scholarly journals Transport and retention of phosphorus in surface water in an urban slum area

2013 ◽  
Vol 10 (8) ◽  
pp. 10277-10312
Author(s):  
P. M. Nyenje ◽  
L. M. G. Meijer ◽  
J. W. Foppen ◽  
R. Kulabako ◽  
S. Uhlenbrook
Keyword(s):  
Surface Water ◽  
Management Practices ◽  
Domestic Wastewater ◽  
Suspended Sediments ◽  
Base Flow ◽  
Low Flow ◽  
Surface Erosion ◽  
Wastewater Management ◽  
Bed Sediments ◽  
Total P

Abstract. The transport of excessive phosphorus (P) discharged from unsewered informal settlements (slums) due to poor on-site sanitation is largely unknown. Hence, we investigated the processes governing P transport in a 28 km2 slum-dominated catchment in Kampala, Uganda. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h) from a primary channel draining the catchment and from a small size tertiary channel draining one of the contributing slum areas (0.5 km2). Samples were analyzed for orthophosphate (PO4-P), particulate P (PP), total P (TP) and selected hydro-chemical parameters. Channel bed and suspended sediments were collected to determine their sorption potential, geo-available metals and dominant P forms. We found that P inputs in the catchment originated mainly from domestic wastewater as evidenced by high concentrations of Cl (36–144 mg L-1), HCO3 and other cations in the channels. Most P discharged during low flow conditions was particulate implying that much of it was retained in bed sediments. Retained P was mostly bound to Ca and Fe/Al oxides. Hence, we inferred that mineral precipitation and adsorption to Ca-minerals were the dominant P retention processes. Bed sediments were P-saturated and showed a tendency to release P to discharging waters. P released was likely due to Ca-bound P because of the strong correlation between Ca and total P in sediments (r2 = 0.9). High flows exhibited a strong flush of PP and SS implying that part of P retained was frequently flushed out of the catchment by surface erosion and resuspension of bed sediment. Our findings suggest that P accumulated in the channel bed during low flows and then was slowly released into surface water. Hence, it will likely take some time, even with improved wastewater management practices, before P loads to downstream areas can be significantly reduced.

scholarly journals Assessment of Domestic Wastewater Management Practices in the Communal District I of Maradi City, Niger Republic

2015 ◽  
Vol 03 (08) ◽  
pp. 57-65 ◽  
Author(s):  
Ousmane Laminou Manzo ◽  
Hassidou Saidou ◽  
Salamatou Abdourahamane Illiassou ◽  
Saoudé Tidjani Idrissa
Keyword(s):  
Management Practices ◽  
Domestic Wastewater ◽  
Wastewater Management

scholarly journals Phosphorus transport and retention in a channel draining an urban, tropical catchment with informal settlements

2014 ◽  
Vol 18 (3) ◽  
pp. 1009-1025 ◽  
Author(s):  
P. M. Nyenje ◽  
L. M. G. Meijer ◽  
J. W. Foppen ◽  
R. Kulabako ◽  
S. Uhlenbrook
Keyword(s):  
Surface Water ◽  
Informal Settlements ◽  
Suspended Sediments ◽  
Urban Slum ◽  
Base Flow ◽  
Sub Saharan Africa ◽  
Phosphorus Transport ◽  
Untreated Wastewater ◽  
Urban Catchments ◽  
Runoff Events

Abstract. Urban catchments in sub-Saharan Africa (SSA) are increasingly becoming a major source of phosphorus (P) to downstream ecosystems. This is primarily due to large inputs of untreated wastewater to urban drainage channels, especially in informal settlements (or slums). However, the processes governing the fate of P in these catchments are largely unknown. In this study, these processes are investigated. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h) from a primary channel draining a 28 km2 slum-dominated catchment in Kampala, Uganda, and from a tertiary channel draining one of the contributing slum areas (0.54 km2). The samples were analysed for orthophosphate (PO4-P), particulate P (PP), total P (TP), suspended solids (SS) and hydrochemistry. We also collected channel bed and suspended sediments to determine their geo-available metals, sorption characteristics and the dominant phosphorus forms. Our results showed that the catchment exported high fluxes of P (0.3 kg km2 d−1 for PO4-P and 0.95 for TP), which were several orders of magnitude higher than values normally reported in literature. A large proportion of P exported was particulate (56% of TP) and we inferred that most of it was retained along the channel bed. The retained sediment P was predominantly inorganic (> 63% of total sediment P) and consisted of mostly Ca and Fe-bound P, which were present in almost equal proportions. Ca-bound sediment P was attributed to the adsorption of P to calcite because surface water was near saturation with respect to calcite in all the events sampled. Fe-bound sediment P was attributed to the adsorption of P to iron oxides in suspended sediment during runoff events given that surface water was undersaturated with respect to iron phosphates. We also found that the bed sediments were P-saturated and showed a tendency to release P by mineralisation and desorption. During rain events, there was a flushing of PP which we attributed to the resuspension of P-rich bed sediment that accumulated in the channel during low flows. However, first-flush effects were not observed. Our findings provide useful insights into the processes governing the fate and transport of P in urban slum catchments in SSA.

