Greywater Discharge Research Articles

Improved greywater quality after biofiltration with a fibre-biofilter derived from plantain pseudo stem

In this study, we addressed the prevalent issue of untreated greywater discharge into waterbodies in many developing countries, despite the associated public health risks. Our approach involved utilizing fibers extracted from plantain pseudo-stems to enhance the quality of greywater through simple biofiltration setups. Greywater sourced from the GETFund Hostel of the University of Energy and Natural Resources in Sunyani, Ghana, served as the focal point of our investigation. Through the application of this biofilter, we achieved notable reductions in two crucial parameters for assessing greywater quality: biochemical oxygen demand (BOD) and chemical oxygen demand (COD), averaging at 30.4 % and 28.67 %, respectively. Furthermore, we conducted comparative analyses between the efficacy of plantain pseudo-stem fibers and carbonized coconut shell adsorbent, both individually and in composite form as biosorbents. While certain combinations of biofilters led to slight increases in conductivity, pH, and total dissolved solids (TDS) in the treated greywater, these variations were anticipated and attributed to potential organic matter leaching during the biofiltration process. Employing Fourier-transform infrared (FT-IR) spectroscopy, we detected significant spectral changes indicative of successful organic matter removal from the greywater. Specifically, we observed an intensified phenolic hydroxyl (OH) peak at 3300 cm⁻¹, which shifted marginally to 3335 cm⁻¹ post-biofiltration. Additionally, the emergence of a carboxylic hydroxyl stretch at 2850 cm⁻¹ post-biofiltration provided strong evidence supporting the efficacy of our approach in mitigating organic contaminants in greywater.

Occurrence and characteristics of microplastics in greywater from a research vessel

The discharge of greywater from ships, an uncounted sea-based source of microplastics (MPs), is a growing concern. Yet, empirical data on MPs from this source are currently limited. Here, the abundances and characteristics of MPs in greywater from a research vessel were investigated according to water usage type (e.g., galley, cabin, and laundry). The mean abundance of MPs was highest in greywater from the laundry (177,667 n/m3), followed by the cabins (133,833 n/m3) and galley (75,000 n/m3). However, no significant differences were found in the MP abundances among greywater types due to high variability of triplicate samples collected every five days. Fiber-type MPs accounted for 66% of the total MP abundance and fragment-type MPs for 34%. Microplastics in the size range of 100–200 μm exhibited the highest levels among size classes. The dominant polymer identified in all greywater samples was polyester (53%), followed by polypropylene (23%). Marine coating origin MPs (6%) were also observed in all types of greywater. The greywater generation rate during the cruise was 0.15 m3/person∙day. Annual MP emissions per person by the greywater discharge of the research vessel was estimated to be 4.1 × 106 n/person∙year (equivalent to 3.0 g/person∙year).

Kinetics and isotherms of heavy metals removal from laundry greywater by chitosan ceramic beads

The rise of laundry facilities in the residential areas has become main concern on the water quality due to untreated laundry greywater discharge directly into the drainage. The use of detergents, softener and other cleaning additives have contributed to the heavy metals concentration in surface water. Hence, the current study investigated the adsorption behavior of chitosan ceramic beads and the removal efficiency of heavy metal ions from laundry greywater, including Pb2+, Zn2+, and Fe2+ ions. The effects of dosage, pH, time, temperature, and initial to Pb2+, Zn2+, and Fe2+ were evaluated for the efficiency of the adsorption process. The efficacy results of adsorbent's dose in Pb2+, Zn2+, and Fe2+ ions removal process with 38.89 mg/g, 29.87 mg/g and 49.55 mg/g respectively. The isotherm model, Freundlich, and Temkin model plot the experimental adsorption data set to infer the maximum adsorption capacity. The adsorption study observed that the removal of Pb2+, Zn2+, and Fe2+ ions from chitosan ceramic beads best fits the Freundlich Isotherm model. Kinetic models pseudo-first order, pseudo-second order, and the Elovich Equation model were used in this study to understand the kinetics of removal of Pb2+, Zn2+, and Fe2+ ions from laundry greywater. Adsorption kinetic study monitored pseudo-first kinetic model for the removal of Pb2+ ions with an R2 value of 0.98 was the best fitted kinetic model while Elovich Equation fitted for the removal of Zn2+ and Fe2+ with an R2 value of 0.92 and 0.96 respectively. The most significant contribution of this work is an understanding of the optimal isotherms and kinetics model that can describe the behavior of Pb2+, Zn2+, and Fe2+ ions adsorption on chitosan ceramic beads. The study provides the details of the chitosan ceramic beads potential to the adsorption of Pb2+, Zn2+, and Fe2+ ions from laundry greywater for safe disposal.

