Applicability and costs of nanofiltration in combination with photocatalysis for the treatment of dye house effluents

Abstract

SummaryNanofiltration (NF) is a capable method for the separation of dyes, which can support and even improve the applicability of photocatalysis in effluent-treatment processes. The membrane process usually will need a special pre-treatment to avoid precipitation and fouling on the membrane surface. Conceptually NF can be applied in the pre-treatment prior to the catalytic reactor or in connection with the reactor to separate the liquid phase from the reaction system and to recycle finely suspended catalysts and/or organic compounds. When concerning such reaction systems on a bigger scale, cost figures will prove the usefulness of those concepts. Different applications of photocatalysis on the lab-scale have been published in recent years. Membrane technology is used almost in all those processes and an overview will be given of those recently published systems that have been reported to be potentially useful for a further scale-up. NF membranes are mostly used for the more sophisticated separation step of these processes and the additional costs of the NF treatment, without any associated equipments, will be described and illustrated. The total specific costs of industrial NF treatment processes in usefully adjusted and designed plants range from 1 to 6 US$/m3 treated effluent. Combination concepts will have a good precondition for further development and upscaling, if the NF costs discussed here in detail will be, together with the costs of photocatalysis, economically acceptable.

Nanofiltration applied to the landfill leachate treatment and preliminary cost estimation

“…On the other hand, the maximum Cl − rejection was 14% in a study performed by Trebouet et al (2001). As also reported by some other studies (De Almeida et al, 2019;Samhaber and Nguyen, 2014), monovalent ions such as Na + and Cl − , which are present in significant amounts in landfill leachates, can permeate an NF membrane. Baker (2012) points out that chloride is a monovalent anion, and the rejection of this type of ion is not characteristic of the NF membrane.…”

“…The treatment cost of the pre-treated effluent by NF is equivalent to US$ 8.26 m −3 . According to an estimate made by Samhaber and Nguyen (2014), the total cost of the industrial NF treatment process ranges from US$ 1 m −3 to US$ 6 m −3 . However, few studies mention the use of NF to treat landfill leachate (Amaral et al, 2016;Chaudhari and Murthy, 2010;De Almeida et al, 2019) and none of these studies have examined in detail the landfill leachate management costs.…”

Coupling of Nanofiltration and Thermal Fenton Reaction for the Abatement of Carbamazepine in Wastewater

“…The installation costs of the membrane plant per unit membrane area reported in the literature are 400$ m –2 for sufficiently large plants (>500 m 2 of total membrane area), yielding a total installation cost of roughly $30 000 to treat the unit flow rate. 53 Operational costs of the membrane system include the following: (i) membrane replacement costs (replacement of the membrane every 3 years leads to an extra cost 54 of approximately 0.02$ m –3 ); (ii) energy-associated costs: for a pumping system with 70% efficiency and including energy recovery, and for a cost of energy of 0.19$ kW h –1 , the specific costs to drive the separation 55 are roughly 0.04$ m –3 ; (iii) costs for the disposal of the concentrate stream (flow of 0.3 m 3 h –1 , namely, 30% of the unit flow rate of wastewater), at 0.11$ per each m 3 volume of the feed wastewater stream (i.e., 30% of the 0.38$ m –3 cost for wastewater disposal), and (iv) chemical reagents for membrane cleaning (roughly 0.01$ m –3 ). 54 As such, the total operational cost of the system made up of NF followed by the Fenton reaction is estimated to be approximately 0.23$ m –3 .…”

Innovative photocatalytic luminous textiles optimized towards water treatment: Performance evaluation of photoreactors

“…Indeed, it has been already reported by previous researches that suspended TiO 2 particles used in photoreactors give high activity due to their high surface area [11,12]. However, the semiconductor cannot be easily separated from the treated solution, and hence a recycling process is needed, which is a costly and complicated method to be applied on large scale [13]. Therefore, the immobilization of the photocatalyst became a useful option to avoid this problem [14], but the majority of the designed photocatalytic reactors suffer from poor light penetration, since they involve external light [15].…”