Constructed Wetlands (CWs) can guarantee an efficient wastewater treatment and an appealing green space at the same time. However, they require large areas for their construction that in many cases is not available. Two domestic wastewater treatment options were designed and studied with the purpose of having a low space requirement: the Duplex-CW and the Constructed Wetroof (CWR). Several modifications and improvements have been tested in order to select the most appropriate Duplex-CW and CWR design. Overall, this thesis contributes to the development of two efficient domestic wastewater treatment technologies. The CWR is the foremost option to save land areas since it requires 0 m2 of land per person equivalent.

1. General Introduction. 2. Literature Review. 3. Use of Marine and Engineered Materials for the Removal of Phosphorus from Secondary Effluent. 4. Effect of Aeration on Pollutants Removal, Biofilm Activity and Protozoan Abundance in Conventional and Hybrid Horizontal Subsurface-Flow Constructed Wetlands. 5. Aeration and Recirculation in a Stack Arranged Hybrid Constructed Wetland for Treatment of Primary Domestic Wastewater. 6. Evaluation of the Performance and Space Requirement by Three Different Hybrid Constructed Wetlands in a Stack Arrangement. 7. Material Selection for a Constructed Wetroof Receiving Pre-Treated High Strength Domestic Wastewater. 8. Constructed Wetroofs: A Novel Approach for the Treatment and Reuse of Domestic Wastewater at Household Level. 9. General Discussion and Conclusions.

Maribel Zapater Pereyra was born in Piura, Peru on the 26^th January 1984. She graduated from the School of Civil Engineering in 2005 from the University of Piura, Piura, Peru. In 2009 she obtained her MSc in Desert Studies from the University of the Negev, Sde Boqer, Israel. In 2010 she initiated her PhD research in The Netherlands with the aim of designing and developing novel constructed wetlands with low space requirement.

During her PhD studies, she participated in different international conferences. She was also involved in internships with the company ECOFYT (The Netherlands) and with the University of Stuttgart (Germany). Ms. Zapater Pereyra has published several scientific publications, including proceedings and peer-reviewed journals. She continues to be an active young professional with an interest in the applied sector of sanitary and environmental engineering.