The Nigeria’s drainage challenges: An opinion paper on the in-street waste water and its environmental consequences

The drainage system is more than a building saving venture, but of life and environment. Inadequacy of drainage system characterised every nook and cranny of major parts in Nigeria, including the Federal Capital Territory, though, it is more pronounced in slums, rural and suburban areas, which accommodate the larger populace. Lack/Inadequacy of drainage system has resulted into improper disposal of greywater, as drainage system is designed to convey waste water to safer place for proper disposal are not available. The consequence of this is seen in a stream of household greywater flow out of the house to the main street. The sight of pipe conveying greywater from bathroom and laundry is a common view in most part of Nigeria, especially in a suburban area, where there is a high dense population. Different severe environmental consequences have resulted from this act, which might be a threat to public health. Also, the practice can also act as a precursor to other ailments in the society. Therefore, there is a need to create awareness on the negative impact of indiscrimate discharge of waste water on the environment. Hence, this paper seeks to review the improper greywater discharge on the street and its possible environmental consequences.

A multi-functional nature-based solution (NBS) for greywater treatment and reuse at the same plot

Water stress is destined to worsen due to rapid urbanization, high population growth as well as huge water demand and climate change in the upcoming days. To make the cities more water resilient, greywater treatment and reuse can be a sustainable solution to prevent discharge of greywater into the environment and reduce the import of freshwater into the cities. The aim of this study was to investigate the feasibility of implementing a multi-functional nature-based solution (NBS) for decentralized greywater treatment and reuse at the same plot. Therefore, an aerated vertical-flow constructed wetland (AVFCW) with a design capacity of 8 PE (population equivalent) was combined with an innovative cover layer on top, so that the wetland surface can be used wisely (saving space) for irrigation with the treated effluent as well as protect the constructed wetland from high water loss due to evapotranspiration (EVT). In the first investigation phase, the results showed that applying such a cover layer on the wetland surface did not have any influence on the treatment performance of the AVFCW operating at the BDZ-Research and Demonstration Centre for Decentralized Wastewater Treatment in Leipzig, Germany. The results from the second investigation phase showed a highly efficient treatment performance of the AVFCW system (BOD5 > 90%, COD>93%, TSS > 93%, TN > 60% and log-removal for E.coli of 0.81 ± 0.45) when feeding with synthetic greywater at the site. In the effluent from the AVFCW, the mean concentrations of BOD5, TSS and E.coli were found to be as 9 ± 5 mg/L, 4 ± 2 mg/L and 7.0 ± 5.4 MPN/100 mL, respectively, and the achieved results were in compliance with the EU recommended limits for the most restrictive Class A standard treated water quality (BOD5 < 10 mg/L; TSS < 10 mg/L; E.coli < 10 MPN/100 mL) for agricultural irrigation. Soil characteristics data at the depth of 10, 15 and 20 cm within the cover layer showed no remarkable effect of irrigation with treated effluent on the soil properties. Overall, this study demonstrated that the integrated and multi-functional NBS can be implemented as a more practical and attractive technology for greywater treatment and reuse (via sub-surface irrigation) at the same plot and can improve the aesthetic in urban settlements (e.g. backyard garden of the urban households, public park, roadside and touristic areas) as well as in warm climatic conditions of arid/semi-arid regions worldwide.

Greywater Treatment using Pottery Waste Ceramic Filter

Most village houses in Malaysia discharged lots of significant portion of greywater into stream or drains without any treatment. This phenomenon of direct disposal of greywater into the environment caused environmental risk, especially to water body. This study aimed to assess the quality and treatment of greywater discharge using pottery waste ceramic filter (PWCF) for safe disposal. Greywater samples were collected from 27 village households located at Kampung Parit Sempadan, Parit Raja using grab sampling method. Greywater was treated by using PWCF. The effectiveness of the PWCF was optimized using different sizes (0.25, 0.60, and 1.18 mm) of ceramic filter media at different hydraulic retention times (HRT: 1, 2, and 3 h). The t-test analysis showed significant differences between greywater from the two drainage distances. The results revealed that a distance within 81–100 m was significant to the influence of gender and the number of household occupants of the greywater discharged. The results of this study highlight that PWCF reduced the concentration of COD, BOD and TSS in greywater by 99.4%, 74.3 and 100% respectively using particle size of 0.25 mm and HRT of 3 hours. Finally, it deduced that the use of PWCF was effective and can enhance the quality of greywater for safe disposal.

