Alkaline Pretreatment of Kraft Mill Sludge to Improve Its Anaerobic Digestion

Navia, Rodrigo; Esparza-Soto, Mario; Vidal, Gladys; Bornhardt, C.; Díez, M.C.

doi:10.1007/s00128-002-0140-4

Cited by 51 publications

(35 citation statements)

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“…Addition of an alkaline agent led to an increase of COD solubilization, as shown in Fig 3. In fact, after 1 h, soluble COD was stable and reached 9.3% at pH 10 and 30.7% at pH 12, that is to say close to the results given by Navia et al, 3 who observed a solubilization rate of kraft mill aerobic sludge equal to 32% after 24 h of treatment with 80 meq NaOH dm −3 . Nevertheless, study of the TS and VS actually solubilized (Fig 4) showed that the main part of TS solubilized was composed of mineral matter.…”

Section: Influence Of Alkali Treatment At Room Temperaturesupporting

confidence: 89%

“…It was a mechanically stirred autoclave, controlled in temperature via regulation using a Proportional Integral Derivative (PID). The autoclave was equipped with an Hastelloy C tank with a volume of 700 cm 3 . The increase in temperature needed from 30 to 60 min, depending upon the temperature.…”

Section: Materials and Methods Sludgementioning

confidence: 99%

“…• C. Feed and draw off, of a 50 cm 3 volume, was carried out each day by peristaltic pumps, in order to reach a 20 days Hydraulic Retention Time. Biogas production was measured by water moving in graduated test tubes linked to the reactors.…”

Section: Anaerobic Digestion Reactorsmentioning

confidence: 99%

“…Thermal pre-treatments induced an increase in WAS biodegradability as biogas production increased, after 23 days of test, from 54 cm 3 for raw WAS to 65 cm 3 with sludge pre-treated at 130…”

Section: Effects Of Thermo-chemical Pre-treatmentmentioning

confidence: 99%

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Thermal, chemical and thermo‐chemical pre‐treatment of waste activated sludge for anaerobic digestion

Valo

Carrère

Delgenès

2004

J of Chemical Tech & Biotech

321

148

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Abstract:The influence of different pre-treatments was studied in order to observe the effects of temperature, pH and treatment time on Waste Activated Sludge (WAS) solubilization, and anaerobic digestion of pre-treated sludge. Results showed that thermo-chemical pre-treatments were the most efficient on Chemical Oxygen Demand (COD) solubilization, which could reach 83% at 170• C with pH=12. Yet, increase in COD solubilization in thermo-chemical pre-treatment was not linked to an increase in soluble Volatile Solids (VS) as optimal conditions were 170• C, and 130• C with pH=10, for this criterion. So, temperature was found to be the most influential parameter on COD and VS solubilization. Biodegradability batch anaerobic tests confirmed results obtained on WAS solubilization, that is to say that 170• C and 130• C with pH=10 were optimal conditions, with respectively 45% and 21% of anaerobic digestion enhancement. Thus these two conditions were chosen for sludge treatment before continuous anaerobic digestion. Results, after stabilization have shown a better efficiency of 170• C compared with 130• C with pH=10 pre-treatment, since after anaerobic digestion it led to 71% of COD degradation and 59% of Total Solids (TS) degradation, with an improvement of 54% in biogas production. The main differences between those two pre-treatments could be due to the pre-treatments themselves more than to an effect on anaerobic digestion, because the first one led to a partial loss of WAS COD (near 17% of initial COD) and the second one to an increase in TS due to addition of base.

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Section: Influence Of Alkali Treatment At Room Temperaturesupporting

confidence: 89%

Section: Materials and Methods Sludgementioning

confidence: 99%

Section: Anaerobic Digestion Reactorsmentioning

confidence: 99%

Section: Effects Of Thermo-chemical Pre-treatmentmentioning

confidence: 99%

See 2 more Smart Citations

Thermal, chemical and thermo‐chemical pre‐treatment of waste activated sludge for anaerobic digestion

Valo

Carrère

Delgenès

2004

J of Chemical Tech & Biotech

321

148

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“…When compared with other pretreatment methods, alkaline treatment was more efficient because of a simple device, convenience of operation, and high efficiency (Navia et al 2002;Kim et al 2003;Neyens et al 2004;Carballa et al 2006). The alkaline treatment destroys floc structures and cell walls by hydroxyl anions.…”

Section: Introductionmentioning

confidence: 99%

Effects of sludge pretreatment on sludge reduction in a lab-scale anaerobic/anoxic/oxic system treating domestic wastewater

Uan

Yeom

Arulazhagan

et al. 2012

Int. J. Environ. Sci. Technol.

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Excess sludge disposal is one of the serious challenges in biological wastewater treatment. Reduction of sludge production would be an ideal way to solve sludgeassociated problems rather than the post-treatment of the sludge produced. In this study, a new wastewater treatment process combining anaerobic/anoxic/oxic system with thermochemical sludge pretreatment was tested in a laboratory scale experiment. In this study, the effects of the sludge pretreatment on the excess sludge production in anaerobic/anoxic/oxic were investigated. The system was operated in two Runs (1 and 2). In Run 1, the system was operated as a reference and in Run 2, a part of the mixed liquid was pretreated thermochemically and was returned to the bioreactor. The average solubilization efficiency of pretreated sludge was found to be about 35 % during the study period of 220 days. Sludge production rate in Run 2 was less than that in Run 1 by about 52 %. Total phosphorous was removed by enhanced biological phosphorous removal with the removal efficiency of 83-87 % and 81-83 % for Run 1 and Run 2, respectively. Total nitrogen removal in Run 2 (79-82 %) was slightly higher than that in Run 1 (68-75 %). The mixed liquor suspended solids/ mixed liquor volatile suspended solids ratio was identical after both runs in the range 78-83 %. The effluent water qualities were not significantly affected when operated with thermochemical pretreatment at pH 11 and 60°C for 3 h during 7 months. From the present study it is concluded that thermochemical sludge pretreatment of anaerobic/anoxic/ oxic process plays an important role in reduction of sludge production.

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