VGU RESEARCH REPOSITORY
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https://epub.vgu.edu.vn/handle/dlibvgu/1806| Title: | Hydrothermal carbonization of sewage sludge products and by-products | Authors: | Nguyen Nhat Thoai | Keywords: | Sewage sludge;Carbonization;Sustainable treatment | Issue Date: | 2023 | Abstract: | The extensive generation of sewage sludge (SS) is a significant problem for the environment. Hydrothermal carbonization (HTC) has been extensively researched to reach the goal of sustainability for dealing with this abundant source. HTC is one of the processes which thermochemically turns wet biomass into hydrochar as a valuable product and process water (PW) as a considerable by-product. The mechanism of HTC process is complex but, it can be simplified into some main reactions comprising hydrolysis; dehydration, decarboxylation, deamination; polymerization, aromatization and agglomeration. During this process, temperature and moisture play vital roles for the transformation of SS into hydro-char and influence on the entire process. Besides, the involvement of reaction time, catalyst, heating rate and pressure is the optional factor to optimize HTC process. Hydro-char is known as a source containing heavy metals (HMs) and nutrient (N, P) due to such substances presenting in raw SS. The key point is that the hydro-char is able to turn the HMs from soluble and mobile forms into more stable forms. The accumulation of P in hydro-char was due to the reactions of hydrolysis, dissolution, precipitation and adsorption in HTC process. Also, N content contributes to the formation of hydro-char and also presents in the PW. Hydro-char reflects the fuel properties including molar ratios of O/C and H/C and higher heating rate (HHV) as a coal-like product. Basing on such characteristics, hydro-char is possibly applied in energy recovery, agriculture, carbon sequestration and wastewater treatment as the adsorbent. Obviously, the benefits of such solid has been approved but, its drawbacks must be carefully considered to practical application. PW, by contrast, is a burden in HTC process due to the presence of various organic matters, toxicants, and nutrient in. Such substances have been quantified and researched to understand their behaviors in the PW via several studies. Moreover, treatment methods have been focused to deal with this HTC by-product. The multi-criteria assessment (MCA) was generally conducted to identify the appropriate method. Those are the premises to propose the PW treatment scheme which possibly reaches ecological and economical optimum. The process is the combination of biological processes including anaerobic filter (AF) and sequencing batch reactor (SBR) with the tertiary process (polyacrylamide (PAM) and poly aluminum ferric sulphate (PAFS) as coagulants and powdered activated carbon (PAC) as adsorbent). Besides, the recirculation of treated PW to the wastewater treatment plant (WWTP) is remarkably vital to reach the mentioned target. The outcomes of this process still require to have further consideration |
URI(1): | https://epub.vgu.edu.vn/handle/dlibvgu/1806 | Rights: | Attribution-NonCommercial 4.0 International |
| Appears in Collections: | Water Technology, Reuse and Management (WTE) Water Technology, Reuse and Management (WTE) |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| Hydrothermal carbonization of sewage sludge products and by-products.pdf | 4.29 MB | Adobe PDF | View/Open |
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