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The Range of Environmental and Social Concerns
Published in Karlheinz Spitz, John Trudinger, Mining and the Environment, 2019
Karlheinz Spitz, John Trudinger
Erosion is a common problem associated with land clearing and earthworks (excavation, transportation, and placement of soil and/or rock). This applies particularly in mining where large areas are cleared of vegetation, and huge volumes of soil and rock are removed and stored (environmental impacts of erosion are detailed in Chapter Twenty Five). Also, the most erodible material of all is topsoil, which, as discussed in Chapter Twenty Six, represents a valuable resource that usually warrants conserving. However, without application of stringent safeguards, topsoil from disturbed land will end up in nearby streams causing short-term or long-term degradation to aquatic habitats. Erosion of waste rock piles by runoff after heavy rainfall also transports soil and rock materials into nearby streams. Increased turbidity in natural waters will reduce the light available to aquatic plants for photosynthesis. Increased sediment loads can also smother benthic organisms in streams, eliminating important food sources for predators and decreasing available habitat for fish to migrate and spawn (Johnson 1997b). Some eroded materials are simply toxic due to their high metal content, or become so after contact with air, which causes oxidation of sulphide minerals.
Strategies for Mitigation and Remediation of Asphaltene Deposition
Published in Francisco M. Vargas, Mohammad Tavakkoli, Asphaltene Deposition, 2018
J. Kuang, A. T. Khaleel, J. Yarbrough, P. Pourreau, M. Tavakkoli, F. M. Vargas
Turbidity is defined as the cloudiness of a liquid resulting from the suspension of solid particles. Turbidity measurements are usually used to test water quality in water treatment plants (“Turbidity” n.d.). The measurements are performed using a turbidimeter that quantifies the clarity in Nephelometric Turbidity Units (NTU) (Abrahamsen 2012). The measurements are based on light scattering technique, where the suspended particles scatter light passing through the sample and thus reduce the intensity of transmitted light. Turbidimeters include a tungsten-filament lamp and a filter to create light with a known wavelength. The light passes through the sample cell, and the particles in the sample can absorb or scatter light. The scattered light is detected by a detector placed at 90 degrees from the incident beam, and unscattered light is detected by a transmitted light sensor. The absorption of light by the material is corrected for by the ratio of signals from the two detectors (Abrahamsen 2012). The turbidity test provides insight into the optical characteristics of the detected particles. High turbidity value indicates a significant number of suspended particles and thus higher cloudiness (Abrahamsen 2012).
Climate, Site, and Pond Design
Published in Hillary S. Egna, Claude E. Boyd, Dynamics of POND Aquaculture, 2017
Anita M. Kelly, Christopher C. Kohler
Turbidity in water can be corrected by adding chemicals that bind to the suspended particles, thereby clearing up the water (coagulation and flocculation). Chemicals and organic material that can be utilized to reduce turbidity are given in Table 4, with suggested application rates. However, chemicals react differently under different conditions; therefore, concentrations for individual ponds should be predetermined by treating a small sample (jar) of the water. The concentration of chemical to use should be the minimum amount of the chemical that would cause the suspended particles to precipitate out in 1 h. Some chemicals react in a way that is harmful to fish if they are added in large quantities. For example, alum (Al2(SO4)3 · 14 H2O) lowers the pH in soft water ponds (Boyd, 1990). Remember that chemical treatments only provide a temporary solution, and the source of the turbidity needs to be identified and eliminated.
Automated system for performing pH-based titrations
Published in Instrumentation Science & Technology, 2023
Naga P. D. Boppana, Robyn A. Snow, Paul S. Simone, Gary L. Emmert, Michael A. Brown
The alkalinity of water does not have any adverse health effects; however, it has implications on water treatment parameters and chemical dosing for turbidity and softening requirements. Turbidity is frequently removed from drinking water by coagulation and flocculation. This process releases hydrogen ions (H+) into the water, especially when inorganic coagulants, such as alum or ferric chloride are used.[14] Alkalinity concentrations must be more than the value neutralized by the hydrogen ion that is released for effective and complete coagulation to occur.[15] Hard waters are frequently softened by precipitation procedures. The alkalinity of the water must be known to calculate the lime (Ca(OH)2) and soda ash (Na2CO3) requirements for precipitation softening.[16]
Emerging disinfection by-products formation of various molecular weight organic matter fractions in raw water contaminated with treated wastewater
Published in Journal of Environmental Science and Health, Part A, 2023
Dararat Keaonaborn, Warangkana Na-Phatthalung, Suthiwan Keawchouy, Juthamas Jaichuedee, Suthatip Sinyoung, Charongpun Musikavong
The characteristics of the water quality parameters for the raw water and the raw water mixed with treated wastewater are summarized in Table 1. The characteristics of the raw water were obtained from Na-Phatthalung et al.[46] The samples of the raw water and mixed water were relatively neutral (pH 7.0 and 8.1). Turbidity is an indicator of regulating the water quality of the efficiency of certain removal processes which includes coagulation and filtration. The WHO recommends treatment plants should be practiced in a turbidity level of not more than 5 NTU in treated drinking water.[7]The DOC is a composite measure of organic content and is considered as the DBP precursors in the water. The aromatic content of DOM in the water was measured by UV-254 value.[47] The SUVA value is often used as the DOM aromaticity in humic substances and was positively correlated with the MW of the DOM.[48,49] The higher MW of humic substances have the SUVA values of between 3 and 5, whereas the medium MW substances such as fulvic acids have a SUVA value around 2.[50]
Exploring the feasibility of dual media filtration at Morton Jaffray Water Works (Harare, Zimbabwe)
Published in Journal of Applied Water Engineering and Research, 2023
Zvikomborero Hoko, Brian T. Musima, Clarence F. Mapenzauswa
The parameters measured included electrical conductivity (EC), pH, total dissolved solids (TDS), turbidity and temperature. According to Rusydi (2018), EC is is an indirect measure of TDS thus it was used to monitor and evaluate the performance of water treatment systems. pH was considered an essential parameter during the study as Zhang et al. (2018) highlighted that it affects the solubility of heavy metals in water. Therefore, pH affects the level of TDS and thus, impacts the filtration process. EPA (2017) also highlighted that pH has a direct effect on coagulation and flocculation, a process that is necessary to ensure proper sedimentation. In conventional water treatment processes, sedimentation tanks or clarifiers come before filters, thus their performance affects the loading of residual solids to the filters. Sawyer et al. (2003) also stated that the pH of filtered water affects the disinfection process especially when chlorine gas is used as is the case at MJWTW as Hoko and Makado (2011) highlighted. TDS and EC were considered as water quality parameters in this study as according to Iqbal et al. (2004), both have a strong positive correlation with turbidity which is a key drinking water quality parameter as stated by WHO (2011). High water turbidity is often associated with high levels of pathogens (EPA 2009). According to Sawyer et al. (2003), the filtration process of water becomes more difficult as the turbidity increases. Thus, the filters were monitored for turbidity removal.