title: Controlling a combined lagoon/reed bed system using the oxidation-reduction potential (ORP).
abstract: Lagoon systems achieve good and stable effluent data in regard to organic pollutants, but they charge the receiving waters with relatively high ammonium loads. Therefore an existing lagoon-plant was extended by a vertical flow reed-bed for the special purpose of nitrification. This paper presents the efficiency of the combination plant as well as the possibility to monitor and control the reed-bed operation by the oxidation-reduction potential (ORP). The results show that the combination plant achieved excellent purification results, the average efficiency degrees were 97% for COD, 77% for N(total) and 94% for the TKN elimination. The ORP in the effluent of the reed bed showed a clear dependence in its characteristic course and its absolute values on the current nitrification performance, the oxygen supply and the hydraulic behaviour of the reed bed. Therefore the ORP is a very good indicator for the state of the reed bed, which ultimately results from the accumulation of a large number of different influencing parameters. As the preservation of aerobic conditions in the reed bed is the crucial prerequisite for a high nitrification performance and for the avoidance of clogging, the ORP thus offers the possibility of immediate operation control.
authors: Institute for Water Quality and Waste Management, University of Hannover, Welfengarten 1, D-30167 Hannover, Germany. kayser@isah.uni-hannover.de
authors: K
authors: K
authors: Kayser
authors: S
authors: S
authors: Kunst
authors: G
authors: G
authors: Fehr
authors: H
authors: H
authors: Voermanek
mesh_terms: D017753:Ecosystem; D009584:Nitrogen / Q000378:metabolism; D009930:Organic Chemicals / Q000302:isolation & purification; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods*; D014872:Water Movements; D014873:Water Pollutants / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*
chemical_list: D009930:Organic Chemicals; D014873:Water Pollutants; D009584:Nitrogen