A full-scale treatment of freeway toll-gate domestic sewage using ecology filter integrated constructed rapid infiltration

To explore an economical and manageable wastewater treatment process, a full-scale ecology filter integrated constructed rapid infiltration (Eco-CRI) was conducted and applied to treat freeway toll-gate domestic sewage, and the performances of Eco-CRI were investigated to evaluate its technical and economical suitability. The results showed that chemical oxygen demand, suspended solids, ammonia, and phosphorus could be removed efficiently when 1.0 m d−1 of the hydraulic loading rate and 2 h of dosing and 6 h of resting of feed regime were operated, respectively. Clogging, which was by far the biggest operational concern for the soil-based treatment systems, was not observed during the whole operation over a period of 14 months. Based on the results of economical analysis, electrical power consumption of per m3 wastewater treated was only 0.13 kWh. Besides maintenance of dosing pump, regular maintenance of Eco-CRI was just harvesting reeds and earthworms once a year. The facts indicated that Eco-CRI was a cost-effective and technically feasible process for freeway toll-gate domestic sewage treatment, and might serve as an attractive option for wastewater treatment in remote areas where regular maintenance was not feasible and/or in present developing countries like China where uneconomical approaches were not acceptable due to the local socioeconomic situation.