Laundry Wastewater Treatment Research Articles

Anaerobic reactor applied to laundry wastewater treatment: Unveiling the microbial community by gene and genome-centric approaches

Gene and genome-centric approaches were applied to investigate the microbial taxonomic and metabolic diversity profiles from a lab-scale anaerobic reactor applied to laundry wastewater treatment with increasing concentrations of linear alkylbenzene sulfonate (LAS). Therefore, metagenomic analysis was carried out with reactor samples collected under three conditions, (i) Stage I, the reactor was fed with synthetic medium, (ii) Stage II, synthetic medium was replaced by diluted laundry wastewater with specific LAS loading rates (SLLRs) of 1.0 ± 0.3 mgLASgTVS−1d−1 and (iii) Stage III, SLLRs increased to 2.7 ± 0.7 mgLASgTVS−1d−1. Shotgun metagenomic sequencing was performed on an Illumina HiSeq 2 × 150 bp platform. Gene-centric analysis of each step of the metabolic pathway (fumarate addition, β-oxidation, ring cleavage and desulfonation) for anaerobic aromatic degradation showed eight over-representative genera (Achromobacter, Pelodictyon, Pseudomonas, Psychrobacter, Rhodococcus, Stenotrophomonas, Sulfurovum and Syntrophobacter), suggesting a microbial core with an important role in LAS biodegradation. Some of these genera were also recovered through a differential binning method, representing fifteen bacterial and one archaeal metagenome-assembled genomes (MAGs). Biodegradation pathway reconstruction of LAS using six MAGs unveiled the syntrophism for complete degradation of the LAS molecule. Only the MAGs with taxonomic annotation for Syntrophobacter showed genetic potential for fumarate addition, whereas in the ring cleavage, there was a predominance of genes in MAGs with taxonomic annotation for Pseudomonas fragi and Rhodococcus. This work represents the first report of genome-centric approach to study biological reactors applied in anionic surfactant degradation, contributing with detailed metabolic information of the key microbial actors in LAS degradation and opening perspectives for future biotechnological strategies aiming at bioaugmentation and/or biostimulation of indigenous microbial populations.

Treatment of laundry wastewater containing residual surfactants using combined approaches based on ozone, catalyst and cavitation

The present work investigates the treatment of wastewater by degrading detergents and residual surfactants using individual and combined approaches based on ozone, catalyst and cavitation. The intensification of ozonation has been investigated by the addition of solid ZnO and CuO catalysts. The extent of degradation increased with catalytic ozonation as compared to non-catalytic ozonation. In comparison, the combination with cavitation did not yield any beneficial results. The study of the effect of initial pH of the solution and effect of different catalyst loadings in catalytic ozonation with ZnO established that the maximum degradation as 89.3% was obtained at initial pH of 9 and 0.1 g L−1 of catalyst loading. It was also demonstrated that the reaction followed first order kinetics with rate constant as 0.067 min−1. BOD analysis at optimized conditions demonstrated that catalytic ozonation efficiently converts non-biodegradable harmful surfactants in wastewater to easily digestible compounds, which means that this can be a complimentary process to biological oxidation. Overall the work has clearly demonstrated the efficacy of catalytic ozonation approach for treating the laundry wastewater.

Novel membranes for industrial laundry wastewater treatment

Novel membranes for industrial laundry wastewater treatment

Laundry wastewater treatment using a combination of sand filter, bio-char and teff straw media

