Transitioning urban water systems

Water managers acknowledge on a global scale that current practices are no longer sustainable and have an adverse impact on ecology (disruptions to the water cycle and habitats), public health (water qualities, sanitation services) and the economy (flooding, drought and overuse of resources). The idea of applying transitioning approaches stems from growing recognition that changes in water management are urgently needed. The SWITCH transitioning approach was developed by consolidating the project’s existing stakeholder engagement approach with ideas on transition knowledge, an emerging new field of science

How do we increase public understanding of the benefits provided by SUDS?

Background to researchRecent Scottish Government policy is to develop Scotland as the world’s first Hydro Nation which places more emphasis on water as central to our national identity. This agenda isincreasing the international profile of Scotland’s skills and experience in supporting the good stewardship of water resources. There is a need to increase awareness among thepublic of the benefits that water provides and how our actions can help protect and improve them. Successful legislative and policy reform have been responsible for sustainable urbandrainage systems (SUDS) becoming commonplace in Scotland. There is a deficit of understanding surrounding the multiple benefits which SUDS can offer communities such as pollutioncontrol, flood prevention, enhancement of biodiversity and wildlife habitats. Conveying an understanding of benefits to those who live within close proximity to SUDS can help lendacceptance to these innovative green technologies that are replacing traditional forms of drainage.Objectives of researchKey CREW objectives are to develop a hydro literacy programme that:(a) increases public understanding of the benefits water provides and issues involved in its management(b) increase science engagement through community outreach/public education(c) support Scottish water policy.This project was a public outreach activity that targeted primary and secondary school children located to the north of Dundee where there are excellent examples of SUDS. The key objective was to raise awareness of the Hydro Nation agenda with a scope that was twofold: explain the urban water cycle; and promote awareness and understanding of the local SUDS and related benefits. To realise these objectives we had to ensure alignment of the science, environmental, engineering and social aspects related to SUDS with the curriculum forexcellence and which contributed to general science experiences and outcomes.Key findings and recommendationsDissemination of the Hydro Nation Agenda and the benefits of SUDS were delivered to a total of 106 children (ages 3-10) and 14 adults. Based on feedback, the outreach programmeto schools was deemed an unquestionable success by the Local Authority, teachers and school children alike. This was due to a strategic approach taken for the development anddelivery of a ‘water and SUDS’ learning package that included a variety of mechanisms and activities to fit the time available and suit the knowledge level of the target audiences. Thisfacilitated engagement, enthusiasm, knowledge retention and empowerment – learning whilst also having fun. Evaluation of feedback, and with hindsight, recommendations for improvingfuture outreach initiatives to school children and local community groups include:• Timing is crucial to ensure alignment with the curriculum, particularly secondary schools.• Hands on sessions including experiments and digital technology related to local real world issues combined with local walks were powerful strategies that provided a direct and personal connection that engaged, promoted and embedded learning concepts and new terminology.• Future roll out of the initiative would be beneficial to integrate the SUDS learning package materials with current lesson plans; specifically delivery of a practical legacy teaching asset that could be up scaled/rolled out across Scotland.• The Community Group session was put together quickly with limited time. This was beneficial for the Group regarding imminent dialogue with Dundee City Council planners however a more organised session and discussion would have enhanced understanding of current best practice SUDS.<br/

