A process for reducing the production of sludge by municipal or industrial wastewater purification plants, comprising a step of mesophilic or thermophilic anaerobic digestion (20), or anaerobic digestion combining these two operating modes, of a stream of sludge to be treated (1), and at least one biological solubilization anaerobic treatment step (30); the process comprises, upstream of the anaerobic digestion step, a step of dehydration (10) of the sludge to be treated, followed by a step of mixing (15) the dehydrated sludge with a recirculated fraction of sludge that is more liquid, originating from recycling of the digestion (20), and/or from the anaerobic treatment step (30), and/or centrates originating from a final dehydration (50) of the treated sludge, wherein the recirculation rate is chosen such that the mixture has a dryness suitable for digestion, this mixture then being directed towards the digestion.

Hydrogen sulfide can be removed from a liquid effluent of an anaerobic reactor, by subsequently: —contacting the effluent liquid in counter current with a treated product gas of the anaerobic reactor to absorb hydrogen sulfide in the gas, —collecting the desulfurized effluent liquid after said contacting, —discharging at least part of the collected desulfurized effluent recirculation liquid as a treated effluent. To a remaining part of the desulfurized effluent waste water can be added and mixed, and the mixed water can be fed to the anaerobic reactor. Spent gas of the contacting step can be combined with sulfide-containing product gas of the anaerobic reactor and treated by desulfurization.

Hydrogen sulfide can be removed from a liquid effluent of an anaerobic reactor, by subsequently: —contacting the effluent liquid in counter current with a treated product gas of the anaerobic reactor to absorb hydrogen sulfide in the gas, —collecting the desulfurized effluent liquid after said contacting, —discharging at least part of the collected desulfurized effluent recirculation liquid as a treated effluent. To a remaining part of the desulfurized effluent waste water can be added and mixed, and the mixed water can be fed to the anaerobic reactor. Spent gas of the contacting step can be combined with sulfide-containing product gas of the anaerobic reactor and treated by desulfurization.

A method for producing H.sub.2, methane, VFAs and alcohols from organic material, including the steps of introducing organic material and microorganisms into a completely mixed bioreactor for producing H.sub.2, CO.sub.2, VFAs, and alcohols; recovering H2 and CO2; recovering a first liquid effluent including microorganisms, VFAs, and alcohols; introducing the first liquid effluent into a gravity settler for separating into a first biomass including microorganisms and a second liquid effluent including VFAs, alcohols and microorganisms; introducing the second liquid effluent into a separation module for separating into a second biomass including microorganisms and a third liquid effluent including VFAs and alcohols; recovering at least a portion of the third liquid effluent; and providing a recovered biomass by recovering at least a portion of the first biomass, the second biomass, or both, and introducing the recovered biomass into a biomethanator for production of CH.sub.4 and CO.sub.2.

The present invention relates to an anaerobic reactor (10) for the treatment of industrial and other wastewaters at psychrophilic temperatures, the reactor comprising a mixing chamber (12) in which is located, during use, a granular sludge fluidized bed, the reactor further comprising a biofilm chamber (16) fed from the mixing chamber and housing a biofilm colonized pumice-based carrier material, and a separation chamber (18) in fluid communication with the biofilm chamber and in which treated effluent and biogas produced within the reactor are separated.

The present invention relates to an anaerobic reactor (10) for the treatment of industrial and other wastewaters at psychrophilic temperatures, the reactor comprising a mixing chamber (12) in which is located, during use, a granular sludge fluidized bed, the reactor further comprising a biofilm chamber (16) fed from the mixing chamber and housing a biofilm colonized pumice-based carrier material, and a separation chamber (18) in fluid communication with the biofilm chamber and in which treated effluent and biogas produced within the reactor are separated.

A wastewater treatment process that produces primary sludge and biological sludge. The system and process hydrolyzes the biological sludge in a hydrolysis reactor. The primary sludge is directed to a pasteurization unit and pasteurized. Thereafter, the hydrolyzed biological sludge and the pasteurized primary sludge are directed to an anaerobic digester where the combined sludges are subjected to anaerobic digestion.

Provided is a biological purifier, by which metal ions in untreated waste water containing the metal ions and sulfate ions can be removed in a low temperature environment with a water temperature of 15° C. or less for a long period of time. The biological purifier for untreated waste water containing metal ions and sulfate ions used for removing the metal ions from the untreated waste water by precipitating sulfides of the metal ions, the biological purifier includes chaff retaining sulfate-reducing bacteria; and an organic-containing material containing 5 mass % or more of crude protein.

Water treatment structures may have at least a first geotextile fabric layer; a second geotextile fabric layer; a third geotextile fabric layer; a first filler layer with plastic particles, arranged between the first and second geotextile fabric layers; and a second filler layer with plastic particles, arranged between the second and third geotextile fabric layers, wherein the geotextile fabric layers and the filler layers are within a housing, and wherein the structure is configured such that contaminated water proceeds sequentially through the first geotextile fabric layer, the first filler layer, the second geotextile fabric layer, the second filler layer, and the third geotextile fabric layer. Methods of treating wastewater may involve passing wastewater, after optional oxygenating and pre-filtering, through such alternating layers of geotextile, preferably nonwoven, and polymer particles.

The present disclosure relates to a bacterium-alga coupled sewage treatment device based on energy recycling and a use method thereof. The device comprises a pretreatment device, a photobioreactor, an alga separation apparatus, a continuous flow bioreactor and a secondary sedimentation tank which are sequentially connected in order, the pretreatment device being connected to a municipal sewage inlet pipe, the photobioreactor being connected to a carbon dioxide gas charging device through a gas filling pipeline, one part of a sludge thickening tank being connected to the secondary sedimentation tank, the other part thereof being connected to remaining sludge of the pretreatment device, carbon dioxide generated from the sludge which flows through the thickening tank and is thermally-hydrolyzed and anaerobically-acidified being connected to the photobioreactor through a gas inlet pipeline, and the alga separation apparatus being further connected to a filter press. The present disclosure has the advantages of a rational structural design, reliable and stable operation, a low operation and maintenance cost and high automaticity and intelligence, and being suitable for the use and transformation requirements of a wide range of sewage treatment plants, etc.