Energy and phosphorous recovery through hydrothermal carbonization of digested sewage sludge

Marin-Batista, J.D.; Mohedano, A.F.; Rodrı́guez, Juan J.; Rubia, M.A. de la

doi:10.1016/j.wasman.2020.03.004

Cited by 117 publications

(52 citation statements)

References 34 publications

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“…In another study, hydrothermal treatment of sewage sludge digestate at 180-240 • C did not result in high-rank hydrochars, due to the high ash content of the samples. However, when an acid-leaching step was added, lignite-like upgraded hydrochars were obtained and at the same time the acidic leachate was precipitated with the use of CaO to yield a total P content close to 42 mg g −1 [62]. The upgrading of hydrochar properties has also been confirmed when organic acids (e.g., oxalic acid) were used to extract and bind P [63].…”

Section: Citespace Recent Scientometric Analysis (2018-2020)mentioning

confidence: 90%

Hydrochars as Emerging Biofuels: Recent Advances and Application of Artificial Neural Networks for the Prediction of Heating Values

et al. 2020

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In this study, the growing scientific field of alternative biofuels was examined, with respect to hydrochars produced from renewable biomasses. Hydrochars are the solid products of hydrothermal carbonization (HTC) and their properties depend on the initial biomass and the temperature and duration of treatment. The basic (Scopus) and advanced (Citespace) analysis of literature showed that this is a dynamic research area, with several sub-fields of intense activity. The focus of researchers on sewage sludge and food waste as hydrochar precursors was highlighted and reviewed. It was established that hydrochars have improved behavior as fuels compared to these feedstocks. Food waste can be particularly useful in co-hydrothermal carbonization with ash-rich materials. In the case of sewage sludge, simultaneous P recovery from the HTC wastewater may add more value to the process. For both feedstocks, results from large-scale HTC are practically non-existent. Following the review, related data from the years 2014–2020 were retrieved and fitted into four different artificial neural networks (ANNs). Based on the elemental content, HTC temperature and time (as inputs), the higher heating values (HHVs) and yields (as outputs) could be successfully predicted, regardless of original biomass used for hydrochar production. ANN3 (based on C, O, H content, and HTC temperature) showed the optimum HHV predicting performance (R2 0.917, root mean square error 1.124), however, hydrochars’ HHVs could also be satisfactorily predicted by the C content alone (ANN1, R2 0.897, root mean square error 1.289).

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Section: Citespace Recent Scientometric Analysis (2018-2020)mentioning

confidence: 90%

Hydrochars as Emerging Biofuels: Recent Advances and Application of Artificial Neural Networks for the Prediction of Heating Values

et al. 2020

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“…In another study by Marin-Batista et al HTC of digested sewage sludge was used for phosphorus removal. HTC carried out 180° -240° produced low-rank hydrochars, whereas acid leaching performed at 180 with CaO not only increased the hydrochar yields up to 20.5-23.1 MJ/kg, but also enhanced phosphorus sorption (Marin-Batista et al 2020).…”

Section: Nutrient Recoverymentioning

confidence: 99%

A Review on Sewage Sludge Valorization via Hydrothermal Carbonization and Applications for Circular Economy

Cebi

Çeliktaş

Sarptaş

2021

Preprint

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In pursuit of establishing a circular economy, waste-to-energy approach is gaining increasing attention. In this manner valorization of sewage sludge constitutes a critical importance due to generation in high quantities, difficulties in disposal and associating environmental impacts. Hydrothermal carbonization (HTC) is a relatively recent, however acclaimed method for sewage sludge management and valorization due to process compliance with sludge characteristics. In this review, research studies are evaluated under the categorization of application fields of sludge derived HTC products such as solid fuel production, gas production, soil remediation, nutrient recovery, water treatment and energy storage. Research findings are compiled and a network mapping is employed for the visualization of the current situation and correlation in respective fields. The potential of HTC for sewage sludge valorization and future projections concerning available techniques are assessed within the context of circular economy.

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“…The transformation and distribution of P during HTC of SS has been investigated in many recent studies [21][22][23][24]. Zhai et al [24] showed that feedwater pH affected the P species of HC from SS.…”

Section: Introductionmentioning

confidence: 99%

Acid-Induced Phosphorus Release from Hydrothermally Carbonized Sewage Sludge

Pérez

Boily

Jansson

et al. 2021

Waste Biomass Valor

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Phosphorus (P) recovery from P-rich residues is crucial to sustain food and industrial demands globally, as phosphate rock reserves are being depleted. The aim of this study is to investigate the speciation and recovery of P from hydrochars (HC) of a metal-bearing sewage sludge (SS) produced by hydrothermal carbonization (HTC). We here focus on extractions by acid leaching as P cannot be directly recovered by HTC due to insoluble metal-P compounds. Acid leaching of SS and HCs was investigated using H2SO4 and HCl over a range of leaching times, and explained in terms of how composition affects P and metal release efficiency. HTC at 180, 215 and 250 °C showed that P remained immobilized (> 75% of total P) in the HCs. More than 95% was present as inorganic P, and was the direct consequence of the double addition of iron salts in the wastewater treatment plant. Leaching experiments in 2.5 M acid solutions showed that a near complete release of P could be achieved in HCs, while it was only incomplete in SS (up to 85%). Lower acid concentrations were ineffective for total P recovery. Treatment temperature exceeding 180 °C however decreased P release rates, such that total removal took at least 2 h of reaction time instead of a few minutes. On the other hand, acid leaching transferred more than 70% of iron, manganese, copper and zinc into the leachate, necessitating a post-treatment purification process. This work therefore reveals that HC produced at low HTC temperatures could offer promising avenues for time- and energy-efficient P recovery from SS. Graphic Abstract

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Energy and phosphorous recovery through hydrothermal carbonization of digested sewage sludge

Cited by 117 publications

References 34 publications

Hydrochars as Emerging Biofuels: Recent Advances and Application of Artificial Neural Networks for the Prediction of Heating Values

Hydrochars as Emerging Biofuels: Recent Advances and Application of Artificial Neural Networks for the Prediction of Heating Values

A Review on Sewage Sludge Valorization via Hydrothermal Carbonization and Applications for Circular Economy

Acid-Induced Phosphorus Release from Hydrothermally Carbonized Sewage Sludge

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