https://www.epa.gov/sites/production/files/2015-09/documents/primer.pdf

https://www3.epa.gov/npdes/pubs/mstr-ch3.pdf

http://web.deu.edu.tr/atiksu/ana58/jps1.pdf

http://www.kysq.org/docs/Wastewater_2007.pdf

http://documents.worldbank.org/curated/en/351581468012035853/pdf/170370REPLACEM00as0previous0record0.pdf

http://www.fao.org/docrep/T0551E/t0551e05.htm

It generally depends on the level of purity you expect after the wastewater treatment. 

Of course there is no one method that is ideal for every application. The method must depend on the specific requirements you have. What is the flow rate? The temperature? What is the concentration of organic matter, nitrogen and phosphorous in the incoming waste water? How clean must the water be after treatment? 

You choose the method and design the process according to these specifications.  

Adsorption seems to be most promising method for N and P recovery, read this review for further understanding http://www.sciencedirect.com/science/article/pii/S0001868616302184

Many thanks to Dr.Bp.Naveen, and all dear friends and professors. With my special respect and owner for this heavy duty scientific information in my specialty.