Bathroom Greywater Research Articles

The removal of pollutants from synthetic bathroom greywater by coagulation-flocculation and filtration as a fit-for-purpose method

It has been demonstrated that treated bathroom greywater (TBGW) is a useful substitute for fresh water for non-potable applications in households. Reuse of TBGW for irrigation, toilet flushing, car washing etc. offers a good opportunity to save drinking water and meet the sustainable development goals (SDGs). In this study, synthetic bathroom greywater (SBGW) was compiled in a controlled manner and used as a substitute for bathroom GW. Detailed statistical analysis also was performed to confirm the similarity between real and synthetic BGWs. SBGW is suitable for testing efficiency of applied treatment methods. It was confirmed that coagulation–flocculation with iron(III) chloride and sand filtration was the most effective method of the tested 7 systems. The best and affordable treatment combination generates good-quality treated SBGW (TSBGW) (pH = 7.54 ± 0.29, TURB = 0.54 ± 0.49 NTU, BOD5 = 21 ± 10 mgL−1, COD = 32 ± 11 mgL−1, and TOC = 12.7 ± 6.7 mgL−1) for different non-potable purposes by complying with the regulated limit values for reuse. The elemental analysis of raw, TSBGW and tap water (TW) samples by MP-AES method provided further support for safe recycling. This study leads to the conclusion that the generation of TBGW by fit-for-purpose treatment can effectively meet the circular economy goals at household level. The recycling of GW is of limited importance in the European Union (EU) and legal regulations are not available in many countries. This study provides novel support for regulating the reuse of water in Eastern European countries.

TiO2 nanotubes zeolite nanophotocatalyst performance efficacy toward the photocatalytic degradation of triclocarban in bathroom greywater

Triclocarban (TCC) is persistent in aquatic environments, where it can remain stable for extended periods. It can cause long-term exposure, potentially affecting ecosystems and human health through contaminated fish or water. Therefore, this study aims to investigate the degradation of TCC in bathroom greywater by the application of TiO2 nanotubes coated with zeolite (TNZPC) in photocatalytic degradation. Electrochemical anodization (ECA) and electrophoretic deposition (EPD) were applied to form TNZPC. Field Emission-Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), and X-ray Fluorescence (XRF) verified the characterization of TNZPC accordingly and the degradation kinetics of TCC followed the pseudo-first-order model of Hinshelwood. The highest degradation rate, reaching 95.2%, was observed at pH 11, while the lowest rate was at pH 3, with a degradation efficiency of only 72.6% after 60 minutes of irradiation with utilization of 0.75 cm2 of TNZPC. The mechanism study has verified eleven intermediate products were produced during TCC degradation by the process of oxidation, ozonation, hydroxyl radical (*OH), and dichlorination. The study suggests that finding the optimum conditions such as photocatalyst modification, cationic material, light sources, TCC initial concentration, pH, and TNZPC size play crucial roles in significant TCC photocatalytic degradation.

Greywater generation and reuse among residents of low-income urban settlements in the Oforikrom Municipal Assembly, Ghana

Abstract Greywater management in Ghana has yet to receive the needed attention even though its current generation and reuse practices pose severe environmental and public health concerns, including odour nuisance, groundwater pollution, and risks from pathogens. This study examined the current greywater generation and reuse patterns among low-income urban residents in Kumasi, Ghana. Data were collected from three communities (Ayeduase, Kotei, and Twumduase) through cluster sampling, and a total of 458 questionnaires were administered to households. The average amount of greywater generated for various activities in low-income urban settlements was 53.7 l/c/d. The results showed that greywater reuse is not common among the study participants, but those who reuse it prefer laundry to kitchen and bathroom greywater. The proportion of greywater reuse was estimated at 20.1%, with 2.6, 0.9, and 17.9% of households reusing greywater from the kitchen, bathroom, and laundry, respectively. Factors that significantly influenced greywater reuse included age, the community of residence, and the type of house. The study suggests that increased education and awareness about greywater treatment, reuse, and impacts in low-income urban communities could lead to increased participation in its management.

