Reclaiming wastewater means removing phosphorus from the final effluent. There's just no getting around this fact. Phosphorus levels at the influent are going to be different based on the location of the wastewater treatment plant, but the process to reduce it to safe levels is about the same in all locations.
Here's what you can do.
An aluminum-based or iron-based coagulant is used to bind with the phosphorus in the wastewater supply. Once this chemical is added and the binding process has finished, a tertiary filtration system is used to pull out the phosphorus. This process can be repeated more than once in locations where there are high levels of phosphorus levels in the influent.
Hope it helps.
In addition to responses 1 and 2, it is worth remembering the so-called 'organic' removal option.
Extracted sludge systematically contains phosphorus at around 20 g P/kg DM. This rate can be increased using an anaerobic tank at the inlet pumping station that allows for processing of bacteria so that it will store more phosphorus (about 30-40 g P/kg DM). You still have to 'manage' excess sludge so that it does not release the trapped phosphorus (ensure there is no thickener overflow or a silo).
This set-up avoids the use of chemicals, which are expensive, not to mention that transporting them increases the carbon footprint.