Reuse Options Research Articles

Electrodialytic Remediation of Different Heavy Metal-Polluted Soils in Suspension

Electrokinetic remediation of heavy metal-polluted soil faces different challenges in relation to implementation. One challenge is to cope with the nonlinear and transient geochemical changes in the soil and another is to increase the remediation rate. Both these challenges are met when treating the soil in a suspension in an electrodialytic cell. The soil suspension is stirred and uniform during treatment. Previously, it has been shown that a faster remediation can be obtained when remediating a stirred soil suspension compared to a stationary water saturated soil (all other parameters the same). The present work shows that the method for treating stirred suspensions was robust in the sense that in 1–3 weeks, three of four soils were decontaminated from heavy metal concentrations, where the soils must be deposited to concentrations where the soil can be allowed used for some purposes in Denmark. From the fourth soil of the investigation, 92 % Pb was removed during 14 days, but as the initial concentration was very high (33.6 g Pb/kg), the final concentration was still high and the soil maintained classified where there are no reuse options in Denmark, so optimization of the treatment for this soil is necessary to meet the goal. The good results were obtained even without optimization of processing parameters, but the investigation underlined that the optimal parameters are highly soil and pollution specific.

Recycling and reuse of very low level radioactive steel in motorway tunnel scenario

Since a number of nuclear power plants are approaching the end of their lifetime is continuously increasing, decommissioning issues and radioactive waste management have become widely discussed topics. Considerable amounts of materials arising from decommissioning could be categorized as very low level radioactive waste. In line with international incentives for optimization of radioactive material management, alternative concepts of recycling and reuse of materials are suggested, analyzed and discussed. One of these concepts of such optimization is the conditional clearance of materials with their subsequent recycling and reuse in the industrial sector. The present paper describes an option of recycling and reuse of conditionally cleared steel in motorway tunnels.The analyzed scenario assumes that very low level radioactive steel would be reused in the form of steel reinforcing components, such as reinforcing mesh and bars, assembled in the primary and secondary linings of a motorway tunnel.However, prior to real application, a radiological impact assessment has to be done in order to prove compliance with radiation protection criteria. Methodology for implementation of the concept of conditional clearance was created and applied on two selected NPPs located in the Slovak Republic, which are currently under decommissioning. Assessment of relevant exposure pathways, which are likely to occur in the analyzed scenario, was performed.The aim of the paper is to derive and to justify new clearance levels for each radionuclide contained in steel reinforcement components in order to reuse the maximum amount of very low level radioactive steel considering radiation protection criteria. An increase of recyclable amount of radioactive steel could bring benefits in the form of saving considerable financial resources.

Applying a multi-criteria genetic algorithm framework for brownfield reuse optimization: Improving redevelopment options based on stakeholder preferences

The reuse of underused or abandoned contaminated land, so-called brownfields, is increasingly seen as an important means for reducing the consumption of land and natural resources. Many existing decision support systems are not appropriate because they focus mainly on economic aspects, while neglecting sustainability issues. To fill this gap, we present a framework for spatially explicit, integrated planning and assessment of brownfield redevelopment options. A multi-criteria genetic algorithm allows us to determine optimal land use configurations with respect to assessment criteria and given constraints on the composition of land use classes, according to, e.g., stakeholder preferences. Assessment criteria include sustainability indicators as well as economic aspects, including remediation costs and land value. The framework is applied to a case study of a former military site near Potsdam, Germany. Emphasis is placed on the trade-off between possibly conflicting objectives (e.g., economic goals versus the need for sustainable development in the regional context of the brownfield site), which may represent different perspectives of involved stakeholders. The economic analysis reveals the trade-off between the increase in land value due to reuse and the costs for remediation required to make reuse possible. We identify various reuse options, which perform similarly well although they exhibit different land use patterns. High-cost high-value options dominated by residential land use and low-cost low-value options with less sensitive land use types may perform equally well economically. The results of the integrated analysis show that the quantitative integration of sustainability may change optimal land use patterns considerably.

