RESUMEN
Wastewater resources can be used to produce microbial protein for animal feed or organic fertiliser, conserving food chain resources. This investigation hasemployed thefermented sewage to photoheterotrophically grown purple non-sulfur bacteria (PNSB) in a 2.5 m3 pilot-scaleraceway-pond with infrared light to produce proteinaceous biomass. Fermented sewage with synthetic media consisting of sodium acetate and propionic acids at a surface-to-volume (S/V) ratio of 10 m2/m3 removed 89%, 93%, and 81% of chemical oxygen demand, ammonium nitrogen, and orthophosphate, respectively; whereas respective removal in fermented sewage alone without synthetic media was 73%, 73%, and 72% during batch operation of 120 h. The biomass yield of 0.88-0.95 g CODbiomass /g CODremoved with protein content of 40.3 ± 0.3%-43.9 ± 0.2% w/w was obtained for fermented sewage with synthetic media. The results revealed enhanced possibility of scaling-up the raceway reactor to recover resources from municipal wastewater and enable simultaneous high-rate PNSB single-cell protein production.
RESUMEN
The application of waste-derived iron for reuse in wastewater treatment is an effective way of utilizing waste and attaining sustainability in the overall process. In the present investigation, bio-electro-Fenton process was initiated for the cathodic degradation of surfactants using waste-iron catalyzed MFC (WFe-MFC). The waste-iron was derived from spent tonner ink using calcination at 600 °C. Three surfactants namely, sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide, and Triton x-100 were selected as target pollutants. The effect of experimental factors like application of catalyst, contact time, external resistance, and anodic substrate concentration on the SDS degradation was investigated. At a neutral pH, the cathodic surfactants removal efficiency in WFe-MFC was above 85% in a contact time of 180 min with the initial surfactant concentration of â¼20 mg L-1 and external resistance of 100 Ω. The long-term operation using secondary treated real wastewater with unchanged cathode proved that the catalyst was still active to produce effluent SDS concentration of less than 1 mg L-1 in 4 h of contact time after 16 cycles. In a way, the present investigation suggests a potential application for spent tonner ink in the form of Fenton catalyst for wastewater treatment via bio-electro-Fenton MFC.