Direct Disposal Research Articles

Phycoremediation of Hazardous Mixed Industrial Effluent by a Marine Strain of Phormidium sp

The potential of the marine microalgal isolate Phormidium sp. to detoxify/reduce various pollutants from a highly hazardous mixed industrial effluent (MIE) is evaluated. The microalgae are grown in the MIE at 30% (v/v%) strength for 21 days under controlled environmental conditions. The reductions/changes in concentrations of biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate, nitrite, total phosphate, and toxic metals (chromium, nickel, manganese, copper) are monitored. Notably, the isolate grew quite well, reducing the levels of BOD by 93% and those of COD by 71% in 6 to 9 days. Concentrations of other measured contaminants are also reduced to within the permissible limits of discharge. Higher rates of hatchability in Artemia salina cysts and survivability of its hatchlings are observed in the algae‐treated wastewater than in the untreated wastewater, indicating safe discharge of the wastewater. These observations are valuable, as they indicate that many environmental strains of microalgae possess the potential to detoxify certain hazardous MIEs and can adequately improve the quality of water for reuse/discharge, thereby safeguarding our natural environments from the detrimental effects of direct disposal.

Building Model-Driven Decision Support System in Product Redesign Plan

Product recovery strategy requires a thoughtful consideration of environmental implications of operational processes, undergone by a manufactured product in its entire product lifecycle, from stages of material processing, manufacturing, assembly, transportation, product use, product post-use and end-of-life. At the returns stream from product use stage, those parts and/or component assemblies from a used product have several disposition alternatives for recovery, such as direct reuse, remanufacture, recycle or disposal. Due to such complexity of the manufacturing processes in recovery, current decision methodologies focus on the performance measures of cost, time, waste and quality separately. In this article, an integrated decision model for used product returns stream is developed to measure the recovery of utilisation value in the aspects of cost, waste, time, and quality collectively. In addition, we proposed a model-driven decision support system (DSS) that may be useful for manufacturers in making recovery disposition alternatives. A case application was demonstrated with the use of model-driven DSS to measure recovery utilisation value for the used product disposition alternatives. Finally, the future work and contributions of this study are discussed.

The economic competitiveness of promising nuclear energy system: A closer look at the input uncertainties in LCOE analysis

In this study, we aimed to provide important information about the potential economic benefits and risks of nuclear electricity generation associated with existing and prevailing nuclear technologies and to examine the economic effects of nuclear fuel cycle strategies in Korea. An economic analysis model that evaluates the overall life-cycle costs of nuclear energy systems coupled with multiple fuel cycle options was specially developed by using the levelized cost of electricity (LCOE) as the fundamental methodology. This model is capable of identifying a range of techno-economic uncertainties underlying each individual nuclear energy system taking into account the state of the art in fuel cycle technologies. It can also quantify and incorporate the resulting impacts into a system-wide LCOE distribution for each fuel cycle option based on Monte Carlo probabilistic simulation. We analyzed and discussed examples of the economic performance of 13 promising candidates for nuclear energy systems integrated with extensive fuel cycle technologies (including one direct disposal and 12 specific reprocessing and recycling fuel cycle options). We also conducted a sensitivity analysis to investigate the major sensitivity factors of the system component cost in each fuel cycle option and their impacts on individual economic performances. Furthermore, a closer look at the techno-economic uncertainties of advanced fuel cycle technologies in a break-even analysis offers evidence of the potential economic feasibility and cost-reduction opportunities in the reprocessing and recycling options relative to the direct disposal of spent nuclear fuel.

Treatment Study of Ink Wastewater for Industries: A Review

Now-a-days rules and regulations are becoming strict regarding environmental protection in industrial sectors. The quantity of waste water generation from the industries are rapidly increasing as production of goods and material increases, as per demand of increased population. The corrugated cardboard boxes are extensively used for commercial, industrial and domestic goods packaging. Extensive application of cardboard boxes rather than plastic, enhance the eco friendliness and pollution free environment. In the process of cardboard manufacturing, printing process and washing of machines, thereby generating large quantity of waste water. This waste water typically contains various contents viz. cornstarch adhesive, colored ink, oil and solids. The direct disposal of this type of waste water is never ever allowed under the environmental regulations and laws. The main purpose behind this review paper is to find out the appropriate and reliable method to treat colored waste water and allow the treated water disposed in land without danger to human health, well-being of the plants and surrounding areas of industry. The second important aim is reuse of treated water in industry for all secondary purposes like washing of machines, flushing and for gardening purposes. The aim of this paper is to focus on past and present treatment option available for ink waste water treatment.

