Biodegradable organic matter removal in biological filters: evaluation of the CHABROL model

One of the problems of nitrogen removal from wastewater when applying sequencing batch reactor (SBR) technology, is the specific use of organic matter for denitrification purposes. Since easily biodegradable organic matter is rapidly consumed under aerobic or anoxic conditions (i.e. aerobic oxidation or anoxic denitrification, respectively), it is an important factor to consider when scaling up SBRs from the laboratory to real plant operation. In this paper, we present the results obtained in relation to scaling up reactors from lab-scale to pilot-plant scale, treating real wastewater from two different locations: the laboratory and in situ, respectively. In order to make using easily biodegradable organic matter more efficient, the filling phases of SBR cycles were adjusted according to a step-feed strategy composed of 6 anoxic-aerobic events. Feeding only occurred during anoxic phases. The results obtained demonstrated that the methodology may be useful in treating real wastewater with high carbon and nitrogen variations, as it always kept effluent levels lower than the official standards require (effluent total COD lower than 125 mg COD/L and effluent Total Nitrogen lower than 15 mg N/L).

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Electricity generation through a photo sediment microbial fuel cell using algae at the cathode

Water Science & Technology ◽

10.2166/wst.2017.485 ◽

2017 ◽

Vol 76 (12) ◽

pp. 3269-3277 ◽

Cited By ~ 16

Author(s):

B. Neethu ◽

M. M. Ghangrekar

Keyword(s):

Power Generation ◽

Organic Matter ◽

Microbial Fuel Cells ◽

Carbon Capture ◽

Algal Growth ◽

Oxygen Demand ◽

Sediment Organic Matter ◽

Overlying Water ◽

Organic Matter Removal ◽

Removal Efficiencies

Abstract Sediment microbial fuel cells (SMFCs) are bio-electrochemical devices generating electricity from redox gradients occurring across the sediment–water interface. Sediment microbial carbon-capture cell (SMCC), a modified SMFC, uses algae grown in the overlying water of sediment and is considered as a promising system for power generation along with algal cultivation. In this study, the performance of SMCC and SMFC was evaluated in terms of power generation, dissolved oxygen variations, sediment organic matter removal and algal growth. SMCC gave a maximum power density of 22.19 mW/m2, which was 3.65 times higher than the SMFC operated under similar conditions. Sediment organic matter removal efficiencies of 77.6 ± 2.1% and 61.0 ± 1.3% were obtained in SMCC and SMFC, respectively. With presence of algae at the cathode, a maximum chemical oxygen demand and total nitrogen removal efficiencies of 63.3 ± 2.3% (8th day) and 81.6 ± 1.2% (10th day), respectively, were observed. The system appears to be favorable from a resources utilization perspective as it does not depend on external aeration or membranes and utilizes algae and organic matter present in sediment for power generation. Thus, SMCC has proven its applicability for installation in an existing oxidation pond for sediment remediation, algae growth, carbon conversion and power generation, simultaneously.

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