Shiyan Cheng

Date Approved


Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department or School


Committee Member

Heather Holmes, Ph. D.

Committee Member

Timothy Brewer, Ph. D.

Committee Member

Steven Pernecky, Ph. D.


The process of wastewater treatment includes the removal of inorganic solids such as sand and gravel as well as organic materials, phosphorus, and nitrogen. Activated sludge, containing a variety of living organisms, is added into the wastewater treatment system. Short-chain fatty acids (SCFAs), an energy source of the bioorganisms, are produced during activated sludge digestion, and play a significant role in phosphorus and nitrogen removal as well as the removal of organic materials during the process of wastewater treatment. Extensive research has been carried out recently in search of optimized conditions to increase the level of fatty acids in the activated sludge. It has been suggested that pH, carbohydrate concentration, sodium dodecyl sulfate (SDS), and ultrasonic sample treatment have significant effects on hydrolysis and acidogenesis. However, investigations into the effects of these variables have until now been conducted individually. In the present work, a comprehensive study of the effects of these variables on the fermentation process was carried out, following the development of a feasible method for the detection of SCFAs in activated sludge using gas chromatography with flame ionization detection. Then, SCFA production was utilized as an indicator for the efficacy of wastewater treatment using samples from the Ann Arbor Wastewater Treatment Facilities.

Included in

Chemistry Commons