Impact of effluent from fertilizer factories on the Lakhyariver water quality

Abstract

Industrialization has become essential for economic growth and employment generation in Bangladesh. But the speeding up of the process of industrialization without adequate waste management facilities has become the cause of degradation of environment and quality of life. Indiscriminate disposal of polluting wastes beyond assimilation capacity of the water bodies has become the cause of deterioration of water quality and aquatic ecosystem. The Buriganga, the Dhaleswari, the Lakhya, and the Baht rivers have become highly contaminated around the industrial clusters. For instance, The Urea Fertilizer Factories (Polash and Ghorasal) produce around 1,400 tons urea per day. The industry has an effluent treatment plant with inadequate capacity. Most of the untreated effluent is being discharged into the Lakhya River through pump. A study was carried out in Polash and Ghorasal Urea Fertilizer Factories to assess the impact of effluent on the Lakhya River water quality. Comprehensive waste water sampling by grab sampling method and flow measurement by float velocity method were carried out for five weeks (one sample per week) at five sampling stations at Polash and Ghorasal Urea Fertilizer Factories during June-July, 2007. Water quality samplings by grab sampling method were also carried out for five weeks (one sample per week) at four stations in the Lakhya River system at the same time and Riverflows on the period of October-06 to September-07 were collected from Institute of Water Modelling. Effluents at both the places and the water sample from selected points in the river were analysed for pH, Temperature, DO, BOD5, COD, NHrN, NHrN. TS, TSS, and TDS during June-July, 2007 at the Environmental Engineering workshop of Bangladesh University of Engineering and Technology, Bangladesh. The results showed that the effluents were alkaline while the level of DO, BOD5, COD, NHrN. NHrN. TS, TSS, and TDS relatively high. The upstream water was near to neutral pH (average pH, 7. 66:tO.102) with high dissolved oxygen but low in the levels of the other parameters. The river water after the effluent discharge points was alkaline (average pH, 8.16:tO.08) and the levels of other parameters were high due to heavy pollution load especially Ammonia discharged from fertilizer factories. The results suggested that the water in the river was polluted and not good for human consumption. It is therefore recommended that the disposal of improperly treated or untreated wastes should be stopped to save the river water from further deterioration. Although the values of some water quality parameters in some cases were lower than the allowable limits, the continued discharge of the effluents in the river may result in severe accumulation of the contaminants and unless the authorities implement the laws governing the disposal of wastes this may affect the lives of the people.