On-site greywater treatment and reuse in multi-storey buildings (original) (raw)
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International Journal of Advances in Engineering and Management, 2021
The aim of this study was to review and compare the physical, chemical and biological treatment options for greywater for recycling in order to achieve pollution reduction and water conservation. The Performance, advantages and disadvantages of twenty treatments were investigated which included granular filtration, microfiltration, ultrafiltration, nanofiltration, reverse osmosis, chemical coagulation-flocculation, electrocoagulation, electrooxidation, photooxidation, adsorption, wetlands, aerated lagoons, rotating biological contactors, sequencing batch reactors, expanded bed up-flow bioreactors, vertical flow bioreactor, membrane bioreactors, trickling biofilter, anaerobic up-flow biofilter and up-floe anaerobic sludge blanket. Each treatment method was evaluated and compared with others using a standard set of criteria with the objective of selecting the most applicable and economically and environmentally feasible treatment system (or systems) that results clean water for recycling. Eight criteria (cost, maintenance and control, efficiency, suitability, value added product, environmental and health impact and size and land requirement) were selected for evaluation and each criterion was assigned a figure based on its relative important. A comparative analysis was performed on the 20 treatment methods using the eight criteria. The granular filter scored the highest (89) among the physical treatments, the electrochemical coagulation scored the highest (80) among the chemical treatments group and the rotary biological contactors scored the highest (89) among the biological treatments group. The top 3 treatments were granular filter (89), rotary biological contactors (89) and sequencing batch bioreactor (88), A through review of the literature indicated that non of the 20 treatment options can be used alone safely to treat greywater for reuse onsite for toilet flushing, landscape, crop irrigation and other non-potable uses. It is, therefore, recommended that a combination of granular filter and rotating biological contactors be used to treat greywater from a large group of houses, apartment complex, large commercial establishment or recreational facility and a combination of granular filter and sequencing bed bioreactor be used to treat greywater from a single house, a school or small business such as a sport center or shopping mall. The utilization of treated greywater reduces the demand for fresh clean water and provide substantial benefits for the municipal wastewater system by reducing the amount of wastewater to be treated.
Journal of Applied Sciences, 2019
Background and Objective: Scientific knowledge, pertinent to the bio-remediation method adapted in sewage treatment plant for grey water effluent recycling has to be developed. Physico-chemical and biological water quality monitoring and analysis from the treatment would proven to the treatment efficiency. The present study was attempted to treat the domestic effluent of grey water category using Effective Micro-organisms (EM) in the sewage treatment plant (STP) of Thiagarajar College, Madurai, India and the physicochemical qualities and microbial population were examined, for the water samples collected from different treatment points of the STP. Methodology: Effective micro-organisms in the extended form, following fermentation was used as the bio-remediation way of grey water recycling. Water samples were collected at different treatment points of the STP, for water quality analysis. Microbial population was analyzed using presumptive test and the colony growth was determined and bacterial growth curve was analyzed for the survival potential of isolated bacterial organism in the water treatment environment. Multi-variate statistical analysis was performed to compare between the treatment points on their water quality. Results: A considerable reduction in the BOD, acidity, nitrogen level, moderation of acidic pH, close to neutral. Dendrogram analysis revealed that a greater variability was found for conductivity of the water sample either with TDS and hardness, whereas the later two components show closer similarity. The BOD, alkalinity, hardness and sulfate showed the strongest weight age, when compared to the other analyzed parameters, through Principal Component Analysis. Conclusion: Microbial method of effluent recycling efficiently controls the physical, chemical and biological pollutants and contaminants from the domestic grey water. Staphylococcus aureus microbial population was found removed completely, following the recycling done in this experiment.
Greywater characterization and loadings – Physicochemical treatment to promote onsite reuse
Journal of Environmental Management, 2017
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 70e75% 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.
A review of the most popular systems for greywater treatment
DESALINATION AND WATER TREATMENT, 2018
With the scientific evidence of climate change is occurring, water conservation has now become extremely important and every drop of water counts. More than 60% of the domestic wastewater is a by-product of households, municipal wastewater. Known as greywater, it can be easily recycled but has historically been discarded instead. However, countries, municipalities, and communities have now realized the importance of graywater recycling and reuse. Studies and practices have been started to remove and or eliminate major pollutants so that the recycled water can be used for irrigation, toilet flushing, and many other uses. Different types of filtration systems can be used, such as slow sand filtration, rapid sand filtration, slanted soil, and others common systems techniques like sequencing batch reactor, upflow anaerobic sludge blanket reactor used in wetlands. This review aims to discuss the most efficient systems for greywater treatment, by comparing more than 20 systems for their biological, chemical and physical removal of pollutants.
Greywater management through development of effective treatment technology
In India, many habitations experience severe water scarcity particularly during summer season. Due to the decline in the availability of freshwater sources, it is important to explore affordable, implementable and safe solutions to alleviate water problems. The reuse of greywater is the best alternative and water management practice to preserve water resource and face water scarcity in rural and urban areas. This laboratory scale study presents the finest design of greywater treatment system, which is a combination of natural and physical treatment consist of feed cum collection tank and filtration followed by storage and disinfection. The greywater reuse system is developed for the treatment of various sources of greywater. The economical performance of the system were investigated separately for the treatment of bathrooms, laundries and mixed greywater collected from different locations in urban and peri-urban areas of Nagpur, Maharashtra, India.
