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Synthetic soil organic matter from waste-derived organic materials

PGR-P-670

Key facts

Type of research degree
PhD
Application deadline
Friday 17 April 2020
Project start date
Tuesday 1 September 2020
Country eligibility
UK and EU
Funding
Competition funded
Source of funding
Research council
Supervisors
Dr Andrew Ross and Professor Doug Stewart
Schools
School of Chemical and Process Engineering, School of Civil Engineering
Research groups/institutes
Waste Management and Resource Recovery, Water, Public Health and Environmental Engineering
<h2 class="heading hide-accessible">Summary</h2>

This project aims to examine the potential for producing synthetic soil organic matter from waste-derived secondary organic materials, and to test its efficacy for improving degraded soils.

<h2 class="heading hide-accessible">Full description</h2>

<h5>Rationale</h5> <p>Intensive farming practices are resulting in soil degradation through the loss of soil organic matter (SOM) and nutrients. SOM is critical to soil health, so its loss affects crop yields, impacts on the economics of farming, and can contribute to desertification of previously productive land. Secondary organic materials such as crop residues, animal wastes, food waste and human waste, contain valuable organic matter and nutrients so can be used to replace soil organic matter otherwise lost during tillage and harvest. While it has long been good practice to return farm wastes to the land, and in recent years to apply sewage sludge and digestate to agricultural soils, these secondary organic substrates are only lightly processed, and their application to land is not currently optimised for long-term soil health and could be viewed as a form of disposal.</p> <h5>Background</h5> <p>Secondary organic materials differ in their composition from SOM. SOM is dominated by humic substances, which are dark-coloured, stable heterogeneous organic compounds produced slowly over time by the decay and transformation of plant and animal residues by bacteria and fungi (e.g. oxidation of phenolics in the presence of nitrogenous compounds). Most organic matter in the secondary organic materials is mineralised to CO2, and only a small proportion will produce the precursor molecules that are slowly converted over time to humic substances. Therefore, application of secondary organic materials is an ineffective way of replacing SOM.<br /> Alternatively, secondary organic materials can be further processed to extract valuable products. &nbsp;Hydrothermal treatment, in which elevated temperatures and pressures are used to mimic natural coalification, can be used to extract valuable fuel products. Depending on the temperature, synthetic coal, oil and gas can be extracted. The major by-product of this process is a range of humic-like materials, that are readily separated from liquid and gaseous products, and which represent a starting point for the development of synthetic SOM.&nbsp;</p> <h5>Experimental methods</h5> <p>It is anticipated that the optimum product will involve blending of synthetic humic substances produced by different feedstocks subjected to various hydrothermal processes.&nbsp; Important considerations will be the fate and possible recovery of nutrients during processing and, as there are strong drivers to find better applications for animal and human wastes, the fate of pharmaceuticals, contaminant trace metals and microplastics. Experimental methods are likely to include, electron microscopy, and various chromatography and spectroscopy techniques, along with plant growth trials.</p>

<h2 class="heading">How to apply</h2>

<p>Formal applications for research degree study should be made online through the&nbsp;<a href="https://eps.leeds.ac.uk/civil-engineering-research-degrees/doc/apply">University&#39;s website</a>. Please state clearly in the research information section&nbsp;that the research degree you wish to be considered for is &ldquo;Synthetic soil organic matter from waste-derived organic materials&rdquo; as well as&nbsp;<a href="https://eps.leeds.ac.uk/civil-engineering/staff/93/professor-doug-stewart">Professor Doug Stewart</a>&nbsp;as your proposed supervisor.</p> <p>If English is not your first language, you must provide evidence that you meet the University&#39;s minimum English language requirements (below).</p> <p><em>We welcome applications from all suitably-qualified candidates, but UK black and minority ethnic (BME) researchers are currently under-represented in our Postgraduate Research community, and we would therefore particularly encourage applications from UK BME candidates. All scholarships will be awarded on the basis of merit.</em></p>

<h2 class="heading heading--sm">Entry requirements</h2>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

<h2 class="heading heading--sm">English language requirements</h2>

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid.

<h2 class="heading">Funding on offer</h2>

<p><strong>UK/EU</strong> &ndash;&nbsp;Engineering &amp; Physical Sciences Research Council Studentship&nbsp;for 3.5 years. A full standard studentship consists of academic fees (&pound;4,600 in Session 2020/21), together with a maintenance grant (&pound;15,009 in Session 2019/20) paid at standard Research Council rates. UK applicants will be eligible for a full award paying tuition fees and maintenance. European Union applicants will be eligible for an award paying tuition fees only, except in exceptional circumstances, or where residency has been established for more than 3 years prior to the start of the course.&nbsp;&nbsp;Funding is awarded on a competitive basis.</p>

<h2 class="heading">Contact details</h2>

<p>For further information regarding the application procedure, please contact Doctoral College Admissions:<br /> e: <a href="mailto:phd@engineering.leeds.ac.uk">phd@engineering.leeds.ac.uk</a>, t: +44 (0)113 343 5057.</p>


<h3 class="heading heading--sm">Linked funding opportunities</h3>
<h3 class="heading heading--sm">Linked research areas</h3>