Antibiotics in hospital effluent and domestic wastewater treatment plants in Doha, Qatar

Wastewater samples were collected from the main hospital’s effluent (HWW), influents and effluents of the old wastewater treatment plant (OWWTP) built in 1990 and the new one (NWWTP) built in 2010 located in Doha, Qatar. Analytical methods were optimized to determine the concentrations of eight selected antibiotics (ABs): penicillin, amoxicillin, gentamicin, ciprofloxacin, tetracycline, erythromycin, metronidazole, and clavulanic acid. Samples were prepared through automated solid phase extraction (SPE) before analysis using liquid chromatography - mass spectrometry (LC–MS) with positive ion electrospray. Among the eight target compounds tested, recoveries were obtained in the range of 47.5–98%. The highest concentration of metronidazole and ciprofloxacin were detected in the HWW at levels of 5.46 μg/L and 1.99 μg/L, respectively. In effluents samples collected from both WWTPs, clavulanic acid was the most prominent compound at concentration of 84.74 μg/L. The highest concentration of erythromycin (7.20 μg/L) was detected in the influent sample collected from OWWTP. Amoxicillin, penicillin, and erythromycin were below the detection limit (0.1 μg/L). There was a significant statistical correlation between the concentrations of most of the studied antibiotics. Ciprofloxacin was highly correlated with erythromycin, clavulanic acid, and metronidazole in all influent samples, whereas the concentration of erythromycin was highly correlated with those of amoxicillin, ciprofloxacin, tetracycline and penicillin in all effluent samples. No significant difference (P ≥ 0.05) was found between concentrations of the targeted antibiotics in the NWWTP and OWWTP. Generally, both treatment plants showed effective removal rates (99.44%) of penicillin and metronidazole. However, clavulanic acid and ciprofloxacin were not removed from the effluent of either plant, even though the effluent passed through the ultrafiltration stage in the new WWTP. The findings reveal that HWW is not the only source of ABs in wastewater but direct disposal onto the sewer system could be the major source. The study calls for further investigation of additional pharmaceuticals and other emerging contaminants in the wastewater of Qatar as well as their metabolites and biodegradation products as well as application of advanced treatment technologies for highest removal rate and safe water reuse options.

A Design Method to Improve End-of-Use Product Value Recovery for Circular Economy

Circular economy (CE) is being increasingly accepted as a promising sustainable business model, supporting waste minimization through product life cycles. The product end-of-use (EOU) stage is the key to circulate materials and components into a new life cycle, rather than direct disposal. The economic viability of recycling EOU products is significantly affected by designers' decisions and largely determined during product design. Low economic return of EOU value recovery is a major barrier to overcome. To address this issue, a design method to facilitate EOU product value recovery is proposed. First, product EOU scenarios are determined by optimization of EOU component flows. The EOU scenario depicts which modules (groups of components) will be allocated for reuse, recycling, or disposal, the order of joint detachment (the joints for modules connection), and recovery profit. Second, in the given study, bottlenecks, improvement opportunities, and design suggestions will be identified and provided following the EOU scenario analysis. Pareto analysis is used for ranking joints, according to their detachment cost and for indicating which joints are the most suitable for replacement. An analytic hierarchy process (AHP) is employed to select the best joint candidate with trade-off among criteria from the perspective of disassembly. In addition, disposal and recycling modules are checked to eliminate hazardous material and increase material compatibility. A value-based recycling indicator is developed to measure recyclability of the modules and evaluate design suggestions for material selection. Finally, based on heuristics, the most valuable and reusable modules will be selected for reconfiguration so that they can be easily accessed and disassembled. A hard disk drive is used as a case study to illustrate the method.

Optimal Design of Crystallization Processes for the Recovery of a Slow-Nucleating Sugar with a Complex Chemical Equilibrium in Aqueous Solution: The Case of Lactose

Lactose is the major carbohydrate in milk, and similarly to other sugars, it can exist as two anomers in solution, the α and β forms, with a ratio depending on factors including temperature and pH (mutarotation equilibrium). Lactose is extracted from whey mostly to prevent environmental pollution. In fact, the presence of this sugar can contribute to a dramatic increase in the biological oxygen demand (BOD) of whey, making its direct disposal potentially dangerous for the environment. However, preserving our ecosystem is not the only reason why lactose is recovered. Purified lactose is in fact a high-value product that is commonly used as an excipient in pharmaceutical formulations and as a carrier in dry-powder inhalers. Despite the increasing interest that lactose crystallization has recently received, a full understanding of this process is still missing, particularly the link between the process parameters of the crystallization step and the properties of the final product in terms of crystalline stru...

