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Support material used in constructed wetlands has been shown to be a key element and significant mechanism in the process of contaminants removal from sewage including phosphorus compounds. Recycled waste tires processed into small chips that are similar to conventional stone aggregate are currently used in the construction of septic system leach fields and could be a green alternative as support material in constructed wetlands. During three years, the performance of a gravity subsurface horizontal flow constructed wetland using recycled shredded-tire chips as support material to treat on-site the high strength wastewater from a bakery was monitored. Grab samples of the effluent from the septic tank and the constructed wetland were collected quarterly and submitted to a certified laboratory. Final treatment efficiency (percentage removal) was low for potassium (36%), intermediate for total nitrogen (56%), and total Kjeldahl nitrogen (57%), and relatively high for total phosphorus (65%), total suspended solids (69%), ammonia-nitrogen (87%), five-day biochemical oxygen demand (92%), Escherichia coli (97%), and fat-oil and grease total (99%). Nitrate-nitrogen final mean value was consistently below 1 mg/L, and iron concentration increased from less of 2 mg/L in the sewage to 55 mg/L in the constructed wetland effluent. These results show that recycled shredded-tire chips could be an

Sewage can be considered one of the richest and most productive waters for crops since it contains nitrogen (5 -7%) and phosphorus (3 -5%) and in constructed wetlands it could be used as fertilizer. The feasibility of growing corn on a recirculating vertical flow constructed wetland (RVFCW) treating sewage on-site was examined. Corn was planted at 107,000 seeds/ha. Effluents from a septic tank and a RVFCW were analyzed for water quality variables. Treatment efficiencies (removal) were high for fecal coliform bacteria (99.9%), biochemical oxygen demand (98.4%), total suspended solids (95.6%), ammonium-nitrogen (95.3%), total Kjeldhal nitrogen (94.7%), total nitrogen (79.5%), and total phosphorus (75.5%), while relatively low for potassium (48.8%). Corn yield (only kernel) was 10,026 kg/ha. These results show that a RVFCW could be a sustainable alternative technology to grow corn providing a mechanism to remove pollutants from wastewater, reduce sanitation problems, and improve economic and social benefits.

The three main components of chemical fertilizers for field crops are nitrogen, phosphorus, and potassium, and they are considered limiting factors to plant growth. The concentration level of these macronutrients on treated wastewater effluents is considered appropriate to support crop production. The purpose of this case study was to use a real-scale model to treat and reuse sewage onsite using a recirculating vertical flow constructed wetland (RVFCW) as an engineered ecosystem planted with sunflowers (Helianthus annuus L.). Effluents from both the septic tank and the RVFCW were analyzed for water quality variables. Treatment efficiencies (removal) were high for fecal coliform bacteria (98%), biochemical oxygen demand (98%), ammonium-nitrogen (97%), total Kjeldahl nitrogen (96%), total suspended solids (92%), total nitrogen (77%), and total phosphorus (76%), while they were relatively low for potassium (38%). These results show that sunflowers growing on top of the RVFCW could be a sustainable alternative technology and a green mechanism to remove pollutants from sewage. A nutrient recovery through the direct use of sewage as fertilizer and water reuse is feasible.

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