Biodegradation of polyacrylamide by anaerobic digestion under mesophilic condition and its performance in actual dewatered sludge system

2014 ◽  
Vol 153 ◽  
pp. 55-61 ◽  
Author(s):  
Xiaohu Dai ◽  
Fan Luo ◽  
Jing Yi ◽  
Qunbiao He ◽  
Bin Dong
Keyword(s):  
Anaerobic Digestion ◽  
Dewatered Sludge ◽  
Mesophilic Condition

Nutrient solubilization and its availability following anaerobic digestion

2013 ◽  
Vol 67 (4) ◽  
pp. 756-763 ◽  
Author(s):  
Chirag M. Mehta ◽  
Damien J. Batstone
Keyword(s):  
Anaerobic Digestion ◽  
Inorganic Compounds ◽  
Operating Conditions ◽  
Solid Surfaces ◽  
Soluble Form ◽  
Acid Extraction ◽  
Waste Streams ◽  
Agriculture Waste ◽  
Total P ◽  
Mesophilic Condition

This study aims to investigate solubilization of elements (P, N, K, Ca and Mg) during anaerobic digestion (AD) of solid agriculture waste. It is important to maintain particularly phosphorous in the aqueous phase to be able to subsequently recover it in a concentrated form via crystallization. Batch AD was carried out at a mesophilic condition (37 °C) and pH 7.0 ± 0.2 on a variety of piggery and poultry solid waste streams. Less than 10% of the total P, Ca and Mg was in soluble form in the digestate. Most of the N and K remained soluble in the digestate. A bioavailability test (citric acid extraction) showed P, Ca and Mg in the digestate were totally available. Complete solubilization of P, Ca and Mg occurred below a threshold of pH 5.5. This indicates these nutrients were released during digestion, and then either bound to form inorganic compounds or adsorbed on solid surfaces in the digestate. These effects reduce the feasibility of post-digestion recovery of the nutrients via struvite crystallization. Strategies to improve nutrient solubilization and recovery during the AD include addition of complexing chemicals, operation at depressed pH, or otherwise modifying the operating conditions.

Full-scale application of anaerobic digestion process with partial ozonation of digested sludge

2005 ◽  
Vol 52 (1-2) ◽  
pp. 245-252 ◽  
Author(s):  
H. Yasui ◽  
K. Komatsu ◽  
R. Goel ◽  
Y. Y. Li ◽  
T. Noike
Keyword(s):  
Anaerobic Digestion ◽  
Full Scale ◽  
Digested Sludge ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
New Process ◽  
Sludge Cake ◽  
Dewatered Sludge ◽  
Solid Liquid ◽  
Solid Liquid Separation

For improving sludge digestion and biogas recovery, a new anaerobic digestion process combined with ozonation was tested at a full-scale unit for 2 years and its performance was compared with a simultaneously operated conventional anaerobic digestion process. The new process requires two essential modifications, which includes ozonation for enhancing the biological degradability of sludge organics and concentrating of solids in the digester through a solid/liquid separation for extension of SRT. These modifications resulted in high VSS degradation efficiency of ca. 88%, as much as 1.3 times of methane production and more than 70% reduction in dewatered sludge cake production. Owing to accumulation of inorganic solids in the digested sludge, water content of the dewatered sludge cake also reduced from 80% to 68%. An energy analysis suggested that no supplemental fuel was necessary for the subsequent incineration of the cake from the new process scheme. The process is suitable to apply to a low-loaded anaerobic digestion tank, where power production is used.

scholarly journals Effects of Microwave Pretreatment of Dewatered Sludge from an Oxidation-Ditch Process on the Biogas Yield in Mesophilic Anaerobic Digestion

2016 ◽  
Vol 14 (3) ◽  
pp. 158-165 ◽  
Author(s):  
Taketo Togari ◽  
Ryoko Yamamoto-Ikemoto ◽  
Hiroshi Ono ◽  
Kengo Takashima ◽  
Ryo Honda ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Oxidation Ditch ◽  
Microwave Pretreatment ◽  
Biogas Yield ◽  
Dewatered Sludge

The role of iron and aluminium in digestion and odor formation

2007 ◽  
Vol 56 (9) ◽  
pp. 59-65 ◽  
Author(s):  
J.T. Novak ◽  
N. Verma ◽  
C.D. Muller
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Iron Content ◽  
Wastewater Treatment Plants ◽  
Divalent Cations ◽  
Volatile Solids ◽  
Dewatered Sludge

The role of iron and aluminium in determining volatile solids reduction and odors from anaerobically digested, dewatered sludge cakes was evaluated from data collected from a variety of wastewater treatment plants. It was found that volatile solids reduction generally increased as the iron content of the sludge increased. It was also observed that odors increased with increasing iron. No correlation with aluminium or divalent cations was found. Based on these data it appears that the volatile solids reduction by anaerobic digestion is not useful for predicting the odors from anaerobically digested sludges.

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