Assessment of the potential for criticality in the far field of a used nuclear fuel repository

This study aims to assess the likelihood for criticality in the far field of a repository for direct disposal of commercial light water reactor used nuclear fuel. Two models are used in combination: (1) a neutronics model to estimate the minimum critical masses of spherical, water-saturated depositions of fissile material; (2) a transport model to simulate the dissolution of waste packages arranged in an array and the subsequent transport of fissile solutes through fractured bedrock to a single accumulation location. The neutronics model shows that heavy metals from different types of used fuel present the same minimum critical mass behavior in the parameter space of initial enrichment and burnup, dictated largely by the fissile content. However, the magnitude of the minimum critical mass varies significantly within that parameter space, and secondary effects like the presence of absorbing nuclides play a minor role. The transport model employs various subsurface transport scenarios, and for each scenario the mass of each isotope and the overall fissile content of the accumulation is reported from the time of canister failure up to one hundred million years at various distances from the repository edge. Taking the results of the two models in concert, it is shown that even if the accumulation of a critical mass is possible under conservative conditions, these conditions are unlikely to be present in the vicinity of a carefully engineered repository. Based on the results of each model, recommendations for risk mitigation in terms of waste characteristics and repository design are given.

Comparison of the occurrence of antibiotic residues in two rural ponds: implication for ecopharmacovigilance.

As a well-accepted drug-administration strategy for the minimization of environmental risks posed by pharmaceutical residues, ecopharmacovigilance (EPV) needs to guard against and control the pharmaceutical pollution sources. However, the underlying routes by which pharmaceuticals reach the environment vary significantly under different scenes, so it is necessary to implement different EPV measures in different backgrounds. This study detected the occurrence of antibiotic residues in two ponds within a Chinese rural community; assessed their ecological risks; compared and analyzed the geographic and demographic information, as well as the antibiotic-related anthropogenic behaviors of residents living around ponds, in order to trace the main entrances of antibiotics into the water environment; and then propose the EPV measures according to rural conditions. The results showed that the pollution degree of antibiotic residues was different between two studied ponds, which was manifested by the different antibiotic types and levels in water samples. And the possible main sources of antibiotic pollution in the studied rural water environment might include the application of human excretions and animal manures as fertilizers on the farmland, antibiotic use and inappropriate disposal in the clinic, and the direct disposal of the leftover antibiotics. From the perspective of drug administration, we then identified some suggestions on EPV measures which could be taken under existing rural conditions, including encouraging eco-directed sustainable prescribing of antibiotics in human and animals, improving take-back collection of unused antibiotics, building monitoring mechanism for antibiotic residues in the natural environment, identifying high-priority antibiotic residues, and implementing targeted EPV.

MEMBRANE TECHNOLOGY FOR THE TREATMENT OF FISH INDUSTRY EFFLUENT

Membrane filtration emerges as an alternative for the treatment of fish processing effluent. The aim of this work was to verify the ability of membrane filtration on reducing the pollutant load of tilapia processing effluent. The filtrations were performed with 150, 30 and 10 kDa membranes. The physicochemical parameters of the effluent in natura and the permeates were compared among themselves and with the standards for launching foreseen in the Brazilian legislation to evaluate the possibility of direct disposal in water bodies. The three membranes had the same potential to remove total solids, nitrogen and nitrite from the effluent. Membranes 30 and 10 kDa caused similar effects on the removal of Chemical Oxygen Demand and proteins. Oils and greases, pH and fixed solids did not change with the filtrations. All the membranes were effective in reducing the color of the effluent. The effluent in natura was already in agreement with the standards for discharge regarding to temperature, pH, total nitrogen and nitrite, and the use of the membranes allowed it to meet the standards for floating materials. The color and the content of oils and grease in permeates were above the levels allowed for the discharge in freshwater, so suggesting the use of an additional operation to comply with the legislation.