Occurrences and fate of an antibiotic amoxicillin in extended aeration-based sewage treatment plant in Delhi, India: a case study of emerging pollutant

In recent years, pharmaceutical and personal care products (PPCPs) have been detected in various environmental matrices, including ground water, surface water, and municipal wastewater. In order to evaluate the impact of PPCPs on environment, their distribution must be accurately established in these matrices first, as very limited studies have been carried out especially in the Indian subcontinent. In this study, the occurrence and removal of an antibiotic, Amoxicillin, at a sewage treatment plant (STP) located in Delhi has been studied. Amoxicillin was selected for its widespread use as a prescribed over the counter drug.Sampling exercises were carried out over a period of six months so as to cover seasonal variations. Sewage samples were collected from the influents and effluents of STP to determine the occurrences and removal of the amoxicillin. Concentration of amoxicillin in the untreated raw sewage at the STP varied from “not detected” (ND) to 172.6 ng L-1. After treatment, it varied from ND to 62.5 ng L-1. Average removal efficiency was 49.7%. Presently, there is great focus on the reuse of the treated sewage. So, findings of the study can help to build a better understanding of reuse options for treated effluents and preparation of appropriate water resources management plans.

Water security and its challenges for Malaysia

Water Security in Malaysia is a national issue. The Malaysian water services industry faces issues which need to be tackled immediately for it to be viable and sustainable. Among them are the decentralized water services sector, ineffective governance structure, unsustainable tariffs, huge investments required to develop the water supply and sewerage infrastructure, inefficient operation by the operators and high non-revenue water (NRW) losses. In Malaysia, the "Sectorial" approach embedded in the present water management system and its transformation towards "Integrated Water Resources Management" (IWRM), is still in a state of inertia. This paper presents the need to transform, from a "Supply" Management mode (a characteristic of a developing country) to a "Water Demand" Management mode (a characteristic of a developed country). Issues on "Water Demand" Management for the Environment which can be a threat to the need for sustainable development for biodiversity are highlighted here. Reliable water accounting systems are found still lacking in this country, especially in the Agriculture and Environmental Sectors, where figures are still highly based on "traditional" assumptions. Water Quality deterioration remains an issue especially for the Water Supply and Environment Sectors. Available surface water resource is depleting in many regions and states in the Peninsular. Apart from the Reduce, Reuse and Recycle (3R) option for surface water, another option would be to begin a concerted effort for groundwater exploitation. However there are still grey areas of knowledge in the groundwater resources in this country for affirmative decisions and development of appropriate policies. It is also found that, there are no concerted plans to prepare the public for the change from "Supply" Management to "Demand" Management. In a developed nation, this change is through stakeholder platforms and supported by appropriate policies, rules and regulations that are based on validated Sciences, Technologies and Innovations (STI). Transforming from "Supply" Management to "Demand" Management is a formidable task. This requires the wisdom and knowledge of all experts in the Water Resources Sector.

Organic and nutrient reduction in a fish processing facility – A case study

Fish processing plant consumes relatively large quantity of water and generates equally large volumes of wastewater with high organic and nutrient strength that must be pre-treated prior to sewer discharge. As the trade waste regulations are becoming more stringent now days, it is important that this high strength wastewater should be treated through better water management strategy. This requires huge investments for effluent treatment plants in order to meet the required specification for the trade waste discharge. A major squid and scallops processing plant is presented as a case study to highlight the interrelated issues of the resultant deterioration in water quality and the economic consequences of this impact. The main objective of this study is to develop a wastewater management plan for this processing plant that would address key issues required to meet trade waste limits. The characteristics of wastewater streams generated from various sources have been analysed and have the potential of being reused within the fish processing plant have also been identified. The results of the analysis of various key water quality parameters provided a basis for the selection and identification of feasible options for wastewater treatment, reuse and recycling.