scholarly journals Surveying causes of surface water pollution at Sao River, Binh Thuy district, Can Tho city, Vietnam

2021 ◽  
Vol 9 (2) ◽  
pp. 103-110
Author(s):  
Nguyen Thanh Giao
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Surface Water ◽  
Solid Waste ◽  
Biological Activities ◽  
Water Environment ◽  
Oxygen Demand ◽  
Surface Water Quality ◽  
Domestic Wastewater ◽  
Wastewater Management

Surface water sources play an important role in human and biological activities and the socio-economic development of the region. Therefore, the assessment of water quality and determination of the causes of water pollution in Sao river is essential for good management of the surface water environment. The study was conducted from July to December 2020. Water samples were collected at the time of low tide to evaluate the water quality indicators of temperature, pH, conductivity (EC), dissolved oxygen (DO), biological oxygen demand (BOD), total suspended solids (TSS), ammonium (N-NH4+), orthophosphate (P-PO43-) and coliform. The source of pollution was determined by direct interviews with households living near Sao river. The results showed that surface water quality in Sao river had signs of organic pollution and microbiological pollution due to BOD, TSS, N-NH4+, P-PO43-, coliform exceeded the allowable limits of National Technical regulation on surface water quality (QCVN 08-MT:2015/BTNMT, column A1). The results of the interview revealed that 70% of respondents said that water was seriously polluted and the main sources of pollution were domestic solid waste and domestic wastewater. Therefore, to improve surface water quality in Sao river, solid waste and wastewater management is urgently required. It is necessary to promote the monitoring and management of water quality with the participation of local authorities and communities.

Sewage Treatment by Waste Stabilization Pond Systems

2018 ◽  
Vol 3 (1) ◽  
pp. 7-14
Author(s):  
J. Kenneth, R. S. Suglo
Keyword(s):  
Management Practices ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Wastewater Management ◽  
Stabilization Pond ◽  
Waste Stabilization Pond ◽  
Quality Guidelines ◽  
Waste Stabilization ◽  
High Reduction ◽  
Wastewater Samples

Sewage generated in Ghana is commonly discharged into the environment without any form of treatment to reduce the degree ofcontamination and mitigate potential public health and environmental issues. Although some attempts have been made in someparts of Ghana to utilize the waste stabilization pond (WSP) system to treat domestic sewage, the ponds often fail to achievetheir purpose due to lack of basic maintenance and supervision. To assess the utility of the WSP system for treating sewage,wastewater samples were collected from the raw sewage, anaerobic, facultative and maturation ponds of WSPs at Obuasi inGhana, and analyzed for physicochemical and microbiological contaminants. The results show that the final pond effluent meetsrecommended microbiological and chemical quality guidelines. The waste stabilization pond system demonstrates high removalefficiencies of wastewater contaminants. The biochemical oxygen demand, total suspended solids, nitrate and faecal coliformsreduction efficiencies of 97.3%, 97.6%, 83.3% and 99.94% respectively are highly significant, and compare well with reportedremoval efficiencies in the literature. Additionally, the ponds have high reduction efficiencies for heavy metals and pathogenicmicroorganisms. The wastewater treatment system complies with standard wastewater management practices, and provides auseful method for treating and disposing wastewater in Ghana.

Agricultural best management practices and surface water improvement and management

1995 ◽  
Vol 31 (8) ◽  
pp. 109-121 ◽  
Author(s):  
D. L. Anderson ◽  
E. G. Flaig
Keyword(s):  
Water Management ◽  
Surface Water ◽  
Best Management Practices ◽  
Management Practices ◽  
Agricultural Runoff ◽  
South Florida ◽  
Lake Okeechobee ◽  
Runoff Water ◽  
Best Management ◽  
Management Plans

Restoration and enhancement of Lake Okeechobee and the Florida Everglades requires a comprehensive approach to manage agricultural runoff. The Florida Surface Water Improvement and Management (SWIM) Act of 1987 was promulgated to develop and implement plans for protecting Florida waters. The South Florida Water Management District was directed by Florida legislature to develop management plans for Lake Okeechobee (SWIM) and the Everglades ecosystem (Marjory Stoneman Douglas Everglades Protection Act of 1991). These plans require agriculture to implement best management practices (BMPs) to reduce runoff phosphorus (P) loads. The Lake Okeechobee SWIM plan established a P load reduction target for Lake Okeechobee and set P concentration limitations for runoff from non-point source agricultural sources. Agricultural water users in the Everglades Agricultural Area (EAA) are required to develop farm management plans to reduce P loads from the basin by 25%. The Everglades Forever Act of 1994 additionally emphasized linkage of these landscapes and consequent protection and restoration of the Everglades. Agricultural BMPs are being developed and implemented to comply with water management, environmental, and regulatory standards. Although BMPs are improving runoff water quality, additional research is necessary to obtain the best combination of BMPs for individual farms. This paper summarizes the development of comprehensive water management in south Florida and the agricultural BMPs carried out to meet regulatory requirements for Lake Okeechobee and the Everglades.

