In　a　previous　study,　a　soil　plant-based　natural　treatment　system　was　successfully　developed　for　post-treatment　of　anaerobically　digested　strong　wastewater　full　of　potential　nutrients　(nitrogen,　phosphorus,　and　potassium).　For　upgraded　performance,　an　innovative　decentralized　treatment　system　was　further　developed,　in　which　an　anaerobic　digestion　stage　and　a　natural　treatment　system　stage　are　placed　within　a　greenhouse.　This　allows　the　CO2　generated　by　the　processing　of　wastewater　and　biogas　consumption　to　be　sequestrated　within　the　greenhouse　for　elevating　its　concentration　level　and　potentially　enhance　nutrient　removal　and　recovery　from　the　applied　wastewater.　To　investigate　the　feasibility　of　the　system,　a　bench-scale　experiment　was　conducted　using　CO2　chambers.　Valuable　Kentucky　bluegrass　was　planted　in　two　soil　types　(red　ball　earth　and　black　soil)　at　three　CO2　concentrations　(340　ppm,　900　ppm,　and　1400　ppm).　The　results　confirmed　the　positive　effects　of　elevated　CO2　concentration　on　the　biomass　production　and　turf　quality　of　Kentucky　bluegrass　as　well　as　the　resulting　higher　nutrient　recovery　efficiencies.　More　importantly,　it　was　demonstrated　that　the　elevated　CO2　concentration　significantly　stimulated　the　soil　nitrifying　microorganisms　and　thus　improved　the　nitrogen　removal　efficiency　(a　critical　issue　in　ecological　wastewater　treatment).　A　CO2　concentration　of　1400　ppm　is　therefore　recommended　for　use　in　the　system.　The　mechanism　underlying　this　phenomenon　was　shown　to　be　an　indirect　effect,　in　which　the　higher　CO2　concentration　first　positively　influenced　growing　plants,　which　then　stimulated　the　soil　nitrifier　communities.　The　effects　of　soil　type　(a　design　parameter)　and　hydraulic　and　nutrient　loading　rates　(an　operational　parameter)　on　system　performance　were　also　examined.　The　results　favored　black　soil　for　system　establishment.　Based　on　the　findings　of　this　study,　our　proposed　system　is　thought　to　have　the　potential　to　be　scaled　up　and　adopted　by　rural　communities　worldwide　for　the　reclamation　and　reuse　of　strong　wastewater,　addressing　the　agricultural　non-point　source　pollution,　and　achieving　the　sustainable　development.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.