Dissertation/Thesis Abstract

Full Scale Study of Pathogen, Metal Pollutants, Nutrients, and Polybrominated Diphenyl Ethers in Class a Biosolids Stabilized by Thermal Hydrolysis and Anaerobic Digestion Processes
by Wang, Xuanzhao, M.S., University of Maryland, College Park, 2017, 135; 10620721
Abstract (Summary)

Class A biosolids are solid by-product of wastewater treatment which meet Environmental Protection Agency requirements to be used as fertilizer in farms, vegetable gardens, and can be sold directly to consumers. In 2014, this study’s target nutrient recovery facility adopted thermal hydrolysis pretreatment and anaerobic digestion to upgrade biosolids quality from Class B (previously lime-stabilized) to Class A. In order to certify if this newly produced material met all regulatory requirements, we performed laboratory analysis to characterize fecal coliforms, volatile solids, and metals content. In addition, we showed a baseline for nutrient management of total nitrogen, phosphorus, and the change in levels of polybrominated diphenyl ethers (PBDEs). Samples were collected for over a year since the start of THP-AD operation. Results were compared with the Class B biosolids produced at the same facility. Based on EPA standards, Class A biosolids were produced with stable quality after March, 2015, 16 weeks after process initiation. This work suggests that THP-AD is effective in producing Class A biosolids. In general, PBDEs in biosolids decreased from 1790 ± 528 (Class B) to 720 ± 110 µg/kg d.w. Our results suggest that the total levels of PBDEs decrease, however, the impact of the THP-AD on specific congeners are complex.

Indexing (document details)
Advisor: Torrents, Alba
Commitee: Andrade, Natasha Almeida, Kjellerup, Birthe Veno
School: University of Maryland, College Park
Department: Civil Engineering
School Location: United States -- Maryland
Source: MAI 57/01M(E), Masters Abstracts International
Subjects: Environmental engineering
Keywords: Anaerobic digestion, Biosolids, PBDEs, Thermal hydrolysis
Publication Number: 10620721
ISBN: 978-0-355-30125-0
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