This study investigates a post-denitrification process without the addition of an external carbon source combined with an enhanced biological phosphorus removal (EBPR) in a membrane bioreactor (MBR). Three trial plants, with two different process configurations, were operated on two different sites, and a variety of accompanying batch tests were conducted. It was shown that even without dosing of an external carbon source, denitrification rates (DNR) much above endogenous rates could be obtained in post-denitrification systems. Furthermore, the anaerobic reactor located a head of the process had a positive impact on the DNR. Given these surprising results, the project team decided to identify the carbon source used by the microorganisms in the postdenitrification process. Batch tests could demonstrate that lysis products do not play a major role as a C-source for postdenitrification. The following hypothesis was proposed to explain the observations: the glycogen, internally stored by the substrate accumulating bacteria, if anaerobic conditions are followed by aerobic conditions could act as carbon source for denitrification in post-denitrification system. First exploratory batch tests, where the glycogen evolution was monitored, corroborate this

The main goal of this project is to develop new sustainable sanitation concepts which have significant advantages in relation to ecological as well as to economical aspects compared to the conventional systems (end-of-pipe-system). After successful project completion the new sanitation concepts should be used in Berlin areas, where sewer systems are not installed and these concepts are appropriate, as well as other locations (national and international). The technical management of the project has been achieved as foreseen, but the administrative project manger has changed in July 2005 since the head of the Berlin Centre of Competence for Water has changed. All technical equipments, besides of the bio-gas plant, are realised. The bio-gas plant will be installed about the end of 2005. In contrary to the EU-proposal the concept with vacuum separation toilets has been installed for technical reasons in the office building instead in the apartment house. Before installing of these toilets gravity separation toilets have been operated for 1 ½ years. Furthermore not in 15 but in 10 flats of the apartment house was it possible to install gravity separation toilets. The addition tasks Life-Cycle-Assessment (Task 5), Industrial style urine treatment for utilization (Task 7) and Fertiliser usage (Task 8) undertaken by different Universities are in the works. The users accept the separation toilets in general, but more the gravity than the vacuum separation toilets. Both have to be improved, especially the flush. The worse assessment for the vacuum separation toilets was expected since they are altered gravity separation toilets. An optimised vacuum separation toilet is not available on the market at present. The results from the faeces separator show that far the most solids can be retained in the filter bags, but there is still a high solids-concentration in the filtrate. For huge settlements a different, continuously working separator is necessary. Due to the high solid concentration in the faecal filtrate the soil filter as a pre-treatment step was blocked very soon and went out of operation. With the 2-chamber septic tank for greywater and faecal filtrate treatment an effluent quality could be obtained which does not lead to clogging of the downstream constructed wetland. The results of the constructed wetland are as expected. From the work of Task 5 and the experiments of Task 7 no reliable results are available until now. The experiments of Task 8 show that the fertilising results from the urine are similar with those from mineral fertilisers. Until the end of the project the different tasks will continue. The digestion of the faeces from the vacuum separation toilets with the bio-gas plant will start in January 2006. In relation to the financial issues 790,482 € (51 %) of the total eligible costs of 1,552,116 € and 1,230,640 € (55 %) of the total real costs of 2,223,474 € respectively have been spent until now. Herewith, the 30 % threshold of the total real costs is transcended.

As part of the EU-Life ENREM demonstration project the Department of Chemical Engineering, TU Berlin, was appointed to conduct the preliminary pilot trials in a representative site for verification of basic process designs and operation criteria of the full-scale MBR demonstration plant. In addition to conception and construction of the pilot plant, this investigation consists of two successive trial phases with distinct operation conditions: the first one being dedicated to the assessment of the “irregular sludge wastage strategy” (the biomass is accumulating in the reactor, which is partly emptied when the sludge concentration reaches a given value), and the second one being planned to verify normal operation conditions with daily sludge wastage. This progress report describes implementation and results of the first phase, for which a pilot plant of 140L was operated over 6 months with waste water of a decentralized area. The influent contained high concentrations of nitrogen (100-200 mg/L), phosphorus (10- 20 mg/l) and COD (1000-2000 mg/L). Also surprising were the high VFA concentrations (100-300 mg/L) which ensured a good EBPR process. The COD and also the enhanced biological phosphorus removal (EBPR) were not impacted by the irregular sludge wastage. COD effluent concentrations were around 50 mg/L and TP effluent was 0.1 to 0.3 mg/L. The high nitrogen influent concentrations were problematic. Due to changing TS concentrations and changing nitrification rates TN effluent was 10 to 30 mg/L with a NH4-N content of 0 to 20 mg/L. Denitrification rates were measured between 1 and 3 mgN/gVS h and were depending on TS concentration, with higher rates at lower TS concentrations. Polysaccharide concentrations in the sludge water phase were higher with low TS concentrations and low oxygen concentrations. Higher PS values led to faster fouling. Results of the trials suggest that the oxygen concentration should be kept above 2mg/L to ensure both sufficient nitrification and lower fouling. Since also high TS concentrations are needed to ensure complete nutrients removal the optimum TS range is relatively small and it must be concluded that the irregular sludge wastage strategy was not beneficial in this case and the demonstration plant should be run with regular sludge removal.

