Annual Conference 2018 - programme & speakers (13th September)
Please find listed below a selection of the abstracts from sessions featuring on day two of the 2018 conference.
KEYNOTE: THE HISTORICAL DEVELOPMENT OF CONSTRUCTED WETLANDS FOR WASTEWATER TREATMENT
Professor Jan Vymazal, Czech University of Life Sciences Prague, Faculty of Environmental Sciences
Constructed wetlands (CWs) have been used for wastewater treatment for more than half a century. Two major groups of CWs can be distinguished according to the presence/absence of water on the wetland surface – surface flow and subsurface flow systems.
While subsurface technology is commonly used in Europe and Asia, surface flow technology is preferred in North America and Australia.
The majority of CWs have been designed to treat municipal sewage but recently, stormwater runoff, agricultural drainage of river water have been extensively treated with CWs.
KEYNOTE: SEPTIC TANKS OF THE FUTURE
Allan Mason, Senior Project Manager, Research & Innovation, Scottish Water
Sewage treatment in small rural communities has traditionally involved the use of septic tanks. There are estimated to be at least 400,000 in Scotland with 1000 owned and operated by Scottish Water. Well maintained systems that are operating as intended present very little individual risk, however evidence from the Scottish Environmental Protection Agency indicates that the cumulative impact of these systems are causing pollution of rivers and surface water supplies, including those that are used to supply drinking water. Increasingly septic tanks are viewed as an inappropriate method of sewage treatment for the future due to the sludge tankering requirements and the lost opportunities to utilise the sludge locally for energy production. From a technology point of view septic tanks can be considered poorly optimised anaerobic reactors.
The Septic tanks of the future project, in partnership with Cranfield University, is exploring future flowsheets to meet the needs of future community sanitation. It has been identified that the combination of anaerobic ponds and constructed wetlands meets a number of requirements around passive / low maintenance solutions and providing a local amenity for rural communities. The use of the two technologies provide a number of added value opportunities including co-management of local biowastes, the production of biogas and reduced desludging frequencies to every 3-7 years. These opportunities align with current thinking on sustainable rural services in Scotland, Circular Economy and Decarbonisation of our service.
INGOLDSTHORPE WETLAND - FROM ENGAGEMENT TO DELIVERY
Dr Jonah Tosney, Senior Project Manager, Norfolk Rivers Trust & Joff Edevane, Environmental Standards Manager, Anglian Water
The recently constructed Ingoldisthorpe Wetland is a partnership project delivered by Anglian Water, Norfolk Rivers Trust and the Environment Agency. This one hectare wetland was constructed in 2018 to strip remaining ammonia and nutrients from the Ingolisthorpe Water Water Recycling Plant before it enters the River Ingol, a Norfolk chalk stream currently failing WFD for phosphate levels.
The presentation tells the story of the development of the partnership from initial engagement to delivery, highlights the benefits of the project to a major water company and also demonstrates the multiple benefits delivered by the wetland.
The wetland itself is a cost effective solution in terms of both carbon and cash and is already attracting a diverse array of native wildlife and has provided an educational venue for the local primary school. In addition to removing ammonia and phosphorus from the effluent we expect the wetland to be an effective way of stripping less well understood contaminate such as micro-plastics and PCPs, and the partnership will monitor its performance over several years.
LEA BROOK VALLEY - ONE YEAR ON
Rev David Walker, Commercial Director, Detectronic Ltd & Brian Smith, Sewerage Optimisation Manager, Yorkshire Water Land Management
Rev David Walker and Brian Smith will share the journey which Lea Brook Valley Green Team and Yorkshire Water have been on over the last twelve months.
The Balancing Pond within the Lea Brook Valley installed in the mid 1970s and currently owned by Yorkshire Water, boasts a beautiful wetland and diverse bio habitat. Michael and Brian have been facilitating a management plan allowing Lea Brook Valley green team to become legal custodians of the site, bringing it into the wider LBV management Plan for 2020.
- Identifying common goals and shared responsibilities
- Getting management buy-in
- Managing the asset short and long term
- Legalities of a lease agreement and transfer of responsibilities
- Benefits and challenges of enabling local communities
- NPV now and future
- AMP7 and biodiversity
INNOVATIVE PARTNERSHIP SOLUTIONS TO WASTEWATER TREATMENT
Tim Harris, Catchment Technical Specialist, United Utilities
To meet the challenges of the water framework directive whilst delivering sustainable value for our customers United Utilities has invested in partnership projects to develop integrated, catchment wide solutions to wastewater treatment problems.
We have been evolving our understanding of this approach through work completed in the Petteril catchment in Cumbria, where delivering an integrated approach with our partners has allowed greater natural capital benefits to be delivered to the catchment whilst also improving wastewater treatment at a reduced cost to our customers.
Through our strategic partnership as part of Natural Course we are actively engaging organisations to develop collaborative partnerships with a view to using green infrastructure solutions to deliver multiple benefits at a reduced cost and to develop new ways of using wetland technology to deliver innovative wastewater treatment.