Morphology and Physical Analysis of Waste Paper Sludge Ash (WPSA) Polymeric Mortar

Waste paper sludge ash (WPSA) is a byproduct and problematic waste of paper industries. The investigation was driven by the increasing demand for reuse options in paper-recycling industry. This paper present on the morphology and physical analysis studies on polymerization of WPSA mortar. Two (2) types of polymeric mortar mixes containing WPSA with alkaline activators and without alkaline activators were prepared. The morphology of each mixes was determined using Spectra Electron Microscope (SEM) and the physical test is focus on compressive strength. However, the element diffraction of each mixes using Energy Dispersive X-Ray Spectroscopy (EDX) was also carried out as a method to identify the polymerization of polymeric mortar. From the result obtained it is found that the utilization of WPSA reduced the polymerization of polymeric mortar due to more pores. From the EDX analysis it is also revealed that the WPSA polymeric mortar also contained less synthetic aluminous silicate compound. However, the strength gain up to 6MPa and it is comparable with other high calcium material mortar.

Academics perception towards various water reuse options: University of Trás-os-Montes e Alto-Douro - UTAD Campus (Portugal) as a case study

Any strategy of water reuse has to achieve social acceptance to be successful. This paper presents the results of a multiple choice survey that attempted to establish the general attitude toward water reuse by asking academics in UTAD (Portugal) a wide range of questions. The survey included 20 reuse options, which were clustered into three reuse categories, specifically: low, medium and high contact levels. Correlation analysis between the level of support of low, medium and high contact options and demographic characteristics, personal and environmental beliefs was performed.Results show that a high proportion of the participants supported low and medium contact reuse options. Correlation was found to exist between the income classes and to the level of support of medium and high reuse options and between education level and the support for high contact reuse options.The responses to the survey suggested that some beliefs influence the level of support.

Community Engagement and Environmental Life Cycle Assessment of Kaikōura’s Biosolid Reuse Options

This paper reports a life cycle assessment undertaken to assess the environmental impact of a range of biosolid reuse options selected by the Kaikōura community. The reuse options were identified as: vermiculture and open-air composting; mixture with biochar; direct land application to disturbed sites for forestry using native tree species; and application to exotic forestry plantations or pastoral farmland. The aim of the study was to calculate the possible environmental impacts of the reuse options so the information can be used in a community dialogue process where the fate of the biosolids is decided upon. All reuse options showed improved environmental performance relative to landfilling. The direct application to land options showed the least environmental impact and the composting options had the most environmental impact. This is the first time this approach has been applied to biosolids management in New Zealand, and whilst there are limitations, the approach should be encouraged in other communities because it increases the engagement of the community with waste management decision-making and the environment.

Climate Change Adaptation Indicators to Assess Wastewater Management and Reuse Options in the Mekong Delta, Vietnam

Climate change adaptation indicators have played a critical role in the increased understanding of potential climate change impacts. In this research, 6 climate change adaptation indicators were identified for Can Tho City in the Mekong Delta of Vietnam: (1) Rice production from wastewater during winter-spring crop; (2) % of irrigation water demand satisfied by treated wastewater; (3) % of nutrient demand satisfied by treated wastewater; (4) % remaining flow downstream of Can Tho in the Hau River; (5) environmental benefits; and (6) total investment cost for wastewater treatment. These indices were selected to assess various options/strategies for wastewater management and reuse in Can Tho City as a means to improve the City’s resilience to climate change. From an environmental perspective, this study shows the benefits for Can Tho City to set up a strategy to treat and reuse wastewater from catfish farming as the priority among four assessed scenarios with different climate change impact factors. It is concluded that adaptation can be assessed by the indicators because they can define whether adaptation policies and measures are implemented and whether vulnerability is reduced through effective actions.

Evaluation of gradual hydroponic system for decentralized wastewater treatment and reuse in rural areas of Palestine

A pot experiment was conducted to evaluate the performance of a gradual multi-stage vertical flow hydroponic system as an option for decentralized wastewater treatment and reuse. The low cost of such option and the ease of its application make it feasible for rural areas where low cost decentralized options of wastewater treatment and reuse have a great potential in improving environmental and economic conditions in these areas. To evaluate the performance of such option, a five-stage vertical flow gradual hydroponic pot experiment was conducted in a greenhouse in the new campus of An-Najah National University. The experiment included five types of plants: two types of corn, barely, alfalfa, and sunflowers. Wastewater flow was applied through a drip system for the five types of plants. Wastewater was drained by gravity from one pot to the next through a gradual vertical flow hydroponic system. Quality of wastewater entering the first pot and leaving the last pot for each set of plants was monitored throughout the growing season. Results showed an over 90% removal efficiency of soluble organics and suspended solids, and about 60% removal efficiency of nitrogen through the system. The proposed gradual hydroponic treatment system was proved to be a successful alternative method to treat and reuse wastewater. Thus, gradual hydroponic systems could be successfully used as small decentralized wastewater treatment systems. This system could be used in producing crops with economic returns in Palestinian rural areas, where agriculture has a significant contribution in the income and employment of communities.

