There are many companies ...

There are many companies working with industry on decentralized wastewater treatment.  Here are just a few:

http://www.premiertechaqua.com/wastewater-sewer-treatment-plants

http://www.bioprocessh2o.com/

http://cambrianinnovation.com/

http://www.purposeenergy.com/

Please let me know if you would like more information.