Nutrient Analysis of Food Waste from Ships’ Greywater in the Baltic Sea

This case study presents the results of assessments of the potential risk of pollution by food waste in different applied shipping scenarios. A four-step model was used to analyse the applied procedures. The first step of the study involved the identification of possible strategies for on-board food waste management. In the second step, physicochemical tests of visually selected greywater detected high contents of nutrients (NTotal ≤ 238 mg·L−1 and PTotal ≤ 71 mg·L−1). Daily nutrient content (DNC) calculations of different food waste management scenarios allowed us to estimate the highest emission value from the discharge of greywater mixed with shredded food waste in the third step. In the final stage of the study, the results obtained made it possible to qualitatively assess the impact of DNC load on food waste management methods in the Baltic Sea environment. This study highlights the potential risk of polluting the Baltic Sea with nutrients and other contaminants in various scenarios, which will impact the marine recovery process. The presented research helps to outline waste management approaches for the reduction of these risks.

Assessment of geotechnical and physico-chemical properties of age-long greywater-contaminated soils in basement complex areas, southwest Nigeria

Bathroom-rich greywater coming directly in contact with virgin soil for years contaminates soil and alters its properties. The degree of alteration of soil properties may also depend on geological settings from which the soil was formed. The present study was designed to investigate the physico-chemical and geotechnical properties of greywater-contaminated soil (GCS) in different soils of basement complex formation. Soil samples were collected from greywater discharge zones and control soil (CS) in two locations (Mapo in Ibadan, Oyo State and Isolu in Abeokuta, Ogun State, Nigeria) at the depths of 0.5, 1.0 and 1.5 m from the surface, and the soil properties were analysed following standard procedures in the laboratory. The experiment consists of two modes: CS with no presence of greywater and GCS. The results of this study showed that alteration of most analysed properties depends greatly on sampling depth. There is increased in soil pH, cation exchange capacity, dry density (DD), saturated hydraulic conductivity (Ksat) and shear strength (SS) in GCS at Mapo over their control values, while porosity, Atterberg limits (ALs), plasticity index and moisture content (MC) were reduced relative to the CS at all sampling depths. However, only bearing ratio improved at each sampling depth in GCS at Isolu, while alterations in other analysed properties did not follow clear trend. Correlation coefficient showed positive correlation between % clay and AL, porosity and ALs; MC and ALs at 1% level, while negative correlation exists between DD and ALs, % sand and ALs as well as Ksat and ALs at the two locations. Two-way ANOVA showed that there is a significant difference at 5% level (p < 0.05) based on sampling depths for most analysed properties except SS, organic matter and soil resistivity. Further investigation is needed to study the trend of alteration of soil properties with depth on GCS at other soil types and geological formations.

Environmental impacts of grey water discharge from ships in the Baltic Sea

Discharge of grey water from ships is today unregulated in most sea areas, including the Baltic Sea. Annually, an estimated 5.5 million m3 grey water is emitted to the Baltic Sea with largest contribution from RoPax (4.25 million m3) and cruise ships (0.65 million m3). In total 44 different contaminants in grey water was identified and sorted into the sub categories organic compounds (28) and metals (16). Zinc and copper had the highest average concentrations with yearly inputs of 2.8 tons (zinc) and 1.5 tons (copper). 159 tons of nitrogen and 26.4 tons of phosphorus were estimated to be discharged to the Baltic Sea annually. An environmental risk assessment of contaminants, performed at a shipping lane in the Baltic Sea, showed the risk for adverse effects from grey water to be low. Nitrogen and phosphorus input from grey water contributes to 0.25% of the exceedance of, for the Baltic Sea set, eutrophication target.

Smart Sewers 1: Sewer Configuration at Rural Houses

The layout of houses and other buildings impacts the way in which foul sewer pipework is positioned internally and externally. Less water to waste through conservation measures reduces the distance that gross solids transfer in sewers and increases the number of sewer blockages. Dwelling houses are often laid out where the solids from faecal flushes are at the head of the sewer line with other flows entering downstream. Discharges from appliances such as washing machines, dishwashers, baths, showers and kitchen/utility sinks are often not utilised in the transfer of the gross solids when they enter downstream of the faecal flushes. At present, no recommendations or specific design guidance exist regarding the design of internal building layouts relating to sewer configuration requirements. Furthermore, to date, no specific research exists which examines pipeline configuration scenarios outside buildings in terms of the link between multiple grey water discharge points and solid transfer in a sewer system. The aim of this study was to investigate sewer layout at houses in terms of maximising greywater flow in relation to solid transfer. This study showed that smart sewers are needed which utilise all the foul water leaving a building as it was found that up to 100% of greywater in some instances is completely missed out in terms of solid transfer. Consequently, optimal sewer design is far from being realised and internal building layouts should be designed with consideration of the faecal flushes and greywater flows.