Numerous researchers have expressed concern over the emerging water scarcity issues around the globe. Economic water scarcity is severe in the developing countries; thus, the use of inexpensive wastewater treatment strategies can help minimize this issue. An abundant amount of laundry wastewater (LWW) is generated daily and various wastewater treatment researches have been performed to achieve suitable techniques. This study addressed this issue by considering the economic perspective of the treatment technique through the selection of easily available materials. The proposed technique is a combination of locally available absorbent materials such as sand, biochar, and teff straw in a media. Biochar was prepared from eucalyptus wood, teff straw was derived from teff stem, and sand was obtained from indigenous crushed stones. In this study, the range of laundry wastewater flow rate was calculated as 6.23–17.58 m3/day; also studied were the efficiency of the media in terms of the removal percentage of contamination and the flux rate. The performances of biochar and teff straw were assessed based on the operation parameters and the percentage removal efficiency at different flux rates; the assessment showed 0.4 L/min flux rate to exhibit the maximum removal efficiency. Chemical oxygen demand, biological oxygen demand, and total alkalinity removal rate varied from 79% to ≥83%; total solids and total suspended solids showed 92% to ≥99% removal efficiency, while dissolved oxygen, total dissolved solids, pH, and electrical conductivity showed 22% to ≥62% removal efficiency. The optimum range of pH was evaluated between 5.8–7.1. The statistical analysis for finding the correlated matrix of laundry wastewater parameters showed the following correlations: COD (r = −0.84), TS (r = −0.83), and BOD (r = −0.81), while DO exhibited highest negative correlation. This study demonstrated the prospective of LWW treatment using inexpensive materials. The proposed treatment process involved low-cost materials and exhibited efficiency in the removal of contaminants; its operation is simple and can be reproduced in different scenarios.

Advanced Treatment of Pre-treated Commercial Laundry Wastewater by Adsorption Process: Experimental Design and Cost Evaluation

Advanced Treatment of Pre-treated Commercial Laundry Wastewater by Adsorption Process: Experimental Design and Cost Evaluation

Sequential process of coagulation/flocculation/sedimentation- adsorption - microfiltration for laundry effluent treatment

Laundries use in their washing process various chemical inputs, which give to their effluents alkalinity, organic load, color, suspended solids and surfactants, and these effluents cause damage to aquatic ecosystems if discarded without treatment. Hence, the effluent from this type of activity requires adequate treatment. Therefore, the aim of this work was to treat the effluent from an industrial laundry by a sequential process of coagulation/flocculation/sedimentation-adsorption-microfiltration (C/F/S-ADS-MF) and evaluate the final treated water quality. In the C/F/S stage, the statistical analysis (ANOVA, p-value<0.05; Fisher’s test, p-value > 0.05) indicated that 140 mg L−1 was the best natural coagulant concentration. To surfactants adsorption by activated carbon, the contact time required to establish the system equilibrium was 10 h, and the kinetic model of pseudo-second-order best represented the experimental data. The MF presented a permeate flux of 60.51 L h−1 m−2. The water quality parameters were improved with sequential process application, resulting in global removal efficiency of 99.9% for color, 80% for chemical oxygen demand, 92.9% for surfactants and 99.4% for turbidity. Therefore, the proposed sequential process showed to be a promising technique for industrial laundry wastewater treatment.

Fouling mechanism identification and analysis in microfiltration of laundry wastewater

Microfiltration (MF) is known as a promising and green technique that can effectively treat domestic and industrial wastewaters. Inevitably, membrane fouling and scaling hinder productivity and large-scale implementation of this process. The aim of the present study is to evaluate the membrane fouling and flux decline behavior during laundry wastewater treatment. The filtration tests were performed using real domestic laundry wastewater at different transmembrane pressures (0.5–1.5 bar) and feed flowrates (30–80 L/h). Several fouling models including the single and multistage Hermia models were fitted to experimental data. The results of the single-stage Hermia model showed that the cake layer formation (with R2 greater than 0.94) was the main contributor to the flux decline regardless of the operating condition. Results also revealed that by increasing the feed pressure, the contribution of the cake formation mechanism enhanced while an opposite behavior was observed when the feed flow rate increased. However, the single stage model could not accurately predict the performance during the entire filtration time. A more detailed analysis indicated that at least a three-stage model (complete pore blocking in early stage, intermediate pore blocking in middle stage, and cake formation in final stage) could model the flux decline during the entire filtration time with acceptable accuracy (with R2 greater than 0.96). Therefore, the multistage Hermia model was used for determining either fouling mechanism, ways for postponing fouling of the membranes, and flux decline behavior during the membrane filtration of laundry wastewater experiments.

