The removal mechanism of nitrobenzene by the Cu-Fe/Carbon material under different aeration conditions

Applicability of the rock-bed filtration technique was investigated through pilot-plant experiments in Bangkok, Thailand. Polluted canal water was used as horizontal flow influent to two reactor channels filled with rocks. During one year operation, HRT, filter media, and aeration mode, were changed in several runs. The results showed that 1) the rock-bed filtration with aeration and the HRT more than 6 h can successfully improve polluted klong water by reducing the pollutants (e.g. 60-120mg/L of SS to 20-40 mg/L and 15-30 mg/L of BOD to 5-20 mg/L); 2) main removal mechanism seems to be the sedimentation resulting from the settleability enhanced by aeration, and the biofilm attached onto rocks also works in the reduction of soluble organic matter; 3) a combination of three rock sizes arranged in descending order showed best results; 4) longer HRT (13 h) produces better effluent but is not so effective if it exceeds 9 hours; 5) 60-70% of sediment IL was decomposed in a year, and porosity in rock beds reduced approximately 16%.

Download Full-text

Nitrogen removal from wastewater treatment lagoons

Water Science & Technology ◽

10.2166/wst.1999.0296 ◽

1999 ◽

Vol 39 (6) ◽

pp. 191-198 ◽

Cited By ~ 8

Author(s):

Timothy J. Hurse ◽

Michael A. Connor

Keyword(s):

Wastewater Treatment ◽

Nitrogen Removal ◽

Treatment Plant ◽

Ammonia Removal ◽

Contour Plot ◽

Removal Mechanism ◽

Dissolved Oxygen Concentration ◽

Physical Processes ◽

Contour Plots ◽

Removal Processes

In an attempt to gain a better understanding of ammonia and nitrogen removal processes in multi-pond wastewater treatment lagoons, an analysis was carried out of data obtained during regular monitoring of Lagoon 115E at the Western Treatment Plant in Melbourne. To do this, a contour plot approach was developed that enables the data to be displayed as a function of pond number and date. Superimposition of contour plots for different parameters enabled the dependence of ammonia and nitrogen removal rates on various lagoon characteristics to be readily assessed. The importance of nitrification as an ammonia removal mechanism was confirmed. Temperature, dissolved oxygen concentration and algal concentration all had a significant influence on whether or not sizeable nitrifier populations developed and persisted in lagoon waters. The analysis made it evident that a better understanding of microbial, chemical and physical processes in lagoons is needed before their nitrogen removal capabilities can be predicted with confidence.

Download Full-text

Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

Canadian Journal of Microbiology ◽

10.1139/w11-042 ◽

2011 ◽

Vol 57 (7) ◽

pp. 606-610 ◽

Cited By ~ 6

Author(s):

Rumyana Eneva ◽

Stephan Engibarov ◽

Tanya Strateva ◽

Radoslav Abrashev ◽

Ignat Abrashev

Keyword(s):

Vibrio Cholerae ◽

Pathogenic Bacteria ◽

Environmental Isolates ◽

Anaerobic Conditions ◽

Temperature Optimum ◽

Ph Optimum ◽

Cholera Vibrio ◽

Key Factor ◽

Aeration Conditions ◽

The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

Download Full-text