Abstract: The invention relates to a process for removal of sulfur compounds from wastewater, which process provides recovery of elemental sulfur. The process is carried out in two separate anaerobic reactors. In the first reactor organic compounds are converted to acid compounds and sulfur compounds are converted to sulfide compounds. The sulfide compounds are stripped from said first reactor with a stripping gas. Subsequently, the effluent of the first reactor is fed to a second anaerobic reactor, in which organic compounds, such as the acid compounds, are converted to produce biogas, while any unconverted sulfur compounds from the previous step are converted to sulfide compounds as well. Finally, the sulfide compounds are removed from the second reactor in a stripping system, and converted to elemental sulfur in an adsorber.

Abstract: The invention relates to a process for removal of sulfur compounds from wastewater, which process provides recovery of elemental sulfur. The process is carried out in two separate anaerobic reactors. In the first reactor organic compounds are converted to acid compounds and sulfur compounds are converted to sulfide compounds. The sulfide compounds are stripped from said first reactor with a stripping gas. Subsequently, the effluent of the first reactor is fed to a second anaerobic reactor, in which organic compounds, such as the acid compounds, are converted to produce biogas, while any unconverted sulfur compounds from the previous step are converted to sulfide compounds as well. Finally, the sulfide compounds are removed from the second reactor in a stripping system, and converted to elemental sulfur in an adsorber.

Abstract: Method for anaerobic removal of a sulphur compound from waste water containing such compound, comprising the steps of: 1) feeding the waste water to an anaerobic digestion system; 2) converting the sulphur compound in the digestion system to a sulphide; 3) circulating an effluent containing the sulphide from the digestion system in a by-pass channel, the channel comprising a stripper system for stripping the sulphide from the effluent; 4) removing the sulphide from the effluent by contacting with a transporting gas in the stripper system; and 5) converting the sulphide to sulphur; wherein 6) the sulphide is absorbed from the transporting gas in an absorber system by an absorbing liquid, which absorbing liquid is passed in a closed loop through the absorber system and a regenerator system, and comprises a regenerable redox liquor, which redox liquor has a pH-value in the range of 4 to 7, preferably about 6.5.