RESIDENTS' PERCEPTIONS OF SUSTAINABLE DRAINAGE (SuDS)
Professor John Williams, Professor of Environmental Technology, University of Portsmouth
Resident’s perceptions of benefits and problems is an important factor in promoting the use of SuDS in housing developments, especially for green infrastructure such as wetlands and ponds that take more land but provide multiple benefits.
This paper reports findings from a survey of residents at 6 exemplar sites across England (406/2916 returns) into their perceptions and willingness to pay for SuDS. The 6 sites revealed different concerns based on type of SuDS, geography and how much the residents pay for SuDS upkeep. This suggests that developers could increase awareness and improve perception by targeting residents with site specific information.
UNDERSTANDING IRON & PHOSPHORUS CYCLING IN CHEMICALLY-DOSED CONSTRUCTED WETLANDS
Dr Gabriela Dotro, Senior Research Fellow, Environmental Engineering, Cranfield University
The removal of phosphorus from sewage in small wastewater treatment works is typically achieved by the additional of iron (Fe) or aluminium salts upstream of biological treatment processes, including constructed wetlands (CWs). Whilst this enables removal of P from the liquid, it creates a different biogeochemical environment within CWs that is poorly understood.
This research work evaluated the iron and phosphorus transformations occurring in accumulated sludge from a chemically-dosed horizontal flow tertiary treatment CW, and linked it to management strategies to minimise risk to compliance.
FREE WATER SURFACE WETLAND - LESSONS LEARNED AFTER 33 YEARS
Robert Gearheart, Humboldt State University/Arcata Marsh Research Institute
The City of Arcata (California USA) has operated a Free Water Surface (FWS) constructed wetland / oxidation pond wastewater treatment system (8700 CM^3/d) since 1985. After thirty-three years of effective operations there is a need to both upgrade the system and to perform deferred maintenance.
The lessons learned over this period of time will be identified in this presentation along with the actions needed to insure ongoing treatment effectiveness. The gradual reduction in effectiveness of the treatment wetland has been attributed to a reduction in the hydraulic reduction times associated with the loss of volume due the settled TSS and macrophyte rhizoshere / detritus.
There are six treatment wetlands that operate in parallel. Treatment wetlands perform as progressive clarifiers with an internal solids storage and decomposition function. This accumulated internal load of solids upon anaerobic decomposition release ammonia and BOD into the water column that is combined is combined with the influent ammonia and BOD levels. These accumulated solids are being managed by remobilizing and sizing them with a mixer / cutter system to increase their rate of decomposition and to use more of the down gradient portion of the cell for storage for settled solids. Improvement in solids removal in the Treatment Wetlands with the both the diurnal and seasonal fluctuation in flows will be managed with a SCATA weir setting system that can be controlled in the operations center. The accumulation of aquatic macrophyte vegetated; detrital and rhizosphere material has also reduced the volume in the Treatment Wetlands. This material is strategically being removed, composted and applied to the City forest.
MYTHS AND REALITIES IN REACTIVE MEDIA IN WETLANDS FOR PHOSPHORUS REMOVAL
Bruce Jefferson, Cranfield University
Session description to follow.
CHALLENGES IN DESIGN OF CONSTRUCTED WETLAND TREATMENT SYSTEMS IN FLAT TERRAIN: A CASE STUDY OF RAJAPUR MUNICIPALITY
Bibhuti Ojha Chataut & Ramesh Khanal, Nepal Engineering College
The study is focused on design challenges of wastewater treatment using constructed wetland in a flat terrain: Rajapur Municipality, Nepal. One major problem is low RL difference (4m) between the waste generation point and disposal point (2.5km).
The other constraint is client’s reluctance in adopting mechanical components such as pump because of past experience in poor operation and maintenance practice. The design and analysis of constructed wetland is carried out abiding available guidelines.
After analysis under different alternative scenarios within the above limitations, it is observed that designing gravity flow, self operating and low maintenance constructed wetland system is better realized with improvised sewer network design.
COMBATTING THE LIMITATIONS OF ARTIFICIAL WETLANDS THROUGH MODULAR DESIGN FOR A UK TEST PROJECT
Bassey Okon Bassey, Coventry University, UK
Artificial wetlands have proven quite useful for treatment of municipal and industrial wastewater over the decades, especially in rural areas with advantages and continuous improvements by research. Their optimal performance as compared to conventional systems has however been limited by a number of constraints including vulnerability to climatic and temperature variations, saturation and plugging of substrates, invasive plant species, large footprint, irrational management, non-standard design and a single function of ecological service.
These problems that shorten the lifespan of constructed wetlands will be highlighted in this paper vis a vis attempts to address them by technological offerings. In a bid to resolve the apparent lack of design standard, a modular design will be presented with detailed calculations, process flow diagrams, project delivery timeline and typical cost estimations for a UK market community to demonstrate current design frameworks put in place by the industry regulator.
Subsequent analysis of results in comparison with recent innovative projects reported in the literature, lessons learnt and recommendations are hoped to serve as a paradigm for operators and county councils seeking to reduce the cost of sewage treatment, while utilizing local resources and enhancing the aesthetics of the environment.