Eliminating xenobiotics organic compounds from greywater through green synthetic nanoparticles

Xenobiotic Organic Compounds (XOCs) have been widely considered to be pollutant compounds due to their harmful impacts on aquatic life. However, there have been few rigorous studies of cutting-edge technology used to eradicate XOCs and their presence in bathroom greywater. The present review provides a comprehensive examination of current methodologies used for removing XOCs by photocatalysis of green nanoparticles. It was appeared that zinc oxide nanoparticles (ZnO NPs) have high efficiency (99%) in photocatalysis process. Green synthesis provides proven processes that do not require dangerous chemicals or expensive equipment, making photocatalysis a potential solution for the status quo. XOCs residue was decomposed, and pollutants were eliminated with varied degrees of efficiency using green synthesis ZnO nanoparticles. It is hypothesized that the utilization of photocatalysis can create a greywater treatment system capable of degrading the toxic XOCs in greywater while increasing the pace of production. Hence, this review will be beneficial in improving greywater quality and photocatalysis using green nanoparticles can be an immediate platform in solving the issue regarding the existence of XOCs in greywater in Malaysia. Researchers in the future may benefit from focusing on optimizing photocatalytic degradation using green-synthesis ZnO. It might also help with the creativity and productivity of the next generation of authoritative concerns, notably water conservation.

Evaluation of antibacterial property and greywater treatment performance using composite chitosan/graphene oxide membrane

In this study, composite chitosan/graphene oxide (CSGO) membrane was fabricated through solution casting method using chitosan (CS) and graphene oxide (GO) for its application in bathroom greywater (GW) treatment. The characteristics of CSGO membrane were also evaluated in terms of its physical and molecular structure. It was noted that the blending of hydrophilic GO into CS polymer matrix successfully improved the water flux permeation of all CSGO membrane. Low loading of GO with added porosity, 0.25CSGO(II) has significant improvement in water flux permeation of 23.43 kg/m2h at 4 bars as compared to CS only 2.82 kg/m2h due to the presence of GO that improved the membrane hydrophilicity and permeability. Besides that, composite CSGO membrane has excellent GW treatment efficiency compared to CS membrane where additional 18% chemical oxygen demand (COD) removal was observed in 0.25CSGO(II) membrane. In addition, all CSGO membranes produced treated GW quality of pH 6–9.5, turbidity<5NTU, TSS<10 mg/L and non-detectable level of pathogen. The findings in this study set as a pioneer breakthrough with potential application of composite CSGO membrane in producing excellent treated GW quality that meets the reuse standard for non-potable applications.

Quantity and quality characteristics of greywater from an Indian household.

A year-long study was conducted to assess the quantity and quality characteristics of greywater generated from different sources of an Indian household. The effect of source separation on greywater quantity and pollutant load contribution was also assessed. Composite samples were collected separately over a period of 24h from each of the greywater source, namely hand basin, bathroom, kitchen, and laundry, and were analysed for different physico-chemical and microbiological parameters. The mean greywater generation averaged 62 L per person per day. Quantitatively, kitchen and bathroom greywater contributed 37 and 31% of the total greywater volume, respectively, while hand basin and laundry greywater accounted for 11 and 21% of the total greywater generation. Kitchen greywater contributed about 60% of the organic load in terms of biochemical oxygen demand (BOD) and chemical oxygen demand (COD), while laundry greywater was the major contributor of heavy metals and PO4-P loads. Hand basin and bathroom greywaters were the major sources of total coliforms. The analysis shows that separation of kitchen and laundry greywater is beneficial as it reduces pollutant load considerably.

Nutrient removal from artificial bathroom greywater by phycoremediation using Botryococcus sp.

Nutrient removal from artificial bathroom greywater by phycoremediation using Botryococcus sp.

