Synthesis of PHAs using Carbon Source from Ferrous Activated Persulfate Oxidation combined with Alkaline Fermentation of Excessive Activated Sludge.

Document Type

Conference Proceeding

Publication Date



Polyhydroxyalkanoates (PHAs) are considered to be one type of promising biodegradable plastics because their thermal and mechanical properties are similar to thermal plastic then offer better application. The major obstacle that hinders large-scale application of PHAs is the high production cost, including the carbon source cost and the low production yield. Studies carried out by our research team found that the PHAs can be accumulated within the bacteria in activated sludge and the production yield had been greatly improved under appropriate Carbon to Nitrogen (C:N) Ratio and Carbon to Phosphorus (C:P) Ratio. The findings suggested the PHAs production is able to combine with wastewater treatment. However, high carbon source consumption is still required for a higher production yield to offer substrate pressure for PHAs accumulation. On other hand, wastewater treatment plants produce tons of excessive activated sludge (EAS) to send to landfill sites. Recent years, advanced oxidation process (AOP) methods have been widely used to improve the efficiency of sludge fermentation and persistent chemical oxidation. Among the sludge various fermentation methods, ferrous activated persulfate oxidation method offers appropriate duration and strong oxidation effects to digest the EAS to be short-chain fatty acids(SCFAs) for PHAs production. To lower down the PHAs production cost, this study aims to reused the digested excessive activated sludge from wastewater process for PHAs synthesis. Excessive Activated Sludge (EAS) samples will be digested with persulfate and ferrous ions together with citric acid to determine the optimal concentration based on the digestion of extracellular polymeric substance (EPS) and intracellular substances detected by Three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy. The optimized digested samples will be used to adjusted the C:N ratio for PHAs production. The outcomes from this study will provide significant improvements of alkaline fermentation efficiency, reduce the EAS disposal and further lower down the production cost of PHAs.

Source Publication

The 3rd International Conference on Biological Waste as Resource 2018 (BWR2018), Hong Kong

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