Abstract: Overburden from surface coal mining in many regions can produce a rain runoff laden with selenium, in the selenate form, as well as rare earth elements (REEs). This occurs from rainwater leaching through exposed selenium/mineral-containing rocks in the overburden. The mineral-containing runoff water is caught in ponds, or deep mine water is collected from pools. Alternatively, leachate can be collected from coal gob or refuse piles. Extraction of REEs, as well as remediation of deleterious substances such as selenium, is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. After a period of use of the SMI, the spent SMI is subjected to a recovery process for REEs.

Abstract: Overburden from surface coal mining in many regions can produce a rain runoff laden with selenium, in the selenate form, as well as rare earth elements (REEs). This occurs from rainwater leaching through exposed selenium/mineral-containing rocks in the overburden. The mineral-containing runoff water is caught in ponds, or deep mine water is collected from pools. Alternatively, leachate can be collected from coal gob or refuse piles. Extraction of REEs, as well as remediation of deleterious substances such as selenium, is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. After a period of use of the SMI, the spent SMI is subjected to a recovery process for REEs.

Abstract: At coal mining sites rain runoff can be laden with selenium, in the selenate form. The selenium-containing runoff water is caught in ponds. Remediation of the pond water to remove selenate, or remediation of other contaminated water with selenium or other contaminants, is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. The contaminated water after pretreatment is pumped through the SMI reactor, where the SMI removes selenium and/or other contaminants from the water. For extending effectiveness and life of the SMI the contact bed is either periodically “fluffed” with a high-flowrate upflow of water or gas through the bed, or moved continuously through the column in a continuous medium filtration system. In either event, a gas inert to SMI, such as nitrogen, can be used in fluffing the SMI or lifting the SMI as a continuously moving medium.

Abstract: Overburden from surface coal mining in many regions can produce a rain runoff laden with selenium, in the selenate form. This occurs from rainwater leaching through exposed selenium-containing rocks in the overburden. The selenium-containing runoff water is caught in ponds. Remediation of the pond water to remove selenate is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. The pond water after pretreatment is pumped through the SMI reactor, and can then be run through an oxidation tank and filtered to remove iron. For extending effectiveness and life of the SMI the contact bed is either periodically “fluffed” with a high-velocity upflow of water through the bed, or moved continuously through the column in a continuous medium filtration system. A biocide can be added to runoff water prior to the contact bed.

Abstract: Overburden from surface coal mining in many regions can produce a rain runoff laden with selenium, in the selenate form. This occurs from rainwater leaching through exposed selenium-containing rocks in the overburden. The selenium-containing runoff water is caught in ponds. Remediation of the pond water to remove selenate is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. The pond water after pretreatment is pumped through the SMI reactor, and can then be run through an oxidation tank and filtered to remove iron. For extending effectiveness and life of the SMI the contact bed is either periodically “fluffed” with a high-velocity upflow of water through the bed, or moved continuously through the column in a continuous medium filtration system. A biocide can be added to runoff water prior to the contact bed.

Abstract: Overburden from surface coal mining in many regions can produce a rain runoff laden with selenium, in the selenate form. This occurs from exposed selenium-containing rocks in the overburden, from which selenate is leached out by the nearly-pure rainwater. The selenium-containing runoff water is caught in ponds. Remediation of the pond water to remove selenate down to permissible levels for discharge to lakes and streams is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. After a prefiltering step, the pond water is pH-adjusted as needed and pumped through the SMI reactor. The treated water can then be run through an oxidation tank and filtered to remove iron. For extending effectiveness and life of the SMI the contact bed is periodically “fluffed” with a high-velocity upflow of water through the bed, expanding and loosening the contact bed to prevent or break up compacting of the SMI medium.

Abstract: Overburden from surface coal mining in many regions can produce a rain runoff laden with selenium, in the selenate form. This occurs from exposed selenium-containing rocks in the overburden, from which selenate is leached out by the nearly-pure rainwater. The selenium-containing runoff water is caught in ponds. Remediation of the pond water to remove selenate down to permissible levels for discharge to lakes and streams is performed by treatment with sulfur-modified iron (SMI) in a contact bed of an upflow reactor vessel. After a prefiltering step, the pond water is pH-adjusted as needed and pumped through the SMI reactor. The treated water can then be run through an oxidation tank and filtered to remove iron. For extending effectiveness and life of the SMI the contact bed is periodically “fluffed” with a high-velocity upflow of water through the bed, expanding and loosening the contact bed to prevent or break up compacting of the SMI medium.

Abstract: Arsenic and TOC are removed from drinking water or wastewaters by use of finely-divided metallic iron in the presence of powered elemental sulfur or other sulfur compounds such as manganese sulfide, followed by an oxidation step. A premix may be produced for this process, by adding the iron, sulfur and oxidizing agent to water in a predetermined pH range. The iron and sulfur are mixed for a period of time dependent upon the temperature and pH of the water and the presence of complexing or sequestering minerals and organic acids in the water. An oxidizing agent is added to the mixture and agitating is continued. In a preferred embodiment the oxidizing agent is hydrogen peroxide. Water is decanted from the mixture after a sufficient reaction time, to produce a concentrated premix. This premix can be added to water intended for drinking or to industrial effluents containing toxic materials.