A Decision Support Methodology for Integrated Urban Water Management in Remote Settlements

This paper describes a decision support methodology for the selection of a wastewater treatment system based on integrated urban water management principles for a remote settlement with failing septic systems. Thirty-two service and treatment technologies options were considered, these included: (i) conventional gravity sewerage, (ii) common effluent drainage, (iii) community sewage treatment plant based on various technology options (lagoon treatment, Living Machine®, sequencing batch reactor, membrane biological reactor, rotating biological contactor, recirculating textile filter, extended aeration) with and without urine separation, greywater diversion or treatment and reuse at household scale. The options were assessed using a framework that considered technical, economic, environmental and social factors relevant to the local community and associated stakeholders (water utility, government agencies) and tools such as engineering design, life cycle assessment and multi-criteria analysis for evaluation of overall sustainability. Adoption of a systems approach allowed the identification of benefits and trade-offs among stakeholders creating opportunities for adoption of more innovative treatment options and maximisation of the sustainability of the service. The treatment option that maximised the social, environmental and economic benefits for the settlement consisted of individual households adopting greywater treatment, storage and reuse, urine separation and a community wastewater treatment plant with recirculating textile filter technology. This solution provided the required sanitation, increased the sources of water supply to residents, satisfied environmental regulator requirements, minimised nitrogen discharge to waterways and provided an option for beneficial reuse of urine for neighbouring farmers at a cost and management needs acceptable to the water utility.

Challenges to treated wastewater reuse in arid and semi-arid areas

This paper evaluates technical, legal, social and economic challenges facing treated wastewater in the West Bank as an example of arid and semi-arid areas. Although treated wastewater reuse is recognized as a strategic option in augmenting agricultural water supplies in arid and semi-arid areas, there are many challenges that face the utilization. Legal challenges include adopting relevant and appropriate standards for reuse, which could be implemented at the farm level. Social and economic considerations should be considered in developing reuse options and strategies. In the West Bank, treated wastewater reuse standards and guidelines have been adopted. Field surveys and interviews with farmers showed that farmers are willing to irrigate many crops utilizing treated wastewater. However, this study shows that there are discrepancies between what farmers are willing to implement and what planners and policy makers would recommend. Farmers indicated a good understanding of the technical solutions on how to make treated reuse safe and technically sound. However, emphases on social and economic implications are highly essential for the success of reuse. Surveys of farmers showed that they need to understand and know the economic costs, returns and benefits of the different qualities of treated wastewater (TWW) to select appropriate reuse alternatives. Therefore, public awareness campaigns are highly needed to address the legal, social, economic and institutional consideration for TWW reuse. Participation of farmers in developing guidelines, standards, policies and plans for agricultural reuse is very important for the sustainability of treated wastewater reuse.

Comparison of GCM simulations and reconstructions for the last 2k

Red mud remains the largest environmental issue for the alumina industry due to its high pH (>13), fine-grained nature (>90% is <10 μm), elevated sodium concentration (>50 g/kg), and soluble alkalinity (≈30 g/kg as equivalent CaCO3), which reduce the transport and reuse options of red mud. The neutralization of red mud provides potential reuse options because neutralization lowers pH, increases grain-size (e.g., coagulation), and precipitates or converts alkalinity. This paper investigates the geochemistry of 3 treatments of a red mud to affect neutralization and potentially convert materials from a waste material to a resource. This study investigates two commonly used neutralization techniques, a CO2-neutralized red mud (CNRM), a Basecon™-neutralized red mud (Basecon™), and a more novel approach of a CO2-neutralization followed by a Basecon™-neutralization (Hybrid) to understand the effects that these treatments have on neutralization process. Data indicate that the neutralization techniques form two distinct geochemical groups when discriminated on total alkalinity alone, that is treatments with, and treatments without alkalinity precipitation. However, each treatment has distinct alkalinity speciation (hydroxide-dominant or carbonate/bicarbonate dominant) and residual Ca, Mg and Al in the treatment solution. Similarly, solids produced differ in their reaction pH and ANC, and contrary pH and ANC, a contrary to other studies, Dawsonite was not seen to precipitate during any neutralization. However, despite this approximately 17 g/kg CO2 was sequestered during CNRM and hybrid neutralizations and all treatments increased either the transport or reuse options of red mud in some way.