Assessment of household greywater discharge from village houses using Streeter–Phelps model in stream

Assessment of household greywater discharge from village houses using Streeter–Phelps model in stream

Smart Water Meter Using Electrical Resistance Tomography

Smart flow monitoring is critical for sewer system management. Obstructions and restrictions to flow in discharge pipes are common and costly. We propose the use of electrical resistance tomography modality for the task of smart wastewater metering. This paper presents the electronics hardware design and bespoke signal processing to create an embedded sensor for measuring flow rates and flow properties, such as constituent materials in sewage or grey water discharge pipes of diameters larger than 250 mm. The dedicated analogue signal conditioning module, zero-cross switching scheme, and real-time operating system enable the system to perform low-cost serial measurements while still providing the capability of real-time capturing. The system performance was evaluated via both stationary and dynamic experiments. A data acquisition speed of 14 frames per second (fps) was achieved with an overall signal to noise ratio of at least 59.54 dB. The smallest sample size reported was 0.04% of the domain size in stationary tests, illustrating good resolution. Movements have been successfully captured in dynamic tests, with a clear definition being achieved of objects in each reconstructed image, as well as a fine overall visualization of movement.

Shedding light on the invisible: addressing the potential for groundwater contamination by plastic microfibers

The processes of microplastic fiber pollution in groundwater are unknown. The recent research on this contaminant threat is generally focused on surface waters (mainly oceans and rivers), while aquifer contamination is only marginally mentioned as an issue needing further investigation. Synthetic microfibers can be introduced into soils in different ways (e.g. wastewater treatment plants or greywater discharge, septic tank outflows, direct injection of contaminated water in cases of managed aquifer recharge, losing streams, etc.), and can thus reach aquifer systems due to leaching or infiltration in soil pores. Microfibers can then adsorb persistent bioaccumulative and toxic chemicals, which include persistent organic pollutants and metals, and become a carrier of harmful substances in the aquifer system, hence contributing to the overall contamination in both urban and rural areas. For this reason, it is of paramount importance, not only to assess the occurrence and fate of microplastic fibers in groundwater, but also to study the role of microplastics as carriers of contaminants within the aquifer and to advance standardization and organization of monitoring campaigns. Only by addressing these key challenges can hydrogeologists contribute to the state of the art on microplastic pollution and ensure that groundwater is not neglected in the environmental assessments tackling this contaminant of emerging concern.

Greywater in the drains of a sewered community in Ghana

Abstract With less than 5% sewerage coverage and abysmal greywater management, Ghana's environment could be highly polluted, especially water resources. The few sewered communities may be guilty of pollution from greywater discharge into stormwater drains. In this study, Asafo, Ghana, was used as a case study to assess greywater characteristics in the major drains in a sewered community. The approach involved desk study reviews and laboratory analysis of greywater samples. The findings showed some inhabitants discharge greywater into neighbourhood drains instead of sewers. Most greywater sources from reviews and sampled drains failed the discharge limits for major contaminants including turbidity (39.4–2,880 NTU), BOD5 (64–700 mg/L), COD (207–2,308 mg/L), TSS (70–4,720 mg/L), TDS (420–2,860 mg/L), nutrients – TKN, NH3-N, NO3−-N, NO2−-N (0–218.5 mg/L), total P and PO43−(1.24–26.18 mg/L), elemental species – Na, K, Mg, etc (0–1.6 mg/L), and microbiological – total and faecal coliforms, and E. coli (2.95–10.4 log CFU/100 ml). High strength greywater accounted for odour emissions where flows stagnated. Greywater characteristics are highly variable but have potential for biological treatment as the BOD5:COD ratios ≥0.5. Ghanaian greywater, including flows from a sewered community, is untreated and polluted, and our environment is unsafe.

