In addition, the collected samples were analyzed for physicochemical and microbiological parameters related to compliance with the Target Water Quality Guideline Range for aquatic ecosystems (DWAF, 1996); as well as in comparison with the general requirements for wastewater treatment (DWAF, 1984). The Target Water Quality Guideline Range for aquatic ecosystems was met in 50% of cases (DWAF, 1996).
Rationale for the Study
Water quality concerns have led to an increasing demand for water quality monitoring (Antonopoulos et al., 2001). To address the national challenges of water availability and utilization in South Africa, extensive water quality research has been carried out in many rivers in South Africa (DWAF, 2001; Harris et al., 1991; Van Wyk, 2001; Naidoo, 2005 Bezuidenhout et al. al., 2002).
Research Aim
In addition, this study serves as a tool in proposing remedial and mitigation measures to improve river water quality. Quantifying the impacts of pollution sources can provide essential information for designing and implementing appropriate pollution strategies (Van Wyk, 2001).
Research Objectives
This baseline study assesses the impacts of wastewater treatment plant discharges and other anthropogenic impacts on the water quality of three specific rivers in the eThekwini Municipal Area, namely: uMhlangane River; uMgeni River and uMhlatuzana River. 4 of land and water in the vicinity of rivers and their impact on water quality and.
Introduction
Wastewater
Preliminary Treatment
- Screening
- Grit Removal
- Flow Measurement
Preliminary treatment is defined as the removal of wastewater constituents that may cause maintenance or operational problems with the treatment operations, processes and ancillary systems (Tchobanoglous et al., 2004). The preliminary treatment phase ends after the heavier solids such as gravel and sand are allowed to settle into channels for removal to a landfill (WISA, 2002).
Primary Treatment
Flow measuring devices are usually installed downstream of the screens, and their primary function is to accurately measure the amount of wastewater entering the treatment plant. In most sewage treatment plants, the efficiency of primary and secondary clarifiers in removing and concentrating sludge controls the volatile solids loads in anaerobic digesters (Gerhardi, 2003).
Secondary Treatment
- Aeration and Activated Sludge Treatment
- Biological Filtration
- Secondary Settling
Part of the sludge is removed as waste sludge from the aeration basin and transferred to the digester, while the flow from the clarifier is disinfected before being discharged to the For secondary sedimentation of the biofilter effluent, the sewage flows into the humus tank from the biofilter underpass.
Tertiary Treatment
- Stabilization Ponds
- Disinfection
- a Chlorination
- b Ultraviolet Radiation
- c Ozonation
All sludge from the settling tanks of trickling filters is sent to sludge processing facilities or returned to the primary treatment plants for settling with primary solids (Tchobanoglous et al., 2004). There are many disinfection techniques in use (Table 2.3) (Ahuja, 2009). The most commonly used disinfectants include chlorination; UV radiation and ozonation.
Solids Treatment
Anaerobic digestion, enabled by the biological breakdown of organic compounds, destroys most of the volatile solids in the sludge (thereby reducing the volume of the sludge) and reduces putrefaction. The third and final stage of the process, methanogenesis, involves the production of methane and carbon dioxide. In addition, anaerobic digestion of sewage sludge can in many cases produce enough digester gas to meet most of the energy requirements for plant operation (Tchobanoglous et al., 2004).
Water Quality
Water Quality Parameters
- Physico-chemical Parameters
- a Chemical Oxygen Demand (COD)
- b Dissolved Oxygen (DO)
- c Electrical Conductivity (EC)
- d pH
- e Total Dissolved Solids (TDS)
- f Suspended Solids
- g Turbidity
- h Ammonia, Nitrites and Nitrates
- i Chloride
- j Permanganate Value (PV4)
- Microbiological Parameters
This is a measure of the amount of solid sediments that are carried in suspension by the water. It is an indication of the amount of suspended particles in water and influences the microbial water quality. The degree of chloride presence can also be an indication of deterioration of water quality.
