PARALLEL PERFORMANCE COMPARISON BETWEEN AQUATIC ROOT ZONE — AND TEXTILE MEDIUM -INTEGRATED FIXED-FILM ACTIVATED SLUDGE (IFFAS) WASTEWATER TREATMENT SYSTEMS

Aquatic root zone treatment depends on contact of wastewater with roots from plants growing at the water surface. Combining extended-air, activated sludge treatment with biofilms growing on roots creates an integrated fixed-film activated sludge treatment system (IFFAS). This study made parallel, pilot scale comparisons of an aquatic root zone - IFFAS treatment system with a synthetic textile medium - IFFAS treatment systems, and an activated sludge treatment system. Flow to each treatment train was 1000 gpd of raw domestic influent. Both IFFAS treatment systems exhibited the same COD treatment (95% removal +/-3%). Seventy percent of root zone — IFFAS total nitrogen effluent values were ≤10 mg/L, but less than 20% of the textile medium — IFFAS effluent values were ≤ 10 mg/L. Retention of biosolids in plant roots appeared to enhance treatment performance and stability. Yield was apparently lowest in the planted train.