Treated wastewater is commonly disposed of in Germany by discharge into surface waters. Within the project ELaN, alternative approaches were investigated for dealing with treated wastewater. Main focus was placed on re-use to recycle valuable nutrients and to help prevent falling water levels in Northeast Germany. In part F (‘Ecotoxicology’) of the project, ECT investigated ecotoxicological effects in the aquatic (treated wastewater, and surface and groundwater influenced by treated wastewater) and terrestrial compartment (soil that received wastewater). A battery of various standardised aquatic and terrestrial test methods was used. In addition, ecotoxicity of an alternative fertilizer produced within the wastewater treatment process (MAP) and of the anti-dandruff substance climbazole was investigated. In order to assess the long-term risk of approximately 30 years of wastewater irrigation, a flow-through model system with soil columns was run in situ at the wastewater treatment plant. The results regarding climbazole demonstrate that a substance contained in cosmetics and personal care products can exhibit an ecotoxicity that resembles that of structurally-related pesticides. The results for MAP demonstrate that its long-term toxicity toward earthworms is similar to that of common inorganic phosphate fertilizers at equivalent application rates. Treated wastewater was repeatedly found to exhibit phytotoxicity, but it did not affect the survival of invertebrates (crustaceans) or vertebrates (fish embryos). Phytotoxicity was reduced by soil passage, depending on soil properties. The drawback of an enhanced purification of treated wastewater by soil passage was clearly demonstrated to consist in the accumulation of organic micropollutants and metals in the soil. This resulted in only weak ecotoxicological effects after three years of real irrigation, but in stronger effects in a 30-years irrigation simulation scenario. In addition, it was demonstrated that irrigation of contaminated soil can result in the remobilization and elution of pollutants at ecotoxicologically relevant levels, potentially leading to groundwater contamination. Decisions on the re-use of treated wastewater at the landscape level should be based on a comprehensive and case-specific weighting of the advantages (e.g. reduced impact on effluent-receiving surface waters) and the disadvantages (e.g. accumulation of pollutants in soil). A broad test battery consisting of aquatic and terrestrial test is an important component of such an evaluation.
A description of the project results can be found in the following publications:
Maassen, S., Richter, E., Coors, A., Guimarães, B., Balla, D. (2017). Dissipation of micropollutants in a rewetted fen peatland: a field study using treated wastewater. Water 9:449. [read more]
Richter, E., Hecht, F., Schnellbacher, N., Ternes, T.A., Wick, A., Wode, F., Coors, A. (2015). Assessing the ecological long-term impact of wastewater irrigation on soil and water based on bioassays and chemical analyses. Water Research 84, 33-42.
Theobald, T., Rühmland, S. Richter, E., Coors, A., Barjenbruch, M., Kern, J. (2014). Phophorrecycling aus dem Abwasserstrom. Wasserwirtschaft Wassertechnik, 4/2014, 59-62.
Richter, E., Wick, A., Ternes, T.A., Coors, A. (2013). Ecotoxicity of climbazole, a fungicide contained in anti-dandruff shampoo. Environmental Toxicology and Chemistry 32, 2816-2825.
Theobald, T., Richter, E., Coors, A., Kern, J. (2013). Neue Wege im regionalen Phosphor-Management. ForschungsReport Ernährung – Landwirtschaft – Verbraucherschutz, FoRep 2/2013, p. 12-15.