Water Quality Legislation
- The Constitution of the Republic of South Africa (108 of 1996)
- The National Water Resources Strategy (NWRS)
- The National Water Act (NWA) (36 of 1998)
- The National Environmental Management Act (NEMA) (107 of 1998)
- The South African Target Water Quality Guidelines (TWQGR)
Indicator organisms are used to indicate the possible presence of pathogens (WRC, 2006); and provide evidence of human or warm-blooded animal faecal contamination (Ritter, 2010). 108 of 1996, which is the supreme law of the land; framework environmental legislation, such as the National Environmental Management Act no. Section 26(1) of the NWA provides that the use of water resources shall be monitored, measured and recorded; the prohibition of any activity for the protection of the water source and the obligation to treat waste before discharge into the water source.
Anthropogenic Impacts
Agricultural, Forestry and Mining Activities
The use of poor agricultural practices (such as non-contour ploughing), combined with unfair or excessive use of fertilizers such as urea, ammonium nitrate or ammonium phosphate can result in the leaching of these fertilizers into adjacent rivers during periods of heavy rainfall, which can cause elevated concentrations of nitrate , ammonium and phosphorus in receiving water. Forest cover removal reduces precipitation evapotranspiration and increases surface stormwater runoff, causing erosion and suspended sediment pollution of receiving waters (Lee et al., 2004). Receiving waters from acid coal mine drainage usually have a very low pH (down to 2) and a high total dissolved solids (Dallas and Day, 2004).
Industrial Activities
Excessive inflow of faecal material from anthropogenic sources and animal farms can pose major problems due to the potential adverse health effects when the water is used for drinking, recreational purposes and shellfish harvesting (Reeves et al., 2004). Mining alters the topography of the land, thereby causing high runoff rates; high turbidity and soil erosion. Various pollutants from power plants, waste disposal sites and agricultural land can potentially contaminate groundwater (Sargaonkar et al., 2008).
Urbanization
Rapid urbanization results in the proliferation of informal settlements as the demand for housing and services outstrips their supply. Often informal settlements are built close to rivers, for access to water supply and waste disposal. In many cases, sewage and excreta from these informal settlements are discharged into stormwater drainage pipes, which flow directly into nearby rivers (Paulse et al., 2007).
Conclusion
Informal settlements are characterized by a dense distribution of small temporary shelters built from diverse materials, degradation of the local ecosystem and by serious social problems (Mazur, 1995). Faecal pollution from non-point agricultural pollution can also cause deterioration of water quality by releasing significant levels of faecal bacteria and nutrients into waterways (Monaghan et al., 2007). Faecal pollution of catchments occurs from natural wildlife as well as from anthropogenic sources (Mudge and Duce, 2005).
Introduction
Description of the eThekwini Municipality (EM)
This section of the river has undergone significant modifications to accommodate human activities, including intensive and large-scale urbanization and modification of the river's course (WRC, 2002). The river flows through the valley, surrounded by extensive housing. Trunk sewers from Hillcrest to UWWTW are in the Environmental Impact Assessment stage (WSDP, 2012). The nature and extent of treatment is described by permit 651 B, which is issued by the Department of Water and allows a maximum E.coli discharge of 1000 cfu /100 ml. In terms of general wastewater treatment requirements, regulation 991 specifies a COD not to exceed 75 mg/l (DWAF, 1984).
In terms of the general requirements for the purification of waste water, regulation 991 specifies a PV 4 that does not exceed 10mg/l (DWAF, 1984). In terms of the general requirements for the purification of waste water, regulation 991 specifies Conductivity not exceeding 75mS/m (DWAF, 1984).
The uMhlangane River and KwaMashu Wastewater Trearment Works (KWWTW)
The uMgeni River and Northern Wastewater Treatment Works (NWWTW)
The uMhatuzana River and the uMhlatuzana Wastewater Treatment Works (UWWTW)
Conclusion
Introduction
Location of Sampling Sites for Data Collection
Methodology of Sample Collection
Methodology for Analyses of Data
62 difference between the mean values of two samples at the level of significance (in this study, the level of significance is less than or equal to 0.05) was performed on all samples to determine any significant change in water quality at the sampling sites.