Greywater Treatment Using GAC Biofilm Reactor and Sand Filter System
Australian journal of basic and applied sciences, 2012
A system involving a granular activated carbon (GAC) biofilm up-flow expanded bed (UEB) reactor and a slow down-flow packed sand filter was established for treating mosque grey water (ablution water). The faecal coliforms (F.C.), chemical oxygen demand (COD), total suspended solids (TSS), nitrate (NO3), and ammonia as nitrogen (NH4-N) were investigated under continuous flow operation using a hydraulic retention time (HRT) ranging from 1-6 hr over the period from 5/9/2010 to 6/2/2011. The system was arranged so that the GAC reactor is the first stage of treatment, and the sand filter is the second stage. Influent and effluent samples from the system were analysed weekly. The system demonstrated satisfactory removal of faecal coliforms with removal efficiencies of 63-80 %, and the efficiencies of COD and TSS removal were 70 % and 72 %, respectively. The system showed low removal efficiencies of nitrate which was 0-13 %. No ammonia removal was recorded in that range of retention time, ...
DESIGN AND TREATABILITY STUDIES OF GREYWATER
This paper presents the design of laboratory scale grey water treatment system, which is restricted to four stages of physical operations. The continuous flow-based constructed bio-bed filter for grey water treatment is a technique for reusing the domestic grey water. The system has been found as more effective for treating the Physico-chemical parameters such as pH, electrical conductivity, TSS, TDS, BOD, COD. The results reported the removal efficiency in the biological oxygen demand (86.2%), chemical oxygen demand (81.1%). Consequently, this biofiltration method is natural, simple, and low cost-effective treatment.
Treatment and effective utilization of greywater
Applied Water Science, 2019
Sustainable management aims at the governance of natural resources to meet the needs of future generations. The limited resources of freshwater in arid regions have led to the development of alternative water management strategies. To meet the future challenges of water scarcity, an attempt has been made in this study to utilize treated greywater obtained by gravitygoverned filtration technique and disinfection for domestic usage. The study addresses the possibilities of groundwater recharge with the treated greywater. The method focuses on a gravity-governed flow through a column containing activated carbon, sand and gravel. The greywater used for the treatment contains a mixture of equal proportions of water collected from three different sources such as kitchen sink, shower and washing machine in Fahaheel, Salmiya and Farwaniya areas of Kuwait. The study concluded that for a volume of 1167 cm 3 filtration media used, the designed column was 34% effective for first 1100 mL of greywater. Later, the column was regenerated by washing with distilled water and the regenerated column still proved to be effective with a removal efficiency of 26% for next 600 mL of greywater. The quality of the treated greywater was assessed in terms of physical, chemical and microbiological parameters as per the standard methods to check the suitability for domestic purposes. The results obtained were also compared with the groundwater quality of Kuwait group and Dammam aquifers, and it was inferred to be at par with their quality. The TDS of treated greywater has been reduced from 4910 to 1508 mg/L, which is also lower than the TDS in groundwater of both the aquifers, and pH was reduced from 10.29 to 7.94. The present study proved its efficiency equally to other existing methods, and the efficiency of removal for some of the analyzed parameters was measured as 23%, 95%, 52%, 88%, 100% and 100% for pH, color, TDS, turbidity, total coliform and E. coli, respectively. Hence, the study is simple and cost-effective approach that can be adopted for the treatment and reused greywater for domestic and agriculture and also for recharging the aquifers to prevent saltwater intrusion along the coastal aquifers.
Analytical Study and Performance Evaluation of a Lab-Scale Greywater Treatment Plant
European Scientific Journal, ESJ, 2015
This study presents the recycling of greywater for non-potable applications such as toilet flushing, concrete production, and irrigation. In this study, a laboratory-scale greywater treatment plant was designed and fabricated to treat greywater with a combination of physical and natural treatments systems. These natural systems include natural-draft aerator system, coagulation by natural coagulant (Moringa Oleifera), and filtration by sand and sawdust filter media. A total of five samples of raw greywater were collected every morning from two female hostels, namely Prof. Dora Akunyili and Chief Stella Okoli hostels in Nnamdi Azikiwe University, (NAU) Awka,Nigeria. These samples were analyzed for turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), total dissolved solid (TDS) and total hardness. Analysis of Variance (ANOVA), Coefficient of variance and Correlation Matrix were used to analyse data obtained. Differences in parameter concentration between the influent and effluent parameters were considered significant at 5% level of significance (i.e p ≤ 0.05). The concentration of these parameters decreased significantly as a result of the treatment. Coefficient of Variation indicates that most influent and effluent parameters have coefficient of variations that are less than 10% meaning that the raw greywater samples were well collected and consistent in quality. A correlation matrix show that biochemical oxygen demand (BOD), turbidity and total suspended solid (TSS) are strongly related. This shows that the system is consistent in treatment and may be adopted for treatment of greywater for non-potable uses in areas with limited water supply.
Journal of Cleaner Production, 2015
Implementation of decentralized greywater treatment systems can potentially solve freshwater scarcity issue as greywater is generated in large amounts, and reuse of treated greywater could reduce the demand of freshwater. Nevertheless, greywater treatment systems are sophisticated, involving many units of process equipment. Hence, there is a need to develop greywater treatment systems that can be easily operated, maintained, low cost and does not compromise treated effluent quality. An aerobic digestion unit integrated with a hydrogen peroxide disinfection unit was evaluated in this study for the purpose of greywater treatment to the standard for non-potable usage. This system was successful in removing 88% and 68% of total suspended solids and chemical oxygen demand respectively, with optimal operation settings determined to be 5 h of hydraulic retention time and an organic loading rate of 2.16 gCOD/Lday. Disinfection with hydrogen peroxide at concentration of 1 mL/L removed approximately log CFU/100 mL of bacteria and all bacteria can be eradicated after 1 day of storage. The system evaluated in this study was found to be simpler in comparison to other treatment processes used. Though further optimization will be required maximize the treatment efficiency of this system, it has the potential for implementation in small communities due to minimal microbial activity after storage and relatively small area required for treatment.