Laundry Effluent Research Articles

Approaches for Sampling and Sample Preparation for Microplastic Analysis in Laundry Effluents

The continuous growth in the production, unsustainable use, and disposal of plastics in recent decades has led to the emergence of a new type of pollutant, microplastics (MPs). In this article, the focus is on the form of MPs, which are produced by the fragmentation of textile fibres during washing processes. The problems associated with the characterisation and quantification of MPs in this type of sample are related to the wide range of concentrations, forms, and degree of degradation as well as physico-chemical and biological properties. Although the basic principles for the analysis of microplastics present in the environmental samples are known, there is the lack of standardised methods for the analysis of MPs in laundry effluents and domestic washing. Therefore, the continuous development of sophisticated analytical techniques and methodologies is required for the reliable collection and isolation, quantification, and characterisation of one of the most challenging analytes. The aim of this review is to outline the key steps of MPs analysis in laundry effluents and domestic washing, focusing on those steps that are underestimated in the current literature: sampling and sample preparation for analysis. Precisely these analytical steps, which can become the main source of analytical measurement system errors, ensure the quality of the analysis. This paper emphasises the importance of monitoring background contamination and presents guidelines to ensure quality control specifically for this type of analyte.

Chemical oxygen demand and biochemical oxygen demand analysis of discharge waters from laundry industry: monitoring, temporal variability, and biodegradability

In Europe, chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) are used as organic indicators for the analytical characterization of laundry water. However, the values of these indicators are derived from one-off analytical measurements at a defined frequency. In addition, there are few data on the temporal variability of COD and BOD5 parameters and on water biodegradability beyond 5 days. In this work, samples of physicochemical treated wastewater were collected for 1 year and their content in COD and BOD5 measured, with BOD monitored over 35 days. The results showed that, for the 24 samples studied, the average and standard deviation values were 835 ± 176 mg/L for COD and 445 ± 114 mg/L for BOD5, indicating a biodegradability index of 2.0 ± 0.4. The interpretation of the data also indicated that the concentrations were close to emission limit value, particularly for BOD5. BOD21 values were particularly high compared to the initial COD, indicating the biodegradability of water. Laundry effluents were also rich in substances very quickly biodegradable, which has been demonstrated by the values of the ratio between BOD7 and BOD5. However, a significant proportion of surfactants is not degraded, as shown by measurements of total organic carbon and anionic surfactant analysis. The results of this study could help the industrial partner involved in our project to guide its choice of the complementary method to better treat wastewater and to reduce its organic load.

USO DE COAGULANTES NO TRATAMENTO DE EFLUENTE DE LAVANDERIA HOSPITALAR: A BUSCA POR PROCESSOS FÍSICO-QUÍMICOS SUSTENTÁVEIS VISANDO REMOÇÃO DE POLUENTES E MICRORGANISMOS PATOGÊNICOS

USE OF COAGULANTS IN THE TREATMENT OF HOSPITAL LAUNDRY EFFLUENT: THE SEARCH FOR SUSTAINABLE PHYSICAL-CHEMICAL PROCESSES TO REMOVAL POLLUTANTS AND PATHOGENIC MICROORGANISMS. Hospital laundry is an important source of environmental pollution because its effluent contains high loads of organic matter and microorganisms. Conventionally, the treatment is carried out using aluminum sulfate, a low-cost and highly efficient coagulant that is related to secondary contamination due to the generation of non-biodegradable sludge, its ability to accumulate metals and toxicity. Aiming for sustainable alternatives, the efficiency of tannin from the natural coagulant and Moringa oleifera seed was evaluated in relation to aluminum sulfate, seeking to adapt the color and turbidity parameters and determine the antimicrobial activity of the seed. Using a concentration of 100 mg L-1 of aluminum sulfate, 97.4 and 93.95% of color and turbidity removals in the effluent were obtained, respectively. With 50 mg L-1 tannin showed an efficiency of 84.96% for color removal and 89.75% for turbidity. Tests were also carried out with Moringa oleifera seeds using saline seed extract, crushed seeds and aqueous seed extract, with a reduction in conductivity by more than 99%, removing pollutant ions for the saline extract. Of the methodologies used, the best result was obtained with the aqueous extract, achieving removals of 89.63% of color, 78.33% of turbidity, and inhibition of more than 98.1% of microorganism growth.