Combined Application of Coagulation/Flocculation/Sedimentation and Membrane Separation for the Treatment of Laundry Wastewater

The wastewater from industrial laundries has a high quantity of contaminants from the washing process, as well as chemical additives. Aiming at the treatment of this type of wastewater, the present study evaluated the performance of a combined coagulation/flocculation/sedimentation process (C/F/S) and membrane separation to treat laundry wastewater in relation to physicochemical parameters of water quality. For this purpose, a Doehlert experimental design was applied to the C/F/S step using the natural coagulant Tanfloc POP® with maximum color and turbidity removal efficiency obtained of 80.27% and 86.50%, respectively, under conditions of pH of 6.4 and a coagulant concentration of 110 mg·L−1. The supernatant from the C/F/S step was used in the sequential microfiltration (MF) and ultrafiltration (UF) experiments. The maximum values of color, total nitrogen, dissolved solids, and turbidity removal were similar to MF and UF membranes at transmembrane pressure of 1.4 bar, with the greatest flow of permeates (92.2 L·h−1·m−2) presented by the MF membrane at 1.4 bar. The total efficiency of the combined C/F/S-MF process indicated the quality of the treated wastewater since it reduced 98.4% of the color, 99.1% of turbidity, 71.7% of the surfactants, and more than 55% of the total dissolved solids (TDS), chemical oxygen demand (COD), and total organic carbon (TOC) from the industrial laundry wastewater. This study showed that the C/F/S-MF combined process could be an efficient treatment of laundry wastewater.

Development of combined membrane filtration, electrochemical technologies, and adsorption processes for treatment and reuse of laundry wastewater and removal of nonylphenol ethoxylates as surfactants

In this paper, we investigated the treatment and reusability of laundry wastewater (LW) by novel sequential integrated system including ultrafiltration (UF) of raw wastewater at first step and treatment of filtrate (permeate effluent) by the use of either adsorption processes (AD) (granular activated carbon GAC or polymeric resin PR) or nano-filtration (NF) system, or electro-oxidation (EO) to remove mainly total suspended solids (TSS), turbidity, chemical oxygen demand (COD), and surfactants such as nonylphenol ethoxylates (NPEO3-17) in order to meet the environmental rejection and reusability standards. Concentrate (retentate effluent) of UF and NF were also treated using electrocoagulation (EC) and electro-oxidation (EO) methods, respectively. Optimum conditions in order to obtain best results were determined in each case. The UF separated the raw wastewater into a filtrate with a low organic pollutant content (300–400 mg/L of dissolved COD) and a concentrate with a total COD of 700–1200 mg/L and 140–200 mg TSS/L. Following application of UF, NPEO3-17 were found not only in the concentrate but also in the filtrate and subsequently were treated using mentioned techniques which was effectively removed by NF and AD.

Removal of Anionic Surfactant from Residential Laundry Wastewater using Jackfruit (Artocarpus heterophyllus) seeds

The study presented in this article investigated the removal of a long chain anionic surfactant from residential laundry wastewater using jackfruit (Artocarpus heterophyllus) seeds. The main ingredients of laundry wastewater are the surfactants. Therefore, great attention should be given to the treatment and disposal of laundry wastewater. The use of natural substitutes in treating wastewater has no harmful effects, and it is considered an effective step towards protecting the environment and promoting sustainability. Jar test experiments were conducted in order to determine the optimum conditions for the removal of surfactants, chemical oxygen demand (COD), biological oxygen demand (BOD), turbidity in terms of effective dosage, and pH control. The surfactant, COD, BOD, and turbidity removal efficiencies were 91.66%, 82.86%, 77.66%, and 85.14% at the optimum initial pH value of 6, the optimum dose of 2.5 g/L, and optimum mixing time of 25 minutes, respectively. It can be concluded that Artocarpus heterophyllus seed powder was a feasible and cost-effective natural coagulant for the removal of anionic surfactant from laundry wastewater. The results showed that the pseudo-second-order equation is the suitable model for this system.

