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Conventional systems for urban sanitation and wastewater management in middle- and high-income countries
Published in Thomas Bolognesi, Francisco Silva Pinto, Megan Farrelly, Routledge Handbook of Urban Water Governance, 2023
Management of eutrophication impacts is more complex since it involves the management of suspended solids, organic matter, and nutrients. The environmental impacts of wastewater are closely linked to the chemical composition, specifically the concentrations of nitrogen (N), phosphorus (P), and dissolved organic matter, i.e., biochemical oxygen demand (BOD). Nitrogen and phosphorus are key nutrients for plants and are therefore the main causes of eutrophication. BOD is a measure of the amount of dissolved oxygen that will be consumed during microbial decomposition of the organic matter in the wastewater; it is also measured as chemical oxygen demand (COD). Discharging wastewater with high levels of N, P, and BOD/COD into surface waters can result in eutrophication and a corresponding increase in algae and plant growth. The subsequent high organic decomposition rates in eutrophic waters lead to oxygen depletion that endangers fish and other aquatic animals, ultimately resulting in fish kills and water quality degradation. This degradation of water quality and loss of aquatic life can have significant consequences for the natural environment, the biodiversity, and the communities that depend on it for their economic livelihoods.
Aerobic Effluent Treatment Processes, Biohythane Processes and Biofertilizers
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
Chemical oxygen demand (COD) is a measure of water and wastewater quality. The COD is the amount of oxygen consumed to chemically oxidize organic materials present in the water. The COD test is often used to monitor the efficiency of wastewater treatment plants. The basis for the COD test is that nearly all organic compounds can be fully oxidized to carbon dioxide and water in the presence of a strong oxidizing agent under acidic conditions. The stoichiometry of this oxidation process is shown in Eq. 20.1 (AOAC, 1980).CnHaObNc+(n + a4−b2−34c)O2→nCO2+(a2−32c)H2O+NH3 (20.1)
Treatment of Palm Oil Mill Effluents
Published in Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang, Treatment of Industrial Effluents, 2019
Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang
On the other hand, POME is a colloidal suspension, produced from the mixture of sterilizer condensate, separator sludge, and hydrocyclone waster in a ratio of 9:15:1, respectively. POME can cause contamination due to the existence of easily degradable organic matter, thereby referring to the content of high chemical oxygen demand (COD) and biological oxygen demand (BOD) that have a value of 50,000 and 25,000 ppm, respectively. Chin et al. (1996) also reported that POME contains 6,000 mg/L of oil and grease, 59,530 mg/L of SS, and 750 mg/L of nitrogen. Therefore, POME can cause water pollution. The general idea on how POME can cause water pollution is that the POME discharge contained microorganisms that will compete mainly on the uptake of oxygen with the aquatic life. This incident will eventually cause the aquatic life to have less oxygen than previously, thus slowly hindering the growth of aquatic life and in the long term preventing their existence. Table 4.1 provides the general characteristics of POME. High COD and BOD content might cause the oxygen content in the water to be reduced, and this would eventually lead to the death of aquatic life.
Performance of acid mine drainage sludge as an innovative catalytic oxidation source for treating vehicle-washing wastewater
Published in Journal of Dispersion Science and Technology, 2021
The relationship between TOD and COD removals from wastewater is attained, and a linear correlation with a high accuracy is achieved. The results in Figure 7 display this relationship concerning TOC and COD after the wastewater has been chemically oxidized via Fenton treatment. The linear correlation between TOC and COD in the water is good, and the fitting equation is with an efficient correlation coefficient of 0.95. COD is considered a comprehensive indicator of the degree of contamination of water by organic matter referring to the fraction of oxygen that could be oxidized in water and consumed through the chemical oxidation. However, TOC reflects the absolute amount of the total organic matter containing all carbon in water.[60] Thus, this linear fitting confirms that the measurement of TOC could be used for a reliable achievement of the wastewater COD to evaluate the process performance that could be driven in a rapid and accurate monitoring way. This result agrees with the previous investigation of Dubber and Gray.[60] However, the finding is in contrast to that reported by Aziz and Tebbutt[61] in the datasets analyzed. This could be due to the variability in treatment efficiencies between the systems analyzed and the wastewater ingredients.
Trace elements speciation and sources characterization in the main watercourses, middle-upper Egypt
Published in Human and Ecological Risk Assessment: An International Journal, 2021
Moustafa Gamal Snousy, Peiyue Li, Esam Ismail
A strong positive loading of both BOD and COD indicates that biological degradation and chemical oxidation has a significant role in water chemistry. Moreover, DO points out strongly negative loading. As mentioned by Al-Badaii et al. (2013), DO shows a negative loading because of contaminations. Sial et al. (2006) stated that the COD loading of freshwater resulted from organic and inorganic contaminants introduced into surface water causes oxygen levels depletion. Mainly, these parameters are related to agriculture activities. Furthermore, pollution may be caused by surface runoff accompanied by the cultivation of the adjacent areas where fertilizers are applied and domestic wastewater without the seasonal effect of temperature. Generally, the first factor describes ionic and trace elements composition of surface water resulting from natural processes such as minerals dissolution and ion exchange during host sediment weathering and reveals the role of anthropogenic contaminations.
Efficiency of pollutants removal in treated palm oil mill effluent (TPOME) using different concentrations of sodium alginate-immobilized Nannochloropsis sp. cells
Published in International Journal of Phytoremediation, 2021
Quin Emparan, Razif Harun, Yew Sing Jye
Current conventional technologies such as ponding systems, or/and coupled with open digester tanks and/or extended aeration require long hydraulic retention time (HRT), up to 66 days to treat POME (Ding et al. 2016). These systems do not completely remove the organic matter and nutrients from the treated palm oil mill effluent (TPOME), hence, creating environmental pollution and health risks. The Department of Environment (DOE) of Malaysia has set the latest discharge limit of BOD and COD is 20 and 1000 mg/L, regardless of which treatment systems are used (Tabassum et al.2015). COD is the measure of oxygen equivalent of an organic matter of a sample that is susceptible to be oxidized by a strong chemical oxidant (Emparan, Harun, Jye 2019). Therefore, the POME treatment with high efficiency, cheap, and environmentally friendly technologies are required in order to comply with the local regulation.