Abstract: Arsenic and TOC are removed from drinking water or wastewaters by use of finely-divided metallic iron in the presence of powered elemental sulfur or other sulfur compounds such as manganese sulfide, followed by an oxidation step. A premix may be produced for this process, by adding the iron, sulfur and oxidizing agent to water in a predetermined pH range. The iron and sulfur are mixed for a period of time dependent upon the temperature and pH of the water and the presence of complexing or sequestering minerals and organic acids in the water. An oxidizing agent is added to the mixture and agitating is continued. In a preferred embodiment the oxidizing agent is hydrogen peroxide. Water is decanted from the mixture after a sufficient reaction time, to produce a concentrated premix. This premix can be added to water intended for drinking or to industrial effluents containing toxic materials.

Abstract: Arsenic and TOC are removed from drinking water or wastewaters by use of finely-divided metallic iron in the presence of powered elemental sulfur or other sulfur compounds such as manganese sulfide, followed by an oxidation step. A premix may be produced for this process, by adding the iron, sulfur and oxidizing agent to water in a predetermined pH range. The iron and sulfur are mixed for a period of time dependent upon the temperature and pH of the water and the presence of complexing or sequestering minerals and organic acids in the water. An oxidizing agent is added to the mixture and agitating is continued. In a preferred embodiment the oxidizing agent is hydrogen peroxide. Water is decanted from the mixture after a sufficient reaction time, to produce a concentrated premix. This premix can be added to water intended for drinking or to industrial effluents containing toxic materials.

Abstract: Arsenic and TOC are removed from drinking water or wastewaters by use of finely-divided metallic iron in the presence of powdered elemental sulfur or other sulfur compounds such as manganese sulfide, followed by an oxidation step. A premix may be produced for this process, by adding the iron, sulfur and oxidizing agent to water in a predetermined pH range. The iron and sulfur are mixed for a period of time dependent upon the temperature and pH of the water and the presence of complexing or sequestering minerals and organic acids in the water. An oxidizing agent is added to the mixture and agitating is continued. In a preferred embodiment the oxidizing agent is hydrogen peroxide. Water is decanted from the mixture after a sufficient reaction time, to produce a concentrated premix. This premix can be added to water intended for drinking or to industrial effluents containing toxic materials.

Abstract: Arsenic and TOC are removed from drinking water or wastewaters by use of finely-divided metallic iron in the presence of powdered elemental sulfur or other sulfur compounds such as manganese sulfide, followed by an oxidation step. A premix may be produced for this process, by adding the iron, sulfur and oxidizing agent to water in a predetermined pH range. The iron and sulfur are mixed for a period of time dependent upon the temperature and pH of the water and the presence of complexing or sequestering minerals and organic acids in the water. An oxidizing agent is added to the mixture and agitating is continued. In a preferred embodiment the oxidizing agent is hydrogen peroxide. Water is decanted from the mixture after a sufficient reaction time, to produce a concentrated premix. This premix can be added to water intended for drinking or to industrial effluents containing toxic materials.

Abstract: Arsenic and TOC are removed from drinking water or wastewaters by use of finely-divided metallic iron in the presence of powdered elemental sulfur or other sulfur compounds such as manganese sulfide, followed by an oxidation step. A premix may be produced for this process, by adding the iron, sulfur and oxidizing agent to water in a predetermined pH range. The iron and sulfur are mixed for a period of time dependent upon the temperature and pH of the water and the presence of complexing or sequestering minerals and organic acids in the water. An oxidizing agent is added to the mixture and agitating is continued. In a preferred embodiment the oxidizing agent is hydrogen peroxide. Water is decanted from the mixture after a sufficient reaction time, to produce a concentrated premix. This premix can be added to water intended for drinking or to industrial effluents containing toxic materials.

Abstract: A method and system for removing toxic substances such as selenium from industrial and agricultural drain water, and particularly refinery effluent liquor, achieves very high removal of the toxic substance economically, by a chemical reduction process. Preferably, the effluent liquor is first filtered, which ordinarily is effective to remove selenium suspended in the liquor. Next the liquor is heated, preferably to about 150.degree. F., and a reducing agent such as finely powdered iron is added to bring, for example, the selenium down from a +6 valence to +4 and lower valences. Sulfur is added to the slurry to greatly improve the effectiveness of the iron in reducing the liquor. The slurry is constantly agitated. After a reaction time which may be about 15 minutes, an oxidizing agent is added, with the temperature of the slurry then raised to at least about 180.degree., with continued agitation.

Abstract: A method and system for removing toxic substances such as selenium and molybdenum from agricultural irrigation water achieves nearly 100% removal of the toxic substance economically, by a chemical reduction process. The process is particulary efficacious for removing naturally occurring selenium and molybdenum from irrigation water which has seeped through the ground and taken compounds of these metals into solution. Preferably, the drain tile water solution is first concentrated, to about 30% dissolved solids. This may be economically accomplished by on site evaporation in an open pond which is impermeable to seepage. Next the concentrated brine solution is heated, preferably to about 150.degree. F., and a reducing agent such as finely powdered iron is added to bring, for example, the selenium down from a +6 valence to +4 and lower valences. Wettable sulfur is added to the slurry to greatly improve the effectiveness of the iron in reducing the solution. The slurry is constantly agitated.

Abstract: A manure digester and power generating system includes a mixing tank for receiving manure, a closed, anaerobic manure digester tank of fixed volume, and a gas-fueled engine and a generator coupled to the engine, for generating electrical power. Manure is scraped into the mixing tank daily, where it is mixed with water to produce a manure slurry of desired consistency, and heated to a prescribed temperature. The digester tank is of fixed volume and may be of a generally rounded cross-sectional shape and elongated in length, and into its inflow end the contents of the mixing tank are transferred daily, on a daily batch basis. Anaerobic-digesting microbes are maintained in the digester tank to digest the manure slurry and produce methane gas and by-products. Temperature in the digester tank is maintained at about 90.degree. to 100.degree. F.