System for removal of phosphorus and nitrogen from water

A system for removal of nitrogen and phosphorus from starting material water, the system comprising:

• an elevated pH phosphorus removal stage configured to raise pH of the starting material water comprising both nitrogen and phosphorus to greater than or equal to 8.5 to 9.5 to precipitate a phosphorus salt from the water, the phosphorus salt comprising struvite, calcium phosphate, or a combination thereof, and configured to remove the precipitated phosphorus salt from the water, to form water from the elevated pH phosphorus removal stage, wherein the elevated pH phosphorus removal stage is configured to remove 90-98% of reactive phosphorus in the starting material water as measured according to US EPA Method 365.1;
• an electrolytic nitrogen removal stage comprising an electrolytic cell configured to contact the water from the elevated pH phosphorus removal stage with the electrolytic cell to remove nitrogen therefrom as nitrogen gas, to form water from the electrolytic nitrogen removal stage, the electrolytic cell comprising a cathode comprising stainless steel and an anode that comprises titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2—RuO2—IrO2/Ti), wherein passing the water from the elevated pH phosphorus removal stage through the electrolytic nitrogen removal stage removes 80-100% of ammonia therefrom;
• and
• a galvanic phosphorus removal stage configured to contact the water from the electrolytic nitrogen removal stage with a galvanic cell to form a precipitate comprising a salt that comprises phosphorus, the salt comprising
• AlPO4 or a hydrate thereof, the AlPO4 comprising the phosphorus and Al from the anode,
• aluminum hydroxide or a hydrate thereof, the aluminum hydroxide comprising Al from the anode, or
• a combination thereof,
• wherein the galvanic phosphorus removal stage is configured to separate the salt comprising the phosphorus from the treated water to form water from the galvanic phosphorus removal stage, wherein the galvanic cell comprises
• an anode comprising Al, wherein the anode is about 90 wt % to about 100 wt % Al,
• a cathode having a different composition than the anode, the cathode comprising Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu, and
• a conductive connector that electrically and physically connects the anode and the cathode, the conductive connector comprising an alloy comprising Cu and Zn, wherein the conductive connector comprises a screw, a bolt, or a combination thereof;
• wherein the water from the galvanic phosphorus removal stage has a lower phosphorus concentration and a lower nitrogen concentration than the starting material water, wherein the water from the galvanic phosphorus removal stage has
• a total phosphorus concentration of about 0.0001 ppm to 0.05 ppm, and
• a total nitrogen concentration of about 0 ppm to about 1 ppm.