Abstract
Water pollution has become a major environmental concern for public and environmental health in developing countries. Water resources are being contaminated mainly due to mixing of domestic, municipal, and industrial wastewaters. The wastewater management and treatment situation is deplorable mainly because of financial constraints, the unavailability of technically trained human resources, and electricity shortages. Moreover, there is a challenge for the scientific community and wastewater management experts to explore cost-effective, simple, reliable, and efficient wastewater treatment systems. Therefore, the present review highlights the option of trickling filter (TF) systems for wastewater treatment in developing countries like Pakistan, India, Bangladesh, and African regions, etc. In addition, the solutions to the operational/performance issues of the TF system are explored and discussed in greater detail for designing/construction of new TF systems and retrofitting the existing TFs.