Reusability performance of green zinc oxide nanoparticles for photocatalysis of bathroom greywater

Abstract This study aims to investigate the potential of green zinc oxide nanoparticles (ZnO NPs) in reusability performance for photocatalysis of bathroom greywater. It was found that ZnO NPs photocatalytic treatment of real bathroom greywater (RBGW) effluent reduces both the COD and BOD5 concentrations by 72.01, 62.75 and 57.79% (COD) and 70.18, 60.32 and 57.56% (BOD5) respectively for the first, second and third cycle. Meanwhile for the photocatalysis of ABGW, it was observed that COD and BOD5 were removed by 82.27, 68.27 and 60.96% (COD) and 82.91, 74.37 and 60.39% (BOD5) for the first, second and third cycle respectively. Besides, TSS and turbidity were reduced by 52.34, 46.85 and 37.98% (TSS) and 80.38, 67.65 and 56.81% (turbidity) respectively in RBGW and for ABGW, TSS and turbidity were reduced by 60.94, 52.37 and 41.95% (TSS) and 80.68, 72.63 and 69.91% (turbidity) for the first, second and third experimental run respectively. This designates that green ZnO NPs can be reused multiple times as an effective photocatalyst. However, ZnO NPs were used in the dispersed form, which causes difficulty in the separation of ZnO NPs from the greywater. Thus, further investigation in producing appropriate fixed film should be focused. Moreover, phytotoxicity analysis of V. radiate seeds in the treated ABGW and RBGW was not significantly different from their germination in water. This assured the less lethal nature of the degradation metabolites in greywater effluent. This investigation would be a solution to wastewater treatment plant for reusing photocatalyst in order to achieve the development of advanced and greener technologies.

What is the impact of personal care products selection on greywater characteristics and reuse?

Accounting for up to three quarters of the wastewater volume resulting from domestic activities but containing only a third of its organic content, greywater is seen as an alternative water source for non-potable reuse. This unique study explores the question whether consumers' product selection could affect the treatability and reuse of bathroom greywater. Fifty five personal care and household products (PCHP) were analysed for their effects on a range of water quality parameters including their aquatic and soil toxicity using Microtox® and MicroResp™. The organic content of these PCHPs varied considerably, not only from one category to another (0.2 gTOC.L−1 for hair conditioners to 2.7 gTOC.L−1 for toothpastes), but also within each category (0.1 gTOC.L−1 to 3.6 gTOC.L−1 amongst the shampoos). As expected, the PCHPs' macronutrient content was low, suggesting some limitation towards biological treatment of bathroom greywater. Regarding the impact of product selection on toxicity towards aquatic and soil microorganisms, the results revealed a higher sensitivity of Vibrio fischeri to the individual PCHPs than the MicroResp™ soil microorganisms. In the latter case, 75% of the products caused a stimulation response from the microorganisms although some decreases in basal respiration were observed for specific PCHPs within product categories. However, based solely on MicroResp™, the short-term discharge of treated bathroom greywater, regardless of consumer product selection, is unlikely to have a negative impact on soil microbial activity. Overall, the work has demonstrated the importance of consumer choice on the pollution load and treatability of greywater. However, no clear link between greywater characteristics and factors that normally determine consumer product selection (branding, type) were identified. This means it is not currently possible for consumers to actively manage the issue through choice such that process designers and technology developers must ensure technologies are sufficiently robust to manage the potential variations that could occur.

Photocatalysis of xenobiotic organic compounds in greywater using zinc oxide nanoparticles: a critical review

AbstractThe direct discharge of raw bathroom greywater has increased the concentrations of various pollutants in the water bodies. Typically, greywater contains large quantities of xenobiotic organic compounds (XOCs) owing to an increase in consumption of personal care and bath products. Therefore, it urges for a suitable technology to eliminate these compounds from contaminated waters. Photocatalytic degradation using Zinc Oxide nanoparticles (ZnO NPs) has the potentiality to eliminate various XOCs. However, ZnO NPs have high tendency to aggregate, which may lower the photocatalytic degradation rate. Therefore, there is an urgency to modify ZnO NPs to overcome the limitation. The present review was conducted to determine a suitable method for the modification ZnO NPs. Besides, the potential of the modified ZnO NPs in degrading XOCs in greywater as a photocatalyst was also discussed.