Vacuum drying of advanced gas reactor fuel

The UK will shortly cease reprocessing spent advanced gas reactor (AGR) fuel in favour of direct disposal, however since a permanent geological disposal facility is not envisaged as being available until 2075 interim storage will be required. The initial intention is to continue wet storage but it is possible that this may not be viable for as long as is hoped. Dry storage is commonly used worldwide for the interim storage of zirconium clad spent nuclear fuel however AGR fuel is stainless steel (SS) clad and as such a new safety case will be required to ensure that fuel can be adequately and safely dried.A rig has been designed to allow a comparison of the two main drying techniques in use; vacuum drying and flowed gas drying. This paper looks primarily at the design and development of the rig. Some of the initial data is presented to indicate how the rig was developed as a result of early results and is followed by some of the later test data to illustrate the improvements made.

Environmental assessment of existing and alternative options for management of municipal solid waste in Brazil

Life cycle assessment (LCA) was used to evaluate and compare three different categories of management systems for municipal solid waste (MSW) in Brazil: (1) mixed waste direct disposal systems, (2) separate collection systems, based on wet-dry streams, and (3) mixed waste mechanical-biological systems, including materials recovery. System scenarios were built around main treatment techniques available and applicable in developing countries, and considered barriers as well as potential synergies between waste management and other industrial production. In the first category systems, we measured the impact magnitude of improper disposal sites (semi-controlled and controlled dumps) still used for approximately 40% of collected MSW, and found that sanitary landfills could decrease it 3–5 fold (e.g. GWP, from 1100–1200 to 250–450 kg CO2 eq. t−1 waste). As an alternative, waste incineration did not show significant benefits over sanitary landfilling, due to limitations in energy utilization and the low-carbon background electricity system. Category two of systems, revealed recycling benefits and the necessity as well as potential risks of biological treatment for wet streams. Simple wet-dry collection could result in relatively high levels of contamination in compost outputs, which should be mitigated by intensive pre- and post-treatment. Potential impact of air emissions from biological degradation processes was important even after anaerobic digestion processes. Biogas upgrading and use as vehicle fuel resulted in bigger savings compared to direct electricity production. Lastly, category three, mechanical-biological systems, displayed savings in most environmental impact categories, associated with materials recovery for recycling and refuse-derived fuel (RDF) production and utilization in cement manufacturing.

Electrochemical detection and removal of pharmaceuticals in waste waters

Summary The main classes of pharmaceuticals found in environmental samples, wastewaters included, contain various compounds such as antibiotics, antipyretics, analgesics, anti-inflammatories, antimicrobials and hormones. These compounds and their bioactive metabolites are continuously introduced into the aquatic systems at ng L−1 or pg L−1 levels by several routes including emission from production sites, direct disposal of drugs in households and hospitals, excretion after drug administration to humans and animals and water treatments in fish farms. Due to their toxicity and accumulation into living organism, their presence constitutes a serious environmental problem even at trace concentrations and, unfortunately, they are resistant to biological degradation processes, escaping almost intact from conventional wastewater treatments. Various detection methods using unmodified and modified electrodes with enzymes, antibodies and aptamers are presented, while the main part of this review is focusing on the removal of drugs from wastewaters by electrochemical methods. The main challenges as well as future trends regarding the electrochemical detection and removal methods are also pointed out.

Enantiomeric profiling of amphetamine and methamphetamine in wastewater: A 7-year study in regional and urban Queensland, Australia

Enantiomeric profiling was used in this study to investigate the consumption of amphetamine and methamphetamine in regional and urban Southeast Queensland, Australia over a period of seven years. S(+) methamphetamine was predominantly consumed in both urban and regional areas, showing a two and three fold increase in urban and regional catchments respectively between 2011 and 2017. The ratio of amphetamine to methamphetamine (AMP/METH) in wastewater reflected the expected excretion profile of methamphetamine consumption indicating the presence of amphetamine in this study was primarily the result of methamphetamine metabolism. However, the occasional occurrence of R(−) amphetamine in samples containing higher AMP/METH ratios, suggested the consumption of racemic amphetamine. The R(−) methamphetamine enantiomer was also identified in several samples, possibly indicative that the phenyl-2-propanone (P2P) synthesis process rather than the more typical reduction of ephedrines was also being used to manufacture methamphetamine. Furthermore, we identified two samples with a significantly different enantiomer ratio for the METH and AMP as well as a much lower AMP/METH concentration ratio suggesting contribution from direct disposal of methamphetamine into the sewer. This study demonstrated that enantiomeric profiling in wastewater-based epidemiology can provide valuable information for evaluating the origin of amphetamine in wastewater as either a metabolite of methamphetamine consumption or amphetamine itself.

