Case specific: Addressing co-digestion of wastewater sludge, cheese whey and cow manure: Kinetic modeling.

The study investigated the methane production efficiency in a semi-continuous laboratory experiment with periodic feeding of wastewater sludge (WWS) as primary substrate and addition of whey (CW) and cow manure (CM). The short-term behavior of a real-scale anaerobic digester with WWS and the methane production improvements with different feeding mixtures of WWS, CW and CM were addressed. Gradual addition of CW to WWS (WWS:CW:CM = 70:20:0 to 70:55:0) increased the average daily methane production to 48.

Hydrometallurgical recovery of silver and gold from waste printed circuit boards and treatment of the wastewater in a biofilm reactor: An integrated pilot application.

A hydrometallurgical process for the recovery of gold and silver from waste printed circuit boards (PCBs) was experimentally verified and tested at pilot scale. The process comprises four sequential leaching stages; the first two based on HCl, correspond to base metals (e.g.

Modeling biological denitrification in the presence of metal ions and elevated chloride content: Insights into abiotic and biotic mechanisms regulating metal bioprecipitation.

Biological denitrification is a critical process in which microorganisms convert nitrate to nitrogen gas. Metal ions, such as those found in industrial wastewater, can be toxic to microorganisms and impede denitrification. It is critical to identify the mechanisms that allow microorganisms to tolerate metal ions and understand how these mechanisms can be utilized to improve denitrification efficiency by modeling the process.

Fractionation and leachability of Fe, Zn, Cu and Ni in the sludge from a sulphate-reducing bioreactor treating metal-bearing wastewater.

This work presents and discusses experimental results on the characterisation and metal leaching potential of a biogenic, metal-rich sulphidic sludge, generated in a sulphate-reducing bioreactor, operated to treat acidic synthetic solutions bearing Fe, Zn, Ni and Cu. The sustainability of the metal removal bioprocess strongly depends on the fate of the sludge. To propose appropriate management practices, a detailed characterisation of the sludge is necessary.

Metal precipitation in an ethanol-fed, fixed-bed sulphate-reducing bioreactor.

A batch upflow fixed-bed sulphate-reducing bioreactor has been set up and monitored for the treatment of synthetic solutions containing divalent iron (100mg/L and 200mg/L), zinc (100mg/L and 200mg/L), copper (100mg/L and 200mg/L), nickel (100mg/L and 200mg/L) and sulphate (1700 mg/L and 2130 mg/L) at initial pH 3-3.5, using ethanol as the sole electron donor. The reactor has been operated at the theoretical stoichiometric ethanol/sulphate ratio.

Characterization, morphology and composition of biofilm and precipitates from a sulphate-reducing fixed-bed reactor.

The characteristics of the biofilm and the solids formed during the operation of a sulphate-reducing fixed-bed reactor, fed with a moderately acidic synthetic effluent containing zinc and iron, are presented. A diverse population of delta-Proteobacteria SRB, affiliated to four distinct genera, colonized the system. The morphology, mineralogy and surface chemistry of the precipitates were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX).