by Justus and Thijs
The final week has started for us. The report is being finished and the final presentation prepared. In the last weeks we have been busy collecting the last data and writing the report. We have done the volume analyses of the sewer system and we spent a day at the WWTP. Finally, last week we gave a presentation at the Dutch embassy about our findings. They were very interested and it was rewarding to share the information we obtained.
Since we are ending our work we would like to share some of our conclusions. We have investigated the sewer network in Maputo. The system consists of two systems. One old system, named system one, that discharges into the bay, and a newer system, system two, that conveys the wastewater to the treatment plant. System two would convey a part of water in system one to the treatment plant; for this, the system relies on two pumps that are not working because of excessive sand in the pipes. We calculated the flow into the treatment plant based on drinking water use. We calculated that the average flow is 46 L/s . The average flow into the bay is 239 L/s. If the pumps will work the flow into the bay can be brought down to an average 166 L/s, which would increase the flow at the treatment plant to 119 L/s.
We have identified four critical parts in the system. First, the pumps should be switched-on once the sand is taken out of the pipes. Second, the wastewater treatment plant should be cleaned and improved, which has been planned. Third, considering that sewer discharges pollute the bay, these discharges should be stopped: all wastewater discharged through system two could be intercepted using a new sewer line, conveying this wastewater to a new WWTP or to the existing one, once it is overhauled. Finally, the manholes and the drain entries that are often filled with garbage and sand, which clogs the pipes and pollutes the bay.
For all these actions financing is needed and a source of revenue could be the sanitation fee. We know that CRA is working hard on the implementation of this fee, so we can expect it to happen soon.
The twelve weeks we have stayed in Maputo were very nice. We experienced how it is to work in a different and sometimes challenging environment. We were lucky to see some of the nice tourist hotspots close to Maputo, such as Inhaca Island, Kruger park, Swaziland and Macaneta beach. We have been working hard and we were able to answer all our research questions. It was a interesting and profitable time for ourselves and for our studies. Hopefully we can come back sometime.