Adsorption Combined Phytoremediation System for Treatment of Laundry Wastewater

Laundry activities grow rapidly in Indonesia in the recent year, remaining the problem of environmental pollution because of the use of detergent. The purpose of the current study was to investigate the ability of sludge of drinking water treatment plant (DWTP) as adsorbent combined with phytoremediation system to remove chemical oxygen demand (COD), phosphate and surfactant in laundry wastewater. Batch and continuous blow studies were conducted on different variables such as adsorbent mass, contact time, and type of plant for phytoremediation system. The results of the current study show that adsorption combined phytoremediation system could remove COD, phosphate, and surfactant up to 77.5%, 54.3%, and 99.9%, respectively. Based on the results, it means that the adsorption combined phytoremediation system could be considered as an appropriate environmental technology for laundry wastewater treatment in the near future.

The Effect of Light-Emitting Diodes Illumination Period and Light Intensity on High Rate Algal Reactor System in Laundry Wastewater Treatment

The Effect of Light-Emitting Diodes Illumination Period and Light Intensity on High Rate Algal Reactor System in Laundry Wastewater Treatment

Preliminary Studies on Integrated Process of Microfiltration and Photocatalysis Used in Laundry Wastewater Treatment

Preliminary Studies on Integrated Process of Microfiltration and Photocatalysis Used in Laundry Wastewater Treatment

Effect of surfactants on the treatment of radioactive laundry wastewater by direct contact membrane distillation

AbstractBACKGROUNDDirect contact membrane distillation (DCMD) was applied to treat the radioactive laundry wastewater produced from nuclear power plants (NPPs), with surfactants.RESULTSThe experimental results show that when 0.08 mmol L‐1 surfactants was added into feed solution, the permeate flux reduced sharply by 3–30% in 1 h, and the largest reduction was found in the case with non‐ionic surfactant. The decontamination factors (DF) of Sr(II), Co(II), and Cs(I) were correspondingly decreased 10–100 times within 4–8 h. Compared with the no salt‐added case, the addition of high concentration salt (100–300 g L‐1) slowed down the reduction rate of the permeate flux caused by sodium dodecyl benzene sulfonate (SDBS). The wetting of membranes by surfactants mainly results from the spontaneous adsorption of surfactant molecules onto the membrane surface and the reduction of solution surface tension. However, the high concentration of NaNO3 in SDBS solution decreases the critical micelle concentration (CMC) of SDBS to less than 0.06 mmol L‐1, and thus SDBS micelles formed, which were hard for the membrane surface to absorb.CONCLUSIONThe study shows that surfactants could cause serious reduction in permeate flux and rejection of nuclides, and thus they should be removed from the feed solution of DCMD process. © 2018 Society of Chemical Industry

The application of moving bed bio-reactor (MBBR) in commercial laundry wastewater treatment

Large, laboratory scale biological treatment tests of real industrial wastewater, generated in a large industrial laundry facility, was conducted from October 2014 to January 2015. This research sought to develop laundry wastewater treatment technology which included tests of a two-stage Moving Bed Bio Reactor (MBBR); this had two reactors, was filled with carriers Kaldnes K5 (specific area – 800 m2/m3) and were realized in aerobic condition. Operating on site, in the laundry, reactors were fed actual wastewater from the laundry retention tank. The laundry wastewater contained mainly surfactants and impurities originating from washed fabrics; a solution of urea to supplement nitrogen content and a solution of acid to correct pH were added. The daily flow of raw wastewater Qd varied from 0.6–1.0 m3/d. Wastewater quality indicators showed that the reduction of pollutants was obtained: BOD5 by 95–98%, COD by 89–94%, the sum of anionic and nonionic surfactants by 85–96%. The quality of the purified wastewater after the start-up period met legal requirements regarding the standards for wastewater discharged into the environment.