Conclusion
Introduction
From Appendix A, the t-test results for TDS at all locations show that there is a significant difference between upstream and downstream water quality, as t.calc > t.crit (p ≤ 0.05). Appendix A shows that the t-test results for chlorides at all locations indicate a significant difference between upstream and downstream water quality, as t.calc > t.crit (p ≤ 0.05). The ammonia results for the t-test from Appendix A indicate at all locations that there is a significant difference between the upstream and downstream water quality since t.calc >.
This is a total of 7 cases of water quality improvement from upstream to downstream. Overview of the situation and challenges for water quality monitoring and reporting in South Africa.
Total Dissolved Solids (TDS)
The TWQGR for TDS in relation to aquatic ecosystems is < 15% deviation from the normal cycles of the water body. According to DWAF (1996), changes in long-term trends in TDS concentration are more important than individual values; therefore, the mean or seasonal mean values for the concentrations in the data set should be compared to the TWQGR. Comparing the average of each of the A cities with the corresponding B city, the TDS increased from A cities to B cities by and 128% for Zana;.
Chlorides
Ammonia
Zana A is most likely affected by the waste water from the Hillcrest WWTW and the overflows from pumping stations. Because these locations are all below the WWTP discharge point, the discharges from the WWTP are the most likely cause of these excesses, as already discussed. The most likely reason for this increase in ammonia from upstream to downstream is the discharge from the WWTP and has already been discussed above.
Dissolved Oxygen (DO)
The speed of the increase in the dissolution of oxygen can be accelerated if the turbulence in the water increases, which causes the penetration of air from the atmosphere, while the reduction in the concentration of dissolved oxygen can be caused by the resuspension of anoxic sediments, as a result of river floods or deepening activities. Regarding the general requirements for wastewater treatment, Regulation 991 specifies dissolved oxygen of at least 75 percent saturation (DWAF, 1984). However, in the case of Gane, the results indicate no significant difference between upstream and downstream water quality, as t.calc < t.crit (p ≤ 0.05).
Chemical Oxygen Demand (COD)
As noted above, DO saturation for all sites ranged from 31.9% to 56%, well below the required 75% saturation. The irregularly elevated peaks at locations A are most likely the result of rainfall and subsequent increased runoff. At sites B, elevated COD was likely due to high levels of organic matter in the discharge.
Permanganate Value (PV4)
Conductivity
Escherichia Coli (E.coli)
The source of this contamination for Umg A is the informal settlement with poor sanitation upstream near Reservoir Hills. Zana A is most likely affected by wastewater discharges into the river from the Hillcrest WWTW and pump station overflows. The cause of non-compliance on the B sites is the poor quality of the waste water discharged from the WWTP.
Turbidity
Most sites far exceeded the requirement of 1000 cfu/ml, indicating the presence of pathogens and poor sanitary quality of the water (WRC, 2006); (Liberti et al., 2000). Indicator organisms (E.coli) provide evidence of faecal contamination from humans and warm-blooded animals (Ritter, 2010). 73 Elevated turbidity levels accelerate microbial growth, as microbial growth in water is most extensive on the surface of particles and within loose, naturally occurring flocs.
Nitrites and Nitrates
Conclusion
74 B exceeded the general requirements, while other sites were compliant; the average DO at all sites was well below the general requirement; the average PV4 at Ghana B exceeded the overall requirement while the other site met the requirements; the average conductivity at Umg B exceeded the general requirements, while all other sites met the requirements; The t-test results showed that there is a significant difference between upstream and downstream water quality for the following parameters and sites: pH and PV4 at Umg;.
Conclusion
The discharge point of the WWTW is located in the downstream area and the reason for the decline in water quality can be attributed to the discharge of inadequately treated sewage into the river. For Umg A, informal settlement with poor sanitation facilities located upstream near Reservoir Hills is the most likely cause of water quality decline. 77 affected by effluent discharges to the river from Hillcrest WWTW; industrial discharges and pump station discharges and Gane A is most likely affected by faecal pollution from cattle grazing along the river and industrial discharges into the canal.
Recommendations
DWAF (Department of Water Affairs and Forestry). 1996c): South African Water Quality Guidelines-Industrial Use, Volume 3. Assessment of the impact of industrial runoff on the water quality of receiving rivers in urban areas of Malawi. The impact of port and associated industrial activities on the water quality of the Durban harbor and their effects on inhabited ecosystems.