A water vision for Johnstone

The Water Vision is based on ideas from The Netherlands which promote communication with the public on key water related issues in a local authority area. A Water Vision for Johnstone was developed in Renfrewshire, Scotland where serious flooding has occurred in the past and new, predominantly non-structural approaches to surface water management were demanded. The paper outlines the development of a ‘Water Vision for Johnstone’ which became a key outcome of the Interreg III B project ‘Urban Water’.The Water Toets (Assessments) are statutory procedures in the Netherlands which come into play from the concept stage of developments onwards to full implementation. They are undertaken jointly on behalf of the spatial planning authority and the water authorities to evaluate the impact of development on the water network. In contrast, the Water Vision is a less well-defined process to identify community needs and aspirations but in many areas the vision is essential to support the Water Toets. The Water Vision is initiated by planning officers from the municipalities asking very basic questions of their communities about what they required of the water network. It was felt that adopting such a proactive approach where virtually any question about water bodies and drainage infrastructure could be asked, would not be practicable in the UK and it was decided to assemble information about water issues in the area, the agencies involved and potential ways forward, before approaching the public.Johnstone was selected as a test area as it was felt that this locality included many of the water related problems that can be found throughout Renfrewshire. Key water issues were identified and a range of possible solutions provided. Problems, solutions and organisations responsible for different aspects of the water network are described in the document, using images and plans to facilitate the public awareness. Normally the man in the street would not be expected to be as familiar with the nature of water-related problems as the general public in the Netherlands. The Water Vision is yet to go to public consultation as it is currently primarily a planning tool in which council processes are embedded. However, it is planned that workshops including all key stakeholders involved in water management will be held. Those bodies currently responsible for water management will then be encouraged to discuss the various options and opportunities available in a creative and integrated manner. By working together as a team in addressing water related issues it will be possible to develop a vision for the future that better assists the public in moving forward together

The SWITCH transition manual

This study evaluated the potential for efficient treatment of domestic wastewater, while satisfying energy efficiency requirements. Various treatment systems and the influences of their physical configurations and operational characteristics on wastewater treatment and energy efficiency were initially considered and evaluated. Review of literature identified high rate anaerobic systems as viable low energy systems for domestic wastewater treatment, with reported high removal of influent chemical oxygen demand (COD) and high net energy balance for the anaerobic baffled reactor (ABR). Low energy recovery is reported in literature as a limitation of anaerobic domestic wastewater treatment, and anaerobic domestic wastewater treatment systems have failed to meet effluent discharge standards, and post-treatment using aerobic processes have been recommended in order to ensure high effluent quality. Therefore, the ABR was selected as a feasible option that can be developed as the first stage of an anaerobic-aerobic low energy domestic wastewater treatment system. The literature review also identified the net energy consumption per cubic metre (m3) of treated wastewater during the treatment process as an energy efficiency evaluation criterion.Energy efficiency for domestic wastewater treatment facilities should be achieved if efficient treatment performance can be sustained at ambient temperature, instead of the fixed mesophilic temperature that is commonly adopted in anaerobic treatment processes. To identify an energy efficient design of the ABR in terms of hydraulic retention time and operational temperature, the performance efficiencies of ABR bench models were monitored at ambient temperature and 37oC at hydraulic retention times (HRT) of 48, 36, 24, 12 and 6 hours, which corresponded to organic loading rates (OLR) of 1.25, 1.67, 2.5, 5.0 and 10.0 kg COD/m3 day. 88.43, 90.00, 84.03, 77.01 and 59.35% of the influent COD (mean = 2479.50 mg/L) were removed at 48, 36, 24, 12 and 6 hour HRTs, respectively, in the 37oC bench reactor, while 70.16, 70.36 and 74.99% of the influent COD were removed at 48, 36 and 24 hour HRTs, respectively, in the ambient temperature bench reactor. Steady state performance, in the form of stable pH values, was not observed in the ambient temperature reactor at 12 hours HRT before the end of the bench experiments. Retention of influent total solids was observed to correlate to hydraulic retention time, with increase retention of total solids corresponding to increase in hydraulic retention time. Furthermore, observed total solids retention in the ambient temperature reactor were less than the total solids retention in the 37oC reactor.Anaerobic reduction of domestic wastewater sludge and the corresponding methane production were also evaluated using bio-chemical methane potential (BMP) batch assays at ambient temperature and compared to a fixed mesophilic temperature of 37oC. Low reduction of volatile solids was observed in the BMP assays, with 40% at ambient temperature compared to 56% at 37oC for primary sludge, and 22% at ambient temperature compared to 38% at 37oC for secondary sludge. Critical limitations of the anaerobic stage at ambient temperature were determined to be the biological reduction and conversion of the organic contaminants to soluble COD and volatile fatty acids (VFA). Also, achieving and maintaining steady state performance required a longer time period at ambient temperature than at 37oC, potentially due to the slow growth of the anaerobic microorganisms at ambient temperature. These limitations indicate the need for long (≥ 24 hours) retention periods for efficient operation at ambient temperature. The ABR bench models were evaluated for energy efficiency with the identified energy efficiency criteria, and the operational condition with the highest energy efficiency was determined to be 12 hours HRT at 37oC. Finally, design criteria for the anaerobic stage of the anaerobic-aerobic system were proproposed, along with a process model as a preliminary step for future process research