Removal of microfiber and surfactants from household laundry washing effluents by powdered activated carbon: kinetics and isotherm studies.

Domestic laundry wastewater discharge contributes significantly to the presence of microfiber and surfactant pollutants in aquatic ecosystems, which have detrimental and toxic effects on humans and the environment. Investigating the efficacy of powdered activated carbon (PAC) in removing micro-/nanofibers with or without surfactant from household laundry effluent is the purpose of the current research. To simulate real-world scenarios, PAC adsorption kinetics and isotherms in laundry effluents under controlled conditions were studied. These studies showed that the kinetics obeyed a pseudo-second-order process and the isotherms varied between Langmuir and Freundlich models depending on the water types. In the results of experiments using distilled water and tap water, it was observed that the adsorption capacity was higher in tap water. When the adsorption of 0.1 μm filtered synthetic garments, detergent, and tap water was compared with the adsorption of the raw sample, it was observed that the adsorption capacity of the 0.1 μm filtered version was higher. Even though this study is preliminary, the results indicate that PAC has the capacity to serve as a viable approach for mitigating micro-/nanoplastic and surfactant contamination from laundry wastewater, thereby offering valuable guidance for advancing eco-friendly laundry techniques.

Efficiency of Coagulation/Flocculation for the Removal of Complex Mixture of Textile Fibers from Water

Synthetic fibers enter wastewater treatment plants together with natural fibers, which may affect treatment efficiency, a fact not considered in previous studies. Therefore, the aim of the present study was to evaluate the efficiency of the coagulation/flocculation process for the removal of a mixture of textile fibers from different water matrices. Natural and synthetic fibers (100 mg/L; cotton, polyacrylonitrile, and polyamide) were added to a synthetic matrix, surface water and laundry wastewater and subjected to coagulation/flocculation experiments with ferric chloride (FeCl3) and polyaluminum chloride (PACl) under laboratory conditions. In the synthetic matrix, both coagulants were found to be effective, with FeCl3 having a lesser advantage, removing textile fibers almost completely from the water (up to 99% at a concentration of 3.94 mM). In surface water, all dosages had approximately similar high values, with the coagulant resulting in complete removal. In laundry effluent, the presence of surfactants is thought to affect coagulation efficiency. PACl was found to be effective in removing textile fibers from laundry wastewater, with the lowest removal efficiency being 89% and all dosages having similar removal efficiencies. Natural organic matter and bicarbonates showed a positive effect on the efficiency of FeCl3 in removing textile fibers from surface water. PACl showed better performance in coagulating laundry wastewater while surfactants had a negative effect on FeCl3 coagulation efficiency.

Effect of surface modification of polyester fabric on microfiber shedding from household laundry

PurposeSynthetic textile materials are noted as one of the major contributors to microfiber pollution through laundry. Though many research works evaluated microfiber pollution, the solutions provided to control microfiber shedding are meager. The existing products collect or filter the microfiber from laundry effluent and restrict the direct leaching. However, no methods were proposed to effectively reduce the shedding from the textile itself.Design/methodology/approachThis research is aimed to analyze the influence of surface modification of polyester knitted textiles by sodium hydroxide, on microfiber shedding. Response surface methodology was adapted to optimize different treatment parameters (alkali concentration, treatment time and temperature).FindingsThe results show that the sodium hydroxide concentration and treatment time had a negative correlation with microfiber shedding reduction. Whereas, treatment temperature had a positive correlation with microfiber shedding reduction. The statistical analysis revealed that 0.4 M concentration, 90°C temperature and 24 min of treatment time was the best process condition for minimum microfiber release. The same was confirmed with a practical experiment and a significant reduction of 80.63% in microfiber shedding after alkali treatment was found.Originality/valueAlkali treatment of different knitted polyester fabrics with various knit structures and mass per square meter showed a significant reduction in microfiber shedding. The repeated laundry performed for 20 washes with surface-modified samples showed a significant reduction in microfiber release at every wash cycle and ensured the longevity of the effect.

