Livestock wastewater contains a large amount of nutrients that are available for recovery. In this study, a proof of concept process based on forward osmosis (FO) was proposed and investigated for in-situ formation of struvite from digested swine wastewater. This FO system took advantage of a drawback reverse solute flux (RSF) and used the reversed-fluxed Mg^{2+} for struvite precipitation, thereby accomplishing recovery of both water and nutrient. With 0.5 M MgCl2 as a draw solution, high purity struvite formed spontaneously in the feed solution and the water flux through the FO membrane reached 3.12 LMH. The precipitated struvite was characterized and exhibited a similar composition to that of commercial struvite. The FO system achieve >50% water recovery, >99% phosphate recovery (given sufficient magnesium supply), and >93% ammonium nitrogen removal from the digested swine wastewater. The recovered products (both struvite and water) could potentially generate a value of 1.35 $ m^{-3}. The results of this study have demonstrated the feasibility of nutrient recovery from livestock wastewater facilitated by FO treatment. / Master of Science / Forward Osmosis (FO) effectively separates water from dissolved solutes with a semi-permeable membrane. This separation feature can be used in real water body to recover nutrients, concentrate wastewater for further treatment and produce energy for power plant. And the water body rich in nutrients induces the plants growth. These plants consume tons of oxygen in the water which decrease biodiversity in the water body, cause new species invasion and economical lose. The nutrients-rich water has caused trouble to our human being for decades, and one of them is livestock wastewater. Specifically, in this study, the piggery wastewater was used to be treated by FO system. FO has not been used to treat piggery waste/wastewater without additive from previous literature review. In this study, a FO reactor was built up for in-situ nutrient recovery as struvite, which is a valuable slow-release fertilizer. The experiments from this study proved the concept for in-situ struvite recovery from digested livestock wastewater via FO treatment with simultaneous water recovery, and will encourage further exploration of FO promoted resource recovery form wastes.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/81881 |
| Date | 19 January 2018 |
| Creators | Wu, Zhenyu |
| Contributors | Environmental Sciences and Engineering, He, Zhen, Wang, Zhiwu, Dietrich, Andrea M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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