title: Congruence in the performance of model nitrifying activated sludge plants located in Germany, Scotland and Spain.
abstract: A laboratory model nitrifying activated sludge plant treating OECD synthetic sewage was designed and constructed by each of three laboratories in Germany, Scotland and Spain in order to produce a sludge inoculum for 5 rapid toxicity bioassays. The plants were run for 3 years and produced sludge for the microbially based bioassays Vibrio fischeri bioluminescence, ATP luminescence and respiration, and, nitrification and enzyme inhibition. Although the initial sludge inoculum for the plants differed, as did some of the running conditions such as temperature regime, the sludge produced within the different countries had similar characteristics with respect to sludge age, total suspended solids and volatile suspended solids. Nitrification was generally maintained over the 3-year period although there were occasions when the process was inconsistent. Nitrification recovery was afforded by reseeding with a nitrifying sludge from a local wastewater treatment works (WWTW) or imposition of starvation conditions for a period of time. The sludge produced was used to carry out toxicity testing and results compared well with those using sludge from a WWTW. Overall, the use of sludge generated in the laboratory could be used for toxicity testing negating the need to resort to the use of natural WWTW sludge, which may contain a range of toxic substances due to uncontrolled industrial and domestic inputs and an unbalanced microbial consortium.
authors.affiliation: Department of Biological Sciences, Pollution Research Unit, School of Life Sciences, Napier University, 10 Clinton Road, Edinburgh EH10 5DT, Scotland, UK. n.christofi@napier.ac.uk
authors.forename: Nick
authors.initials: N
authors.lastname: Christofi
authors.forename: Elena
authors.initials: E
authors.lastname: Aspichueta
authors.forename: David
authors.initials: D
authors.lastname: Dalzell
authors.forename: Alejandro
authors.initials: A
authors.lastname: De la Sota
authors.forename: Javier
authors.initials: J
authors.lastname: Etxebarria
authors.forename: Teresa
authors.initials: T
authors.lastname: Fernandes
authors.forename: Monica
authors.initials: M
authors.lastname: Gutierrez
authors.forename: John
authors.initials: J
authors.lastname: Morton
authors.forename: Ursula
authors.initials: U
authors.lastname: Obst
authors.forename: Peter
authors.initials: P
authors.lastname: Schmellenkamp
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D001681:Biological Assay; D019149:Bioreactors; D005858:Germany; D007220:Industrial Waste; D008163:Luminescent Measurements; D009584:Nitrogen / Q000378:metabolism; D012606:Scotland; D012722:Sewage / Q000737:chemistry*; D013030:Spain; D014733:Vibrio; D014865:Waste Disposal, Fluid / Q000379:methods*; D014873:Water Pollutants / Q000633:toxicity*
chemical_list: D007220:Industrial Waste; D012722:Sewage; D014873:Water Pollutants; D000255:Adenosine Triphosphate; D009584:Nitrogen