scholarly journals Hydrothermal carbonization as an alternative sanitation technology: process optimization and development of low-cost reactor

2021 ◽  
Vol 1 ◽  
pp. 139
Author(s):  
Jae Wook Chung ◽  
Gabriel Gerner ◽  
Ekaterina Ovsyannikova ◽  
Alexander Treichler ◽  
Urs Baier ◽  
...  
Keyword(s):  
Total Energy ◽  
Energy Recovery ◽  
Waste Treatment ◽  
Low Cost ◽  
Resource Recovery ◽  
Hydrothermal Carbonization ◽  
Process Water ◽  
Stable Operation ◽  
Technical Feasibility ◽  
Human Faeces

Background: The provision of safe sanitation services is essential for human well-being and environmental integrity, but it is often lacking in less developed communities with insufficient financial and technical resources. Hydrothermal carbonization (HTC) has been suggested as an alternative sanitation technology, producing value-added products from faecal waste. We evaluated the HTC technology for raw human waste treatment in terms of resource recovery. In addition, we constructed and tested a low-cost HTC reactor for its technical feasibility. Methods: Raw human faeces were hydrothermally treated in a mild severity range (≤ 200 °C and ≤ 1 hr). The total energy recovery was analysed from the energy input, higher heating value (HHV) of hydrochar and biomethane potential of process water. The nutrient contents were recovered through struvite precipitation employing process water and acid leachate from hydrochar ash. A bench-scale low-cost reactor (BLR) was developed using widely available materials and tested for human faeces treatment. Results: The hydrochar had HHVs (23.2 - 25.2 MJ/kg) comparable to bituminous coal. The calorific value of hydrochar accounted for more than 90% of the total energy recovery. Around 78% of phosphorus in feedstock was retained in hydrochar ash, while 15% was in process water. 72% of the initial phosphorus can be recovered as struvite when deficient Mg and NH4 are supplemented. The experiments with BLR showed stable operation for faecal waste treatment with an energy efficiency comparable to a commercial reactor system. Conclusions: This research presents a proof of concept for the hydrothermal treatment of faecal waste as an alternative sanitation technology, by providing a quantitative evaluation of the resource recovery of energy and nutrients. The experiments with the BLR demonstrate the technical feasibility of the low-cost reactor and support its further development on a larger scale to reach practical implementation.

scholarly journals Process Waters from Hydrothermal Carbonization of Sludge: Characteristics and Possible Valorization Pathways

2020 ◽  
Vol 17 (18) ◽  
pp. 6618
Author(s):  
Michela Langone ◽  
Daniele Basso
Keyword(s):  
Heavy Metals ◽  
State Of The Art ◽  
Value Added ◽  
Hydrothermal Carbonization ◽  
Process Water ◽  
Technical Feasibility ◽  
Toxic Compounds ◽  
Sludge Characteristics ◽  
Innovative Process ◽  
Feasibility Constraints

Hydrothermal carbonization (HTC) is an innovative process capable of converting wet biodegradable residues into value-added materials, such as hydrochar. HTC has been studied for decades, however, a lack of detailed information on the production and composition of the process water has been highlighted by several authors. In this paper the state of the art of the knowledge on this by-product is analyzed, with attention to HTC applied to municipal and agro-industrial anaerobic digestion digestate. The chemical and physical characteristics of the process water obtained at different HTC conditions are compared along with pH, color, organic matter, nutrients, heavy metals and toxic compounds. The possibility of recovering nutrients and other valorization pathways is analyzed and technical feasibility constraints are reported. Finally, the paper describes the main companies which are investing actively in proposing HTC technology towards improving an effective process water valorization.

scholarly journals Conversion of Slaughterhouse Wastes to Solid Fuel Using Hydrothermal Carbonization

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1768
Author(s):  
Jongkeun Lee ◽  
Sungwan Cho ◽  
Daegi Kim ◽  
JunHee Ryu ◽  
Kwanyong Lee ◽  
...  
Keyword(s):  
Solid Fuel ◽  
Energy Recovery ◽  
Waste Treatment ◽  
Value Added ◽  
Hydrothermal Carbonization ◽  
Treatment Temperature ◽  
Environmentally Benign ◽  
Retention Efficiency ◽  
Heating Value ◽  
Energy Retention

