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CC BY V4.0, Open Access
Dissertation
VERMIFILTRATION AS A LOW-COST TECHNOLOGY FOR MANAGING DAIRY WASTEWATER
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000003346
Handle:
https://hdl.handle.net/2376/122461
Abstract
Dairy manure needs to be treated to mitigate its adverse impacts on the environment. Vermifiltration, an emerging low-cost and environmentally friendly wastewater treatment, is one such potential treatment. For this study, we evaluated the efficacy of a vermifilter for treating dairy wastewater with respect to effluent quality and potential mitigations of air emissions. A pilot-scale unit was installed on a commercial dairy for these evaluations. Additional studies, at a lab-scale, investigated the effects of earthworm density, organic loading rate, and hydraulic loading rate on the performance of the vermifilter. Wastewater parameters of interest included: total solids, total suspended solids, chemical oxygen demand, total nitrogen, total ammonia-nitrogen, nitrate-nitrogen, total phosphorus, and orthophosphate. The vermifilter achieved organic, nutrients, and solids reduction efficiencies of up to 90%. Results indicated that vermifiltration has a high potential to reduce organics, nutrients, and solids concentration in dairy wastewater. Results also indicated potential reductions of up to 100% of ammonia, methane, and nitrous oxide emissions, implying that vermifilters have the potential for mitigating gaseous emissions from dairy wastewater. With respect to earthworm density, organics, nutrients, and solids; reductions of up to 95% were observed, with higher reductions occurring at higher earthworm densities (>10,000 worms m-3). Eisenia fetida densities beyond 10,000 worm m-3 did not improve the performance of the vermifilter unit towards reducing either organics, nutrients, or solids in dairy wastewater. Higher reductions of organics, solids, and nutrient occurred at lower HLR (< 1 m3 m-2 d-1) and OLR (< 2.5 kg [COD] m-2 d-1). These findings suggested that HLR <1 m3 m-2 d-1 and OLR < 2.5 kg [COD] m-2 d-1 are desirable in vermifilters when the goal is to achieve higher organics, solids, and nutrients reductions during treatment of dairy wastewater. Overall, this research shows that vermifilters can effectively be used to treat dairy wastewater.
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Details
- Title
- VERMIFILTRATION AS A LOW-COST TECHNOLOGY FOR MANAGING DAIRY WASTEWATER
- Creators
- Gilbert John Miito
- Contributors
- Pius M Ndegwa (Advisor)Claudio O Stöckle (Committee Member)Joe Harrison (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Agricultural, Human, and Natural Resource Sciences, College of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 163
- Identifiers
- 99900652103801842
- Language
- English
- Resource Type
- Dissertation