PhD research project; Safe application of humanure

Organisation/Company

Wetsus - European centre of excellence for sustainable water technology

Research Field

Environmental science » Earth science
Agricultural sciences » Soil science

Researcher Profile

First Stage Researcher (R1)

Positions

PhD Positions

Application Deadline

6 Apr 2026 - 15:00 (Europe/Amsterdam)

Country

Netherlands

Type of Contract

Temporary

Job Status

Full-time

Hours Per Week

40

Offer Starting Date

1 Oct 2026

Is the job funded through the EU Research Framework Programme?

Not funded by a EU programme

Reference Number

2026.14

Is the Job related to staff position within a Research Infrastructure?

No

Risk assessment of pharmaceutical residues from humanure into soil
Intensive agriculture has increased crop productivity but disrupted natural nutrient cycles, contributing to soil degradation and water pollution. A key sustainability challenge is closing nutrient loops while reducing dependence on synthetic fertilizers derived from finite resources.

A considerable portion of the (micro)nutrient requirements for food production can be satisfied through the recycling of animal and human excreta (humanure). Recycling human excreta as digested humanure could offers a circular solution bringing back nitrogen, phosphorus, micronutrients, and organic carbon to the soil. Digested humanure is produced during the anaerobic treatment of source-separated toilet discharges. Unlike conventional sewage sludge, source-separated humanure is produced without dilution from stormwater or industrial wastewater and typically contains lower concentrations of heavy metals. Therefore, in terms of pollutants, humanure is a preferred amendment to return nutrients and organic carbon to soil making it a promising soil amendment.

At present, EU regulations encourage the use of sewage sludge in agriculture while imposing safeguards to mitigate adverse effects on soil, vegetation, animals, and human health. While quality standards for heavy metals are met, challenges remain with other pollutants, such as pharmaceuticals. Safe agricultural application requires careful risk assessment. Residual compounds may persist during anaerobic digestion, accumulate in soils, leach to groundwater, or be taken up by crops, potentially entering the food chain. Addressing these uncertainties through systematic monitoring, degradation studies, and risk assessment is essential to ensure environmental safety and public health protection while advancing circular nutrient management.

Research challenges
This project aims to provide essential information regarding the safe application of humanure on soil, facilitating circular nutrient cycles in a responsible manner.

A central challenge of this project is to reliably assess the environmental fate of pharmaceuticals present in digested humanure after soil application. The potential effects of humanure on soil include the introduction of pathogenic organisms, antimicrobial resistance (AMR), heavy metals, and pharmaceutical residues. Furthermore, the addition of nutrients in various N:P ratios, carbon, and pharmaceuticals may alter soil characteristics.

Your assignment
This project will combine risk assessment of pharmaceuticals with lab and field tests of digested humanure on soil. For the 100 most commonly prescribed pharmaceuticals in the Netherlands, their excretion profiles and their physico-chemical properties will be used to predict their persistance in soil. Through laboratory-scale and field tests, you will examine the fate of these compounds and compare them with model results, as well as assess their effects on soil.
During this project you will:

– conduct a soil risk assessment based on 100 most used pharmaceuticals in the Netherlands
– analyze levels of selected compounds in digested humanure
– design lab-scale experiments in different types of soil where (spiked) digested manure is applied, to determine fate – of pharmaceutical residues in soil.
– design and conduct field tests to validate results from the risk assessment model and lab-scale experiments.
propose a strategy for safe application of humanure on soil

Your profile
You have a master’s degree in environmental sciences, soil science, or equivalent. You have a strong interest in environmental risk assessment and the fate of organic contaminants in soil systems. You are an independent, motivated student with an affinity for multidisciplinary research. You are comfortable with using computer models as well as being in the lab. You have affinity with analytical determination of pharmaceuticals in difficult matrices. You are able to dive into topics outside your current knowledge base, but know how to separate main and secondary topics. You like working in a dynamic environment and enjoy tackling challenges as they arise. Being in possession of a driver’s license is a plus.
Keywords: pharmaceuticals, soil, risk assessment,
Professor/University group/Wetsus supervisor(s): University promotor: TBA. University co-promotor: dr. ir. Caroline Moermond (RIVM, Radboud University);
Wetsus supervisor(s): Dr. Lucía Hernández-Leal
Project partners: Engineered soil amendments theme

Only complete applications in English submitted via the application webpage before the deadline will be considered eligible.

Guidelines for applicants:  https://phdpositionswetsus.eu/guide-for-applicants/

Website

https://phdpositionswetsus.eu/

Research Field

Agricultural sciences » Soil science

Education Level

Master Degree or equivalent

You have a master’s degree in environmental sciences, soil science, or equivalent. You have a strong interest in environmental risk assessment and the fate of organic contaminants in soil systems. You are an independent, motivated student with an affinity for multidisciplinary research. You are comfortable with using computer models as well as being in the lab. You have affinity with analytical determination of pharmaceuticals in difficult matrices. You are able to dive into topics outside your current knowledge base, but know how to separate main and secondary topics. You like working in a dynamic environment and enjoy tackling challenges as they arise. Being in possession of a driver’s license is a plus.

Languages

ENGLISH

Level

Excellent

Number of offers available

14

Company/Institute

Wetsus

Country

Netherlands

City

Leeuwarden

Postal Code

8911 MA

Street

Oostergoweg 9

Geofield

City

Leeuwarden

Website

http://www.wetsus.nl

Street

Oostergoweg 9

Postal Code

8911 MA

E-Mail

phdpositions@wetsus.nl

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