Polyacrylamide in hydraulic fracturing fluid causes severe membrane fouling during flowback water treatment

Sustainable wastewater management strategies are required to further minimize impacts of high-volume hydraulic fracturing (HVHF) as current practices such as reuse or direct disposal have long term limitations. Membranes can provide superior effluent quality in HVHF wastewater treatment, but the application of these systems is severely limited by membrane fouling. However, the key fouling components in HVHF wastewater have not yet been clearly identified and characterized. Here we demonstrate that fouling of microfiltration membranes by synthetic flowback water is mostly due to polyacrylamide (PAM), a major additive in slickwater fracturing fluids. A synthetic fracturing fluid was incubated with Marcellus Shale under HVHF conditions (80 ℃, 83 bar, 24 h) to generate synthetic flowback water. Different HVHF conditions and fracturing fluid compositions generated a fouling index for flowback water ranging from 0.1 to 2000 m−1, with these values well correlated with the peak molecular weight (MW) (ranging from 10 to 1.5 × 104 kDa) and the concentration of high MW components in the water. The lowest fouling index was observed when PAM was further degraded by ammonium persulfate under HVHF conditions, although this is infrequently used with PAM in current fracturing operations. These results highlight the importance of PAM and its degradation products in fouling of subsequent membrane systems, providing insights that can help in the development of effective treatment processes for HVHF wastewater.

ASSESSMENT OF GROUNDWATER RESOURCES FOR IRRIGATION PURPOSES IN ASSIUT GOVERNORATE, UPPER EGYPT

A general increase of water demand in Egypt is prominently denoted. This situation is more noticeable in the Middle and Upper Egypt of arid Zone and limited water resources in which Assiut is one of the governorates of this Zone. The main objectives of this study are to assess the groundwater quality for irrigation, and to present solutions for managing and protecting these resources in Assiut area. To achieve that, one hundred and nine groundwater samples were collected from Quaternary aquifer during autumn of the year 2013. Chemical analysis was carried out and analyzed for major and trace elements according to the irrigation water guidelines of (FAO, 1985), and Rowe, et al. 1995, taking into account the spatial variations and the representation of the hydrochemical data. The results show that 47% none degree of restriction on use and 52% Slightly to moderate degree of restriction on use, According TDS hazarded. 55 % belongs to (C2-S1) good water for irrigation all crops in all soils and45 % belongs to (C3 -S1) good water for irrigation all crops in all soils under ordinary and specific condition like adequate drainage and leaching, According U.S. salinity laboratory staff classification depend on (EC,TDS and SAR) hazarded. while according to RSC (residual sodium carbonate100% Low RSC hazard (safe water for irrigation. 89% Excellent water for irrigation sensitive all crops and low likelihood of soil problems and11% good to permissible for irrigation semi - tolerant and tolerant crops and slightly to moderate likelihood of soil problems according Boron content, in compared to recommended limits in (FAO, 1995, 2010) guideline for irrigation water. Consequently, it is recommended to prevent the sewage and domestic waste water, and the industrial waste water from direct disposal without treatment to the ground wells, irrigation canals and River Nile; avoiding the construction of open septic tanks, especially near the pumping wells; controlling the use of fertilizers and pesticides in the agriculture purposes; selected the suitable crops for every sector (area) according to the chemical character's of the available irrigation water and soil properties.

Optimization of disposal method and scenario to Reduce High Level Waste Volume and Repository Footprint for HTGR

To reduce volume of High Level Waste (HLW) and the footprint in the geological repository of a High Temperature Gas-cooled Reactor (HTGR), this study optimizes the disposal method and scenario of the HLW.By virtue of high burn-up, high thermal efficiency and pin-in-block type fuel, the HTGR more effectively reduces the HLW volume and its footprint than those of Light Water Reactor (LWR) in our previous study. In this study, the disposal method and scenario are optimized. To optimize the disposal method, the geological repository layout is the horizontal emplacement based on the KBS-3H concept, rather than the vertical emplacement based on the KBS-3V concept adopted in our previous study.In comparison with the earlier study, the horizontal emplacement reduced the repository footprint in direct disposal by 20% in the same scenario. By extending the cooling time by 40 years before disposal, the footprint was reduced by 50%. In disposal with reprocessing, extending cooling time by 1.5 years between discharge and reprocessing reduced the number of canister generated by 20%. Extending the cooling time by 40 years pre-disposal reduced the footprint per unit of electricity generation by 80%.Moreover, by employing four-group partitioning technology without transmutation, the footprint can be reduced by 90% with a cooling time of 150 years.

