The researchers studied how desludging and upgrading waste stabilisation ponds in Botswana improved the quality of wastewater for agricultural use. After the upgrade, the ponds had better removal of contaminants like biochemical oxygen demand and total suspended solids. The effluent also had lower levels of E. coli and coliforms. However, there were still issues with helminth eggs and phosphate levels in the final effluent. Overall, the upgrade helped, but more work is needed to maintain and improve the system for better performance.