Chapter No. 10. Toxicity
Due to the presence of particular components and characteristics, biological wastewater treatment processes can be exposed to the inhibitory or even toxic effects of certain chemical or physical agents (e.g. amines, nitrites, extreme pH and temperature). While inhibition can be interpreted as the partial reduction in biological activity at either short- or long-term, toxicity is understood as the lethal effect suffered by microorganisms (leading to their death) after a relatively short-term exposure period. From a wastewater treatment perspective, one of the main consequences is a poor wastewater treatment performance unable to comply with the required effluent standards expected from a process. The effects can be reversible or irreversible dependent upon the exposition time, tolerance and/or potential adaptation of the microorganisms, concentration of the inhibitory or toxic compounds, among other factors.
This chapter presents different concepts related to how to determine and describe the effects of toxicity on biological wastewater treatment processes in three video lectures recorded by Prof. Jorge Orozco García from Instituto Tecnologico y de Estudios Superiores de Monterrey, in Monterrey, Mexico.
Time framework for the chapter: 1 week
Aims of the Chapter
· To present different techniques for the detection of inhibitory or toxic agents in biological wastewater treatment systems.
· To describe different levels and types of inhibition and commonly used models applied for their description.
· To analyze and discuss potential strategies to deal with the presence of toxic or inhibitory agents in wastewater treatment systems.
· To assess and describe through mathematical expressions the effects caused by inhibitory or toxic agents on the microbial conversions that take place in biological wastewater treatment processes.