EAWAG news 57e (December 2003)
Urban Wastewater Management in Transition (Entire volume)
| Editorial |
| (Screenversion 70 KB; Printversion 90 KB) |
| Willi Gujer |
| Lead Article |
| From Transport to Water Protection
(Screenversion 485 KB; Printversion 1.2 MB) Max Maurer Urban drainage is in transition from functioning simply as a transport system to becoming an important element of water protection; however, this transition has been only partially successful since certain properties of today’s sewage system represent inherent weaknesses. The cleaning efficiency of the sewage system as a whole, for example, is limited due to significant dilution with grey water and leaky sewage pipes. It is with this background that science is looking for ways to optimize existing structures and develop alternative approaches bringing sustainable urban drainage to a higher level. |
| Research Reports |
| Micropollutants - New Challenge
in Wastewater Disposal? (Screenversion 160 KB; Printversion 205 KB) Hansruedi Siegrist Through improved methods of chemical analysis, pharmaceutical and hormone-active substances are increasingly being detected in our water bodies. In most cases, they enter the waste water after being excreted in urine. In the sewage plant, a fraction of the substances is eliminated through sorption and biological degradation. The remaining part enters water bodies with the treated waste water. This article describes possible measures aiming at eliminating the residual substances. These include on the one hand, permanent measures at the source such as an eco label for pharmaceuticals, the pre-treatment of hospital waste waters and the separate treatment of urine. However, on the other hand, as the measures at the source can only be implemented over the long term, it is expedient to also consider technical measures such as raising the sludge age in the activated sludge tanks of sewage treatment plants and, for critical cases, the ozonation of the purified waste water. |
| The Driving Forces for Change in
Wastewater Treatment (Screenversion 120 KB; Printversion 165 KB) Dieter Rothenberger How do changes in the economic and social framework affect the future technical development of wastewater treatment? The EAWAG research group CIRUS - Centre for Innovation Research in the Utility Sector - focuses on this question in the German study “Integrated Microsystems for Supply”. |
| NoMix Technology: How Good is
the Acceptability? (Screenversion 310 KB; Printversion 1,1 MB) Judit Lienert The successful implementation of an innovative technology depends on many factors. Apart from its technical superiority compared to traditional solutions, the needs of the stakeholders play a vital role. We were interested to know whether the market is ready for the NoMix technology, a sanitary concept for urine source separation, which would revolutionize our current system of wastewater management. Surveys showed that consumers and farmers have a positive attitude, given that the NoMix technology is adequate, inexpensive, and safe. Sanitary firms are confident that they can further develop NoMix toilets, but they demand strong commitment from wastewater professionals who will, therefore, play a deciding role in putting the NoMix technology into practice. |
| Alternative Environmental Sanitation
Approaches in Developing Countries (Screenversion 175 KB; Printversion 530 KB) Antoine Morel Half of the world population does not have access to hygienic sanitation systems. The conventional “top-down approaches” often fail. Therefore, EAWAG together with an international group of experts developed the “Household-Centred Environmental Sanitation (HCES) Approach” which places the household in the centre of the planning process. |
| Project STORM - Wastewater Discharge
During Rain Events (Screenversion 280 KB; Printversion 1 MB) Vladimir Krejci During rainy periods, only some of the waste water runs through treatment plants. In combined sewer systems, the excess flow is discharged directly or, after some simple treatment, into surface waters. Until recently, planning for these overflow structures has been based on unspecific problem criteria and empirical methods. In order to improve water protection and cost efficiency, environmental factors and uncertainty assessments will increasingly become incorporated into the planning and decision-making processes. |
| Toward Sustainable Urban Stormwater
Management (Screenversion 250 KB; Printversion 820 KB) Markus Boller As a result of the decision made in the nineties to install separate stormwater drainage for settlements, our current methods of wastewater disposal will change considerably in future years and decades. There is, however, more and more evidence that also rain water carries a certain pollutant load. In order to find suitable measures for the protection of the environment, sources, concentrations and hydraulic dynamics need to be well characterized. This article introduces instruments for the reduction of substantial load and first steps of their implementation. |
| How “Tight” is our
Sewer System? (Screenversion 190 KB; Printversion 355 KB) Jörg Rieckermann Urban sewer systems are subjected to constant stress by traffic and soil movement. Combined with natural fatigue of materials, these conditions lead to damage to underground pipes, causing exfiltration of sewage into the ground water as well as infiltration of ground water into the sewer pipes. EAWAG is currently developing a new method to quantify these processes by using both natural and artificial tracers, which will help us in planning more efficient remedial action. |
| Management of Wastewater Treatment
Plants on the Test Stand (Screenversion 115 KB; Printversion 155 KB) Stefan Binggeli Each year, two billion tons of waste water are collected from urban areas, then treated and returned to the natural water cycle. In order to process such an enormous volume of water, the technical and logistical processes must work together flawlessly. Weak links in the organizational process are not only economically relevant, but may pose a safety risk. Evaluation and optimization of the logistical and organizational frameworks should, therefore, be a fixed part of the overall operation. EAWAG has developed a new procedure for self evaluation and process reengineering, allowing wastewater treatment plants to conduct extensive process analysis and to improve them where necessary. |
| In Brief (Screenversion 115 KB; Printversion 335 KB) |
Please feel free to submit questions or suggestions any time to the editor Martina Bauchrowitz.