Hygienization of Surplus Activated Sludge By Dry Ice

Nowicka, E.; Machnicka, A.

doi:10.1515/eces-2014-0047

Cited by 6 publications

(9 citation statements)

References 31 publications

(30 reference statements)

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“…Also, other authors observed a beneficial effect of sewage sludge pre-treatment with SCO 2 on its AD. As reported by Nowicka et al (2014) [27], the use of SCO 2 for SAS pre-treatment prior to AD enabled a 49% increase in biogas production in the most effective variant compared to the crude SAS [27]. At a SCO 2 /SAS ratio of 0.55/1, Zawieja (2019) [33] obtained 0.62 dm 3 /gVS biogas with a CH 4 concentration reaching ca.…”

Section: Stage 2 321 Ad Efficiencymentioning

confidence: 89%

“…S1 and S2 were divided into variants (V), depending on the volumetric ratio of SCO 2 /AGS: (control without SCO 2 ) V1, (1:10) V2, (1:5) V3, (1:3) V4, (1:2.5) V5, and (1:2) V6. The SCO 2 /AGS proportion used was estimated based on the results from the literature [27,28] and previous research [21,29]. Figure 1 presents an organizational scheme of the research.…”

Section: Experiments Organizationmentioning

confidence: 99%

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The Use of Solidified Carbon Dioxide in the Aerobic Granular Sludge Pre-Treatment before Thermophilic Anaerobic Digestion

et al. 2023

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The most common technology for the recovery of energy and valuable materials from sewage sludge is anaerobic digestion (AD). Ensuring thermophilic conditions during AD has been proven to cause process intensification and an improvement in its final outcomes. Nonetheless, the search is underway for other methods to bolster the effectiveness of the AD of aerobic granular sludge (AGS), which is characterized by a compact and complex structure. A prospective AGS pre-treatment technology entails the use of solidified carbon dioxide (SCO2). The present study focused on an evaluation of the AGS pre-treatment with SCO2 on the thermophilic AD technological effects. It evaluated the effect of the SCO2 pre-treatment method on changes in the concentrations of organic and biogenic compounds in the dissolved phase and the yield and kinetics of biogas and methane production in periodical reactors, as well as enabled the development of an empirical organizational model of biogas production. SCO2 introduced to AGS caused an increase in the content of COD, N-NH4+, and P-PO43− in the AGS dissolved phase at SCO2/AGS volumetric ratios ranging from 0 to 0.3. A further increase in the SCO2 dose did not cause any statistically significant differences in this respect. The highest biogas and methane yields were obtained at SCO2/AGS of 0.3 and reached 482 ± 21 cm3/gVS and 337 ± 14 cm3/gVS, respectively. The higher SCO2 doses used led to a significant decrease in the pH value of the AGS, which, in turn, contributed to a decreasing CH4 concentration in the biogas.

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Section: Stage 2 321 Ad Efficiencymentioning

confidence: 89%

Section: Experiments Organizationmentioning

confidence: 99%

The Use of Solidified Carbon Dioxide in the Aerobic Granular Sludge Pre-Treatment before Thermophilic Anaerobic Digestion

et al. 2023

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“…dry ice mixed with excess sludge in a volume ratio from 0.15: 1, to 0.75: 1 and assumed a 12-hour modifi cation time. According to the literature data as a result of subjecting sludge to the freezing/ thawing process, there is an increase in the concentration of organic matter in the dissolved form expressed as SCOD, VFAs as well as TOC value (Chen 2014, Gao 2011, Nowicka and Machnicka 2013. This theory has been confi rmed by research conducted by Hong et al (Hong et al 1995).…”