Evaluation of environmental pollution and possible management options of heavy oil fly ash

Due to the presence of toxic metals, dumping of heavy oil fly ash (HOFA) is causing ever-growing environmental problem including the pollution of air, water and soil. The present study investigates the possible environmental impacts associated with the land disposal of HOFA generated in the power plant. Different modeling and laboratory analysis were integrated to address the real environmental problems. Leaching behavior of heavy metals within the HOFA were investigated by laboratory batch leaching tests, which confirmed that most of the toxic elements in the HOFA can easily leach into the environment with rain water. The level of atmospheric dust surrounding a HOFA dumping site was predicted using the Industrial Source Complex (ISC3) air dispersion model, and the results indicated that the dumping of HOFA could be a potential hazard for local air quality. The study also revealed different reuse options of HOFA. The characteristic analysis confirmed HOFA can be used as a natural adsorbent to remove pollutants from wastewater or as soil stabilizing material by blending with cement.

Two years monitoring of the natural system for wastewater reclamation in Santa Lucía, Gran Canaria Island

The objective of this work is to describe the performance of the Santa Lucía natural system for wastewater reclamation (NSWWR) in its first two operating years, where it was run under distinct conditions from the initial design. This plant, located in the island of Gran Canaria, has yielded a wealth of information on the implementation of low-cost technologies in subtropical areas with water scarcity, both ecologically as well as socially sustainable, and the option of installing similar plants in coastal zones. The system also served as a local pilot plant for a natural technology of wastewater reclamation, alternative to conventional solutions, whether centralized or onsite, usually applied for the treatment of domestic wastewater in rural areas. In fact, over the years local wastewater treatment has demonstrated clear advantages: no need for electricity, no leakage of raw sewage along the sewerage systems, social and landscape integration, exploitation of by-products like macrophyte-derived material for local handcrafts, and reuse of reclaimed water for irrigation. Remarkably, the plant operated under forced conditions of a hydraulic overload of 200%; however, the influence of a climate with stable mean temperatures and mild winters may have contributed to a satisfactory overall performance. Mean removal efficiencies were even higher than expected: more than 80% for biochemical and 75% for chemical oxygen demand (BOD5 and COD), and 90% for total suspended solids (TSS). Mean decrease of nitrogen and phosphorus were 50 and 30%, respectively, while abatement of fecal indicators attained 2log units. The data collected from the Santa Lucia wastewater reclamation system represent an exceptional case study, which may be potentially transferred to other rural or littoral communities that lack sanitation and reclamation systems. Moreover, the option of wastewater reuse and zero discharge is particularly attractive for arid zones.

Growing floricultural crops with brackish water

In the current review we focus on the opportunity to use brackish water in the cultivation of floricultural plants, plants for which, due to their high economic value, growers have traditionally used good quality water for irrigation. Now, even for these crops the use of alternative water sources for irrigating nursery plants is needed because of the limited supplies of fresh water in many countries; understanding how saline water can be used will also enhance sustainable development in floriculture. While salt stress usually reduces plant growth, any such reduction might not be negative for ornamentals, where shoot vigour is sometime undesirable, although on flower crops salt stress can delay flowering or decrease flower quality characteristics. However, a decrease in growth rate is not enough to characterize the salt tolerance of ornamental plants, but traits like tip and marginal leaf burn, as consequence of sodium and chlorine accumulation, have to be considered for their effects on aesthetical value. With this in mind, some halophytes should be considered for floriculture because of their ability to cope with saline environments; their potential to tolerate salt is an important factor in reducing production costs. Consequently, the identification of ornamental halophytes is important for producing a commercially acceptable crop when irrigated with brackish waters. Many aspects of a plant's reaction to salt are genetically determined, so selection of suitable genotypes or breeding for salt tolerance in ornamentals are interesting options. Developing salt-tolerant floricultural crops, together with typical management practices that avoid excessive salinity stress in the root media, will provide the grower with economically and environmentally sound wastewater reuse options.