Predictive models in the ultrasonic disinfection of hospital-effluents: a review and suggestion for future research

At the end of this review on applications of ultrasonic waves in the inactivation of microorganisms in hospital laundry effluents, the fourth type of predictive model is proposed, based on the application characteristics of the experimental plans. The number of works for the disinfection of wastewater by ultrasound waves (US) associated with other techniques or individuals has been increasing. The use of ultrasound to produce lethal effects on microorganisms is attractive because it is considered a "green" technology in that it involves sound energy and does not require additional chemicals, or a very small amount. Also, the US as a tool for water reuse processes - operates at low pressure and temperature and does not produce toxic or greenhouse gases. Hospital laundry effluents are characterized by different microorganisms, a fact that can hinder the application of conventional physical-chemical technologies. To contribute to future developments in the application of ultrasound (US), this work uses some typical US applications in the disinfection of aqueous effluents. To propose strategies for carrying out new works, comments are made regarding an approach oriented towards new advances based on the need to interrelate the variables involved in the studies, at the same time that these variables are correlated with the rate of inactivation. For this, it is discussed the predictive models and their contributions, according to the number of factors that should be involved for a better understanding of the rate of microbial inactivation.

Characterization of microfibers emission from textile washing from a domestic environment

Microfibers and microplastics are widely recognized emerging pollutants, which have the potential to cause an Eco-toxicological effect. Cellulosic and synthetic fibers are being released almost equally to the environment. Synthetic fibers released were non-biodegradable resulting in a significant negative impact on the environment. In the present study, four different households using fully automated washing machines (2 top-load, 2 front-load) were studied in a domestic laundry environment under real conditions. Laundry effluents were collected and contaminants analysis was carried out. The results estimated that the average emission rate of the four households was 7,453,635 MF/7Kg (FL, H1), 7,375,500 MFs/6Kg (FL, H2), 10,692,255 MFs/7Kg (TL, H3) and 7,589,017 MFs/6.2Kg (TL, H4). Synthetic fiber's emission rate was only about 19 %, and the average length range of microfibers released was found to be in the range of ≤5 μm (48.64 %), and the least amount of emission was found in the >500 μm range (11.49 %).

Comparison between effects of manothermosonication and isolated ultrasonic techniques on microbial inactivation of a hospital laundry effluent

Microbial inactivation using only Ultrasound (US) vibrations presents considerable advantages by applying green techniques with non-generation of greenhouse gases, eliminating chemicals, and operating conditions close to environmental conditions. However, industrial effluent treatment systems have been investigated as a microbial inactivation step, using isolated US associated with thermal (T) and manometric (P) microbial inactivation techniques. A stainless-steel bench prototype was built for the present study, operating in continuous mode, with a 2.5 L volume test chamber. The indicator microorganism detected in the effluent of a hospital laundry located in the Agreste region of the state of Pernambuco, Brazil, was the E. coli bacterium. In addition to the isolated US effect, US/T, US/P, and US/T/P combinations were obtained using a central composite design (CCD). The factors used for the CCD were frequency, hydraulic detention time, temperature, and pressure. The results showed that the lethality rate increased with the frequency and time of hydraulic detention but was reduced when increasing temperature from 30°C to 50°C and increasing pressure between 1.0 bar and 1.8 bar. Isolated ultrasonic vibrations, at 120 kHz and with 10-minute HRT, reached an inactivation efficiency of 98%. Such a value was found using the thermomannosonic condition around 40 min. The use of the isolated US vibration technique proved advantageous, mainly due to the efficient inactivation results and potential energy and chemical reductions.

Bioremediation potential of industrial laundry effluent by agaricomycetes from brazilian tropical dry forest

Mycotic bioremediation of effluents from industrial jeans laundries is a necessary biotechnological treatment to prevent contamination of water bodies. In phase I, the discoloration of Indigo Carmine Dye (ICD) and Textile Effluent (TE) by seven species of Agaricomycetes from the brazilian tropical dry forest (Caatinga) was evaluated. First, nutritional stress was caused by Nitrogen Limitation (NL) at three experimental times, T1 (1 day). T2 (4 days) and T3 (7 days). In phase II, microorganisms were cultivated in the initial growth times Gi1 (10 days) and Gi2 (25 days), Without Addition of Nutrients (WAN) and stress was induced by NL (T1). Subsequently, ICD and TE discoloration tests continued for 28 days. In the ecotoxic analysis, the biotreated samples in phase II were tested on nauplii of Artemia HIGH 5 without the addition of food. In phase I, the percentages of ICD and TE discoloration were greater than 55% using fungi F1, F2, F5 and F6 for 10 days without sterility. In phase II, the best percentages of discoloration were found for TE in Gi1 and for ICD in Gi2, with F1 and F5 (identified by molecular biology). The results showed that Gi1 (WAN) increased the biodegradation of TE and Gi2 (WAN) favored the biodegradation of ICD, in T1 (NL) without sterility. The best enzymatic activity of laccase and lignin peroxidase was presented in F5. The enzyme extracts had a Michaelis-Menten kinetic behavior. All samples of TE bioremediated in phase II no showed toxicity on Artemia sp. in 48 hours of experimentation.

