A method of treating a wastewater is provided and can be used, for example, to treat a gas well production wastewater to form a wastewater brine. The method can involve crystallizing sodium chloride by evaporation of the wastewater brine with concurrent production of a liquor comprising calcium chloride solution. Bromine and lithium can also be recovered from the liquor in accordance with the teachings of the present invention. Various metal sulfates, such as barium sulfate, can be removed from the wastewater in the production of the wastewater brine. Sources of wastewater can include gas well production wastewater and hydrofracture flowback wastewater.