Urban Wastewater Management of Willemstad, Curaçao, and Environmental Implications
Curaçao's coral reefs are subjected to a deteriorating momentum risking the health and therefore sustainability of this vital ecosystem. Despite the dependency of the Island's prosperity on the condition of the ecosystem, research suggests that wastewater management is likely to be a significant contributor to this effect. Incorporating both open literature results and information obtained from an extensive constructed research network, this study demonstrates essential aspects of the urban wastewater management system of Willemstad regarding the quantity and quality of the urban wastewater fluxes and their potential environmental implications. The system, which merely connects 33\% of Curaçao's population, is concluded to be outdated and insufficient with respect to capacity as well as treatment efficiency. Although it is solely designed for pure domestic wastewater, this study concluded and demonstrated the significant impact of illegal discharge onto this system by industrial sectors leading to both high contamination loading and increased wastewater volumes. The combination of these features is the major cause of wastewater discharge pathways into marine environments. Arising from the constructed urban wastewater flux model, which visualizes the wastewater management system, 14 discharge locations correlated to significant environmental contamination pathways are identified with Piscadera Bay, Rif Mangrove area, Playa Kanoa and Shut concluded as the utmost importance. Furthermore, the model revealed that the urban wastewater is predominantly directed towards the treatment plant Klein Hofje via either the northern trajectory (Bonam - Suffisant F - Garipitoweg - Argentianweg - Klein Hofje) or the southern one (SVB - Klein Hofje). Also, the quantity and quality of the fluxes are estimated based on the connected area and the potential industrial activities within it. However, validation of these estimations is recommended since no water quantity and quality analysis was performed or available for conducting the modelled estimations. Furthermore, since the system is partly a combined sewage system, hence harvesting stormwater fluxes as well, its effect is recommended to incorporate in the model and estimations for accuracy purposes. Lastly, the government reports that at least 90\% of all industrial wastewater is discharged either directly into the ocean or onto the sewer system. Since the actual ratio as well as the water quality remains unknown this is recommended for future research. Overall, this study enables tailored future research programs to overcome the discussed limitations and with that significantly contribute to eliminating the current existing white spot concerning the effect of urban wastewater fluxes on the marina ecosystem of Curaçao.
