Progressive stress response of the anaerobic granular sludge to nickel nanoparticles: experimental investigations and mathematic modelling

2019 ◽  
Vol 6 (5) ◽  
pp. 1536-1548 ◽  
Author(s):  
Chuan-Shu He ◽  
Liang Huang ◽  
Rong-Rong Ding ◽  
Hou-Yun Yang ◽  
Yi-Xuan Wang ◽  
...  
Keyword(s):  
Stress Response ◽  
Nickel Nanoparticles ◽  
Granular Sludge ◽  
Experimental Investigations ◽  
Anaerobic Granular Sludge

Long-term exposure to Ni-NPs induced progressive and unrecoverable inhibition of the activity of the AGS.

Response of anaerobic granular sludge to long-term loading of roxarsone: From macro- to micro-scale perspective

2021 ◽  
Vol 204 ◽  
pp. 117599
Author(s):  
Rui Tang ◽  
Haiping Luo ◽  
Henning Prommer ◽  
Zhengbo Yue ◽  
Wei Wang ◽  
...  
Keyword(s):  
Granular Sludge ◽  
Anaerobic Granular Sludge ◽  
Micro Scale

Toxicity of Sulfite and Cadmium to Anaerobic Granular Sludge

1994 ◽  
Vol 29 (4) ◽  
pp. 581-598
Author(s):  
C.F. Shew ◽  
N. Kosaric
Keyword(s):  
Granular Sludge ◽  
Upflow Anaerobic Sludge Blanket ◽  
Shock Load ◽  
Anaerobic Sludge ◽  
Anaerobic Granular Sludge ◽  
Scanning Electron Micrographs ◽  
Bacterial Growth Rate ◽  
Digestion Rate ◽  
Sulfate Reducing ◽  
Load Conditions

Abstract Toxicity of sulfite (Na2SO3) and cadmium (CdCl2) ions to anaerobic granular sludge was investigated in 1.2 litre bench-scale upflow anaerobic sludge blanket (UASB) reactors during process acclimation and shock load conditions. Minimal sulfite toxicity was observed under gradual and shock load conditions at sulfite concentrations of up to 1000 mg S/L if proper acclimation was allowed to occur. No long-term toxic effects were observed although the COD digestion rate was temporarily inhibited by shock load of sulfite. Scanning electron micrographs indicated that more sulfate-reducing bacteria were present in the granules developed in the reactors with sulfite supplement although rod-shaped Methanosaeta-like bacteria were still dominant. High bacterial growth rate was observed in the reactors which were supplied with the feed containing sulfite. The COD digestion rate was inhibited at a cadmium loading rate of 2.4 g Cd per day under both acclimation and shock load conditions. Acclimation did not seem to improve the bacteria to tolerate the toxicity of cadmium. The concentration of free cadmium was very low in the reactors under normal conditions, but increased rapidly when the COD digestion in the reactors ceased. The bacteria could not be reactivated after inhibited by cadmium. When reactors were operated at low specific COD loading rates, more inorganic precipitates were formed inside the granules which consequently settled faster.

scholarly journals Influence of material degradation on weld seam quality in hot gas butt welding of polyamides

2021 ◽  
Author(s):  
Max Bialaschik ◽  
Volker Schöppner ◽  
Mirko Albrecht ◽  
Michael Gehde
Keyword(s):  
Weld Seam ◽  
Experimental Investigations ◽  
Heating Process ◽  
Butt Welding ◽  
Hot Gas ◽  
Process Gas ◽  
Glass Fiber Reinforced ◽  
Extrusion Welding ◽  
Different Gases

AbstractThe joining of plastics is required because component geometries are severely restricted in conventional manufacturing processes such as injection molding or extrusion. In addition to established processes such as hot plate welding, infrared welding, or vibration welding, hot gas butt welding is becoming more and more important industrially due to its advantages. The main benefits are the contactless heating process, the suitability for glass fiber reinforced, and high-temperature plastics as well as complex component geometries. However, various degradation phenomena can occur during the heating process used for economic reasons, due to the presence of oxygen in the air and to the high gas temperatures. In addition, the current patent situation suggests that welding with an oxidizing gas is not permissible depending on the material. On the other hand, however, there is experience from extrusion welding, with which long-term resistant weld seams can be produced using air. Investigations have shown that the same weld seam properties can be achieved with polypropylene using either air or nitrogen as the process gas. Experimental investigations have now been carried out on the suitability of different gases with regard to the weld seam quality when welding polyamides, which are generally regarded as more prone to oxidation. The results show that weld strengths are higher when nitrogen is used as process gas. However, equal weld strengths can be achieved with air and nitrogen when the material contains heat stabilizers.

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