Effects of thermal hydrolysis on organic matter solubilization and anaerobic digestion of high solid sludge

Xue, Yonggang; Liu, Huajie; Chen, Sisi; Dichtl, Norbert; Dai, Xiaohu; Li, Ning

doi:10.1016/j.cej.2014.11.005

Cited by 302 publications

(123 citation statements)

References 15 publications

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“…Influence of the factors evaluated on WAS solubilisation. Seongyeob et al, 2014;Xue et al, 2015). It is also interesting to observe that same solubilisation is obtained for the thermal treatment at high temperature e short time, and lower temperature e higher time (i.e.…”

Section: T ( C) T (Min) No Of Flashes Sb (%) Ch 4 (Ml/gvs) Dch 4 (%)mentioning

confidence: 59%

“…The increase of WAS solubilisation and parallel decrease on methane production at high pre-treatment temperature and long times, indicate that some soluble but nonbiodegradable compounds were produced during severe thermal pre-treatment. This is probably because of the production of melanoidins, as reported by many studies (Ariunbaatar et al, 2014;Xue et al, 2015).…”

Section: Optimization Of the Th Processmentioning

confidence: 75%

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Optimization of a thermal hydrolysis process for sludge pre-treatment

Sapkaite

Barrado

Fdz‐Polanco

et al. 2017

Journal of Environmental Management

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a b s t r a c tAt industrial scale, thermal hydrolysis is the most used process to enhance biodegradability of the sludge produced in wastewater treatment plants. Through statistically guided Box-Behnken experimental design, the present study analyses the effect of TH as pre-treatment applied to activated sludge. The selected process variables were temperature (130-180 C), time (5e50 min) and decompression mode (slow or steam-explosion effect), and the parameters evaluated were sludge solubilisation and methane production by anaerobic digestion. A quadratic polynomial model was generated to compare the process performance for the 15 different combinations of operation conditions by modifying the process variables evaluated. The statistical analysis performed exhibited that methane production and solubility were significantly affected by pre-treatment time and temperature. During high intensity pre-treatment (high temperature and long times), the solubility increased sharply while the methane production exhibited the opposite behaviour, indicating the formation of some soluble but non-biodegradable materials. Therefore, solubilisation is not a reliable parameter to quantify the efficiency of a thermal hydrolysis pre-treatment, since it is not directly related to methane production. Based on the operational parameters optimization, the estimated optimal thermal hydrolysis conditions to enhance of sewage sludge digestion were: 140e170 C heating temperature, 5e35min residence time, and one sudden decompression.

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Section: T ( C) T (Min) No Of Flashes Sb (%) Ch 4 (Ml/gvs) Dch 4 (%)mentioning

confidence: 59%

Section: Optimization Of the Th Processmentioning

confidence: 75%

Optimization of a thermal hydrolysis process for sludge pre-treatment

Sapkaite

Barrado

Fdz‐Polanco

et al. 2017

Journal of Environmental Management

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“…Among the well-known three steps involved in anaerobic digestion, the hydrolysis step has been identified as the rate-limiting step (Higgins and Novak, 1997).And the major reasons for the less digestibility are the microbial cell walls containing glycan strands cross-linked by peptide chains and the existence of a large amount of extracellular polymeric substances (EPS) (Devlin et al, 2011).In order to improve the hydrolysis efficiency and digestibility of sludge, various pretreatment methods also referred as sludge disintegration techniques have been investigated, including chemical treatment using alkaline, acid or ozone (Devlin et al, 2011;Li et al, 2012;Zhang et al, 2009), mechanical treatment with ultrasound, high pressure homogenizer or ball milling (Apul and Sanin, 2010;Wett et al, 2010;Zhang et al, 2012), thermal treatment (Xue et al, 2015), additional enzymes treatment (Yang et al, 2010) and some of their combinations (Kim et al, 2010;Shehu et al, 2012).These pretreatment can normally destruct sludge flocs and cell walls, release intracellular and extracellular organic matters, and consequently accelerate sludge hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

Waste activated sludge hydrolysis and acidification: A comparison between sodium hydroxide and steel slag addition

Zhang

et al. 2016

Journal of Environmental Sciences

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Waste activated sludge hydrolysis and acidification: a comparison between sodium hydroxide and steel slag addition AbstractAlkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA (volatile fatty acid) in a shorter time can be achieved at pH. 10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supernatant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment. AbstractAlkaline treatment with steel slag and NaOH addition were investigated at different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification.More solubilization of organic matters and much higher (volatile fatty acids) VFAs production at a shorter time can be achieved at pH 10 adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under same pH conditions. Phosphorus concentration in supernatant increased with fermentation time and pH in NaOH addition scenarios while in contrast most phosphorus were released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment.

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“…The solubilization of complex particulate organic compounds into simple soluble compounds such as volatile fatty acids (VFAs) was accounted as hydrolysis and acidification. They are followed by the acidogenesis step which converts VFAs to acetate and hydrogen gas that will in turn be consumed by methanogens to produce methane in the final step of the AD process [4,5]. During AD of cellulosic substrate like corn straw, hydrolysis is generally regarded as rate-limiting step [5,6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Different Mixed Microflora on the Performance of Thermophilic Microaerobic Pretreatment

Shi

Meng

et al. 2016

Energy Fuels

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h i g h l i g h t sThe effect of limited oxygen daily supplied on the AD of corn straw was studied. Daily oxygen supplied could obviously improve the AD performance of corn straw. Specific methanogenic activity under microaerobic condition improved slightly. The microbial community structure shift could explain the better AD performance. a r t i c l e i n f o b s t r a c tConventionally, oxygen is considered as inhibit factor of anaerobic digestion (AD). However, recent studies have demonstrated that AD performance could be enhanced by introducing limited amounts of oxygen (or air) directly into the anaerobic digester or during pretreatment step. In this study, impacts of microaeration on the anaerobic digestion of corn straw and the microbial community structure were investigated. Results showed that limited air introduced into fermentation system could improve the methane yield of corn straw. Maximum cumulative methane yield of 216.8 ml/g VS substrate and maximum VS removal efficiency of 54.3% were simultaneously obtained under microaerobic condition with the air load of 12.5 ml/L R per day, which were 16.5% and 10.3% higher than those of sample under anaerobic condition, respectively. Compared to anaerobic condition, the relative abundances of phylum Firmicutes, class Clostridia and order Clostridiales, which associated with hydrolysis process of AD were raised under microaerobic condition. In addition, the relative abundances of oxytolerant Methanosarcina and Methanobacterium were both doubled under microaerobic condition. Accordingly, specific methanogenic activity (SMA) under microaerobic condition improved slightly. The microbial community shift might be the reason for improved AD performance under microaerobic condition.

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Effects of thermal hydrolysis on organic matter solubilization and anaerobic digestion of high solid sludge

Cited by 302 publications

References 15 publications

Optimization of a thermal hydrolysis process for sludge pre-treatment

Optimization of a thermal hydrolysis process for sludge pre-treatment

Waste activated sludge hydrolysis and acidification: A comparison between sodium hydroxide and steel slag addition

Effect of Different Mixed Microflora on the Performance of Thermophilic Microaerobic Pretreatment

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