Environmental assessment of incinerator residue utilisation.

Incineration ashes may be treated either as a waste to be dumped in landfill, or as a resource that is suitable for re-use. In order to choose the best management scenario, knowledge is needed on the potential environmental impact that may be expected, including not only local, but also regional and global impact. In this study, A life cycle assessment (LCA) based approach was outlined for environmental assessment of incinerator residue utilisation, in which leaching of trace elements as well as other emissions to air and water and the use of resources were regarded as constituting the potential environmental impact from the system studied. Case studies were performed for two selected ash types, bottom ash from municipal solid waste incineration (MSWI) and wood fly ash. The MSWI bottom ash was assumed to be suitable for road construction or as drainage material in landfill, whereas the wood fly ash was assumed to be suitable for road construction or as a nutrient resource to be recycled on forest land after biofuel harvesting. Different types of potential environmental impact predominated in the activities of the system and the use of natural resources and the trace element leaching were identified as being relatively important for the scenarios compared. The scenarios differed in use of resources and energy, whereas there is a potential for trace element leaching regardless of how the material is managed. Utilising MSWI bottom ash in road construction and recycling of wood ash on forest land saved more natural resources and energy than when these materials were managed according to the other scenarios investigated, including dumping in landfill.

A framework for planning of sustainable water and sanitation systems in peri-urban areas.

There are billions of people around the world that lack access to safe water supply and basic sanitation, a situation which puts the affected in severe health conditions as well as economical and social despair. Many of those lacking adequate water supply and sanitation systems can be found at the fringe of the cities in so called peri-urban areas, especially in the developing world. Planning in these areas is highly complex due to challenging environmental and physical conditions, high population density and unclear institutional boundaries. This article presents a framework aiming to support the planning process for sustainable water and sanitation systems in peri-urban areas. The suggested framework is based on different available planning approaches from a review of literature and websites of organisations and companies. It consists of a recommendation of important steps in the planning process as well as supporting tools. Further, it incorporates a set of sustainability criteria important for the peri-urban context and allows for the development of site specific systems. The framework has the aim to be flexible for different planning situations, and for suiting planners with different perspectives and amount of resources.

Environmental assessment and cost estimation of drinking water and wastewater systems for transition areas in Sweden.

In the Stockholm region there are around 90,000 households with single systems. These households cause larger phosphorus flows to the Baltic Sea than the 1.8 million people connected to four advanced large-scale treatment plants in the same region. According to city plans, some of these areas with on-site systems in transition to permanent living shall be connected to central systems. The problem is however that this sewer system will take decades to complete. It is also not ensured whether or not all peripheral areas with on-site systems could be connected to the central systems. To help support environmental decisions for the selection of wastewater systems for these areas, an Excel-based model has been developed where the cost for the systems can be assessed and evaluated in relation to their environmental impact. The model deals with two types of environmental issues: substance flow analysis and energy analysis. The cost part considers investigations, investments, design, operation, maintenance and supervision, and calculates total annual cost for the water and wastewater system per person.

Centralised or decentralised sanitation in Swedish summerhouse areas in transition to permanent living?

The standard of wastewater management is high in Sweden. Around 90% of the population is connected to central wastewater treatment plants with high requirements of nutrients removal; however, still the problem with algae blooms in the Baltic Sea exists. The aim of the VeVa project was to develop a simple and user-friendly Excel-based model to support environmental decisions of how to select wastewater systems for housing areas where no central sewer system exists. The VeVa model deals with two types of environmental issues: substance flow analysis and energy analysis. Six system structures were studied for the transition area Lillängsdal in Värmdö municipality sorted in three categories: 1) on-site systems for single households; 2) local collective systems; 3) connection to central systems. All studied system structures, except for a Sand filter system, fulfilled the goals of reducing phosphorus and BOD7 according to Swedish guidelines for on-site systems in sensitive areas. All studied systems, except for the Sand filter system, have the potential to fulfil the Swedish National Environmental goal to recycle 60% phosphorus to productive land. The systems with central wastewater treatment plant and local wastewater treatment are the most energy efficient alternatives that also fulfil the requirements of discharges and environmental goals regarding phosphorus recycling.

Evaluation of the ReVAQ project to achieve safe use of wastewater sludge in agriculture.

The use of wastewater sludge on arable land in Sweden has been limited for some years due to the low quality, in some respects, of the sludge and to the reluctance of farmers and the food industry to use it. To improve the quality of the sludge, the ReVAQ project has been started, and it now involves seven municipal wastewater organisations. The goal of the project is to introduce a process in which the quality is successively improved by a series of actions taken by society. These actions include tracking and eliminating sources of heavy metals and other substances. As there are numerous sources of some of the substances, the work concentrates on the major sources. Another important activity is to provide information to the users of the wastewater system. The project is being evaluated by Urban Water AB. The results from the first two years indicate that it may be possible to reach the primary technical goal: to obtain a sludge quality that corresponds to that of household wastewater. The more ambitious goal of reaching a quality corresponding to that of WC water (the sum of urine and faeces) does not seem realistic without far-reaching changes in society. The organisations involved, which take the work seriously and are goal-oriented, have achieved measurable results in a short time. The work is also accepted and supported by the board members. More effort is needed, however, to inform the users about the system, and to [motivate them to] change their behaviour regarding matters such as the purchase of everyday products and the use of the toilet facilities.

Analysis and evaluation of methodologies to assess technical urban water systems.

The paper reports on the methodology and findings of a recent project on behalf of the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management. The Ministry is seeking procedures for combining ecological and economic criteria to assess which technical urban water alternatives shall receive funding. To this end the current decision making process (DMP) for implementing urban water alternatives in Austria has been analyzed and compared with the situation elsewhere, e.g. in Sweden. The DMP entails specific requirements on assessment, whence the most common decision aid methodologies, ranging from LCA-based to multi-criteria methods, have been described and evaluated from an environmental, economic, legal and practical point of view, turning out recommendations to the Ministry. Their main points are: First the DMP should be kept as simple as possible in order to make it transparent. Second the aggregation of different criteria groups should and can be avoided. Therefore the stakeholders should not be allowed to make trade-offs. Finally clear objectives need to be stated.

Normalising impacts in an environmental systems analysis of wastewater systems.

In an environmental systems analysis of four wasterwater systems, the environmental aspects were prioritised by normalisation of predicted impacts from the studied systems to the total impacts from society. Priority Group 1 (highest priority) consisted of discharges (flows) of nitrogen, cadmium, lead and mercury to water, recycling of nitrogen and phosphorus to arable land and flows of heavy metals to arable land. A conventional wastewater system (A) was compared to irrigation of energy forest with biologically treated wastewater (B), liquid composting of toilet wastewater (C) and a conventional system supplemented with urine separation (D). Analysing the aspects in priority group one, systems B-D improved the management of plant nutrients and decreased the flow of heavy metals to water, while the flow to arable land increased, especially for system B. The suggested method is useful in municipal environmental planning and when choosing a wastewater system.