Discharge quality of bathroom greywater effects on soil and treatment by solar water distillation

Direct discharge of bathroom greywater (BGW) with high content of chemical derivatives from soap and detergent products may alter the receiving environment. Therefore, this research was undertaken to study the quality and effects of BGW and treat the BGW by solar water distillation (SWD). Three samples of BGW were taken at the study area and designated as House A, House B, and House C. Testing of the soil was conducted prior to the irrigation using greywater to specify the soil characteristics. Towards the end of this study, chemical properties of the soil (pH), electrical conductivity (EC), cation exchange capacity (CEC), exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR) of the soil were determined. SWD treatment was tested for pH, biochemical Oxygen demand (BOD), chemical Oxygen demand (COD) and total Suspended Solid (TSS) of the BGW. The pH of the soil before irrigation was 3.22 ± 0.02 and increased to 4.06 ± 0.12, 4.32 ± 0.09, and 4.67 ± 0.05 after irrigation with BGW from House A, B, and C respectively. The highest EC (756 ± 5.68 µs/cm) was found in the BGW from House A, indicating the presence of high range of salt content. For saturated hydraulic conductivity; tap water recorded the highest value of 51.88 cm/h, followed by 24.24 cm/h, 31.12 cm/h, and 45.01 cm/h for irrigation with BGW from House A, B, and C respectively. For CEC, ESP, and SAR, it was found that the BGW from House A recorded the highest values compared to others, with values of 0.835 meq/100gm, 36.41%, and 10.73 respectively. Treatment of BGW with SWD shows the highest removal percentage BOD is 60%, COD is 72.2%, TSS is 64.7%. Hence, the use of SWD has a good potential to enhance the quality of the BGW before directly discharged to the water bodies.

Photocatalytic degradation of basic red 51 dye in artificial bathroom greywater using zinc oxide nanoparticles

The current work aims to optimise the photocatalytic degradation of Basic Red (BR51) in artificial bathroom greywater (ABGW) using zinc oxide nanoparticles (ZnO NPs). A fixed volume (100 mL) of ABGW was exposed to direct sunlight irradiation for 5.5 h to investigate the degradation of BR51 in ABGW is due to photocatalytic degradation.The factors investigated included ZnO NPs (10–200 mg), pH (3–9) and BR51 concentration (1–10 ppm). In order to confirm the degradation of BR51 in ABGW, initial and final absorbance of BR51 in ABGW were recorded. Reusability of the ZnO NPs was evaluated for the degradation of BR51 in ABGW at optimum conditions. The results revealed that the maximum degradation (89.01%) of BR51 was recorded with 100 mg of ZnO NPs, pH 5 and 1 ppm of BR51. In conclusion, the ZnO NPs are able to degrade the BR51dye in ABGW effectively.

Effect of fly ash-lime treatment on the acute toxicity of greywater towards Daphnia magna

Abstract Acute toxicity of raw and treated greywater towards Daphnia magna was assessed in this study. Treatment was performed with exposure of greywater to the fly-lime mixture After 48 h of exposure, 100 % mortality of D. magna was recorded when testing the following volumetric fractions of the raw greywater streams in the tested liquid medium (%; v/v): 10 % for kitchen greywater, 5 – 10 % for bathroom greywater and 1.25 – 10 % for laundry greywater. After greywater treatment with the fly-ash-lime mixture with pH adjustment to 7.0, 80 % of neonates of D. magna survived after exposure to treated laundry greywater in all dilutions at 48 h. At the same time, 100 % of neonates survived exposure to treated bathroom and kitchen greywater at all volumetric fractions. Therefore greywater had acute toxicity to D. magna, i.e. greywater treatment was required before its discharge or reuse. Values of the Pearson’s correlation coefficient between the chemical components of the raw greywater and treated greywater and the survival of D. magna indicated a lack of statistically significant correlation at 5 % level of significance (p-value &gt; 0.05 in all cases), i.e. the survival of D. magna was independent of the concentration of chemical constituents in greywater samples tested. Further studies will have to be conducted on the chronic toxicity of the greywater effluent after treatment with the fly-lime mixture. Experiments from this study will have to be re-run for the fully scaled-up version of the fly-lime mixture-based greywater treatment systems.