Diurnal patterns of micropollutants concentrations in domestic greywater

ABSTRACTIn recent years, much interest has been given to presence of micropollutants in municipal wastewater, some of which are suspected to be endocrine disruptors, toxic or carcinogenic. Much less attention has been paid to their presence in greywater. The present research studies the diurnal patterns of micropollutants in greywater and computes their daily loads. Monitoring was carried-out using auto-controlled sampling system, designed to overcome the erratic greywater generation. Two main generation periods were identified: morning (5:00–11:00) and evening-night (18:00–2:00), contributing about 20% and >50% of daily greywater discharge, respectively. Average specific daily greywater discharge was 57 L p−1d−1, which matches reported value for greywater generated by showers and washbasins in Israel. The most frequently detected micropollutants in this study were methylparben (preservative), galaxolide (fragrance) and oxybenzone (UV-filter), which are common ingredients in many personal care-products. Their daily loads were 2, 840, 1, 887 and 728 µg p−1d−1, respectively.

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.

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.

Sustainable Extensive On-Site Constructed Wetland for some Bacteriological Reduction in Kitchen Greywater

Malaysia is experiencing water pollution crisis recently. In particular, greywater discharge directly to drains. Therefore, a greywater treatment system was designed to overcome this drain pollution. To investigate the operation and performance of the treatment system, constructed wetland was designed and builds for a small single household. Lepironia Articulata was chosen for populating wetland. The wetland was supplied with kitchen greywater. The selected house is appropriate because it lacks proper drainage system. This study evaluates the characteristic of kitchen greywater before and after treatment. The quality parameters of greywater that involve in this study are Total Coliform and E-coli. The range for reduction efficiency for Total Suspended Solid was 16.02 to 60.56, E.coli was 26% to 51% and Total Coliform was 5% to 63%. Generally, this study showed improved kitchen greywater quality before discharging to the nearest water body. The findings can be used significantly to enhance the knowledge in constructed wetland where it can serve as effective and integrated solutions for managing greywater discharging using control at source approach. A constructed wetland was best chosen due to its good visual impact, removal efficiency of organic material and other pollutant, as well economical.

Grey water pollutant loads in residential colony and its economic management

The present paper deals with the organic loadings of grey water with its average and maximum flow rate on an hourly and daily basis generated from the residential colony of G.B. Pant University of Agriculture and Technology, Pantnagar, India. For reliable quantification, the study was conducted at the interval of 1 h for eight consecutive days in each season during the year 2012 to 2013. Following parameters viz biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, phosphorus, and potassium analyses were used to calculate grey water pollutant load. The observed annual average organic pollutant loading in terms of BOD was found to be 29.44 kg/day with maximum load in the summer season. However, this organic loading at maximum flow rate basis (in peak hours) was varied seasonally from 55.3, 52.0, and 83.3 kg/day, respectively, during the monsoon, winter, and summer seasons. The grey water discharge flow rate reveals the need of a treatment system compatible with fluctuating pollutant loads. The bioefficacy of phytoremediation-based technology was assessed and found to be maximum in the summer season. Hence, it is found to be the best suited green alternative for combating the fluctuating pollutant load.

A two-step crushed lava rock filter unit for grey water treatment at household level in an urban slum

Decentralised grey water treatment in urban slums using low-cost and robust technologies offers opportunities to minimise public health risks and to reduce environmental pollution caused by the highly polluted grey water i.e. with a COD and N concentration of 3000–6000 mg L−1 and 30–40 mg L−1, respectively. However, there has been very limited action research to reduce the pollution load from uncontrolled grey water discharge by households in urban slums. This study was therefore carried out to investigate the potential of a two-step filtration process to reduce the grey water pollution load in an urban slum using a crushed lava rock filter, to determine the main filter design and operation parameters and the effect of intermittent flow on the grey water effluent quality. A two-step crushed lava rock filter unit was designed and implemented for use by a household in the Bwaise III slum in Kampala city (Uganda). It was monitored at a varying hydraulic loading rate (HLR) of 0.5–1.1 m d−1 as well as at a constant HLR of 0.39 m d−1. The removal efficiencies of COD, TP and TKN were, respectively, 85.9%, 58% and 65.5% under a varying HLR and 90.5%, 59.5% and 69%, when operating at a constant HLR regime. In addition, the log removal of Escherichia coli, Salmonella spp. and total coliforms was, respectively, 3.8, 3.2 and 3.9 under the varying HLR and 3.9, 3.5 and 3.9 at a constant HLR. The results show that the use of a two-step filtration process as well as a lower constant HLR increased the pollutant removal efficiencies. Further research is needed to investigate the feasibility of adding a tertiary treatment step to increase the nutrients and microorganisms removal from grey water.