Beach Sand Filtration as Pre-Treatment for RO Desalination

Membrane fouling has a strong negative impact on the efficiency of reverse osmosis membranes in seawater desalination. Although reports indicate that water abstracted by beach sand filtration systems on the Mediterranean and Red Seas leads to less membrane fouling compared to direct seawater intakes, only limited information can be found on the efficiency of such systems in removing biodegradable dissolved organic carbon (BDOC), an important fouling agent. This article describes different designs of beach sand filtration systems. In order to investigate the reduction during beach sand filtration of parameters relevant to membrane fouling, such as total organic carbon (TOC), turbidity and total nitrogen, column experiments have been carried out using natural and wastewater spiked seawater with coral beach sand from Hawaii, USA at low and high infiltration rates. Additionally, operational results from existing beach sand filtration sites were collected and supplemented with data from a field site visit of the Dahab beach well desalination plant, Egypt. Preliminary results show good reduction of the targeted parameters and indicate that beach sand filtration would be a valuable pre-filtration step in RO-based drinking water production systems

Beach Sand Filtration as Pre-Treatment for RO Desalination

Membrane fouling has a strong negative impact on the efficiency of reverse osmosis membranes in seawater desalination. Although reports indicate that water abstracted by beach sand filtration systems on the Mediterranean and Red Seas leads to less membrane fouling compared to direct seawater intakes, only limited information can be found on the efficiency of such systems in removing biodegradable dissolved organic carbon (BDOC), an important fouling agent. This article describes different designs of beach sand filtration systems. In order to investigate the reduction during beach sand filtration of parameters relevant to membrane fouling, such as total organic carbon (TOC), turbidity and total nitrogen, column experiments have been carried out using natural and wastewater spiked seawater with coral beach sand from Hawaii, USA at low and high infiltration rates. Additionally, operational results from existing beach sand filtration sites were collected and supplemented with data from a field site visit of the Dahab beach well desalination plant, Egypt. Preliminary results show good reduction of the targeted parameters and indicate that beach sand filtration would be a valuable pre-filtration step in RO-based drinking water production systems

POTENTIAL CONTAMINATION OF GROUNDWATER IN THE WORLD HERITAGE SITE OF SAINT KATHERINE PROTECTORATE, EGYPT

ABSTRACT Groundwater is the main water source for St. Katherine city inhabitants, South Sinai. The rapid population growth, high levels of tourism and poor sewage waste disposal (at least for the foreseeable future) in St. Katherine have resulted in potential contamination of groundwater and subsequent high risk to human health. To evaluate the safety of well water for human use in St. Katherine, water samples were collected from 14 different wells covering various inhabited locations in the area. These samples were subjected to extensive physical, chemical and microbiological analysis. Nitrate values of the majority of the studied wells water exceeded the accepted limits recommended by the Egyptian environmental legislations and the World Health Organization for drinking water standards. Counts of faecal indicators (faecal coliform and faecal streptococci) ranged between 2-142 cfu/100ml in wells. Bacterial pathogens including Salmonella, Shigella and Vibrio spp. were detectable in all wells, indicating heavy contamination of the groundwater with domestic sewage. We discuss the impact of the geological structure of the aquifers and human activities on the safety of groundwater for human use in St. Katherine, as well as possible solutions

Potential contamination of groundwater in the World Heritage Site of the St. Katherine Protectorate, Egypt

Groundwater is the main water source for St. Katherine city inhabitants, South Sinai. The rapid population growth, high levels of tourism and poor sewage waste disposal (at least for the foreseeable future) in St. Katherine have resulted in potential contamination of groundwater and subsequent high risk to human health. To evaluate the safety of well water for human use in St. Katherine, water samples were collected from 14 different wells covering various inhabited locations in the area. These samples were subjected to extensive physical, chemical and microbiological analysis. Nitrate values of the majority of the studied wells water exceeded the accepted limits recommended by the Egyptian environmental legislations and the World Health Organization for drinking water standards. Counts of faecal indicators (faecal coliform and faecal streptococci) ranged between 2-142 cfu/100ml in wells. Bacterial pathogens including Salmonella, Shigella and Vibrio spp. were detectable in all wells, indicating heavy contamination of the groundwater with domestic sewage. We discuss the impact of the geological structure of the aquifers and human activities on the safety of groundwater for human use in St. Katherine, as well as possible solutions. KEY WORDS: Sinai, wells , faecal coliform, faecal streptococci, pathogenic bacteria. Egyptian Journal of Botany Vol.5 2003: 1-