Treatment of wash basin and bathroom greywater with Chlorella variabilis and reusability

Domestic wastewater excluding toilet streams is called greywater. When it is collected only from wash basin and bathroom, it is named as “light greywater” because of embodying a small fraction of contaminants. Light greywater makes up of more than 50% of the domestic wastewater with a great reusability potential when properly treated. Henceforth, greywater treatment can be a part of preservation of fresh water resources. Nowadays, advanced treatment methods requiring high investment and operating costs are used for greywater treatment. However, bioremediation of greywater can be an economic alternative as a result of low energy requirement of microalgal remediation systems. Moreover, microalgae can be harvested to refine its oil for further processes. In this study, treatment of light greywater with Chlorella variabilis is investigated. Wash basin and bathroom light greywater samples were collected and treated separately. After the initial chemical and microbiological analyses, the suspended solids were removed via centrifugation. Then, microalgae cultivated in raw greywater and 30% diluted (with tap water) samples. After 19 days of cultivation, Chlorella variabilis was removed from the media by another centrifuge. Final analyses were done, and removal efficiencies of COD, BOD5, TP and TN were calculated in addition to total coliform, Escherichia coli, Enterococcus, total bacteria, and Pseudomonas aeruginosa analyses. The results show up to 92.3% COD, 91.9% BOD5, 85.6% TN and >97% TP remediation. Additionally, microbiological analysis results show this water can be reused for toilet flushing.

Nutrients removal from artificial bathroom greywater using Botryococcus sp. strain

The discharge of untreated bathroom greywater directly into drain is a most common practice in the rural area. The uncontrolled discharge of greywater from the village houses escalates the pollution among Malaysian river and provide insanitary environment through mosquito and flies breeding grounds. Therefore, the current work aimed to investigate the potential of Botryococcus sp. for removing total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) from artificial bathroom greywater and to determine the bio-kinetic removal rate for these parameters. The artificial bathroom greywater was prepared by using regular brands used in the community, the bathroom greywater quality was tested for BOD, COD, SS, pH, and Turbidity. The removal process was conducted in the lab scale with 108 cell mL-1 of Botryococcus sp. The removal of TN, TP and TOC was measured in interval of 3, 5 and 7 days. The results deduced that Botryococcus sp. removed 51.5% of TN, 49.5% of TP and 42.6% of TOC. Moreover, the bio-kinetic model studies, revealed that the specific removal rate of TN, TP and TOC have a significant relationship with initial concentration in the artificial greywater (R2 = 0.63, 0.95 and 0.95 respectively). The kinetic coefficient of greywater parameters removed by Botryococcus sp. was determined as k=0.357 mg TN 1 log10 cell mL-1 d-1 and km=31.33 mg L-1 (R2=0.73), k=4.58 mg TP 1 log10 cell mL-1 d-1 and km=283.86 mg L-1 (R2=0.95), k=7.9 mg TOC 1 log10 cell mL-1 d-1 and km=322.32 mg L-1 (R2=0.97). The bio-kinetic model indicated that more than 90% of TN, TP and TOC was taken place as a response for Botryococcus sp.

Optimization of ceramic waste filter for bathroom greywater treatment using central composite design (CCD)

The present study aims to develop a filtration system consisting of ceramic wastes as a treatment process of bathroom greywater to reduce chemical oxygen demand (COD), Total suspended solids (TSS), Total nitrogen (TN), and turbidity. Optimization of the reduction efficiency was investigated using response surface methodology (RSM) as a function of the ceramic practical sizes (0.25–1.18 mm) and hydraulic retention time HRT (1–3 h). The functional groups on the surface of the ceramic filter media were determined using Fourier transform irradiation (FTIR), while the scanning electron microscope (SEM) was used to determine the microstructure and the surface morphology of the ceramic particles. Results revealed that the optimal reduction of COD, TSS, TN, and turbidity was influenced by active sites of the filter media (CC, CO, COH, and OH−) and was achieved under the operating conditions of 0.25 mm of ceramic particles after 3 h of HRT, the observed and predicted reduction for COD, TSS, TN, and Turbidity were 38.8 vs. 39.8%; 58.47 vs. 59.59%; 66.66 vs. 67.32%; 88.31 vs. 89.02%, respectively. It can be concluded that the effectiveness of the ceramic filter media is a potential source for the filtration of bathroom greywater.