Wastewater treatment plant effluent and microfiber pollution: focus on industry-specific wastewater.

The production, use, and disposal of synthetic textiles potentially release a significant amount of microfibers into the environment. Studies performed on municipal wastewater treatment plants (WWTPs) effluent reported a higher presence of microfibers due to the mix of domestic laundry effluent through sewage. As municipal WWTPs receive influents from households and industries, it serves as a sink for the microfibers. However, research on textile industry WWTPs that primarily treat the textile fabric processing wastewater was not explored with the concern of microfibers. Hence, the review aims to analyze the existing literature and enlighten the impact of WWTPs on microplastic emission into the environment by specifically addressing textile industry WWTPs. The results of the review confirmed that even after 95-99% removal, municipal WWTPs can emit around 160 million microplastics per day into the environment. Microfiber was the dominant shape identified by the review. The average microfiber contamination in the WWTP sludge was estimated as 200 microfibers per gram of sludge. As far as the industry-specific effluents are analyzed, textile wet processing industries effluents contained > 1000 times higher microfibers than municipal WWTP. Despite few existing studies on textile industry effluent, the review demonstrates that, so far, no studies were performed on the sludge obtained from WWTPs that handle textile industry effluents alone. Review results pointed out that more attention should be needed to the textile wastewater research which is addressing the textile wet processing industry WWTPs. Moreover, the sludge released from these WWTPs should be consideredas an important source of microfiber as they contain more quantity of microfibers than the effluent, and also, their routes to the environment are huge and easy.

Performance of Electrocoagulation Process for Microplastic Fibre Removal from Laundry Wastewater

Laundry wastewater contains not only detergent but also contains fabric fibres and threads. Microplastic fibres have been discovered as a potential source of microplastic fibres in synthetic clothing washed in the environment. To reduce microplastic concentration in wastewater, many approaches have been developed. Electrocoagulation is one of them. Using both synthetic microplastics and laundry wastewater samples, this study examined the performance of electrocoagulation methods to remove microplastics. The flocculation and deposition mechanisms remove microplastic fibre. This research was set up by using a reactor with a volume of 1 L, 60 V of voltage and 60 minutes of contact time. Electrical current of 5A and 10A was applied to remove microplastic fibres during electrocoagulation (EC). The removal efficiency of polyester fibre was 55-68 per cent for 60 minutes with a current of 5A and 42-85 per cent for 60 minutes with a current of 10A. Polyamide fibre removal efficiency in 60 minutes is 53 per cent to 74 per cent at 5A current and 57 per cent to 72 per cent at 10A current. According to this study, it can be concluded that EC can remove microplastic fibre from laundry effluent.

Study of the oxidative degradation of industrial laundry effluent from jeans by chromatography

Textile industries activities can positively affect a city’s economy. However, those industries require a great deal of water and sheds high organic load into water bodies, causing a considerate environmental impact. As potential pollutant substances, the dye’s presence in textile effluents are recalcitrant and can change the chemical and physical properties. It also resists conventional treatments. The treatment based on advanced oxidation processes presents to be efficient on dye’s degradation, but it may generate secondary toxic compounds, therefore is necessary to use techniques to evaluate its toxicity after the treatment. This study evaluated a laundry effluent, both before and after the treatment using the photo - Fenton processes. Applying liquid chromatography, results have shown that the dye's degradation was higher than 90% and a COD decrease to 73%.

