Comprehensive tracking of nutrient flows across anaerobic digestion systems boundaries to enable precision crop fertilisation with anaerobic digestate

Synthetic fertilisers is currently responsible for much of the global food production, however, the flood of excess nitrogen (N) from synthetic N-fertilisers is one of the most severe pollution threats humanity faces today; poisoning water bodies, plants, animals and humans, and contributing to climate change through emissions of the nitrous oxide (N2O), a potent GHG with 265 times the potency of CO2 over 100 year.

<p>N2O emissions from agriculture was estimated to be 13.6 million tonne of CO2 equivalent (Mt CO2e) representing 71% of the total N2O emissions in 2021. This has influenced a global drive to cut down synthetic fertilizer application around the world. One technology able to ensure a sustainable supply of biofertiliser as a replacement for synthetic fetilisers is anaerobic digestion (AD).</p> <p>AD is a natural process whereby microorganisms that thrive under limited (or no) oxygen supply feed on organic materials, causing such materials to structurally break down into simpler materials. This results in the release of a renewable gas (biogas) and a secondary product called digestate, a biofertilizer, which retains the organic carbon for soil enhancement and crop nutrients particularly, nitrogen, phosphate and potash recovered from the parent material and other useful soil microbial biomass. Unlike synthetic fertilisers, which have fixed amounts of plant nutrients, the release and availability of nutrients in the digestate is affected by many factors defined by different system boundaries, including pre-digestion (nature of organic matter, which affects the degree of digestibility); in-vessel (operating conditions, which affects the microbial activities and dissociative forms of nutrients present); and post-digestion (digestate handling, which affects nutrient volatility and distribution into final biofertiliser). These factors causes variability in the nutrients content of the final digestate making it difficult to accurately predict the nutrient content of digestate and reducing farmers' confidence and complete reliance on the product.</p>

<p>Formal applications for research degree study should be made online through the University's website. Please state clearly in the research information section that the research degree you wish to be considered for is Comprehensive tracking of nutrient flows across anaerobic digestion systems boundaries to enable precision crop fertilisation with anaerobic digestate with Dr Cynthia Kusin Okoro-Shekwaga https://eps.leeds.ac.uk/civil-engineering/staff/6694/dr-cynthia-kusin-okoro-shekwaga.</p> <p>If English is not your first language, you must provide evidence that you meet the University's minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p>

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.

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. Some schools and faculties have a higher requirement.

<p style="margin-bottom:11px">A highly competitive EPSRC Doctoral Training Partnership Studentship offering the award of fees, together with a tax-free maintenance grant (currently £19,237 academic session 2024/25) for 3.5 years.  Training and support will also be provided.</p>

<p>For further information please contact Dr Cynthia Kusin Okoro-Shekwaga Email:-  c.k.okoroshekwaga@leeds.ac.uk</p>