Greywater characterization and loadings – Physicochemical treatment to promote onsite reuse

Greywater is the wastewater produced in bathtubs, showers, hand basins, kitchen sinks, dishwashers and laundry machines. Segregation of greywater and blackwater and on site greywater treatment in order to promote its reuse for toilet flushing and/or garden irrigation is an interesting option especially in water deficient areas. The objective of this study was to characterize the different greywater sources in Greek households and to evaluate the performance of alternative physicochemical treatment systems to treat several types of greywater. Based on the results average daily greywater production was equal to 98 L per person per day and accounts for approximately 70–75% of the total household wastewater production (135 L per person per day). Among the different sources, laundry and kitchen sink are the main contributors to the total greywater load of organic carbon, suspended solids and surfactants, whereas dishwasher and bathroom greywater are the main sources of phosphorus and endocrine disrupting chemicals respectively. Depending on sources, greywater accounts for as low as 15% of the total wastewater load of organic carbon (in the case of light greywater sources), to as high as 74% of the total load organic load (in the case of the heavy greywater sources). On the other hand, the nutrients load of greywater is limited. The application of a physical treatment system consisting of coagulation, sedimentation, sand filtration, granular activated carbon filtration and disinfection can provide for a final effluent with high quality characteristics for onsite reuse, especially when treating light greywater.

Removal of nutrients and organic pollutants from household greywater by phycoremediation for safe disposal

The present study aimed to investigate the potential for application of phycoremediation system using Botryococcus sp. for the treatment of bathroom greywater at village houses. The greywater samples were obtained from four houses. The treatment system was conducted at ambient temperature for 21 days. Botryococcus sp. (Accession No. JQ585723.1) was inoculated into the greywater in a dry mass (0.3 mg L−1). The results revealed high effectiveness of the treatment system. The maximum reduction of biological oxygen demand (BOD5) from four types of greywater ranged from 85.3 to 98%, while was between 71.22 and 85.47% for chemical oxygen demand (COD) after 21 days. The reduction of nitrate (NO3−) appeared rapidly within 18 days of the treatment period with 98% of the reduction efficiency. Reduction of ammonia (NH3) and orthophosphate (PO43−) was recorded after 21 days with the efficiency ranged from 86.21 to 99 and 39.12 to 99.3%, respectively. The high removal percentage of potassium (K) (97%) recorded within 3 days, while calcium (Ca) reduction (95%) was noted at the end of the treatment period indicating the high applicability of phycoremediation system to be used in the village houses. Moreover, the system is easily implementable, very low cost where no energy is required, eco-friendly and has no toxic by-products.

Development and experimental validation of the composition and treatability of a new synthetic bathroom greywater (SynGrey)

A new synthetic greywater—SynGrey—was developed that closely matches real bathroom greywater in composition and treatability.

Bathroom Greywater Bioremediation by Microalgae Botryococcus sp.

Objectives: Greywater is generated from domestic wastewater which refers to the untreated wastewater that is collected from household activities such as baths, showers, washing machines, laundry troughs, dishwashers and kitchen sinks, except toilet wastes. Malaysia is experiencing water pollution crisis recently, particularly direct discharge of greywater into the drains. Therefore, phycoremediation of greywater with microalgae is advocated. This study involves phycoremediation of bathroom greywater by microalgae Botryococcus sp. The objective of this research is to measure the efficiency of Botryococcus sp. in assimilating pollutant load. Method: Botryococcus sp. was inoculated in bathroom greywater with 106 cell/ml for phycoremediation process. Findings: The study was carried out to compare the bathroom greywater parameter for initial and after phycoremediation. However, the microalgae Botryococcus sp. grown in bathroom greywater from house A, house B and house C reduced the pollutant load of BOD5 99 %, 86 % and 95 %, COD 87 %, 85.6 % and 85.8 %, and NH4 + 98 %, 93 %, 92 % on the 18th day of phycoremediation respectively. Application/Improvement: This study proved that the cultivation of microalgae in bathroom greywater was successful in addition to produce sustainable biomass products for future application.