Effect of Season and Organic Loading Variation on the Operation of an Indigenously Developed Maize Cobs Trickling Filter (MCTF)

Abstract

Trickling filters are an attractive wastewater treatment option but the past experience of installing and operating them in Pakistan is not very successful as they have not performed up to the mark. It is, therefore, important to identify the underlying operational problems of trickling filter and resolving them. A pilot scale indigenous maize cobs trickling filter (MCTF) was developed using agricultural waste (Maize cobs) as a biological growth medium to investigate the effect of operational parameters like temperature and organic loadings on the performance of trickling filter operation. The developed MCTF wastewater treatment system was experimented under different organic loadings: 9-21 Kg BOD/m3.d; 9-26 Kg COD/m3.d and a temperature range of 2043°C during five months of operation. The results indicated that as the organic loadings increased, the removal (%) of BOD and COD decreased for the developed trickling filter. The removal (%) increased with an increase in temperature. The maximum removal (%) was achieved at an organic loading of 12-15 Kg BOD/COD/m3.d and a temperature range of 3543°C. The main reason of effective BOD and COD removal was rapid development of microbial film (within first two weeks) probably due to the filamentous structure, relatively high specific surface area, and inter-cob voids of the maze cobs. Maize cobs served as an economic, efficient and robust filter media which have better capability to sustain higher organic loadings and temperature fluctuations as compared to other conventional filter media. Keywords— Trickling filter, Maize cobs, Waste Material, Temperature, Organic loadings