Section: Disintegration Of Excess Sludge With Dry Icementioning

confidence: 88%

Archives of Environmental Protection

Zawieja¹

2019

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The essence of the methane fermentation course is the phase nature of changes taking place during the process. The biodegradation degree of sewage sludge is determined by the effectiveness of the hydrolysis phase. Excess sludge, in the form of a fl occulent suspension of microorganisms, subjected to the methane fermentation process show limited susceptibility to the biodegradation. Excess sludge is characterized by a signifi cant content of volatile suspended solids equal about 65 ÷ 75%. Promising technological solution in terms of increasing the effi ciency of fermentation process is the application of thermal modifi cation of sludge with the use of dry ice. As a result of excess sludge disintegration by dry ice, denaturation of microbial cells with a mechanical support occurs. The crystallization process takes place and microorganisms of excess sludge undergo the so-called "thermal shock". The aim of the study was to determine the effect of dry ice disintegration on the course of the methane fermentation process of the modifi ed excess sludge. In the case of dry ice modifi cation reagent in a granular form with a grain diameter of 0.6 mm was used. Dry ice was mixed with excess sludge in a volume ratio of 0.15/1, 0.25/1, 0.35/1, 0.45/1, 0.55/1, 0.65/1, 0.75/1, respectively. The methane fermentation process lasting for 8 and 28 days, respectively, was carried out in mesophilic conditions at 37°C. In the fi rst series untreated sludge was used, and for the second and third series the following treatment parameters were applied: the dose of dry ice in a volume ratio to excess sludge equal 0.55/1, pretreatment time 12 hours. The increase of the excess sludge disintegration degree, as well as the increase of the digestion degree and biogas yield, was a confi rmation of the supporting operation of the applied modifi cation. The mixture of reactant and excess sludge in a volume ratio of 0.55/1 was considered the most favorable combination. In relation to not prepared sludge for the selected most favorable conditions of excess sludge modifi cation, about 2.7 and 3-fold increase of TOC and SCOD values and a 2.8-fold increase in VFAs concentration were obtained respectively.In relation to the effects of the methane fermentation of non-prepared sludge, for modifi ed sludge, about 33 percentage increase of the sludge digestion degree and about 31percentage increase of the biogas yield was noticed.

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“…For destruction of WAS, the dry ice was used in the volume ratios of the WAS to dry ice − 1:1. In our previous work, we dealt with the efficiency of sludge disintegration and then anaerobic digestion supported with the use of dry ice (Nowicka et al 2014 ; Nowicka and Machnicka 2015 ).…”

Section: Methodsmentioning

confidence: 99%

The effect of pre-treatment and anaerobic digestion for pathogens reduction in agricultural utilization of sewage sludge

Machnicka

Grűbel

2022

Environ Sci Pollut Res

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The aim of the research work was to explain the possibilities of application of waste activated sludge (WAS) pretreatment processes prior to anaerobic digestion (mesophilic fermentation). Hydrodynamic disintegration and freezing/thawing disintegration methods were used. Based on the microbiological and parasitological analyses, a significant decrease in pathogenic bacteria, coliphages, and parasite eggs was observed. The number of bacteria analyzed (Salmonella sp., Escherichia coli, Clostridium perfringens) and coliphages were reduced from 19.3to 42.3% after hydrodynamic cavitation. A similar effect was achieved for destruction by freezing/thawing with dry ice between 7.8 and 14.9%. The effectiveness of parasite eggs reduction (Ascaris sp., Trichuris sp., Toxocara sp.) for these disintegration methods ranged from 10.7 to 29.3%. The highest results were observed for the hybrid disintegration method (hydrodynamic cavitation + dry ice disintegration) caused by a synergistic effect. Salmonella sp. in 1 gd.w. decrease about 69.7%, E. coli by 70.0%, Clostridium perfringens by 38.4%, and coliphages by 48.2%. Disruption of WAS by a hybrid method led to a reduction in the number of helminth eggs Ascaris sp. (63.8%), Trichuris sp. (64.3%), and Toxocara sp. (66.4%). After anaerobic digestion under mesophilic conditions, an additional reduction of analyzed bacterial pathogens and helminth eggs were observed. The introduction of hybrid disintegrated WAS to the fermentation chamber resulted in higher efficiency in decrease (from 1 to 23%) in comparison to the control sample (70%WAS + 30%DS (inoculum-digested sludge)).

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Hygienization of Surplus Activated Sludge By Dry Ice

Cited by 6 publications

References 31 publications

The Use of Solidified Carbon Dioxide in the Aerobic Granular Sludge Pre-Treatment before Thermophilic Anaerobic Digestion

The Use of Solidified Carbon Dioxide in the Aerobic Granular Sludge Pre-Treatment before Thermophilic Anaerobic Digestion

Archives of Environmental Protection

The effect of pre-treatment and anaerobic digestion for pathogens reduction in agricultural utilization of sewage sludge

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