Hydrothermal Carbonization—A Sustainable Approach to Deal with the Challenges in Sewage Sludge Management

Ekanthalu, Vicky Shettigondahalli; Morscheck, Gert; Narra, Satyanarayana; Nelles, Michael

doi:10.1007/978-981-15-0532-4_29

Cited by 10 publications

(3 citation statements)

References 8 publications

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“…The sewage sludge used in this study had a moisture content of 78.00% and a total solid content of 22.00%. The initial analysis depicted that the sewage sludge had an ash content of 33.64% DM at 815 °C and volatile solids (VS) of 65.00% DM, which was consistent with the previous investigation ranges (Peng et al, 2016;Wang et al, 2017;Shettigondahalli Ekanthalu et al, 2020). The final analysis results had a typical value for C-H-N-S-O content for sewage sludge in Germany (Roskosch and Heidecke, 2018), with C: 34.70%; H: 4.90%; N: 4.80%; S: 1.60%; and O: 17.60% on a dry basis.…”

Section: Characteristics Of Sewage Sludge and Consequently Produced H...supporting

confidence: 89%

Acid leaching of hydrothermally carbonized sewage sludge: phosphorus recovery and hydrochar characteristics

Shettigondahalli Ekanthalu,

Ender,

Narra

et al. 2023

Front. Environ. Eng.

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The options for managing sewage sludge and its utilization as fertilizer are becoming progressively limited as a result of stringent environmental regulations imposed by the European Union over the past 10 years. The limitation of moisture present in sewage sludge that affects conventional treatment options like incineration can be obviated by using the hydrothermal carbonization (HTC) process. This research investigates the acid leaching of hydrochar produced by hydrothermally carbonizing sewage sludge. The objective is to investigate and compare the effects of formic acid (HCOOH), sulfuric acid (H2SO4), and acetic acid (CH3COOH) at varying pH levels on total phosphorus (TP) mobilization and hydrochar properties. The impact of independent parameters such as carbonization temperature of hydrochar, acid type, acid concentration, and acid leaching retention time on the TP mobilization, chemical oxygen demand (COD) of the leachate, and the fuel characteristic of the hydrochar was explored. A quadratic and cubic model was proposed to correlate the effects of independent parameters on TP and ortho-P mobilization, acid need, COD of leachate, and fuel characteristics of hydrochar using Design of Experiments and Response Surface Modeling. This approach was chosen in order to maximize the amount of data from a constrained number of experimental trials. The outcome of the study indicated a fractional amount of H2SO4 was enough to reach and maintain the lower pH in hydrochar slurry compared to HCOOH and CH3COOH. TP mobilization from solid to liquid is highly favorable in the presence of H2SO4 at lower pH compared to HCOOH and CH3COOH under similar reaction conditions. In addition, it was discovered that lowering the pH using HCOOH and H2SO4 to acid-leach the hydrochar boosted the caloric value of the hydrochar. However, CH3COOH has a contradictory effect.

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Section: Characteristics Of Sewage Sludge and Consequently Produced H...supporting

confidence: 89%

Acid leaching of hydrothermally carbonized sewage sludge: phosphorus recovery and hydrochar characteristics

Shettigondahalli Ekanthalu,

Ender,

Narra

et al. 2023

Front. Environ. Eng.

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“…The future for sewage sludge management will be the replacement of direct or indirect agricultural application with thermal valorization, with a subsequent step of phosphorous recovery [ 1 ]. This will have to be achieved by implementing traditional or innovative technologies for thermal valorization, such as, for example, the hydrothermal carbonization, intended to produce high energy density hydrochar [ 32 , 33 , 34 ]. This solution will be compulsory at least for large WWTPs, with a treating capacity of more than 20,000 or 50,000 e.i.…”

Section: Discussion: Solutions For a Future Sustainable Managementmentioning

confidence: 99%

Production and Destination of Sewage Sludge in the Piemonte Region (Italy): The Results of a Survey for a Future Sustainable Management

Campo

Cerutti

Lastella

et al. 2021

IJERPH

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The management of sewage sludge originated from municipal wastewater treatment plants (WWTPs) is an urgent issue. In 2019, the local authority of the Piemonte region started a survey with the aim of collecting recent data concerning wastewater and sludge management in the WWTPs located in its own territory. The survey’s results revealed that 60% of the sludge (51,000 t, as dry substance, d.s.) produced by the local WWTPs was recovered or disposed of outside of the region, and a similar amount of sludge was recovered in agriculture directly or after composting. The increase in the costs to accommodate sewage sludge in recovery or disposal plants, followed to a recent Italian Sentence (27958/2017), and the more and more stringent requirements fixed by lots of European countries for the application of sludge in agriculture, are pushing the Piemonte region authority to re-organize its own network for sludge management, with solutions based onto proximity and diversification. Whether the provisions of the current German legislation are applied in the future also in Italy, approx. 90% of sewage sludge produced into the Piemonte region should be incinerated, with a subsequent step of phosphorous recovery. The new regional plan, according to the Regional Address Deed, should consider a diversification of sludge treatment and recovery practices. On this basis, a need for new plants for around 40,000 t d.s./y could be planned.

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“…It is a fast process that has a much shorter residence time than dry pyrolysis. However, there are contrasting data on the consistency of the eco-friendly nature of the process, even if tar is not produced and the ash content is reduced [258,259].…”

Section: Benefits and Limitationsmentioning

confidence: 99%

Nature-Based Units as Building Blocks for Resource Recovery Systems in Cities

Hullebusch

Bani

Carvalho³

et al. 2021

Water

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Cities are producers of high quantities of secondary liquid and solid streams that are still poorly utilized within urban systems. In order to tackle this issue, there has been an ever-growing push for more efficient resource management and waste prevention in urban areas, following the concept of a circular economy. This review paper provides a characterization of urban solid and liquid resource flows (including water, nutrients, metals, potential energy, and organics), which pass through selected nature-based solutions (NBS) and supporting units (SU), expanding on that characterization through the study of existing cases. In particular, this paper presents the currently implemented NBS units for resource recovery, the applicable solid and liquid urban waste streams and the SU dedicated to increasing the quality and minimizing hazards of specific streams at the source level (e.g., concentrated fertilizers, disinfected recovered products). The recovery efficiency of systems, where NBS and SU are combined, operated at a micro- or meso-scale and applied at technology readiness levels higher than 5, is reviewed. The importance of collection and transport infrastructure, treatment and recovery technology, and (urban) agricultural or urban green reuse on the quantity and quality of input and output materials are discussed, also regarding the current main circularity and application challenges.

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Hydrothermal Carbonization—A Sustainable Approach to Deal with the Challenges in Sewage Sludge Management

Cited by 10 publications

References 8 publications

Acid leaching of hydrothermally carbonized sewage sludge: phosphorus recovery and hydrochar characteristics

Acid leaching of hydrothermally carbonized sewage sludge: phosphorus recovery and hydrochar characteristics

Production and Destination of Sewage Sludge in the Piemonte Region (Italy): The Results of a Survey for a Future Sustainable Management

Nature-Based Units as Building Blocks for Resource Recovery Systems in Cities

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