Using Gleams to Evaluate the Agricultural Waste Application Rule-Based Decision Support (AWARDS) Computer Program

1993 ◽  
Vol 28 (3-5) ◽  
pp. 625-634 ◽  
Author(s):  
D. A. Ford ◽  
A. P. Kruzic ◽  
R. L. Doneker
Keyword(s):  
Surface Water ◽  
Ground Water ◽  
Management Practices ◽  
Agricultural Waste ◽  
Rule Base ◽  
Rule Based ◽  
Pollutant Loading ◽  
Physical Features ◽  
To Receive ◽  
Complex Computer

AWARDS is a rule-based program that uses artificial intelligence techniques. It predicts the potential for fields receiving agricultural waste applications to degrade water quality. Input data required by AWARDS include the physical features, management practices, and crop nutrient needs for all fields scheduled to receive these nutrients. Based on a series of rules AWARDS analyzes the data and categorizes each field as acceptable or unacceptable for agricultural waste applications. The acceptable fields are then ranked according to their potential for pollutant loading. To evaluate the validity of the AWARDS field ranking system, it was compared to pollutant loading output from GLEAMS, a complex computer model. GLEAMS simulated the characteristics of each field ranked by AWARDS. Comparison of the AWARDS field ranking to the GLEAMS pollutant loading was favorable where ground water and both surface and ground water were to be protected and less favorable where surface water was to be protected. The rule base in AWARDS may need to be refined to provide more reasonable results where surface water is the resource of concern.

scholarly journals Estimation of recharge in mountain hard-rock aquifers based on discrete spring discharge monitoring during base-flow recession

2021 ◽  
Author(s):  
Stefano Segadelli ◽  
Maria Filippini ◽  
Anna Monti ◽  
Fulvio Celico ◽  
Alessandro Gargini
Keyword(s):  
Hard Rock ◽  
Monitoring Program ◽  
Base Flow ◽  
Low Flow ◽  
Reliable Estimate ◽  
Spring Discharge ◽  
Aquifer Recharge ◽  
Clear Cut ◽  
Groundwater Circulation ◽  
Hard Rock Aquifers

AbstractEstimation of aquifer recharge is key to effective groundwater management and protection. In mountain hard-rock aquifers, the average annual discharge of a spring generally reflects the vertical aquifer recharge over the spring catchment. However, the determination of average annual spring discharge requires expensive and challenging field monitoring. A power-law correlation was previously reported in the literature that would allow quantification of the average annual spring discharge starting from only a few discharge measurements in the low-flow season, in a dry summer climate. The correlation is based upon the Maillet model and was previously derived by a 10-year monitoring program of discharge from springs and streams in hard-rock aquifers composed of siliciclastic and calcareous turbidites that did not have well defined hydrogeologic boundaries. In this research, the same correlation was applied to two ophiolitic (peridotitic) hard-rock aquifers in the Northern Apennines (Northern Italy) with well-defined hydrogeologic boundaries and base-outflow springs. The correlation provided a reliable estimate of the average annual spring discharge thus confirming its effectiveness regardless of bedrock lithology. In the two aquifers studied, the measurable annual outputs (i.e. sum of average annual spring discharges) could be assumed equal to the annual inputs (i.e. vertical recharge) based on the clear-cut aquifer boundaries and a quick groundwater circulation inferable from spring water parameters. Thus, in such setting, the aforementioned correlation also provided an estimate of the annual aquifer recharge allowing the assessment of coefficients of infiltration (i.e. ratio between aquifer recharge and total precipitation) ranging between 10 and 20%.

Mining wastewater management and its effects on groundwater and ecosystems

2014 ◽  
Vol 70 (9) ◽  
pp. 1481-1487 ◽  
Author(s):  
A. Celebi ◽  
S. Özdemir
Keyword(s):  
Risk Assessment ◽  
Best Management Practices ◽  
Large Scale ◽  
Management Practices ◽  
Developed Countries ◽  
International Standards ◽  
Wastewater Management ◽  
Mining Areas ◽  
Mining Wastewater ◽  
The Developed Countries

Large-scale mining activities have a huge impact on the environment. Determination of the size of the effect and monitoring it is vital. In this study, risk assessment studies in mining areas and the effect of mining on groundwater and ecosystems were investigated. Best management practices and risk assessment steps were determined, especially in areas with huge amounts of mining wastewater. The pollution of groundwater and its reaching humans is a risk of major importance. Our study showed, using many cases with different parameters and countries, that the management of mining wastewater is vital. Environmental impact assessments and monitoring studies must be carried out before operation and at the closure of the mine. Policies must be in place and ready to apply. Factors of climate, geology, ecology and human health must be considered over a long period. Currently, only the developed countries are applying policies and paying attention to the risk. International assessments and health risk assessments should be carried out according to international standards.

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