2 research outputs found
A membrane aerated biofilm reactor for sulfide control from anaerobically treated wastewater
<p>A upflow anaerobic sludge blanket reactor was operated combined to a membrane aerated biofilm reactor for sulfate removal and for elemental sulfur reclamation. A commercial silicon tube was used as an oxygen delivery diffuser. The process achieved high rates of sulfide removal from the liquid phase (90%). The hydrogen sulfide removal was influenced by the pH value and at pH value of 7.5, 98% of the H<sub>2</sub>S was removed. The elemental sulfur was observed inside the membrane, with content in the biomass of 21%. Through the massive sequencing of the samples, the microbial community diversity and the stratification of biomass inside the silicon tube was demonstrated, confirming the presence of sulfide-oxidizing bacteria on the membrane wall. The most important genera found related to the sulfur cycle were <i>Sulfuricurvum, Geovibrio</i>, <i>Flexispira</i> and <i>Sulforospirillum</i>.</p
High-Rate Partial Nitritation of Municipal Wastewater after Psychrophilic Anaerobic Pretreatment
Partial nitritation/anammox can provide
energy-efficient nitrogen
removal from the main stream of municipal wastewater. The main bottleneck
is the growth of nitrite oxidizing bacteria (NOB) at low temperatures
(<15 °C). To produce effluent suitable for anammox, real municipal
wastewater after anaerobic pretreatment was treated by enriched ammonium
oxidizing bacteria (AOB) in suspended sludge SBR at 12 °C. NOB
were continually washed out using aerobic duration control strategy
(ADCS). Solids retention time was set to 9–16 days. Using this
approach, average ammonia conversion higher than 57% at high oxidation
rate of 0.4 ± 0.1 kg-N kg-VSS<sup>–1</sup> d<sup>–1</sup> was achieved for more than 100 days. Nitrite accumulation (N–NO<sub>2</sub><sup>–</sup>/N–NO<sub>X</sub>) of 92% was maintained.
Thus, consistently small amounts of present NOB were efficiently suppressed.
Our mathematical model explained how ADCS enhanced the inhibition
of NOB growth via NH<sub>3</sub> and HNO<sub>2</sub>. This approach
will produce effluent suitable for anammox even under winter conditions
in mild climates