PhD topic: EcoSan; nutirent recovery or water reuse

Hi all  I have been out of the field of water and sanitation for a few months (have missed it very much) and believe it is time for me to take the next step and do my PhD. The reason I have put it off for a few years is that I have been searching for a relevant and challenging topic. Some background; I am a Namibian civil engineer with a master in water & environmental engineering and 3 years’ experience as a process/civil engineer in South Africa and the Middle East.   I am currently living in the Netherlands and aim to do my PhD through TU Delft or UCT but am certainly open to any school.   I am less technically adept than other process engineers and I would happily include a more social aspect in my research. The topics I am leaning towards are anything that encompasses sanitation provision, WASH, water provision, nutrient recovery and sewage treatment/faecal sludge management (FSM). Futhermore, I am very interested in climate change adaptation and water provision as I completed my masters thesis on the effect of climate change on water stressed environments in northern Namibia. My preference would be to carry out field work in a developing country, or for my work to be relevant in a developing country.   I believe that the best place to look is in the field: thus have you, the water professionals, encountered any interesting and relevant topics related to these? Your input would be very much appreciated. Best regardsMegan Galloway