SUDS treatment train assessment tool

This paper outlines a rationale and scoring system for the stormwater treatment train assessment tool (STTAT) which is a proposed regulatory tool for Sustainable Urban Drainage Systems (SUDS). STTAT provides guidance and regulatory consistency for developers about the requirements of planners and the Scottish Environment Protection Agency (SEPA). The tool balances the risks of pollution to the receiving water-body with the treatment provided in a treatment train. It encourages developers to take SUDS into account early, avoiding any misunderstanding of SUDS requirements at the planning stage of a development. A pessimistic view on pollution risks has been adopted since there may be a change of land use on the development in the future. A realistic view has also been taken of maintenance issues and the ‘survivability’ of a SUDS component. The rationale for STTAT as a response to the requirements of the Water Framework Directive is explored and the individual scores are given in tabular format for receiving water and catchment risks. Treatment scores are proposed for single SUDS components as well as multiple components within treatment trains. STTAT has been tested on a range of sites, predominantly in Scotland where both development and receiving water information was known. The operational tool in use by SEPA is presented

Sustainable Urban Drainage Systems (SUDS) treatment train assessment tool

This paper outlines a rationale and scoring system for the stormwater treatment train assessment tool (STTAT) which is a proposed regulatory tool for Sustainable Urban Drainage Systems (SUDS). STTAT provides guidance and regulatory consistency for developers about the requirements of planners and the Scottish Environment Protection Agency (SEPA). The tool balances the risks of pollution to the receiving water body with the treatment provided in a treatment train. It encourages developers to take SUDS into account early, avoiding any misunderstanding of SUDS requirements at the planning stage of a development. A pessimistic view on pollution risks has been adopted since there may be a change of land use on the development in the future. A realistic view has also been taken of maintenance issues and the ‘survivability’ of a SUDS component. The development of STTAT as a response to the requirements of the Water Framework Directive is explored, the individual scores being given in tabular format for receiving water and catchment risks. Treatment scores are proposed for single SUDS components as well as multiple components within treatment trains. STTAT has been tested on a range of sites, predominantly in Scotland where both development and receiving water information was known. The operational tool in use by SEPA is presented

