The world population is growing, which means that more food needs to be produced. At the same time, the amount of waste produced increases and resources needed for food production are getting scarce. Essential elements in soils are depleted (carbon), require a lot of energy to produced (nitrogen) or scarce (P, micronutrients). Unfortunately, wastewater is conventionally treated after dilution with appreciable amounts of clean drinking water. Recovery of resources in that case is only limited. By collecting blackwater separately all above mentioned elements are present in a concentrated form. This stream can then be treated anaerobically allowing simultaneous resource recovery and energy production while producing fertilizers usable in agriculture. This concept has been applied in several locations under mesophilic conditions.
Research challenges
However, this does not allow the recovery of hygienically safe products (carbon, phosphorous). To achieve this, higher temperature treatments need to be applied. The carbon in the black water is transformed into methane and a minor amount of sludge. P is retained in the sludge in yet unidentified forms, while nitrogen and potassium are present in the effluent. The fate of the micronutrients during treatment is unknown. Thermophilic treatment is a process, converting COD (carbon) in the black water to energy (methane). Phosphorous is largely retained in the sludge, nitrogen (as ammonium) is present in the effluent.
Your assignment
The aim of this project is to optimise the conversion of carbon to either energy or sludge at 55 and 70°C while producing hygienically safe fertilisers for agriculture. For both temperature options, you will perform experiments to find an optimum process condition for production of methane and or hydrogen while producing at much sludge as possible. You will assess the quality of the sludge with respect to application in agriculture needs in terms of safety, and carbon sequestration potential. Moreover, you will investigate the fate of the P which is retained in the sludge (Ca-P salts, struvite or other) as well as the speciation of the micronutrients in the sludge (i.e., Mg, Ca, S, Fe, Mn, Zn, Cu, B, Mo, Ni, and others). Precipitation- and other equilibria are depending on temperature and as such the operation conditions could have a decisive influence on the applicability of the products.
Your profile
We are looking for an excellent, highly motivated and enthusiastic researcher with an MSc degree in the field of environmental sciences (environmental technology/biotechnology) and affinity with (analytical) chemistry. Adequate experimental and theoretical skills are required. Candidates with experience operating reactors of any scale are preferred.
Keywords: environmental technology, blackwater, anaerobic digestion, decentralized sanitation, resource recovery
Supervisory team: : Prof. Dr. Ir Cees Buisman (Wageningen University), Dr. Ir. Miriam van Eekert (Wageningen University), Dr. Lucia Hernandez Leal (Wetsus)
Project partners: Source Separated Sanitation theme
Only applications that are complete, in English, and submitted via the application webpage before the deadline will be considered eligible.
Guidelines for applicants: https://phdpositionswetsus.eu/guide-for-applicants/
