PhD position - Development of an innovative, phosphorus-enriched organic fertiliser for recycling

The Centre for Cleantech and Biomass Resource Efficiency is seeking an exceptional and highly motivated PhD student to contribute to pioneering work in the development of sustainable phosphorus-enriched organic fertilisers. This research aims to address the critical global challenge of phosphorus scarcity by innovating a locally sourced, environmentally sustainable alternative to conventional synthetic fertilisers. This fully funded position offers a unique opportunity to engage in cutting-edge research with significant implications for sustainable agriculture and resource recycling.

Research Focus Research will focus on the development of an innovative phosphorus-enriched organic recycling fertiliser. The project will use advanced fermentation and composting techniques to convert biogenic waste from municipal and agricultural sources, as well as phosphorus-rich by-products from wastewater treatment plants. The primary objective is to produce a fertiliser that not only matches the efficacy of conventional synthetic fertilisers such as Single Super Phosphate (SSP), Di-Ammonium Phosphate (DAP) and Mono-Ammonium Phosphate (MAP), but also provides a cost effective alternative to imported mineral fertilisers.

Key aspects of the research include:

• Formulation and refinement of methods to extract and transform poorly soluble phosphorus from wastewater struvite into forms readily accessible to plants.
• Evaluate the safety and bioavailability of the resulting fertilisers, including trace element analysis.
• Evaluate fertiliser efficacy through controlled greenhouse trials, comparing the performance of the developed recycled fertilisers with conventional organic and mineral fertilisers.
• Investigate the influence of seasonal variations and substrate uniformity on phosphorus content and overall fertiliser efficacy.

 Job Description This interdisciplinary position requires knowledge in areas such as soil science, agronomy, environmental chemistry and waste management. The research will involve both laboratory and greenhouse experiments, with a strong emphasis on the practical application of the fertilisers developed in real agricultural settings. The successful candidate will have the opportunity to work with experts in composting, wastewater treatment and sustainable agriculture.

Candidate requirements

We are looking for a candidate with:

• A MSc degree in Environmental Science, Agronomy, Soil Science, Chemistry, or a closely related field.
• Strong interest and motivation for research in environmental sustainability, particularly in the context of agriculture.
• Excellent communication skills and proficiency in English.
• Experience in at least one of the following areas: microplastic analysis, soil science, plant physiology, environmental chemistry, or greenhouse experiments.
• Ability to work in a multidisciplinary and collaborative environment.

 Position Details

• Starting Date: January 2026 or earlier by agreement.
• Location: Agricultural University of Plovdiv, Bulgaria
• Salary: €1,250/month (€15,000/year), offering high purchasing power by Bulgarian standards.
• Contract Type: Full-time PhD (3–4 years).

 Why choose Plovdiv? Plovdiv, Bulgaria's esteemed cultural capital and one of Europe's oldest cities, offers an unparalleled environment for your PhD research, where centuries of history blend seamlessly with contemporary life. The city boasts a vibrant arts scene, well-preserved Roman ruins and a thriving culinary culture, all framed by the picturesque Rhodope Mountains. With affordable living, welcoming residents and a dynamic international community, Plovdiv is more than just a study destination - it is a place to immerse yourself, expand your horizons and find daily inspiration.

Application Instructions

Interested candidates should prepare the following documents:

• Motivation letter (1–2 pages)
• CV (highlighting relevant skills, experience, and publications)
• Transcripts from undergraduate and master’s studies
• Contact information for two academic referees

Please send your application by email to: cmd_au@abv.bg

Contact person: Kostadinka Popova

Tel.:032/654231