Effect of previous coagulation in direct ultrafiltration of primary settled municipal wastewater

Direct ultrafiltration of primary settled municipal wastewater can be a feasible option for water reuse in several applications by avoiding biological treatment. This paper discusses the effect of previous clarification by coagulation/sedimentation of raw wastewater on ultrafiltration performance and its relationship with the main operation parameters in dead-end mode (flux and backwashing duration). Reversible and residual membrane foulings in a hollow-fibre bench-scale unit were determined over a broad range of filtration parameters and coagulant doses used in the previous clarification of domestic wastewater. Moreover, results were also compared with those obtained by ultrafiltration of biologically treated effluent from a conventional WWTP. Reversible membrane fouling, which can be described by the cake formation model, seems mainly caused by the colloidal fraction of the wastewater. In fact, under optimal coagulant dosage, the cake resistance values (expressed by αω, in m−2) were similar to those obtained with the secondary effluent. Direct observation of the membrane surface suggests a solid accumulation in the vicinity of the membrane after backwashing, which could justify the increase in cake resistance during the initial filtration/backwashing cycles until steady-state conditions are reached. Residual fouling resistance decreased exponentially with the duration of backwashing, obtaining a limit resistance value which was independent of the coagulant dose. Moreover, high efficiency of chemical oxygen demand (COD) removal was achieved by the tested treatment train, regardless of the coagulant dose and the initial quality of the primary effluent.

Properties of wastepaper sludge in geopolymer mortars for masonry applications

This paper presents the results of an investigation into the use of wastepaper sludge in geopolymer mortar systems for manufacturing construction products. The investigation was driven by the increasing demand for reuse options in paper-recycling industry. Both fresh and hardened geopolymer mortar properties are evaluated for samples incorporating dry wastepaper sludge, and the results indicate potential end-use benefits in building product manufacture. Addition of wastepaper sludge to geopolymer mortar reduces flow properties, primarily due to dry sludge absorbing water from the binder mix. The average 91-day compressive strength of mortar samples incorporating 2.5 wt% and 10 wt% wastepaper sludge respectively retained 92% and 52% of the reference mortar strength. However, contrary to the normal trend of increasing drying shrinkage with increasing paper sludge addition to Portland cement matrices, the corresponding geopolymer drying shrinkage decreased by 34% and 64%. Equally important, the water absorption of hardened geopolymer mortar decreased with increasing paper sludge content at ambient temperatures, providing good prospects of overall potential for wastepaper sludge incorporation in the production of building and masonry elements. The results indicate that, despite its high moisture absorbance due to the organic matter and residual cellulose fibre content, wastepaper sludge appears compatible with geopolymer chemistry, and hence serves as a potential supplementary additive to geopolymer cementitious masonry products.

Atomized sludges via spray-drying at low temperatures: An alternative to conventional wastewater treatment plants

Removal of sludges from Wastewater Treatment Plants (WWTP) represents a serious worldwide environmental problem for which alternatives other than their simple incineration are investigated. In this work the treatment of raw sludge from urban WWTP by means of a minimization process through spray-drying is analyzed as well as some proposals for revaluating the resulting dry product. Analysis is supported by some experimental results obtained with a laboratory spray dryer. The experimental procedure at laboratory scale is extrapolated to an industrial plant scale. An economic analysis of the proposal in relation to other possible sludge treatments is presented, taking into account in this case the comparison between the costs of the processes of sludge thickening, stabilization and dehydratation and the costs of spray-drying (especially power consumption), minimization of the final waste and reuse options. Finally, an environmental balance of the process is presented. In contrast with the classical treatment line, this alternative allows transforming sludges, i.e., a waste, into a valuable product with several applications.