E-peroxone process for the treatment of laundry wastewater: A case study

The treatment of laundry wastewater by ozonation, electro-oxidation (EOX), electro-oxidation with oxygen sparging (EOX with O2 sparging) and the combined electro-peroxone (E-peroxone) process was investigated. E-peroxone process is based on the production of H2O2 electrochemically from O2 in sparged ozone generator effluent (O2 and O3 gas mixture) using carbon-polytetrafluorethylene (carbon-PTFE) cathodes. The electro-generated H2O2 then reacts with sparged O3 to produce OH. The concentration of H2O2 and OH was determined as ∼10gL1− and 0.1567μM in the E-peroxone process, respectively. While no OH was produced in EOX, the measured OH concentration was 0.1872μM in the ozonation process, which is greater than E-peroxone. All advanced processes adopted in this study effectively removed turbidity. Although, E-peroxone was not highly effective in eliminating chemical oxygen demand (COD) from laundry wastewater, it removed almost 77% methylene blue active substance (MBAS), whereas EOX and ozonation processes removed 86% MBAS. Besides, anion concentration increased dramatically during E-peroxone treatment. This suggests that E-peroxone is insufficient to remove inorganics. Regarding the toxicity analysis, the lowest toxicity was observed in E-peroxone process as the inhibition rate was reduced to 22.45% from 80.64%. Moreover, specific energy consumption (SEC) values were calculated as 0.003, 0.079 and 0.067kWhkg−1 for EOX, ozonation and E-peroxone, respectively. Hence, E-peroxone was found to be more cost-effective than ozonation in this case. However, EOX was found to be the most cost-effective process for laundry wastewater treatment.

Metagenomic analysis of the microbiome in three different bioreactor configurations applied to commercial laundry wastewater treatment

The taxonomic and functional diversity of three different biological reactors (fluidized bed reactor, FBR; up-flow anaerobic sludge blanket reactor, UASB; and expanded granular sludge bed reactor, EGSB) used for commercial laundry wastewater treatment was investigated using metagenome shotgun sequencing. Metagenomes were sequenced on the Illumina Hiseq platform and were analyzed using MG-RAST, STAMP and PAST software. The EGSB and UASB reactors were more closely related based on taxonomic and functional profiles, likely due to similar granular sludge and procedures adopted to ensure anaerobic conditions. The EGSB and UASB reactors showed a predominance of methanogens and genes related to methanogenesis, with a prevalence of the acetoclastic pathway, in addition to the peripheral and central O2-independent pathways for aromatic compound degradation. By contrast, FBR showed a dominance of aerobic microbiota and pathways for O2-dependent aromatic compound degradation. Therefore, although the reactors showed similar surfactant removal levels, the microbial composition, functional diversity and aromatic compound degradation pathways were significantly distinct.

The use of moving bed bio-reactor to laundry wastewater treatment

Large laboratory scale biological treatment test of industrial real wastewater, generated in industrial big laundry, has been conducted in the period of May 2016–August 2016. The research aimed at selection of laundry wastewater treatment technology included tests of two-stage Moving Bed Bio Reactor (MBBR), with two reactors filled with carriers Kaldnes K5 (specific area – 800 m2 /m3 ), have been realized in aerobic condition. Operating on site, in the laundry, reactors have been fed real wastewater from laundry retention tank. To the laundry wastewater, contained mainly surfactants and impurities originating from washed fabrics, a solution of urea to supplement nitrogen content and a solution of acid to correct pH have been added. Daily flow of raw wastewater Qd was equal to 0.6–0.8 m3 /d. The values of determined wastewater quality indicators showed that substantial decrease of pollutants content have been reached: BOD5 by 94.7–98.1%, COD by 86.9–93.5%, the sum of anionic and nonionic surfactants by 98.7–99.8%. The quality of the purified wastewater, after star-up period, meets the legal requirements regarding the standards for wastewater discharged to the environment.

Possibilities of application of advanced oxidation–membrane separation system for treatment and reuse of laundry wastewater

Possibilities of application of advanced oxidation–membrane separation system for treatment and reuse of laundry wastewater

Application of MBR technology for laundry wastewater treatment

Application of MBR technology for laundry wastewater treatment