Removal of sulfur compounds from wastewater
First Claim
1. Process for removal of sulfur compounds from wastewater, comprising the steps of:
- a) converting in a first anaerobic suspended sludge reactor organic compounds present in the wastewater to acid compounds, forming an effluent comprising the acid compounds;
b) converting the sulfur compounds to sulfide compounds in the first reactor, the remainder of the sulfur compounds being also comprised by said effluent;
c) removing sulfide compounds in said first reactor with a stripping gas, forming a gaseous effluent;
c2) concentrating said effluent, thus forming a clearer effluent and a more concentrated suspension of sludge, part of which suspension is recycled to said first reactor;
d) converting the acid compounds in said clearer effluent to biogas in a second anaerobic reactor; and
e) converting sulfur compounds in said clearer effluent to sulfide compounds in the second anaerobic reactor, forming a second liquid effluent.
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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.
15 Citations
12 Claims
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1. Process for removal of sulfur compounds from wastewater, comprising the steps of:
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a) converting in a first anaerobic suspended sludge reactor organic compounds present in the wastewater to acid compounds, forming an effluent comprising the acid compounds;
b) converting the sulfur compounds to sulfide compounds in the first reactor, the remainder of the sulfur compounds being also comprised by said effluent;
c) removing sulfide compounds in said first reactor with a stripping gas, forming a gaseous effluent;
c2) concentrating said effluent, thus forming a clearer effluent and a more concentrated suspension of sludge, part of which suspension is recycled to said first reactor;
d) converting the acid compounds in said clearer effluent to biogas in a second anaerobic reactor; and
e) converting sulfur compounds in said clearer effluent to sulfide compounds in the second anaerobic reactor, forming a second liquid effluent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification