Assessment of Biological Treatment for Ammonia Removal from Water Resources, Egypt

Abstract

Egypt is depending entirely on the Nile water. The Rosetta branch of the river Nile serves as a vital freshwater source for domestic, agricultural, industrial, fisheries, and recreational purposes in several western Delta governorates of Egypt, with a daily flow averaging 21,500,000 m3/day. The branch faces significant challenges due to escalating ammonia concentrations stemming from agricultural drains along the river, industrial effluents from industrial activities, and fish farming cages. One particular issue arises during low-demand periods when the flow in the Rosetta branch diminishes. Annually, Egyptian authorities close water flows in a series of channels to facilitate maintenance, resulting in reduced water levels. This winter closure has impacted Kafr El Sheikh and El Beheira, located in northern Egypt, as the drainage of industrial wastes during this period has led to a high pollution load of ammonia and other pollutants. The elevated ammonium content has hindered coagulation, encouraged algal growth, and impeded the chlorine breakpoint during water chlorination processes. Laboratory experiments were conducted to investigate the ability of blue-green algae species (Anabaena sp., Scyndesmos sp., Chlorella sp.) and bacteria (Lactobacillus sp.) to uptake ammonia. This study revealed that single algal species achieved a maximum removal percentage of 30% for ammonia concentrations ranging from 5 to 7.5 mg/l, and mixed algal species attained removal percentages between 6% and 12% at constant retention times of 15 to 60 minutes. For single algal species, retention times exceeding 1 hour (2 and 5 hours) resulted in removal percentages ranging from 85% to 100%. For mixed algal species, removal percentages between 9% and 20% were observed for various retention times ranging from 15 minutes to 1 hour. When comparing the use of algal species mixtures, removal percentages of up to 30-50% were achieved. Additionally, the study found that the application of bacterial species (Lactobacillus sp.) to raw water samples with an average ammonia concentration of 7.8 mg/l resulted in a maximum removal percentage of 100% when using a bacterial content of 100-200 ml per 1-liter raw water sample volume, with varied retention times up to 2 hours.