Gaza Wastewater Treatment Plant (GWWTP) is a well-established facility, and was used to study the suitability of individual treatment components as possible low cost treatment systems for semi-arid regions in terms of removal efficiency. Samples were taken at weekly intervals over an 18 week period. During this period there were significant removals of BOD, COD and TSS. The removal efficiencies of BOD and TSS in the anaerobic component were 41% and 44% respectively, while BOD removal efficiencies in the bio-towers and aerated lagoons were 56% and 51% respectively.