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Enhancement of Anaerobic Digestion to Treat Saline Sludge from Recirculating Aquaculture Systems.

Luo GZ, Ma N, Li P, Tan HX, Liu W - ScientificWorldJournal (2015)

Bottom Line: The effectiveness of carbohydrate addition and the use of ultrasonication as a pretreatment for the mesophilic anaerobic digestion of saline aquacultural sludge was assessed.Furthermore, soluble chemical oxygen demand (SCOD), VFA, and PO4 (3-) concentrations increased in the effluents.There was a 114% greater gas generation during the ultrasonication period, with an average production of 0.08 g COD/L · day(-1).

View Article: PubMed Central - PubMed

Affiliation: College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China ; Shanghai Collaborative Innovation Center for Aquatic Animal Genetics and Breeding, Shanghai 201306, China ; Research and Development Center of Aquacultural Engineering of Shanghai, Shanghai 201306, China.

ABSTRACT
The effectiveness of carbohydrate addition and the use of ultrasonication as a pretreatment for the mesophilic anaerobic digestion of saline aquacultural sludge was assessed. Analyses were conducted using an anaerobic sequencing batch reactor (ASBR), which included stopped gas production attributed to the saline inhibition. After increasing the C : N ratio, gas production was observed, and the total chemical oxygen demand (TCOD) removal efficiency increased from 75% to 80%. The TCOD removal efficiency of the sonication period was approximately 85%, compared to 75% for the untreated waste. Ultrasonication of aquaculture sludge was also found to enhance the gas production rate and the TCOD removal efficiency. The average volatile fatty acid (VFA) to alkalinity ratios ranged from 0.1 to 0.05, confirming the stability of the digesters. Furthermore, soluble chemical oxygen demand (SCOD), VFA, and PO4 (3-) concentrations increased in the effluents. There was a 114% greater gas generation during the ultrasonication period, with an average production of 0.08 g COD/L · day(-1).

No MeSH data available.


Schematic diagram of the anaerobic sequencing batch reactor (ASBR). 1 timer; 2 stirrer; 3 biogas; 4 aluminum bags; 5 influent tank; 6 peristaltic pump; 7 water-bath; and 8 effluent tank.
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fig1: Schematic diagram of the anaerobic sequencing batch reactor (ASBR). 1 timer; 2 stirrer; 3 biogas; 4 aluminum bags; 5 influent tank; 6 peristaltic pump; 7 water-bath; and 8 effluent tank.

Mentions: The experiment was conducted at a mesophilic temperature of 35 ± 1°C in oroglas (poly-methyl acrylic acid methyl ester) ASBR reactors (Figure 1), which were placed in a water-bath and stirred continuously at 150 rpm (round per minute). Reactors were 14 cm in diameter and 26 cm high, with an operating volume of approximately 4 L (a work volume of 3 L and a headspace of 1 L). The ASBR operates in a cyclic batch mode, with four distinct phases per cycle. The four phases are feeding (15 min), reacting (46.5 h), thickening (1 h), and drawing (15 min). The thickening and drawing phases are the key steps in the ASBR operation. The thickening phase accumulates sludge, as the solids remain within the reactor. Each reactor was loaded with 3 L of anaerobic sludge. The reactors were sampled and fed manually, using a double siphon and a tube through the digester lid. Biogas was collected in 10-L aluminum bags. The experiment was conducted in the dark.


Enhancement of Anaerobic Digestion to Treat Saline Sludge from Recirculating Aquaculture Systems.

Luo GZ, Ma N, Li P, Tan HX, Liu W - ScientificWorldJournal (2015)

Schematic diagram of the anaerobic sequencing batch reactor (ASBR). 1 timer; 2 stirrer; 3 biogas; 4 aluminum bags; 5 influent tank; 6 peristaltic pump; 7 water-bath; and 8 effluent tank.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4537773&req=5

fig1: Schematic diagram of the anaerobic sequencing batch reactor (ASBR). 1 timer; 2 stirrer; 3 biogas; 4 aluminum bags; 5 influent tank; 6 peristaltic pump; 7 water-bath; and 8 effluent tank.
Mentions: The experiment was conducted at a mesophilic temperature of 35 ± 1°C in oroglas (poly-methyl acrylic acid methyl ester) ASBR reactors (Figure 1), which were placed in a water-bath and stirred continuously at 150 rpm (round per minute). Reactors were 14 cm in diameter and 26 cm high, with an operating volume of approximately 4 L (a work volume of 3 L and a headspace of 1 L). The ASBR operates in a cyclic batch mode, with four distinct phases per cycle. The four phases are feeding (15 min), reacting (46.5 h), thickening (1 h), and drawing (15 min). The thickening and drawing phases are the key steps in the ASBR operation. The thickening phase accumulates sludge, as the solids remain within the reactor. Each reactor was loaded with 3 L of anaerobic sludge. The reactors were sampled and fed manually, using a double siphon and a tube through the digester lid. Biogas was collected in 10-L aluminum bags. The experiment was conducted in the dark.

Bottom Line: The effectiveness of carbohydrate addition and the use of ultrasonication as a pretreatment for the mesophilic anaerobic digestion of saline aquacultural sludge was assessed.Furthermore, soluble chemical oxygen demand (SCOD), VFA, and PO4 (3-) concentrations increased in the effluents.There was a 114% greater gas generation during the ultrasonication period, with an average production of 0.08 g COD/L · day(-1).

View Article: PubMed Central - PubMed

Affiliation: College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China ; Shanghai Collaborative Innovation Center for Aquatic Animal Genetics and Breeding, Shanghai 201306, China ; Research and Development Center of Aquacultural Engineering of Shanghai, Shanghai 201306, China.

ABSTRACT
The effectiveness of carbohydrate addition and the use of ultrasonication as a pretreatment for the mesophilic anaerobic digestion of saline aquacultural sludge was assessed. Analyses were conducted using an anaerobic sequencing batch reactor (ASBR), which included stopped gas production attributed to the saline inhibition. After increasing the C : N ratio, gas production was observed, and the total chemical oxygen demand (TCOD) removal efficiency increased from 75% to 80%. The TCOD removal efficiency of the sonication period was approximately 85%, compared to 75% for the untreated waste. Ultrasonication of aquaculture sludge was also found to enhance the gas production rate and the TCOD removal efficiency. The average volatile fatty acid (VFA) to alkalinity ratios ranged from 0.1 to 0.05, confirming the stability of the digesters. Furthermore, soluble chemical oxygen demand (SCOD), VFA, and PO4 (3-) concentrations increased in the effluents. There was a 114% greater gas generation during the ultrasonication period, with an average production of 0.08 g COD/L · day(-1).

No MeSH data available.