Towards Water and Energy Self-Sufficiency: a Closed-Loop, Solar-Driven, Low-Tech Laundry Pilot Facility (LaundReCycle) for the Reuse of Laundry Wastewater

In the scope of this study, a pilot facility for the recycling of laundry effluent was developed and tested. With the aim to enable nearly complete energy and water self-sufficiency, the system is powered by a photovoltaic plant with second-life batteries, treats the wastewater within the unit and constantly reuses the treated wastewater for washing in a closed cycle. The technology for wastewater treatment is based on a low-tech approach consisting of a physical/mechanical pre-treatment and biological treatment in trickling filter columns. The treatment process is operated in batch mode for a capacity of five washing cycles per day. During five weeks of operation water quality, energy consumption and production, water losses and washing performance were monitored. The system recovered 69% of the used water for the washing machine while treating the wastewater to the necessary water quality levels. The average COD removal rate per cycle was 92%. Energy analysis was based on modelled data of the monitored energy consumption. With the current set-up, an internal consumption rate of 80% and self-sufficiency of 30% were modelled. Future developments aim at increasing water and energy self-sufficiency and optimizing the water treatment efficiency.

Fragmented fibre (including microplastic) pollution from textiles

The threat of microplastic (MP) pollution to our ecosystem is well established. The presence of natural, regenerated, and synthetic fragmented fibres (FF) and their abundance in terrestrial and aquatic environments has been extensively reported. All textiles release FF during their lifecycle, not limited to plastics, which find their way to the environment through different dispersal pathways. Beyond the nature of the polymer, the FF can also can be a carrier of hazardous chemicals. The ubiquitous nature of MPs (and FF) has widely placed them as one of the most enduring and pervasive anthropogenic pollutants. This review is focused on FFs generated and released from textiles during wet (predominantly laundering) and dry exposure conditions. A summary and critical analysis of the current methods to generate, collect, measure, and characterise FF from textile laundry effluent is presented. The impact of key parameters on the release of FF is summarised; including washing equipment/conditions, filtration procedures, characterisation techniques, and the effect of textile materials and structure. The results from key publications are tabulated for direct comparisons, this includes estimated number of FF released per washing cycle and length distribution profile. Though the wet route of release has gained more attention, the release through dry routes is also significant. Hence, a detailed overview of the collection and characterisation of FF from dry routes (atmospheric deposition and textile abrasion) was important. Finally, a comprehensive overview of latest research and industrially-applied mitigation strategies to limit the release of FF from textile sources during laundry is included. The impact of MPs (and FF) is briefly outlined covering the environment, human health and degradation. Improved plastics with reduced environmental impact, plastic recycling and reduced consumption are vital. Still, the release of FFs from textiles remains a challenge since their production is unintentional.

Degradation of surfactants from domestic laundry effluent by electron beam irradiation

Surface active agent (surfactant) is the main ingredient in laundry detergent and other household cleaning agent. TWEEN20 is one of the nonionic surfactant which is widely used in detergent. Laundry effluent is one of the major contributor of domestic wastewater as laundering processes involves water-washing. Surfactant enters the environment when the effluents discharged into surface water and through sludge disposal on land. In order to protect the water bodies from any severe pollution, the effectiveness of high-energy ionizing radiation on decomposition of targeted surfactants, TWEEN20 from domestic laundry effluent at different operating condition were examined in this study. The experimental work was divided into two parts, part I verified the present of surfactants in laundry effluent using powdered and liquid detergents which will be collected from different sampling station. Whereas, part II involved the degradation of targeted pollutants by ionizing radiation technique. Two different type of laundry effluent was collected one using powdered detergent and another one using liquid detergent for fifteen days. Prior to irradiation, the characteristics of the water samples was analyzed in term of chemical oxygen demand (COD), total organic carbon (TOC), pH, and turbidity. Electron beam irradiation (EBI) was able to remove 100% of the TWEEN20 surfactant from laundry effluent for both liquid and powder detergent. The results obtained showed that electron beam irradiation is a very efficient and promising technology for the treatment of laundry effluent.