Contamination profiles, mass loadings, and sewage epidemiology of neuropsychiatric and illicit drugs in wastewater and river waters from a community in the Midwestern United States

In this study, residues of the neuropsychiatric and illicit drugs including stimulants, opioids, hallucinogens, antischizophrenics, sedatives, and antidepressants were determined in influent and effluent samples from a small wastewater treatment plant, a receiving creek, and river waters in the Four Rivers region of the Midwestern United States. Nineteen neuropsychiatric drugs, eight illicit drugs, and three metabolites of illicit drugs were detected and quantitated in the water samples using HPLC–MS/MS. Residual concentrations of the drugs varied from below the detection limit to sub-μg/L levels. The source of residual cocaine and benzoylecgonine in wastewater is primarily from human consumption of cocaine rather than direct disposal. Wastewater based epidemiology is utilized to estimate the community usage of drugs based on the concentration of drug residues in wastewater, wastewater inflow, and the population served by the centralized wastewater treatment plant. The per-capita consumption rate of methamphetamine (1740 mg/d/1000 people) and amphetamine (970 mg/d/1000 people) found in this study were the highest reported per-capita consumption rates in the USA. Antidepressant venlafaxine found to have the highest environmental emission from the WWTP (333 ± 160 mg/d/1000 people) followed by citalopram (132 ± 60.2 mg/d/1000 people), methamphetamine (111 ± 43.6 mg/d/1000 people), and hydrocodone (108 ± 90.1 mg/d/1000 people). Bee Creek, an immediate receiving water body, is found to be a source of several neuropsychiatric and illicit drugs including methamphetamine, methadone, alprazolam, oxazepam, temazepam, carbamazepine, venlafaxine, citalopram, sertraline, oxycodone, and hydrocodone (p < 0.036) in the Clarks River.

Assessment of copper and zinc recovery from MSWI fly ash in Guangzhou based on a hydrometallurgical process

Fly ash commonly accumulates a significant amount of heavy metals and most of these heavy metals are toxic and easily leached out to the environment, posing risks to human health. Thus, fly ash has been classified as a type of hazardous waste and requires proper treatment before disposal in specific landfill sites for hazardous waste. In this study, a hydrometallurgical process developed to recover copper and zinc performed in pilot scale close to industrial scale followed by a landfill compliance leaching test of the ash residue is evaluated. LIX860N-I and Cyanex 572 gave high selectively for extractions, a yield efficiency of 95% and 61% was achieved for copper and zinc respectively. Results of pilot experiments reveals that the combining metal recovery/recycling and landfill disposal of the ash residue in a local regular landfill was demonstrated to be a technically and economically effective strategy. Specifically, the economic and environmental aspects of a scenario, in which the fly ash generated in Guangzhou is processed were systematically assessed. the assessment results show that a 7.15 million US$ of total expense reduction, a less energy cost of 19k GJ as well as 2100 tons less CO2 emissions could be achieved annually comparing to the current alternative, direct disposal of the fly ash as hazardous waste. The results reveal that the hydrometallurgical process has industrial application potential on both economic and environmental aspects and further optimization of the process can give more accurate assessment of the cost and environment effect. In addition, leaching tests and evaluation of solid residue according to the regulations specific to the country should be studied in future.

Extraction, characterization and biological activity of citrus flavonoids

Abstract Citrus is one of the largest and most popular fruit crops commercially grown across the globe. It is not only important in terms of economy but is also popular for its nutritional benefits to human and farm animals. Citrus is available in several varieties, all with attractive colors. It is consumed either fresh or in processed form. After processing, approximately 50% of the fruit remains unconsumed and discarded as waste. The latter includes fruit pith residue, peels and seeds. Direct disposal of these wastes to the environment causes serious problems as these contain bioactive compounds. Release of these bioactive compounds to the open landfills cause bad odor and spread of diseases, and disposal to water bodies or seepage to the underground water table deteriorates water quality and harms aquatic life. In this regard, a number of research are being focused on the development of better reuse methods to obtain value-added phytochemicals as well as for safe disposal. The important phytochemicals obtained from citrus include essential oils, flavonoids, citric acid, pectin, etc., which have now become popular topics in industrial research, food and synthetic chemistry. The present article reviews recent advances in exploring the effects of flavonoids obtained from citrus wastes, the extraction procedure and their usage in view of various health benefits.