Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the p...Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the pollution load into the Elands River in terms of nitrates and orthophosphates. These variables were compared against the Crocodile Catchment Interim Resource Quality Objectives to determine compliances or non-compliance of the Waterval Boven wastewater treatment plant. Generally upstream nitrate levels did not exceed the ideal limit of 0.5 mg·l-1 as indicated in the 2015 to 2016 samples where values ranged between 0.32 mg·l -1 and 0.27 mg·l-1, respectively. Similarly, observed upstream orthophosphates levels were below the ideal limit of 0.03 mg·l-1. However, downstream values of both nutrients exceeded the respective set limits. The nutrient load contribution from the sewage plant was characterised by a simple point-source model. Patterns of the loads into the river were demonstrated on a load duration curve based on the river which equalled or exceed 0.18 m3/s upstream and 1.31 m3/s downstream at 90% of the time. However, the flows were regarded as significantly low to deal with uncontrolled pollution loads. Most of the observed loads fell below the ideal limit of 0.05 mg·l-1 for nitrates both upstream and downstream of the sewage plant. For orthophosphates, most of the upstream loads were below the tolerable limit of 0.1 mg·l-1 whilst the downstream loads were exceeding the tolerable limits. The higher loads downstream in the river were attributed to the sewage discharge from the Waterval Boven wastewater treatment plant and the low river flows. Hence it could be concluded that river water quality should be interpreted based on the river flow regime in a given season.展开更多
The aim of this paper is to analyse the possible impacts of proposed biofuel production at Hoedspruit in the Olifants River Catchment. These impacts are looked at in terms of availability of water and subsequent conse...The aim of this paper is to analyse the possible impacts of proposed biofuel production at Hoedspruit in the Olifants River Catchment. These impacts are looked at in terms of availability of water and subsequent consequences on downstream users, especially the Kruger National Park that is mandated to conserve and protect biodiversity in all facets and fluxes in its area of jurisdiction. Based upon a review of experiences with biofuel production and impacts around the world, water availability for sugar cane production to support proposed biofuel production was found to be a problem in the region that has an average rainfall of only 450 mmper annum. The Olifants River system already has a deficit of about 200 million m3/a;hence the sustainability of the sugar cane based biofuel industry in the proposed area is questioned in this review. It is advised that alternative plants for the production of biofuel that may not consume large quantities of water be examined.展开更多
文摘Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the pollution load into the Elands River in terms of nitrates and orthophosphates. These variables were compared against the Crocodile Catchment Interim Resource Quality Objectives to determine compliances or non-compliance of the Waterval Boven wastewater treatment plant. Generally upstream nitrate levels did not exceed the ideal limit of 0.5 mg·l-1 as indicated in the 2015 to 2016 samples where values ranged between 0.32 mg·l -1 and 0.27 mg·l-1, respectively. Similarly, observed upstream orthophosphates levels were below the ideal limit of 0.03 mg·l-1. However, downstream values of both nutrients exceeded the respective set limits. The nutrient load contribution from the sewage plant was characterised by a simple point-source model. Patterns of the loads into the river were demonstrated on a load duration curve based on the river which equalled or exceed 0.18 m3/s upstream and 1.31 m3/s downstream at 90% of the time. However, the flows were regarded as significantly low to deal with uncontrolled pollution loads. Most of the observed loads fell below the ideal limit of 0.05 mg·l-1 for nitrates both upstream and downstream of the sewage plant. For orthophosphates, most of the upstream loads were below the tolerable limit of 0.1 mg·l-1 whilst the downstream loads were exceeding the tolerable limits. The higher loads downstream in the river were attributed to the sewage discharge from the Waterval Boven wastewater treatment plant and the low river flows. Hence it could be concluded that river water quality should be interpreted based on the river flow regime in a given season.
文摘The aim of this paper is to analyse the possible impacts of proposed biofuel production at Hoedspruit in the Olifants River Catchment. These impacts are looked at in terms of availability of water and subsequent consequences on downstream users, especially the Kruger National Park that is mandated to conserve and protect biodiversity in all facets and fluxes in its area of jurisdiction. Based upon a review of experiences with biofuel production and impacts around the world, water availability for sugar cane production to support proposed biofuel production was found to be a problem in the region that has an average rainfall of only 450 mmper annum. The Olifants River system already has a deficit of about 200 million m3/a;hence the sustainability of the sugar cane based biofuel industry in the proposed area is questioned in this review. It is advised that alternative plants for the production of biofuel that may not consume large quantities of water be examined.
