The present disclosure relates to processes for treating wastewater such as acid rock drainage. The processes may, for example, comprise subjecting the wastewater to a microbial fuel cell process, neutralizing the acid with a base comprising calcium to produce an aqueous composition comprising calcium ions and subjecting the aqueous composition comprising calcium ions to a biological precipitation process to precipitate the calcium ions as calcium carbonate.

A wastewater to chemical fuel conversion device is provided that includes a housing having a first chamber and a second chamber, where the first chamber includes a bio-photoanode, where the second chamber includes a photocathode, where a backside of the bio-photoanode abuts a first side of a planatized fluorine doped tin oxide (FTO) glass, where a backside of the photocathode abuts a second side of the FTO glass, where a proton exchange membrane separates the first chamber from the second chamber, where the first chamber includes a wastewater input and a reclaimed water output, where the second chamber includes a solar light input and a H.sub.2 gas output, where the solar light input is disposed for solar light illumination of the first chamber and the second chamber.

A microbial fuel cell system includes a supply-drain compartment having a supply port and a drain port of an electrolytic solution. The microbial fuel cell system further includes one or more power generation cassettes provided in the supply-drain compartment and each including a microbial fuel cell including: a positive electrode including a first water-repellent layer in contact with a gas phase and a gas diffusion layer attached to the first water-repellent layer; and a negative electrode holding anaerobic microorganisms. The microbial fuel cell system includes one or more purifying cassettes provided in the supply-drain compartment and each including a second water-repellent layer in contact with the gas phase. The power generation cassettes are arranged on the upstream side in a direction in which the electrolytic solution flows from the supply port toward the drain port, and the purifying cassettes are arranged on the downstream side of the power generation cassettes.

The invention relates to bio-electrochemical systems for the generation of methane from organic material and for reducing chemical oxygen demand and nitrogenous waste through denitrification. The invention further relates to an electrode for use in, and a system for, the adaptive control of bio-electrochemical systems as well as a fuel cell.

The present disclosure relates to bioremediation systems and methods for wastewater treatment in heavy industry, including the mining industry. A benefit of the systems and methods disclosed herein can include the reduction of heavy metals in wastewater. Another benefit can be the treatment of acidic wastewater to achieve higher pH levels. An additional benefit can be the use of carbon dioxide to raise the pH level of acidic wastewater, or to produce feedstocks for the growth of anaerobic or aerobic microorganisms that are capable of reducing a concentration of heavy metals in wastewater. A benefit of the systems and methods herein can include the treatment of acid mining drainage wastewater, as well as heavy metal removal from other industrial wastewater. Another benefit of the methods and systems disclosed herein can include reduction of excess carbon dioxide from the environment.

Managed ecosystems, methods for producing managed ecosystems and methods for using managed ecosystems for sequestering carbon dioxide are described herein. Produced water is obtained and purified to sustain a managed ecosystem with saline-tolerant vegetation. The managed ecosystem biologically sequesters carbon dioxide by photosynthetically absorbing carbon dioxide from the atmosphere and by decomposition into a layer of sediment on the ecosystem floor.

A system and a method for separation of ions from ions-containing medium is disclosed herein, that utilizes capacitive-faradaic fuel cells (CFFC) particles coated at least partially with catalysts capable of catalyzing redox reactions provided a reductant (fuel) and/or an oxidant, thereby polarizing the particles to more effectively absorb charged species (ions) from the water upon introducing, e.g., H.sub.2 gas or O.sub.2 gas, in the medium during the adsorption or regeneration. The same concept is utilized in a hybrid electrochemical cell for providing a system and a method for generating and converting electrochemical energy.

The present disclosure relates to the technical field of microbial electrochemical technology, in particular to a graphene-magnetite conductive skeleton electrode, a preparation method and application thereof, and a method for treating petrochemical wastewater. In the present disclosure, the surface roughness of the graphite rod electrode can be increased by the conductive skeleton modified on the surface of the graphite rod electrode, which is beneficial to the enrichment of microorganisms. The increase in the load of microorganisms will mean the amount of electroactive microorganisms will also increase, which will further improve the electron transfer ability, and because the material of the modified layer is a conductive material, it is also more conducive to the transfer of electrons; at the same time, the conductive skeleton modified on the surface of graphite rod electrode can also further enhance the transmission distance of electrons because of the skeleton constructed.

A method for treatment of wastewater includes passing influent wastewater through an anaerobic, anoxic, or bioelectrochemical bioreactor to produce an effluent. The membrane bioreactor includes a membrane with pores having a nominal pore size less than the smallest measured biopolymers and organic nanoparticles in the influent wastewater, thereby preventing them from entering and blocking membrane pores, and further comprising degrading dissolved organics smaller than 20 nm in the influent wastewater within the membrane bioreactor before entering membrane pores.

Methods are described for treating aqueous solutions, including wastewater, to remove nitrogen-containing compounds using electrochemical processes. The method may be conducted electrolytically under an applied voltage or using endogenous current in a fuel cell arrangement. In some embodiments, energy is reclaimed in the form of hydrogen, methane, and other hydrocarbons or organic molecules. Microorganisms may be used as the catalyst for oxidation of the nitrogen-containing compound and/or reduction of hydrogen ions, carbon dioxide, or bicarbonate. Anaerobic or low-oxygen conditions may be used in the zone.