Hydrochemical Characterization of the Continental Terminal Aquifer in Cap Skirring Area, Southwestern Senegal
Ousmane Coly Diouf,
Lutz Weihermuller,
Ndeye Maguette Dieng,
Mathias Diedhiou,
Edgar Yvon Terence Benam Beltoungou,
Seynabou Cisse Faye,
Serigne Faye
Issue:
Volume 8, Issue 4, December 2022
Pages:
71-78
Received:
16 November 2022
Accepted:
1 December 2022
Published:
21 December 2022
DOI:
10.11648/j.ajwse.20220804.11
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Abstract: Cap Skirring area is located in the southwestern part of Senegal, where groundwater is the only resource for drinking water supply. The present study helps to assess and determine the most dominant hydrogeochemical processes controlling the groundwater quality in the Cap Skirring area in Southwestern Senegal. For these purposes, 23 groundwater samples have been collected and analyzed for pH, Ca2+, Mg2+, Na+, K+, SO42-, Cl-, HCO3- and NO3- concentrations and the indices total hardness (TH) as well as total dissolved solid (TDS) were calculated based on the analytical results. The analysis indicated that the groundwater in the study area is generally soft. Comparison of these chemical data with the WHO drinking water standards showed that WHO standards were exceeded mainly in wells D30 (Ca2+, HCO3-) and PD122 (Cl-, NO3-, Na+ and K+), both located in the eastern part of the area. The Piper, Shadha, and other bivariate diagrams presenting the geochemical facies of the groundwater showed the HCO3 – Ca – Mg as the dominant water type (65.2 %) followed by the Cl – Na – K water type (21.7 %), and the Cl – Ca – Mg water type (13.0 %). This hydrogeochemical characterization indicates that the groundwater is mainly recharged by the high seasonal rainfall that occurs in the area. Salinization conditions and reverse ion exchange reactions were also observed in the some groundwater samples. This salinization process was mainly found along the eastern part (“bolong”) of the study area in samples taken at PD 122, PD 144, PD 55, and Marie Diatta or near the Atlantic coast (PD 154).
Abstract: Cap Skirring area is located in the southwestern part of Senegal, where groundwater is the only resource for drinking water supply. The present study helps to assess and determine the most dominant hydrogeochemical processes controlling the groundwater quality in the Cap Skirring area in Southwestern Senegal. For these purposes, 23 groundwater samp...
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On-Line Monitoring and Process Control of SBR Cycles for Nutrient Control from Wastewater
Issue:
Volume 8, Issue 4, December 2022
Pages:
79-88
Received:
22 June 2021
Accepted:
7 December 2022
Published:
29 December 2022
DOI:
10.11648/j.ajwse.20220804.12
Downloads:
Views:
Abstract: Nitrogen (N) and phosphorus (P) are nutrients for the growth of living cells. Their presence is essential for biological treatment of domestic wastewater. However, uncontrolled discharge of nutrients with treated effluent from wastewater treatment plants leads to eutrophication– a condition that promotes growth of undesirable aquatic plants and adversely impacts the quality and aesthetic of the receiving bodies water. To address the increasing regulatory requirements for nutrient control from treatment plant discharges utilities around the globe implement advanced wastewater treatment processes for N and P removal. Among various configurations of biological wastewater treatment reactors Sequencing Batch Reactors (SBR) have been demonstrated as an effective technology for nutrient control. SBR conducts all functions of treatment process including BOD oxidation, nitrification, denitrification, enhanced biological phosphorus removal (EBPR) and clarification of the mixed liquor in the same reactor tank. SBR operates in repeating cycles, each consisting of the above steps in series. Each step carries out a specific biochemical reaction to fulfill the overall treatment goal. The cyclic and stepwise operation of an SBR is precisely controlled by a Programmable Logic Controller (PLC). This paper presents a case study of successful nutrient control by SBR with the help of automatic real time process control by a PLC. It discusses the working principle of SBR and the function of each process step. The test program consisted of continuous monitoring of multiple process parameters to monitor the removal of BOD, TSS and nutrients, in each cycle of the sequencing batch reactor (SBR) at the wastewater treatment plant. On-line, real time, monitoring of pH, oxidation reduction potential (ORP), dissolved oxygen (DO), ammonia-N, nitrite-N, nitrate-N and orthophosphate-P demonstrated excellent correspondence between these parameters and the individual biochemical reactions in each step. Subsequently, the SBR cycle control logic was changed from time and DO based, to ORP based. This demonstrated the potential for a higher energy efficiency in plant operation while maintaining the effluent quality in compliance with the state regulation for BOD, TSS, TN, TP of 5, 5, 3 and 1 mg/L, respectively.
Abstract: Nitrogen (N) and phosphorus (P) are nutrients for the growth of living cells. Their presence is essential for biological treatment of domestic wastewater. However, uncontrolled discharge of nutrients with treated effluent from wastewater treatment plants leads to eutrophication– a condition that promotes growth of undesirable aquatic plants and adv...
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