Dissertation
ENHANCED ANAEROBIC DIGESTION OF DAIRY WASTEWATER
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/117176
Abstract
With a trend towards size intensification, there is growing concern about the management of large volumes of animal waste produced within concentrated animal feeding operations (CAFOs). In this respect, anaerobic digestion (AD) is an environment friendly way to extract bio-energy and reduce some of the adverse environmental impacts of animal waste. The research presented in this dissertation offers alternative approaches for conserving water by operating AD in a manner that reduces production of wastewater while also enhancing biogas production.
The first study examined the potential of recycling the digested separated liquid effluent to the front end of digester and its effects on the methane production. The results showed potential for recycling up to 80% of the separated liquid effluent with no inhibition in methane production. This operation not only saved water inputs into the digester but also resulted in 5% improvement in the methane production compared to “no recycling”. The second study evaluated the effects of various concentrations of ammonia and salinity on digester methane production and microbial dynamics during the AD process. High concentrations of ammonia impacted methane production more than corresponding levels of salinity. Moreover, different microbial communities were observed across the acclimated and un-acclimated digesters. The knowledge of microbial communities’ dynamics in relation to different states of acclimation and inhibitors is key to designing strategies for improving methane and biogas production. Finally, the third study investigated enhancement of biogas production at psychrophilic temperature via treatment of dairy manure with a cationic polymer flocculant (CPAM) in an anaerobic sequencing batch reactor (ASBR). Treating the dairy wastewater with CPAM resulted in significantly higher biogas yield than the untreated wastewater. Moreover, results indicated treating dairy wastewater with CPAM in the first few ASBR cycles was sufficient to sustain enhanced biogas production over several cycles.
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Details
- Title
- ENHANCED ANAEROBIC DIGESTION OF DAIRY WASTEWATER
- Creators
- Iftikhar Zeb
- Contributors
- Pius M Ndegwa (Advisor)Claudio O Stӧckle (Committee Member)Devendra H Shah (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Biological Systems Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 106
- Identifiers
- 99900581829701842
- Language
- English
- Resource Type
- Dissertation