Groundwater

1. Purpose: The purpose of this manual is to provide guidance to Corps of Engineers personnel who are responsible for groundwater-related projects.

2. Applicability: This manual applies to all USACE Commands having responsibility for design of civil works projects.

3. Distribution Statement: Approved for public release, distribution is unlimited.

Abstract: Drinking water supplies are based on ground water resources all over the world. At some localities problems with higher concentrations of iron and manganese found in ground water. These higher concentration of these metals result in metallic taste of water, effect color and flavor of food and cause staining of different products like paper, cloths, and plastics. Therefore World Health Organization has approved the treatment of water if concentrations of iron and manganese are higher than 0.3mg/L and 0.1 mg/L. Several techniques have been applied to remove iron and manganese from groundwater. The issue of higher concentrations of iron and manganese in groundwater wells at Grindalsmoen in Elverum Municipality in the south eastern part of Norway has been investigated by a PHREEQC geochemical model. The aim of this investigation was to analyze the relationships between oxygen levels and precipitation rates of iron and manganese. For this purpose geochemical simulations were performed with PHREEQC model with radial and linear flow. Results proved that concentration of oxygen at the water works (at its corresponding partial pressure) is high enough to precipitate the level of iron and manganese found in groundwater. The concentration of oxygen in equilibrium air at our desired temperature of 6 degree centigrade was 12.3 mg/l calculated by PHREEQC. Geochemical simulations were performed by the one dimensional column flow and radial flow towards well. The phenomenon of sorption was also included in model to see the adsorption behavior of iron and manganese. Overall this geochemical study has provided satisfactory results.

Abstract: The purpose of the study to investigate the impact of the presence of iron and manganese found in  groundwater. The concentrations if both minerals as well as the location of the water source were identified along with its impact on water quality. Also, in this investigation a suitable method or  technique for the removal of both iron and manganese is selected taking into consideration the  local economic and environmental aspects. The removal will be accomplished by oxidizing both iron and manganese using aeration or using dissolved chemical oxidants converting them from  soluble to insoluble precipitates. Precipitates of iron and manganese hydroxides are formed and removed from water through settling and filtration units. In this research the concentrations of iron and manganese were analyzed from groundwater aquifers of a number of towns in the southern part of Libya. These concentrations were compared to the local and international drinking water standards set by the World Health Organization (WHO). Some water samples reported have shown a wide difference in iron and manganese concentration and selected for treatment in this  investigation. A complete treatment system has been designed to remove iron and manganese for  the groundwater at Brak city of Alafia since the iron and manganese exceeds the limits. The  oxidation of iron and manganese was done via aeration followed by flocculation and, settling,  filtration and finally disinfection. At Alafia city, iron and manganese concentrations were 3.1mg/L, and 0.32mg/L respectively as compared to the standards set by the World Health Organization,  2004 for concentrations of 0.3 mg /L, 0.1 mg /L respectively, This process is believed to be very  effective and economically feasible in the removal of both iron and manganese.