Sulfate Removal Mechanism by Internal Circulation Iron-Carbon Micro-electrolysis

The biological sulfate removal in the acidogenic bioreactor with an ultrafiltration membrane system was investigated at 35°C. Sucrose was used as the sole organic substrate. The sulfate concentration in the substrate ranged from 0 to 600mgS·1−1. The chemostat reactor was operated to compare with the membrane bioreactor. The fouling phenomenon caused by FeS precipitate was observed at higher concentration of sulfate. However, it was possible to continuously operate the membrane bioreactor by cleaning the membrane. The efficiency of sulfate removal by sulfate reduction reached about 100% in the membrane bioreactor, and 55 to 87% of sulfide was removed from the permeate by the membrane filtration. The composition of the metabolite was remarkably changed by the change in sulfate concentration. When the sulfate concentration increased, acetate and 2-proponol significantly increased while n-butyrate and 3-pentanol decreased. The sulfate-reducing bacteria play the role as acetogenic bacteria consuming volatile fatty acids and alcohols as electron donors under sulfate-rich conditions. The results show that the acidogenesis and sulfate reduction simultaneously proceed in the membrane bioreactor.

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Pilot-plant experiments for improvement of polluted canal/klong water by rock-bed filtration

Water Science & Technology ◽

10.2166/wst.1997.0300 ◽

1997 ◽

Vol 35 (8) ◽

pp. 83-90

Author(s):

Shigeo Fujii ◽

Chiaki Niwa ◽

Mitsuo Mouri ◽

Ranjna Jindal

Keyword(s):

Organic Matter ◽

Pilot Plant ◽

Horizontal Flow ◽

Removal Mechanism ◽

Soluble Organic Matter ◽

Filter Media ◽

Canal Water ◽

Rock Bed ◽

One Year ◽

Filtration Technique

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%.

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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.

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