Seasonal Variation and Removal of Organic Pollutants in Wastewater Using Low-Cost Treatment Technologies in Tamale Metropolis, Ghana

Felix K Abagale

doi:10.4236/jwarp.2021.134016

Abstract

The use of wastewater as alternative source of water for vegetable crop irrigation has become an eminent component of urban agriculture due to current global water crises in most developing countries, and admits the increasing effects of global climate change. The practise is however noted to be associated with significant health and environment risk due to excessive pollutant load. The study assessed the level of seasonal variation and removal of organic pollutants in wastewater using gravel filters combined with stabilisation ponds at Zagyuri in the Tamale Metropolis. The yard scale experiment consisted of cylindrical containers of different length filled with six different sizes of filter media and connected to stabilisation ponds where wastewater is allowed to pass through for filtration and stabilisation. The results indicated that for both seasons, the average concentration of BOD released into the stream at Zagyuri was 92.98 mg/l and 103.54 mg/l for the dry and wet season respectively whilst the COD was averaged 132.78 mg/l and 143.75 mg/l for the dry and wet seasons respectively. The results of the simple linear regression revealed a strong positive linear relationship between BOD and COD with coefficient of determination (R2) of 0.873 which was statistically highly significantly at Pr value of Pr values of 0.0011 and 5 and COD. The average concentration of BOD was higher than the Ghana EPA recommended levels while that of COD was lower and thus within safety range for discharge into the environment.

Highlights

Despite the increasing effects of climate change coupled with intermittent water scarcity, alternative use of wastewater for vegetable crop irrigation has become an integral component of urban agriculture, especially in most developing countries where demand for all year-round vegetable production is eminent
The results indicated that for both seasons, the average concentration of Biochemical Oxygen Demand (BOD) released into the stream at Zagyuri was 92.98 mg/l and 103.54 mg/l for the dry and wet season respectively whilst the Chemical Oxygen Demand (COD) was averaged 132.78 mg/l and 143.75 mg/l for the dry and wet seasons respectively
The average concentration of BOD was higher than the Ghana Environmental Protection Agency (EPA) recommended levels while that of COD was lower and within safety range for discharge into the environment

Summary

Introduction

Despite the increasing effects of climate change coupled with intermittent water scarcity, alternative use of wastewater for vegetable crop irrigation has become an integral component of urban agriculture, especially in most developing countries where demand for all year-round vegetable production is eminent. The practise of wastewater irrigation remains the sole option for vegetable farmers to supplement the year-round water demand for vegetable production. Despite the important contribution to food security, application of untreated wastewater poses severe risk to public health and the environment due to excessive pollutant concentration and contaminant load. Kulabako et al, [4] mentioned that increase production of organic effluents due to rapid industrial growth poses severe environmental risk. Pollution of the limited water resources by the organic constitutes from the different sources of industrialization, agricultural activities and global environmental changes presents a major issue of concern due to the high toxicity levels and carcinogenic nature [5]

Methods

Results

Conclusion