested-biosolids. To achieve the second aim five drying depths were tested (5, 10, 15, 20 and 25 cm). Nitrogen release per tonne biosolid applied was highest for activated (24 kg), and lowest for anaerobically-digested-biosolid (6 kg). Highest total nitrogen was reported for 10 cm drying depth (3.63%) (4 weeks) and lowest for 25 cm (2.64%) (8 weeks). Selection of appropriate biosolid treatment and dewatering technique is key to improve fertilizer value of biosolids.
Keywords
Thermally-hydrolysed-biosolid; Activated-sludge; Anaerobically-digested-biosolid; Lignin; Soluble compounds; Cellulose; Drying bed; Nitrogen fertilizer value.
Hrčak ID:
254736
URI
Publication date:
30.6.2021.
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