The present invention relates to a treatment system having a barium carbonate (BaCO.sub.3) dispersed alkaline substrate (BDAS) for use in the remediation or at least partial remediation of mine drainage (MD) and/or environmental media contaminated with a source of MD. The invention utilizes chemical, biological and combined treatment systems remove high concentrations of sulfates, hardness, heavy metals and N-compounds, that may exist in the MD as well as high concentrations of alkalinity produced during the remediation process. The invention further extends to a process for treating MD and/or environmental media contaminated with MD and to an apparatus for use in this process.

The field of advanced wastewater treatment, and more specifically, to a natural pyrrhotite biofilter and a method for utilizing same to synchronously remove nitrate-nitrogen and phosphorus from water is provided. The method includes the following steps: (1) preparation of the packing material and construction of the biofilter; (2) start-up of the biofilter; (3) operation of the biofilter. The method disclosed in the present invention on the one hand takes pyrrhotite as the electron donor to help sulfur-based autotrophic denitrifying bacteria reduce nitrates into nitrogen gas, and on the other hand utilizes pyrrhotite and its oxidates to eliminate phosphorus through adsorption and chemical precipitation. Therefore, this method realizes synchronous removal of nitrate-nitrogen and phosphorus in water.

Processes for treatment of spent alkaline stream is disclosed. The process includes passing a spent alkaline stream comprising one or more sulfide compounds and one or more organic compounds to a sulfide oxidation reactor for partial oxidation of the one or more sulfide compounds to provide an effluent stream comprising one or more thiosulfate compounds. The effluent stream is passed to a biological treatment unit to oxidize the one or more thiosulfate compounds to one or more sulfate compounds and biodegrade the one or more organic compounds to carbon dioxide and water to provide a treated alkaline stream.

A process for reducing the volume of a collection of acid producing mine waste material is disclosed. The process comprises: contacting a mine waste material with water under oxidative conditions to produce a mineral containing acidic water and mineral and/or sulphide depleted mine waste material; separating the mineral containing acidic water and mineral and/or sulphide depleted mine waste material; treating the mineral containing acidic water to remove one or more minerals therefrom and provide treated water; and further contacting the mine waste material and/or the mineral and/or sulphide depleted mine waste material with the treated water and carrying out the steps one or more times until a total volume of the mineral and/or sulphide depleted mine waste material is less than a total volume of the starting acid producing mine waste material. Also disclosed is a process for converting acid producing mine waste material to a more environmentally acceptable substantially non-acid producing mine waste material.

The present disclosure relates to a filter material which can be used in reducing the content of contaminants in a raw gas or liquid and a device which comprises the filter material. The disclosure also relates to a method for reducing the content of contaminants in a raw gas or liquid which applies the filter material and/or device.

The invention relates to bio-electrochemical systems for treating wastewater, and sour gas produced by anaerobic digestion of organic material. The invention further relates to novel anode/cathode pairing schemes, and electric and hydraulic architectures for use in bio-electrochemical systems.

A method is presented for biological removal of contaminants like sulfide from ground waters and industrial waters. Sulfide oxidizing bacteria by biological oxidation oxidizes sulfides in water to produce soluble sulfates. The present invention uses a packed bed bioreactor configuration that uses packing material to maximize the concentration of sulfide oxidizing bacteria.

Provided is a process for the environmental-friendly treatment of sulfate-containing wastewater. The acidic, sulfate-containing wastewater is treated in a sulfate reducing bioreactor with influent and effluent looped through to the cathode compartment of an electrochemical cell. The electrochemical cell stabilizes the pH in the bioreactor by the in-situ production of base in the cathode compartment. Additionally, hydrogen is produced which is used in the bioreactor as electron donor for the sulfate reduction. The middle compartment of the electrochemical cell contains a sulfide rich aqueous solution in which the extracted cations are displaced by protons from the anode compartment. This results in the acidification of the sulfide rich solution, which is beneficial for the extraction of sulfides as H.sub.2S. This H.sub.2S can be used for the precipitation of metals in the beginning of the process, forming another loop.

The invention relates to a process for reducing the amount of sulphur compounds in a sulphur compounds contaminated wastewater stream, using a granular sludge treatment system (10) comprising anaerobic microorganisms, wherein the process comprises the steps of adding an aqueous nitrate solution to the wastewater stream, contacting the wastewater stream with the anaerobic microorganisms, and anoxic oxidation of at least part of the sulphur compounds in the sulphur compounds contaminated wastewater stream by the anaerobic microorganisms, resulting in a sulphur compounds depleted wastewater stream. The invention furthermore relates to such a granular sludge treatment system (10).

A sulphur denitrification system includes a liquid input fluidly coupled to a source of saltwater that includes nitrate; a liquid output fluidly coupled to the source of saltwater; a plurality of vertically-oriented tanks, at least one of the tanks including a liquid inlet that is fluidly coupled to the liquid input to receive a flow of the saltwater, a volume configured to enclose a plurality of sulphur particles that support denitrification bacteria that biologically transform the nitrate into at least one of nitrous oxide or nitrogen gas, and a liquid outlet fluidly coupled to the liquid output and the liquid inlets of the tanks; and a circulation system configured to circulate a portion of the saltwater though the liquid input to the liquid inlets of the plurality of tanks, through the plurality of tanks, and from the liquid outlets of the tanks to the liquid output and the liquid inlets of the tanks.