The ENREM project aims at demonstrating a novel wastewater treatment process based on the technology of membrane bioreactor (MBR), set up in a configuration to enable enhanced biological elimination of nutrients. A new plant, and the related sewer system, is to be built in a yet unsewered remote area of Berlin. The plant will be then operated over more than one year, and the process will be optimised. Performances and costs of the treatment system will be then assessed for the size 250 – 10,000pe, corresponding to semi-central schemes. The management of the project has been achieved according to the organisation identified in the LIFE proposal. No relevant modification has been required. Annex 3.1 presents and discusses the key deliverables and milestones depending on the LIFE proposal and the current status. In relation to the technical content, Task 2 “Site and process definition” and Task 4 “Detailed design” are quasi-completed, with however a four month delay which will put back consequently the following actions, such as start of sewer and plant construction, and plant commissioning. Specifically, the following actions were completed, or are on the verge of completion: - Cost-comparison of decentralised treatment solutions to serve 20 unsewered areas of Berlin and selection of demonstration site (district of Margaretenhöhe); - Revision of cost evaluation for infrastructure; - Planning and specification of MBR plant; - Preparation and release of call for tender of MBR plant; - Planning and specification of low-pressure sewer; - Preparation and release of call for tender of low-pressure sewer construction; - Acquisition of legal permits (for plant construction & operation, water discharge); - Acquisition of parcel for MBR plant. In addition, the first trials phase of Task 3 “Preliminary testing on representative site” (period with irregular excess sludge withdrawal) was completed and enabled to validate the design criteria of the MBR demonstration plant. The relationship with the inhabitants of Margaretenhöhe was initiated in order to ensure a smooth construction phase, and a quick connection to the new sewer system. Dissemination activities were undertaken accordingly as shown in Annexes 7.1-7.3, and the project web-site in three languages was set up (see in www.kompetenz-wasser.de). The communications on project are expected to ramp up in 2005 and 2006, as more outcomes and results are getting available. The main task in 2005 will be the construction and commissioning of the low sewer system and the MBR demonstration plant. The start-up of the novel treatment scheme is now expected for October / November 2005. From the budget perspective, the total costs incurred over 2004 were 198,353€. This is 6% of the total budget of the LIFE proposal. The infrastructure costs and most of equipment costs (expected 62% of total budget) should occur in 2005 during the construction and commissioning phases of the scheme. No major budget deviation was noticed so far, and the re-evaluation of the infrastructure costs fit with those of the LIFE proposal.

Two major points of view prevail in modelling aquatic ecosystems. For practitioners, the key question in modelling aquatic ecosystems is how well models describe system reactions to changes – particularly trophic change and climate change – and in consequence, how useful models are for predicting system responses and for informing water-body management. For researchers, the modelling objective is to investigate functional interactions between ecosystem components, to understand complex causalities and to identify knowledge gaps to close with further lab and field work. Ideally, successful modelling should address both purposes. A need for more intensive communication between modellers of both groups, as well as other model users, was identified at a modellers’ workshop organised by the project “OLIGO” in autumn 2005. OLIGO (2003-2007) was a project of the Berlin Centre of Competence for Water (KWB), executed by researchers of the Federal Environmental Agency (UBA) and the Berliner Wasserbetriebe (BWB) and funded by Veolia Water. Following up on the recommendation of this workshop and in the context of finalising this project, UBA together with KWB organised a 2-day workshop in Berlin, 8-9 November 2007. The workshop was hosted by the Berliner Wasserbetriebe and brought together 60 modellers and model users from 6 countries. The workshop aimed to consolidate and document the state of the art in modelling water quality in reaction to nutrient load or climate change, to discuss how well current lake and reservoir models can support and inform decision-makers, including dealing with the uncertainty of model predictions, and to explore future perspectives and needs for the development of models.

The paper presents the build-up of a model for the integrated simulation of the sewage system of Berlin, Germany, focusing on the catchment of the wastewater treatment plant Ruhleben. The Ruhleben catchment, draining 185 km² and a population of 1.38 million inhabitants is characterised by its high portion of combined sewerage. The model comprises the collection system, pump stations, pressurised mains and the wastewater treatment plant. Hydraulic and quality processes are taken into account. A preliminary assessment of the sewage system and the analysis of historical operational data showed a high potential concerning global real-time control of the pump stations. Three different global control scenarios have been studied on the basis of a long time simulation over 50 days and compared with a local control regime. The results show that the coordinated operation leads to a reduction of total emissions. Main improvements can be achieved concerning the discharges from combined sewer overflows. These improvements are of major significance due to the high hazard potential of combined sewer overflows.

A modelling study was carried out to provide a process-based quantitative interpretation of the biogeochemical changes that were observed during an ASR experiment in which reclaimed water was injected into a limestone aquifer at a field-site near Bolivar, South Australia. A site-specific conceptual model for the interacting hydrodynamic and biogeochemical processes that occur during reclaimed water ASR was developed and incorporated into an existing reactive multi-component transport model. The major reactive processes considered in the model were microbially mediated redox reactions, driven by the mineralisation of organic carbon, mineral precipitation/ dissolution and ion exchange. The study showed that the geochemical changes observed in the vicinity of the ASR well could only be adequately described by a model that explicitly considers microbial growth and decay processes, while an alternative, simpler model formulation based on the assumption of steady state biomass concentration failed to reproduce the observed hydrochemical changes. However, both, the simpler and the more complex model approach were able to reproduce the geochemical changes further away from the injection/extraction well. These changes were interpretated as a result of the combined effect of ion exchange, calcite dissolution and mineralisation of dissolved organic carbon.