title: Dewatering model for optimal operation of sludge treatment wetlands.
abstract: Sludge treatment wetlands (STW) are used as a dewatering technology in some European countries since the 80's. Although the efficiency of this technology in terms of sludge dewatering and mineralisation is well known, design and operation parameters are yet to be standardised. The aim of this study is to develop a mathematical model capable of predicting the water loss with time, in order to optimise the feeding frequency enhancing sludge dewatering and expanding the lifespan of the system. The proposed model is validated with experimental data from one pilot and two full-scale STW. The scenarios considered indicate that the optimum feeding frequency decreases with the sludge layer height. In this way, systems with a sludge layer of 20 cm, 40 cm and 80 cm (corresponding to 2, 4 and 8 years of operation), should be fed every 2.5, 10 and 30-40 days, respectively. On the other hand, evapotranspiration (ET) has no effect on the feeding frequency, although it does increase the sludge dryness from 25% to 45% (for ET of 2.5 and 14.5 mm/d in the case of 20 cm of sludge height). According to the model output, the sludge loading rate is determined as a function of evapotranspiration, feeding frequency and sludge height.
authors: GEMMA, Department of Hydraulic, Maritime and Environmental Engineering, Universitat Politècnica de Catalunya, BarcelonaTech, c/Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain. enrica.uggetti@upc.edu
authors: Enrica
authors: E
authors: Uggetti
authors: Albert
authors: A
authors: Argilaga
authors: Ivet
authors: I
authors: Ferrer
authors: Joan
authors: J
authors: García
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D002980:Climate; D008954:Models, Biological; D010865:Pilot Projects; D018526:Plant Transpiration; D012722:Sewage / Q000737:chemistry*; D013030:Spain; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D014867:Water / Q000737:chemistry; D058438:Water Cycle; D018508:Water Purification / Q000295:instrumentation / Q000379:methods; D053833:Wetlands
chemical_list: D012722:Sewage; D014867:Water