dissolved fe 2 oxidation of fe 2 will consume alkalinity and therefore will lower the ph to accelerate oxidation of dissolved fe 2 the aeration basin should maintain a ph of above 7 0 chemicals such as ca oh 2 naoh and na 2 co 3 could be used for ph control still referring to fig3 the final settling tank is to remove iron oxide flocculent formed in the aeration basin the ferric oxide floc fluffy settled to the bottom can be returned to the fluidized zone and transformed by fe 2 into dense particulate matter still referring to fig3 upon final settling a sand filtration bed may be used to further polish the treated water before discharge still referring to fig3 the reactive solid may initially be zero valent iron with the iron oxide mineral formed in situ the iron oxide mineral may coat the zero valent iron still referring to fig3 the system can be operated under various controlled conditions as needed according to some embodiments an iron based technique employs a mixture of zerovalent iron zvi or fe 0 and iron oxide minerals feox and fe ii species to react with adsorb precipitate and remove various toxic metals metalloids and other pollutants from the contaminated wastewater according to some embodiments an iron based physical chemical treatment process that employs a hybrid zerovalent iron feox fe ii reactor to treat toxic metal contaminated wastewater for example according to some embodiments the present system and process involve a hybrid zerovalent iron feox fe ii reactor for removing toxic metals in wastewater according to some embodiments the process employs a fluidized bed system.