Extended Dewatering of Sewage Sludge in Solar Drying Plants

Mathioudakis, V.L.; Kapagiannidis, Anastasios G.; Athanasoulia, E.; Diamantis, Vasileios; Melidis, Paraschos; Aivasidis, A.

doi:10.1016/j.desal.2009.01.011

Cited by 53 publications

(32 citation statements)

References 6 publications

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“…The plant indoor temperature during hot campaign ranged between 28 and 47°C was always higher than the outdoor temperature values which varied between 26 and 40°C, owing to the artificial greenhouse effect. As found by Mathioudakis et al [15], and Lei et al [16], greenhouse indoor temperatures in hot periods were higher compared to external ambient temperatures. Furthermore, the values of relative humidity measured inside the pilot in night exceeded those of day in hot campaign.…”

Section: Drying Conditionssupporting

confidence: 62%

Solar Greenhouse Drying of Wastewater Sludges Under Arid Climate

Belloulid

Hamdi

Mandi

et al. 2016

Waste Biomass Valor

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Wastewater sludges were dried in an open greenhouse pilot in order to provide experimental data about solar greenhouse drying under an arid climate during hot and cold periods. Climatic conditions, solids contents and geometric dimensions were constantly measured. The shape change of samples was constantly recorded with digital scan. The results indicated that solar greenhouse drying reduced the moisture content from about 4 kg water/kg DS to 0.08 kg water/kg DS in hot period and to 0.2 kg water/kg DS in cold period in only 72 h. The higher values of drying rate were obtained in hot season. The maximum ranges obtained were 0.2 kg water/kg DS.h and 0.13 kg water/kg DS.h in hot and cold campaigns, respectively. Furthermore, a large volume reduction representing at least 80 % of initial volume was observed in both periods after 72 h of drying process. Also, shrinkage and cracks phenomena took place inside sludges. An improvement of the microbial condition of treated sludges was noted in hot campaign with a decrease by one order of magnitude after only 24 h for total and fecal coliforms and after 72 h for Clostridium perfringens, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus contents. These pathogenic bacteria were almost constant for fresh and dry sludges in cold period. The paper recommends the solar drying in hot as in cold periods under arid climate considering its average drying rate outside the rainy periods.

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Section: Drying Conditionssupporting

confidence: 62%

Solar Greenhouse Drying of Wastewater Sludges Under Arid Climate

Belloulid

Hamdi

Mandi

et al. 2016

Waste Biomass Valor

View full text Add to dashboard Cite

show abstract

“…However, in most cases it is not cost-effective because of the high energy demands and the by-product status of sludge. Therefore, for the purpose of cost controlling, many studies have focused on the design of new thermal dryers, the optimization of thermal-drying operation and the use of renewable energy (Mathioudakis et al, 2009;Deng et al, 2009;L eonard et al, 2008;Slim et al, 2008;Bennamoun, 2012). In addition, some other studies have been concerned with the drying behavior of sludge with different properties (Ruiz et al, 2007;Wang et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

A novel approach for improving the drying behavior of sludge by the appropriate foaming pretreatment

et al. 2015

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“…Therefore, this system may need to be supported with additional energy to improve final DS. Solar panels can be used to provide additional energy to reach 90% DS or to minimize required sludge drying area (Mathioudakis et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of solar sludge drying alternatives by costs and area requirements

2015

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Thermal drying is a common method to reach above 90% dry solids content (DS) in sludge. However, thermal drying requires high amount of energy and can be expensive. A greenhouse solar dryer (GSD) can be a cost-effective substitute if the drying performance, which is typically 70% DS, can be increased by additional heat. In this study feasibility of GSD supported with solar panels is evaluated as an alternative to thermal dryers to reach 90% DS. Evaluations are based on capital and O&M costs as well as area requirements for 37 wastewater treatment plants (WWTPs) with various sludge production rates. Costs for the supported GSD system are compared to that of conventional and co-generation thermal dryers. To calculate the optimal costs associated with the drying system, an optimization model was developed in which area limitation was a constraint. Results showed that total cost was minimum when the DS in the GSD (DS(m,i)) was equal to the maximum attainable value (70% DS). On average, 58% of the total cost and 38% of total required area were associated with the GSD. Variations in costs for 37 WWTPs were due to differences in initial DS (DS(i,i)) and sludge production rates, indicating the importance of dewatering to lower drying costs. For large plants, GSD supported with solar panels provided savings in total costs especially in long term when compared to conventional and co-generation thermal dryers.

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Extended Dewatering of Sewage Sludge in Solar Drying Plants

Cited by 53 publications

References 6 publications

Solar Greenhouse Drying of Wastewater Sludges Under Arid Climate

Solar Greenhouse Drying of Wastewater Sludges Under Arid Climate

A novel approach for improving the drying behavior of sludge by the appropriate foaming pretreatment

Evaluation of solar sludge drying alternatives by costs and area requirements

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