scholarly journals EFFECT OF CONTROL SYSTEMS ON BACTERIA COMMUNITY STRUCTURE IN SEQUENCING BATCH BIOFILM REACTORS TO TREAT WASTEWATER

2019 ◽  
Vol 17 (4) ◽  
Author(s):  
Y JIN
2012 ◽  
Vol 104 ◽  
pp. 12-18 ◽  
Author(s):  
Yunxiao Jin ◽  
Dahu Ding ◽  
Chuanping Feng ◽  
Shuang Tong ◽  
Takashi Suemura ◽  
...  

2019 ◽  
Vol 69 (13) ◽  
pp. 1531-1536 ◽  
Author(s):  
Lin Gao ◽  
Xin-min Liu ◽  
Yong-mei Du ◽  
Hao Zong ◽  
Guo-ming Shen

Abstract Purpose A reasonable cultivation pattern is beneficial to maintain soil microbial activity and optimize the structure of the soil microbial community. To determine the effect of tobacco−peanut (Nicotiana tabacum−Arachis hypogaea) relay intercropping on the microbial community structure in soil, we compared the effects of relay intercropping and continuous cropping on the soil bacteria community structure. Methods We collected soil samples from three different cropping patterns and analyzed microbial community structure and diversity using high-throughput sequencing technology. Result The number of operational taxonomic units (OTU) for bacterial species in the soil was maximal under continuous peanut cropping. At the phylum level, the main bacteria identified in soil were Proteobacteria, Actinobacteria, and Acidobacteria, which accounted for approximately 70% of the total. The proportions of Actinobacteria and Firmicutes increased, whereas the proportion of Proteobacteria decreased in soil with tobacco–peanut relay intercropping. Moreover, the proportions of Firmicutes and Proteobacteria among the soil bacteria further shifted over time with tobacco–peanut relay intercropping. At the genus level, the proportions of Bacillus and Lactococcus increased in soil with tobacco–peanut relay intercropping. Conclusion The community structure of soil bacteria differed considerably with tobacco–peanut relay intercropping from that detected under peanut continuous cropping, and the proportions of beneficial bacteria (the phyla Actinobacteria and Firmicutes, and the genera Bacillus and Lactococcus) increased while the proportion of potentially pathogenic bacteria (the genera Variibacter and Burkholderia) decreased. These results provide a basis for adopting tobacco–peanut relay intercropping to improve soil ecology and microorganisms, while making better use of limited cultivable land.


2008 ◽  
Vol 58 (10) ◽  
pp. 1889-1894 ◽  
Author(s):  
C. Wantawin ◽  
J. Juateea ◽  
P. L. Noophan ◽  
J. Munakata-Marr

Conventional nitrification-denitrification treatment is a common way to treat nitrogen in wastewater, but this process is costly for low COD/N wastewaters due to the addition of air and external carbon-source. However, ammonia may alternatively be converted to dinitrogen gas by autotrophic bacteria utilizing aerobically autotrophically produced nitrite as an electron acceptor under anoxic conditions. Lab-scale sequencing batch biofilm reactors (SBBRs) inoculated with normal nitrifying sludge were employed to study the potential of an oxygen-limited autotrophic nitrification-denitrification process initiated with typical nitrifying sludge for treating a synthetic ammonia wastewater devoid of organic carbon in one step. The ring-laced fibrous carrier (length 0.32 m, surface area 3.4 m2/m) was fixed vertically in a 3 L reactor. Two different air supply modes were applied:continuous aeration to control dissolved oxygen at 1.5 mg/L and intermittent aeration. High nitrogen removals of more than 50% were obtained in both SBBRs. At an ammonia loading of 0.882 gm N/m2-day [hydraulic retention time (HRT) of 24 hr], the SBBR continuously aerated to 1.5 mg DO/L had slightly higher nitrogen removal (64%) than the intermittently alternated SBBR (55%). The main form of residual nitrogen in the effluent was ammonia, at concentrations of 25 mg/L and 37 mg N/L in continuous and intermittent aeration SBBRs, respectively. Ammonia was completely consumed when ammonia loading was reduced to 0.441 gm N/m2-day [HRT extended to 48 hr]. The competitive use of nitrite by aerobic nitrite oxidizing bacteria (ANOB) with anaerobic ammonia-oxidizing bacteria (anammox bacteria) during the expanded aeration period under low remaining ammonia concentration resulted in higher nitrate production and lower nitrogen loss in the continuous aeration SBBR than in the intermittent aeration SBBR. The nitrogen removal efficiencies in SBBRs with continuous and alternating aerated were 80% and 86% respectively. Specific microorganisms in the biofilm were characterized using fluorescence in situ hybridization. Aerobic ammonia-oxidizing bacteria (AAOB) occurred side by side with putative anammox bacteria (cells hybridizing with probe AMX820) throughout the biofilm, though ANOB were rarely detected.


2012 ◽  
Vol 83 (3) ◽  
pp. 724-737 ◽  
Author(s):  
Ludovic Giloteaux ◽  
Robert Duran ◽  
Corinne Casiot ◽  
Odile Bruneel ◽  
Françoise Elbaz-Poulichet ◽  
...  

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