An apparatus and method are provided for treating wastewater with alkanes such as butane. An oxygen-containing gas may also be introduced into the wastewater. Butane, because of its relatively high solubility, rapidly dissolves in the wastewater, thereby significantly increasing the heterogeneous microbial community and heterotrophic microbial population. This enhanced microbial population may rapidly absorb and mineralize materials in the wastestream. After an initial growth phase, the organic matter available in the wastewater effluent may be rapidly decreased, thereby reducing the amount of BOD, TDS, sludge and other pollutants. In addition, the use of butane reduces noxious odors associated with municipal wastewater sludges and other types of wastewater.
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/291,165 filed May 15, 2001, which is incorporated herein by reference. This application is a continuation-in-part of U.S. application Ser. No. 09/729,039 filed Dec. 4, 2000, now U.S. Pat. No. 6,488,850 issued Dec. 3, 2002, which claims the benefit of U.S. Provisional Patent Application Serial No. 60/234,482 filed Sep. 22, 2000. The 09/729,039 application is a continuation-in-part of U.S. application Ser. No. 09/275,320 Mar. 24, 1999, now U.S. Pat. No. 6,245,235 issued Jun. 12, 2001, which is a continuation-in-part of U.S. application Ser. No. 08/767,750 filed Dec. 17, 1996, now U.S. Pat. No. 5,888,396 issued Mar. 30, 1999.
Bioventing methods create a bacterial treatment zone at a contaminated site by supplying a hydrocarbon food source to the treatment zone, and recirculating the hydrocarbon to the treatment zone. The inventing methods may inject, circulate, extract and reinject hydrocarbons such as butane or other alkanes to the subsurface at a contaminated site to create a bacterial treatment zone. Contaminated vapors extracted from the soil and/or groundwater may be reintroduced into the site. Hydrocarbons that are not consumed by the bacteria in the treatment zone may be extracted and recovered for recirculation into the treatment zone.
Methods and apparatus are disclosed for remediating sulfur-containing pollutants with a hydrocarbon that is used to stimulate the growth of hydrocarbon-utilizing bacteria. The hydrocarbon is preferably an alkane such as butane. The sulfur-containing pollutant may comprise sulfate, sulfite, sulfide, disulfides, mercaptans, alkanesulfonates, dialkyl sulfides, thiosulfate, thiofurans, thiocyanates, isothiocyanates, thioureas, thiols, thiophenols, thioethers, thiophene, tetrathionate, dithionite, dialkyl disulfides, sulfones, sulfoxides, sulfolanes, sulfonic acid, dimethylsulfoniopropionate, sulfonic esters, hydrogen sulfide, sulfate esters, sulfur dioxide and any other sour gases, elemental sulfur and any other sulfur-containing material considered to be a contaminant or pollutant.
Bioventing systems create a bacterial treatment zone at a contaminated site by supplying a hydrocarbon food source to the treatment zone, and recirculating the hydrocarbon to the treatment zone. The bioventing systems may inject, circulate, extract and reinject hydrocarbons such as butane or other alkanes to the subsurface at a contaminated site to create a bacterial treatment zone. Contaminated vapors extracted from the soil and/or groundwater may be reintroduced into the site. Hydrocarbons that are not consumed by the bacteria in the treatment zone may be extracted and recovered for recirculation into the treatment zone.
Methods and apparatus are disclosed for remediating metal contaminants using hydrocarbons which stimulate the growth of hydrocarbon-utilizing bacteria. The metal contaminants may include heavy metals such as arsenic, antimony, beryllium, cadmium, chromium, copper, lead, mercury, iron, manganese, magnesium, radium, nickel, selenium, silver, thallium and zinc. The hydrocarbon may include alkanes, alkenes, Aalkynes, poly(alkene)s, poly(alkyne)s, aromatic hydrocarbons, aromatic hydrocarbon polymers and aliphatic hydrocarbons. Butane is a particularly suitable hydrocarbon which stimulates the growth of butane-utilizing bacteria. Remediation may occur in-situ or ex-situ, and may occur under aerobic, anaerobic or dual aerobic/anaerobic conditions. Examples of applications include the remediation of heavy metals, the remediation of arsenic impacted surface water, groundwater and/or soil, the remediation of acid mine drainage, and the treatment of spent metal plating solutions.
An apparatus and method are provided for treating wastewater with alkanes such as butane. An oxygen-containing gas may also be introduced into the wastewater. Butane, because of its relatively high solubility, rapidly dissolves in the wastewater, thereby significantly increasing the heterogeneous microbial community and heterotrophic microbial population. This enhanced microbial population may rapidly absorb and mineralize materials in the wastestream. After an initial growth phase, the organic matter available in the wastewater effluent may be rapidly decreased, thereby reducing the amount of BOD, TDS, sludge and other pollutants. In addition, the use of butane reduces noxious odors associated with municipal wastewater sludges and other types of wastewater.
