Characterization of slowly-biodegradable organic compounds and hydrolysis kinetics in tropical wastewater for biological nitrogen removal
Document Type
Article
Publication Date
1-1-2020
Abstract
Many developing countries, mostly situated in the tropical region, have incorporated a biological nitrogen removal process into their wastewater treatment plants (WWTPs). Existing wastewater characteristic data suggested that the soluble chemical oxygen demand (COD) in tropical wastewater is not sufficient for denitrification. Warm wastewater temperature (30 degrees C) in the tropical region may accelerate the hydrolysis of particulate settleable solids (PSS) to provide slowly-biodegradable COD (sbCOD) for denitrification. This study aimed to characterize the different fractions of COD in several sources of low COD-to-nitrogen (COD/N) tropical wastewater. We characterized the wastewater samples from six WWTPs in Malaysia for 22 months. We determined the fractions of COD in the wastewater by nitrate uptake rate experiments. The PSS hydrolysis kinetic coefficients were determined at tropical temperature using an oxygen uptake rate experiment. The wastewater samples were low in readily-biodegradable COD (rbCOD), which made up 3-40% of total COD (TCOD). Most of the biodegradable organics were in the form of sbCOD (15-60% of TCOD), which was sufficient for complete denitrification. The PSS hydrolysis rate was two times higher than that at 20 degrees C. The high PSS hydrolysis rate may provide sufficient sbCOD to achieve effective biological nitrogen removal at WWTPs in the tropical region.
Keywords
COD fractionation, Denitrification, Low COD, N, Particulate settleable solids, Readily-biodegradable COD
Divisions
sch_che
Funders
Royal Society,Academy of Sciences Malaysia,Malaysian Industry-Government Group for High Technology (MIGHT) (NA150341/BH152910/IF008-2016),Research University Faculty Program Grant (GPF024A-2019),Ministry of Education Malaysia Fundamental Research Grant Scheme (FP047-2017A)
Publication Title
Water Science and Technology
Volume
81
Issue
1
Publisher
IWA Publishing
Publisher Location
ALLIANCE HOUSE, 12 CAXTON ST, LONDON SW1H0QS, ENGLAND