In response to the urgent need to develop and improve low cost technologies for wastewater treatment, this thesis explores how to treat wastewater with duckweed in a pond system, a solution that contributes both environmental protection and food production. The book reports on the effect of different operational variables, like anaerobic pre-treatment, the combination of algae and duckweed ponds and pond depth. It discusses improved nitrogen removal through the combination of duckweed ponds with algae ponds. It also demonstrates how duckweed pond systems could be designed with shallow depth...