The disclosed technology regards a method and system for removing sodium chloride from production water or fracking water produced in an oil well operation, or other wastewater. Generally, the method includes adding a calcium chloride feed to the source water to create a mixture in an amount so that the calcium chloride present in the mixture is at least 31% w/w of the mixture. The mixture is then agitated, and settled to allow sodium chloride crystals to precipitate out of the mixture, leaving a calcium chloride mixture.

An economical method for recovering phosphate or phosphate and nitrogen from liquid streams. A liquid containing phosphate is introduced into a culture of autotrophic microorganisms in the presence of natural or artificial light, thereby producing a liquid effluent with elevated pH and reduced alkalinity. The alkalinity is reduced through the consumption of bicarbonate/carbonate by the autotrophic microorganisms. The effluent is then chemically treated with low-cost chemicals to provide Ca.sup.++ or Mg.sup.++ ions necessary to form a phosphate precipitate such as calcium phosphate or magnesium-ammonium-phosphate (MAP). The autotrophic microorganisms can be cultivated in ponds, lagoons, or photobioreactors. The pH of the culture is adjustable within a preferred range of 7.5 to 10.5 by adjusting the photobioreactor operation. The process includes an economical flotation separator for solid, liquid, gas separation and a means of concentrating ammonia nitrogen that may also be removed during the process of phosphate reclamation.

The present disclosure relates to a method for treating and recycling, in an environment-friendly manner, sludge and waste water generated in a process for crushing waste concrete and recycling waste concrete into aggregates. Sand is separated from sludge configured from cement components and sand components and is recycled as fine aggregates, and the cement components can be used as concrete admixtures. Furthermore, the present invention introduces a mineral carbonation technique and thereby allows pH of waste water to satisfy an environmental standard and allows high value calcium carbonate to be produced.

Potable drinking water is plagued with widespread arsenic contamination, particularly in developing communities. Ferric ions were introduced to interact with arsenate based on the strong affinity of arsenate for ferric hydroxides, followed by mucilage addition. The mucilage coagulated and flocculated the ferric-arsenate complex and formed visible flocs that settled at the bottom of the tubes. The system showed 75-96% arsenate removal in 1 hour, while longer retention times showed 100% removal. The role of the mucilage was demonstrated by untreated solutions showing no concentration difference and remaining stable for more than 15 days. This mucilage-based technology has the potential to be a relatively inexpensive, environmentally sustainable alternative to synthetic polymer flocculants for removing arsenic from drinking water.

Methods to improve dewatering in industrial and municipal sludges are described. One method involves admixing sludge from a papermaking process and modified cellulose to provide modified sludge with the modified cellulose present in an effective amount to improve dewatering in the treated sludge, such as in allowing use of reduced amounts of coagulant and/or reducing dewatering times, increased dewatered volumes, and reduced sludge product moisture contents, and the like. The dewatered sludge may be formed into a dried particulate, and may be used as filler or other component of concrete, rubber, asphalt, plastics, resin-wood composite products, and other composite products.

A method for removal and recovery of phosphorus includes a precipitation step for precipitating phosphorus from a liquid stream comprising at most 30 mg of phosphorus per litre and at most than 50 mg of suspended solids per litre, using a precipitation agent, to form a precipitate, to form a precipitate; a first separation step for separating the precipitate from the liquid stream; a dissolution step for dissolving the precipitate in phosphoric acid to obtain a first solution; and a second separation step for separating the phosphoric acid and the precipitation agent.

Unconventional hydrocarbons production from shale and tight-sand formations unlocks vast new energy sources to the nation. However, public perception about excessive potable water use in hydro-fracturing and possible pollution routes in discharging and reusing produced water (flow-back water) promotes state's stringent regulations and opens the door to develop effective produced water treatment methods. This invention is therefore aimed at properly treating produced water to avert health and environmental liabilities and convert economic losses to useful by-products using innovative methods to de-oil, de-scale, and de-salt produced water.

A system and method of treating wastewater. In one embodiment, the system comprises a biological reactor fluidly connected to a source of wastewater and having a treated wastewater outlet, a fixed film biological reactor connected to the source of wastewater and having a fixed film effluent outlet, and a ballasted system fluidly connected to the fixed film effluent outlet. The ballasted system may comprise a ballast reactor tank configured to provide a ballasted effluent, and a source of ballast material fluidly connected to an inlet of the ballast reactor tank. The system may further comprise a bypass line having an inlet fluidly connected to the source of wastewater, a first outlet fluidly connected to the ballasted system, and a second outlet fluidly connected to the fixed film biological reactor, the bypass line configured to bypass the fixed film biological reactor.

Disclosed herein is a method for treating shale gas produced water. The method comprises adding a magnesium containing pH raising agent to the produced water, whereby a precipitate comprising magnesium hydroxide is formed; adding a source of carbonate ions to the produced water, whereby a carbonate containing precipitate is formed; and removing the precipitate to provide a treated water.

The present invention relates to a process for the purification of water, wherein a surface-reacted natural calcium carbonate is brought into contact with the water to be purified, the surface-reacted natural calcium carbonate being the reaction product of a natural calcium carbonate with an acid and carbon dioxide, which is formed in situ by the acid treatment and/or supplied externally.