Constructed Wetlands for removal of Phosphorus from Domestic Wastewater-A Patent Review

Research related to phosphorus (P) removal in domestic wastewater treatment has increased manifolds due to stress on freshwater resources globally. Constructed Wetlands (CWs) have gained popularity as an innovative, sustainable, and cost-effective technology in this direction. This review summarizes the various patenting patterns and innovations related to the application of CWs for the removal of P from domestic wastewater. For this purpose, the Relecura patent database has been used. The patent landscape has been analyzed based on application volume, patent geographical details, application organization, main technologies, keywords, concepts, assignees, code analysis, and citation analysis. The results indicate that a total of 115 patents have been filed in this field of research, out of which 76 are patent applications and 39 granted patents which indicates a tough examination cycle and a limited rate of the grant of patent applications. China is leading with a total patent count of 105 and also in terms of citations, inventors, and assignees. Based on citations most of the patents are related to efficient sewage treatment systems by incorporation of solar heating, immobilized bed, moving bed, double layer wetland system, and composite filling material systems. The study cogitates about inventions and utility model patents related to different configurations and types of artificial wetlands employing natural, waste, and synthesized material adsorbents. Synthesized adsorbents utilizing low-cost materials to improve P adsorption have been shown to have an added economic and environmental advantage of extending the filler replacement cycle and minimization of secondary pollution.