Details of Award
NERC Reference : NE/R007314/1
Ecological risk characterisation and modelling for the use of water treatment residuals as soil conditioners
Training Grant Award
- Lead Supervisor:
- Dr IW Oliver, Keele University, Faculty of Natural Sciences
- Grant held at:
- Keele University, Faculty of Natural Sciences
- Science Area:
- Atmospheric
- Terrestrial
- Overall Classification:
- Terrestrial
- ENRIs:
- Natural Resource Management
- Pollution and Waste
- Science Topics:
- Soil science
- Soil chemistry & soil physics
- Soil ecosystems
- Soil management
- Ecotoxicology
- Land - Atmosphere Interactions
- Abstract:
- Long before it reaches our taps, drinking water is made safe for consumption by treating it with aluminium (Al) and/or iron (Fe) salts to remove suspended materials and other impurities. This process, however, leaves behind a waste by-product composed of Al and Fe precipitates, clay particles, organic matter, nutrients and other components depending on the nature of the raw water. Vast quantities of these water treatment residuals (WTRs) are generated around the world, with annual UK production estimated at >250 000 t (dry equivalent). Currently WTRs are disposed of via landfill, but this is very expensive and may be wasting a potentially useful resource. Recent research indicates that WTRs may be highly effective soil conditioners bringing a range of potential benefits including soil stabilisation, fertiliser replacement, nutrient control and contaminant immobilisation. Such soil applications would thus benefit drinking water providers (cheaper disposal) and land managers (soil improvement) and would also help achieve government policy aims on waste minimisation and recycling, allowing us to move towards achieving a truly circular economy. However, to date, insufficient data exist to verify the environmental safety of such land applications of WTRs and so the practice is very tightly restricted by government regulation because of perceived risks surrounding the possibility of metals leaching out of WTRs and the potential consequent adverse impacts on soil chemistry, plants, earthworms and soil microbial functions. This CASE project will use novel techniques to address this knowledge gap by i) quantifying any effects observable in full-scale field trials under 'normal' application rates, and ii) determining, through experiments at the laboratory/mesocosm scale, the range of environmental conditions within which it is safe to apply WTRs (i.e. testing in adverse/ higher risk conditions such as low pH acid soils, and testing at higher application rates). Field trials will utilise sites where WTRs were applied to pasture land ~1 & 4 years ago respectively (+ a 'control' site), established by CASE partner 4R. The sites facilitate assessment of short & medium term impacts of WTR application at a 'normal' rate of ~3-5t/ha. We will quantify effects on: 1) soil physical properties & chemical characteristics (pH, organic matter, texture, metals in soil porewater). 2) herbage (fodder) yield & nutrition status (C:N ratios). 3) earthworm abundance & diversity. 4) soil microbial functions (carbon dioxide respiration, representing decomposition rates & general microbial activity level). Laboratory trials will determine condition limits at which ecotoxicology thresholds are reached in terms of soil porewater chemistry, plant growth, microbial activity and earthworm survival & reproduction. This will facilitate modelling of condition scenarios in which WTR applications can be considered environmentally safe. In turn this will directly support development of new government regulations on WTR use. While on placement with 4R (CASE partner), the student will conduct field sampling and undergo training and skills development in 1) risk assessment and risk mapping in relation to waste applications; 2) project management; 3) environmental regulation compliance and permitting; and 4) professional communication and client liaison. Keele University and 4R form an ideal CASE partnership, with the collaboration bringing together highly skilled and motivated individuals with access to field sites and state of the art equipment + many years of experience in environmental science research and land/waste management. The partnership offers a CASE student an exceptional opportunity for academic research and professional skills development and an excellent opportunity for career building as a successfully completed project has genuine potential to lead to employment with the CASE partner.
- NERC Reference:
- NE/R007314/1
- Grant Stage:
- Completed
- Scheme:
- Doctoral Training
- Grant Status:
- Closed
- Programme:
- NPIF Allocation
This training grant award has a total value of £88,293
FDAB - Financial Details (Award breakdown by headings)
| Total - Fees | Total - Student Stipend | Total - RTSG |
|---|---|---|
| £17,295 | £59,998 | £11,000 |
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