Life performance evaluation of lyophilized Moringa biocoagulant: An alternative for prolonging the biocoagulant efficiency

AbstractThe use of Moringa oleifera (MO) seeds has been the subject of studies to treat water and effluents due to its biocoagulant potential. However, one of the factors that prevent its use at an industrial level is its short shelf life after preparation. In view of this problem, the present study aimed to produce an MO biocoagulant for pre‐treatment via the lyophilization method, to prolong the shelf life of the extract. After optimizing the evaluated preparation conditions (2.38 g of MO for 100 ml of distilled water in 4 min of ultrasound extraction) in synthetic wastewater (using the commercial blue 5G dye), the biocoagulant was produced. Using different salt concentrations (NaCl and KCl) with the goal of improving the extraction, the produced biocoagulant was lyophilized, stored and assessed monthly in a comparative study with the inorganic aluminum sulfate coagulant apply to a textile laundry effluent. Although the biocoagulant produced is less efficient than conventional inorganic ones, the performance evaluation proved to be very satisfactory, obtaining 67.13% color removal and 91.98% turbidity for MO, which when compared to aluminum sulfate achieved removal rates of 81.45% and 92%, respectively. Thus, it is presented as a great alternative for pre‐textile wastewater treatment.

ITNO-K2PC: An improved K2 algorithm with information-theory-centered node ordering for structure learning

The Bayesian Network is considered as one of the most efficient theoretical models in the uncertain reasoning and knowledge representation fields. The Bayesian Network construction consists of two main phases: Structure learning and Parameter Learning. Actually, determining the correct structure represents a major challenge that had been widely studied and still needs to be resolved. In this paper, we introduce a novel algorithm combining an improvement of score based algorithm with an effective nodes ordering method. Based on the parents searching principle of K2 algorithm, we proposed an extension of the used search-space. Besides, using graph acyclic propriety and information theory, we introduce node ordering method. Experiment simulations on the well-known networks prove that the proposed algorithm can efficiently and accurately extract the nearest topology of the original. The real application of our method exhibits its efficiency in the analysis of the phosphate laundry effluents' impact on the watershed in Gafsa area (southwestern Tunisia).

Textile microfibers reaching aquatic environments: A new estimation approach

Textile microfibers are one of the most important sources within primary microplastics. These have raised environmental concerns since its recent identification as pollutants. However, there are still no accurate models to assess their contribution to the microplastic pollution. Hence, in this study, a method to estimate the mass flow of microfibers detached from household laundry that reaches aquatic environments has been developed. The method considers a set of parameters related to the detachment of microfibers, which are, basically: (1) the detachment rate of microfibers from different textile garments, (2) the volume of laundry effluents, (3) the percentage of municipal water that has been treated, (4) the type of used-water treatment applied, and, (5) the proportion of front- versus top-loading washing machines. In this way, 0.28 million tons of microfibers per year were estimated to reach aquatic environments, which is approximately half than the last published valuation. Finally, hypothetical situations were simulated to evaluate the reduction of microfibers by the modification of some of the parameters at different levels (consumer, government entities, and industry). Thus, depending on the implanted alternatives, microfibers that reach the aquatic environments could be reduced between 30% and 65%.

Evaluation of hospital laundry effluents treated by advanced oxidation processes and their cytotoxic effects on Allium cepa L.

Hospital laundries are responsible for a significant part of the amount of wastewater that is generated in hospitals. Hospital laundry wastewater represents a complex mixture of chemicals that arouse concerns about possible environmental risks. The objective of the present study was to evaluate the cytotoxicity of different laundry effluents from the Regional University Hospital of Maringá, Paraná, Brazil, on Allium cepa L. meristematic root cells. The effluents were characterised as rinsing, wetting, prewashing, washing, softening, wastewater (the effluent generated at the end of the washing process), the wastewater that was treated by physicochemical (PC) processes and the wastewater that was treated by advanced oxidation processes (PC + UV, PC + H2O2 and PC + UV/H2O2). The mitotic indexes were calculated by scoring 5000 cells per group and the statistical analyses were performed by one-way ANOVA, followed by Tukey's post-test (α = 0.05). Results showed that the rinsing, wetting, prewashing and wastewater laundry effluents were cytotoxic at 24h of exposure, significantly reducing the mitotic index. Despite the slight cytotoxicity of the PC + UV/H2O2 treatment, physicochemical and advanced oxidation processes efficiently reduced the critical parameters of wastewater, such as the biochemical and chemical oxygen demands, to tolerable levels of effluent discharge. It is essential to perform constant monitoring of these effluents in order to reduce the possible occurrence of environmental impacts.