Avoiding the comingling of water flows coming from different sources and thus obtaining flows with a very low dilution factor is the first and major step key to technical solutions for adequate treatment of household wastewaters. Through their decentral structure and effective recovery of water, energy and fertiliser these systems can be highly cost efficient. Fresh water consumption can be reduced by up to 80% while nutrients can be recovered to a large extent. Source control is also advantageous for hygienic reasons: low volumes are far easier to sanitise. Source separation technology in municipal waste water treatment does often lead decentralised or semicentral systems. The first essential step is the separate collection and treatment of toilet waste in households, which contains almost all pathogens and nutrients. New toilet systems with very low dilution factors, ranging from vacuum- through urine sorting to dry toilets, have been introduced in several projects and proven feasible. New ideas such as the black- and greywater cycle systems are presently under research at the Technical University Hamburg Harburg. Such modular, integrated and small scale systems are only possible through recent advances in membrane technology and, due to their small scale, do have the potential to be installed in densely populated regions. These technologies are options for following the principles of ecological sanitation, to contain, to sanitise and to reuse also in urban areas (EcoSanRes, 2003).

This paper is a follow up of one presented by Otterpohl et al. (1997) in Water Science & Technology. This extension emphasises the responsibility of the professionals in waste- and wastewater management for future development. It shows a lists of 10 technological options for sanitation with source control. The political discussion about future sanitation systems seems to lack input of those working on further development. Even Agenda 21 is a complete failure in this respect - sadly, in a core subject for survival of future generations. The main task of sanitation besides highest hygienic standards is to keep soil fertile. Sanitation with the mixing up of food and water cycles washes all those substances out to the seas that are extremely harmful there (accumulation) and extremely necessary on the land (depletion of fertility and fossil resources). New integrated sanitation and waste management systems will mostly have to respect different qualities of matter from human settlements: blackwater with biowaste, greywater, stormwater runoff and non-biodegradable waste. Based on this distinction, nine differentiating and one mixing systems with resources management are presented. Some of them require careful examination in selected pilot projects.

Knowledge of concentrations or loads in wastewater flows is a basic prerequisite for the design of wastewater treatment units and the assessment of the environmental impacts. With respect to new sanitation concepts that are based on the source-separation of domestic wastewater flows not much general data is available yet on characteristics or design values of the different flows. A desk study of more than 130 references was carried out in order to arrive at design values for different source-separated wastewater flows including the fractions urine, faeces and greywater. The evaluation was carried out focussing on European data. The different values were analysed by the use of statistical parameters. In order to arrive at design values for different parameters, the median as well as minimum-maximum ranges of the available data were calculated. The collected data include volumes and characteristics like organic pollution (COD and BOD), nutrients (N, P, K & S) and heavy metals for the different source-separated flows. Loads and concentrations are listed respectively. A comparison is drawn between data from different regions in order to assess the impact of differences in nutrition and habits.

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The main aim of this EU demonstration project was to test two new sanitation concepts to determine if these concepts are more sustainable, compared with the conventional sanitation system, particularly with regard to nutrient recycling. Two different sanitation concepts were tested. One concept comprised the use of gravity separation toilets, the other used vacuum separation toilets. Results from a life-cycle-assessment investigation show that the new sanitation concepts are more sustainable. A cost analysis for an existing residential area did not prove lower costs for the new sanitation concepts in this special case. The experience from this demonstration project shows that prior to a widespread use of the new sanitation concepts, several improvements have to be made. One important issue is the improvement of separation toilets. Since nutrient recycling, water saving and reuse as well energy reduction become more and more important, further research should be undertaken in this field.