Piggery wastewater characterisation for biological nitrogen removal process design

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Agricultural Pollution Control

Background:

• Biological nitrogen removal is essential for treating piggery wastewater in intensive farming areas.
• Accurate characterization of chemical oxygen demand (COD) fractions is critical for optimizing treatment plant design.
• Existing methods may not sufficiently differentiate between inert and biodegradable COD components in complex effluents.

Purpose of the Study:

• To develop and validate an experimental procedure for quantifying specific COD fractions in piggery wastewater.
• To determine the inert soluble (SI), inert particulate (XI), readily biodegradable (SS), and slowly biodegradable (XS) COD fractions.
• To assess the variability of these COD fractions based on farm management and storage conditions.

Main Methods:

• Experimental procedure development for COD fraction quantification.
• Analysis of four different piggery wastewater samples.
• Measurement of inert soluble (SI) and particulate (XI) COD.
• Measurement of readily (SS) and slowly (XS) biodegradable COD.

Main Results:

• The inert soluble (SI) and particulate (XI) COD fractions were consistently determined as 3-4 g O(2)l(-1) and 17-28 g O(2)l(-1), respectively.
• The total inert COD fraction constituted a significant portion (42-84%) of the total COD in the tested wastewaters.
• Biodegradable COD fractions (SS and XS) exhibited high variability (0-5 g O(2)l(-1) and 4-25 g O(2)l(-1)), influenced by farm practices and storage.

Conclusions:

• The developed method effectively quantifies key COD fractions in piggery wastewater.
• The substantial inert COD fraction highlights challenges and considerations for biological nitrogen removal.
• Variability in biodegradable COD necessitates adaptable treatment strategies tailored to specific farm conditions.