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Performance and applications of dewatering technologies

(v) Operational and maintenance costs: Long-term reduction percentage of the biodigestate parameters
operational costs, including maintenance, labor, after 72 h of sun drying is represented in Figure 3.
and replacement parts, influence the overall In the same study, the combination of sun drying
economic viability of a dewatering system. and dewatering processes was employed to evaluate
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Machines with complex mechanical components, their effectiveness in reducing the moisture content
such as decanter centrifuges, may require frequent in the biogas slurry sample. The weight of the
maintenance and skilled labor, increasing their biodigestate reduced from 95.44 kg to 32.74 kg.
operating expenses. Conversely, screw presses The pH value changed from 8.4 to 7.8, whereas the
and belt filters have simpler designs with lower concentration of total solids changed from 15.95%
maintenance requirements, making them cost- to 24.32%. In terms of nutrient retention, the total
effective alternatives. 33 Kjeldahl nitrogen increased from 0.36% to 0.42%, the
(vi) Environmental impact and sustainability: available phosphorus decreased from 81.48 mg/kg to
Sustainability considerations include waste 70.84 mg/kg, and the available potassium decreased
reduction, energy efficiency, and water reuse from 1,005 mg/kg to 911.44 mg/kg after dewatering.
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potential. Dewatering machines that minimize The reduction percentage of the different parameters
sludge volume and enhance resource recovery of the biodigestate after dewatering is represented in
contribute to environmental sustainability. In Figure 4.
addition, low-chemical or chemical-free dewatering
methods are preferred to reduce the environmental An experimental testing and performance analysis
footprint. 43 was conducted on a dewatering machine by varying
(vii) Adaptability to different materials: Different
industries require dewatering machines with
varied capabilities to handle materials with
diverse compositions, viscosities, and particle
sizes. Some machines perform well with fibrous
materials, such as in the pulp and paper industry,
whereas others are designed for high-density
sludge, as seen in wastewater treatment.
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Selecting a machine that offers versatility ensures
long-term adaptability to changing process
requirements. Figure 3. Changes in parameters after 72 h of sun
drying
5. Comparative analysis of dewatering
machines

The performance of various types of dewatering
machines has been evaluated to assess their
effectiveness in different aspects. The changes
in moisture content in the dewatered digestate
in multiple studies were reviewed. Most studies
employed the sun-drying method, followed by
dewatering, to reduce the moisture content in the
biodigestate. The weight of the biodigestate was
decreased to 5.46 kg from 10.38 kg after 72 h Figure 4. Changes in parameters after the dewatering
of sun drying, along with a 30.2% increase in the process
percentage of total solids. Other than that the pH Note: The solid and liquid form both uses the
value changed from 6.9 to 4.8. In terms of nutrient combination of sun-drying and dewatering process. The
retention, the total Kjeldahl nitrogen reduced from solid form means the total amount of solid present in the
0.3% to 0.09%, the available phosphorus decreased biodigestate, whereas the liquid form means the total
from 89.67 mg/kg to 81.48 mg/kg, and the available liquid present in the bio-digestate after the dewatering
potassium from 1,637.5 mg/kg to 860 mg/kg. The process.
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Volume 22 Issue 5 (2025) 59 doi: 10.36922/AJWEP025130093