A rapid review of the background to source control

Background to researchThe start of the 21st Century witnessed a revolution in drainage practices with the implementation of sustainable drainage systems (SUDS). Prior to 2000, rainfall was managed by directing it away as quickly as possible in underground pipes. Increasing pressures such as watercourse pollution, stricter environmental laws, climate change and urbanisation called for a paradigm shift with Scotland leading the way for implementing SUDS. SUDS are designed to mimic natural drainage processes, managing rainfall in stages as it drains from a development. Collectively this process is called the stormwater treatment train. The first stage is source control, with stages two and three being site and regional controls respectively. Source control principally controls and treats polluted runoff at source (where the rain falls) and if designed and implemented correctly, protect watercourses and downstream SUDS through filtration, infiltration and storage. In Scotland, site and regional control SUDS have become business as usual, however uptake of the stormwater treatment train and the use of source control SUDS in practice is less routine than would be expected.Objectives of researchThe SUDS Working Party in Scotland is an interdisciplinary stakeholder platform to discuss issues relating to the SUDS agenda and promote their use. In 2009, a consultation paper on ‘Implementing the Water Environment and Water Services (Scotland) Act’ set out proposals to improve the sustainable management of Scotland’s water resources. The need for increased source control measures for the mitigation of diffuse pollution and climate change effects in urban areas was identified. To assist in this aspiration, the SUDS Working Party commissioned this study via CREW to identify opportunities and barriers to increasing the uptake of source control in Scotland. This report covers phase one of a three-phase study. It focuses on tracking the evolution of source control to gain an insight into enabling factors and obstacles for successful uptake of the systems. A literature review identified source control origins, the techniques available, and options for their application.Key findings and recommendationsIn the UK, research to validate the performance of source control measures began in the early 1990’s. This was enabled by stakeholder platforms such as the SUDS Working Party and the Scottish Universities SUDS Monitoring Group. By the mid-1990s, the SUDS concept was developed which included source control and outlined water quality, quantity and biodiversity / amenity benefits of the systems. By 2000, Scottish guidance was developed and by 2006 it became law to implement SUDS in all new developments. This was quickly followed by technical standards in 2007. SUDS for roads networks were addressed in 2010. Currently, many types of source control exist, most of which have been validated by research and are commonplace. The state of the art techniques such as rain gardens, green roofs and rainwater harvesting however, have had limited uptake in Scotland.It is evident that the enabling factors for the uptake of SUDS have been the result of top down drivers such as environmental initiatives and regulation. However, clarity surrounding the definition and application of source control as part of the stormwater treatment train is becoming a barrier to its uptake by practitioners. Extensive research provided a bottom up driver to validate effectiveness of the technologies for attenuating pollutants, mitigating flooding and creating habitats. Validation of emerging innovative techniques however, such as green roofs and rain gardens for different development types is limited in Scotland and this may prove to be a barrier in the future

Source control SUDS delivery on a global scale and in Scotland including approach by responsible organisations and professional groups

Background to researchThe Sustainable Urban Drainage Scottish Working Party via CREW commissioned this work on the implementation of source control for SUDS in Scotland. The project is being carried out by researchers based at Abertay University Dundee involves three phases. These are presented in separate reports; this report covers phase 2 of that work. Source control sustainable urban drainage systems (SUDS) are an established technique in many parts of the world. Source control SUDS are a key component of what is termed the stormwater treatment train. Source controls manage the more frequent but smaller polluting rainfall events as close to the source as possible (where the rain falls). Site and regional control SUDS are larger downstream structures which manage the longer term rainfall events and provide additional treatment when required. One of the key advantages of managing the more frequent rainfall events at source is that downstream site and regional SUDS will have longer life spans resulting in overall cost efficiencies. Scotland is regarded as a frontrunner in the UK regarding implementation of SUDS with site and regional drainage structures now considered ‘business as usual’. However the uptake of source control is less routine than would be expected.Objectives of researchPhase one of this research looked at the background to the evolution of source control in Scotland to provide an insight into the enabling factors and obstacles for uptake of the systems since. Phase two(this report) appraises delivery of the systems in seven countries and case studies are developed to understand why source control was implemented and how it was achieved. The current delivery by responsible organisations and professional groups which encourage and influence the source control agenda in Scotland is also appraised. Using these findings, the transition pathway from traditional drainage to source control SUDS are reconstructed and mapped out to highlight the historical and current enabling (and disabling) factors to realise the transition to date. A transition framework is used to highlight the transition strengths developed by responsible organisations over the last two decades which had assisted in accelerating the transition.Key findings and recommendationsKey outcomes of this research include:* In Scotland the source control vision and agenda is fragmented due to different stakeholder drivers and funding mechanisms.* There are examples of the use of incentives in Scotland (i.e. legislative, regulatory, financial,social and environmental) to drive integrated agendas. However these have not been successfully showcased to provide the evidence base for encouraging replication and up-scaling of the methodologies and techniques.* There are limited frontier source control SUDS ‘niches’ to nurture innovative techniques such as raingardens – a learning by doing concept. A more focused research agenda to validate these systems as viable sustainable solutions for Scotland would assist in accelerating uptake.* Lack of sector engagement, particularly with the public is a disabling factor for uptake.A final observation from this phase of the study is that requests from various interested parties for CREW / SUDS Working Party to share outputs indicates the need for this research