In this study, cattle and pig slaughterhouse wastes (SHWs) were hydrothermally carbonized at 150–300 °C, and the properties of SHW-derived hydrochar were evaluated for its use as a solid fuel. The results demonstrated that increasing the hydrothermal carbonization (HTC) treatment temperature improved the energy-related properties (i.e., fuel ratio, higher heating value, and coalification degree) of both the cattle and pig SHW-derived hydrochars. However, the improvements of cattle SHW-derived hydrochars were not as dramatic as that of pig SHW-derived hydrochars, due to the lipid-rich components that do not participate in the HTC reaction. In this regard, there was no merit of using HTC treatment on cattle SHW for the production of hydrochar or using the hydrochar as a solid fuel in terms of energy retention efficiency. On the other hand, a mild HTC treatment at approximately 200 °C was deemed suitable for converting pig SHW to value-added solid fuel. The findings of this study suggest that the conversion of SHWs to hydrochar using HTC can provide an environmentally benign method for waste treatment and energy recovery from abandoned biomass. However, the efficiency of energy recovery varies depending on the chemical composition of the raw feedstock.

scholarly journals Energy Recovery Potential in Industrial and Municipal Wastewater Networks Using Micro-Hydropower in Spain

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 691
Author(s):  
Aida Mérida García ◽  
Juan Antonio Rodríguez Díaz ◽  
Jorge García Morillo ◽  
Aonghus McNabola
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Energy Recovery ◽  
Energy Production ◽  
Municipal Wastewater ◽  
Distribution Networks ◽  
Total Power ◽  
Energy Potential ◽  
Total Energy Consumption ◽  
Recovery Potential

The use of micro-hydropower (MHP) for energy recovery in water distribution networks is becoming increasingly widespread. The incorporation of this technology, which offers low-cost solutions, allows for the reduction of greenhouse gas emissions linked to energy consumption. In this work, the MHP energy recovery potential in Spain from all available wastewater discharges, both municipal and private industrial, was assessed, based on discharge licenses. From a total of 16,778 licenses, less than 1% of the sites presented an MHP potential higher than 2 kW, with a total power potential between 3.31 and 3.54 MW. This total was distributed between industry, fish farms and municipal wastewater treatment plants following the proportion 51–54%, 14–13% and 35–33%, respectively. The total energy production estimated reached 29 GWh∙year−1, from which 80% corresponded to sites with power potential over 15 kW. Energy-related industries, not included in previous investigations, amounted to 45% of the total energy potential for Spain, a finding which could greatly influence MHP potential estimates across the world. The estimated energy production represented a potential CO2 emission savings of around 11 thousand tonnes, with a corresponding reduction between M€ 2.11 and M€ 4.24 in the total energy consumption in the country.

Ecological Waste Treatment and Utilization Systems on Low-Cost, Energy-Saving/Generating and Resources Recoverable Technology for Water Pollution Control in China

1991 ◽  
Vol 24 (5) ◽  
pp. 9-19 ◽  
Author(s):  
Baozhen Wang
Keyword(s):  
Pollution Control ◽  
Rural Areas ◽  
Waste Treatment ◽  
Low Cost ◽  
Fish Ponds ◽  
Receiving Waters ◽  
Recoverable Resources ◽  
Urban And Rural Areas ◽  
Rice Fish ◽  
Utilization Of Wastes

Various ecological waste treatment and utilization systems (EWTUS) available in urban and rural areas in China are described, among which are land treatment and utilization systems (LTUS), eco-pond systems mainly consisting of macrohydrophytes-growing ponds, fish ponds and duck/geese ponds, and comprehensive circulation eco–systems for the treatment and utilization of wastes in rural areas, such as semi–closed eco–system in fish ponds, “rice–fish” and “rice–azolla–fish” symbiotic systems, recycling eco–systems with methane-generating digesters as central link, and comprehensive recycling eco–systems with digesters and eco–ponds as central link. In the various EWTUS, the sewage and wastewaters and other wastes are utilized and converted into various forms of recoverable resources and/or energy, while they are being purified to good quality effluents, meeting their respective discharge standards, and hence acceptable to receiving waters.

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