Evaluation of Membrane Distillation for Treating Hydrothermal Carbonization Aqueous Product (HAP) from Dairy Manure
Authors
Silva, Nicholas Andrew
Issue Date
2020
Type
Thesis
Language
Keywords
Dairy Manure Management , Membrane Distillation , Nutrient Recovery , Water Treatment
Alternative Title
Abstract
Membrane distillation (MD) is a thermally driven separation process that has promise in water and wastewater treatment. Hydrothermal carbonization (HTC) is a thermal treatment process that converts organic matter, such as dairy manure, into a low-grade coal with a byproduct of HTC aqueous product (HAP). The HAP contains the water-soluble components of dairy manure, including nutrients and dissolved organic matter. In this work, HAP produced at HTC temperatures of 200 °C, 230 °C, and 260 °C along with synthetic solutions of glucose, tryptone, or yeast extract were treated using MD to assess its ability to concentrate the nutrients in the presence of dissolved organic matter. Impressive rejections of N and P (> 99%) were observed in each case, with varying degree of fouling and flux decline. Little fouling was observed when treating glucose and 200 °C HAP, though significant fouling was observed for 230 and 260 °C HAP samples, demonstrating the effect of carbon speciation on water flux. Volatile organic matter can still pass through the membrane during the MD process, so further investigation of the effect of volatility on MD performance was conducted. A collection of 76 volatile, semi-volatile, and non-volatile organic solutes was studied to determine which physicochemical properties affect membrane rejection and mass transport. A contaminant concentration model (CCM) was used to estimate the transport coefficients of the organic solutes, which were then compared to laboratory-scale experimental data. Results found that flux through the membrane could be predicted accurately using the CCM for solutes with log(vapor pressure) > 1.46 [Pa], boiling temperatures < 206 °C, enthalpy of vaporization < 44.5 kJ/mol, or log(Henrys) > -0.440 [Pa*m3/mol].
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Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 United States