Wastewater tertiary treatment filtration

Vourch et al49 studied the applicability of the RO process for the dairy industry wastewater. The treated wastewater total organic carbon (TOC) was <7 mg/L. It was found that in order to treat a flow of 100 m3/d, 540 m2 of the RO unit is required with 95% water recovery. Dead-end NF and RO were studied for the treatment of dairy wastewater.50 Permeate COD, monovalent ion rejection, and multivalent ion rejection for the dead-end NF were reported as 173-1095 mg/L, 50-84%, and 92.4-99.9%, respectively. When it comes to the dead-end RO membranes, the values for permeate COD, monovalent ion removal, and multivalent ion removal were 45-120 mg/L, >93.8%, and 99.6%, respectively. Membrane filtration technology can be better utilized as a tertiary treatment technology and the resultant effluent quality will be high. There can be situations where the treated effluents can be reused (especially if RO is used for the treatment). 

With respect to wastewater treatment, label each of the following as primary treatment (pr), secondary treatment (sec), or tertiary treatment (tert) ( ) screening, ( ) comminuting, () grit removal, () BOD removal, () activated carbon filtration removal of dissolved organic compounds, and () removal of dissolved inorganic materials. 

Filtration is employed when the suspended soUds concentration is less than 100 mg/L and high effluent clarity is required. Finely dispersed suspended soUds require the addition of a coagulant prior to filtration. Filters most commonly used in wastewater treatment are a dual media (anthrafUt and sand) or a moving bed or continuous-backwash sand filter. Performance data for the tertiary filtration of municipal and industrial wastewater are shown in Table 10. 

Granular bed filters are used in ten coil coating plants to remove residual solids from the clarifier effluent, and are considered to be tertiary or advanced wastewater treatment. Chemicals may be added upstream to enhance the solids removal. Pressure filtration is also used in this industry to reduce the solids concentration in clarifier effluent and to remove excess water from the clarifier sludge. Figure 7.4 shows a granular bed filter and Table 7.13 presents the heavy metal removal data of a lime clarification and filtration system. 

Other studies attest to more applications of these fibers, for example, filtration with palm fibers could be a potential technology for tertiary wastewater treatment as it provides a green engineering solution [30]. Rriker et al. examined four types of palm surface fibers and determined their mechanical and physical properties for application of this raw material in concrete structures [31]. 

Tertiary sewage treatment is essentially a chemical treatment that removes the fine particles, nitrates, and phosphates in wastewater. The basic procedure is adjusted for the specific substance to be removed. Activated charcoal filtration, for example, is used to remove most of the dissolved organic compounds. And alum (Al2(S04)3) is used to precipitate phosphate ions by dissolving and freeing the aluminum cation. 

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