Treatment Of Waste Streams Research Articles

Decontamination of spent ion-exchangers contaminated with cesium radionuclides using resorcinol-formaldehyde resins

The origin of the emergence of radioactive contamination not removable in the process of acid-base regeneration of ion-exchange resins used in treatment of technological media and liquid radioactive waste streams has been determined. It has been shown that a majority of cesium radionuclides not removable by regeneration are bound to inorganic deposits on the surface and inside the ion-exchange resin beads. The nature of the above inorganic inclusions has been investigated by means of the methods of electron microscopy, IR spectrometry and X-ray diffraction. The method of decontamination of spent ion-exchange resins and zeolites contaminated with cesium radionuclides employing selective resorcinol-formaldehyde resins has been suggested. Good prospects of such an approach in deep decontamination of spent ion exchangers have been demonstrated.

The full-scale anaerobic digestion microbiome is represented by specific marker populations

Anaerobic digestion is a well-established microbial-based technology for the treatment of organic waste streams and subsequent biogas recovery. A robust and versatile microbial community to ensure overall stability of the process is essential. Four full-scale anaerobic digestion plants were followed for one year to link operational characteristics with microbial community composition and structure. Similarities between digesters, community dynamics and co-occurrence between bacteria and archaea within each digester were analysed. Free ammonia concentration (>200 mg N L−1) and conductivity (>30 mS cm−1) hindered acetoclastic methanogenesis by Methanosaetaceae. Thus, methanogenesis was pushed to the hydrogenotrophic pathway carried out by Methanobacteriales and Methanomicrobiales. Firmicutes dominated the overall bacterial community in each of the digesters (>50%), however, principal coordinate analysis of Bray-Curtis indices showed that each of the four digesters hosted a unique microbial community. The uniqueness of this community was related to two phylotypes belonging to the Syntrophomonas genus (Phy32 and Phy34) and to one unclassified bacterium (Phy2), which could both be considered marker populations in the community. A clear differentiation in co-occurrence of methanogens with several bacteria was observed between the different digesters. Our results demonstrated that full-scale anaerobic digestion plants show constant dynamics and co-occurrence patterns in function of time, but are unique in terms of composition, related to the presence of marker populations.

Self-sustaining carbon capture and mineralization via electrolytic carbonation of coal fly ash

This study presents a new electrolytic carbonation process to synergize the treatment of different waste streams generated by power plants, including fly ash, brine wastewater, and CO2. The acidity generated by electrolysis of brine electrolyte directly liberates calcium from fly ash. The metal ions balance the OH− produced at the cathode to form hydroxide, which then fixes CO2 into high purity carbonate precipitates. Results show that electrolysis increased fly ash dissolution by 32.4% compared to the control with spontaneous dissolution of fly ash, and the carbonation process captured 89% more CO2 and increased capture capacity from 9.75 to 18.42kg-CO2/t-fly ash in the NaCl electrolyte. The energy expenditure was 19.4–29.3kJ/mol-CO2, lower than that required for sorbent or solvent based post-combustion carbon capture. The process takes advantage of all waste streams generated on site and can consolidate traditionally separated treatment processes to save costs, produce energy and value-added products, as well as generate carbon benefits.

Application of sorption-reagent materials in the technology of liquid radioactive waste treatment

Some examples of sorption-reagent materials and variants of their application in the practice of treating liquid radioactive waste have been considered. The data on the strontium sorption on samples of a sorption-reagent material under dynamic conditions at different degrees of dilution and different concentrations of seawater have been presented. These data demonstrate that the most efficient practical applications of sorption-reagent materials consist of decontaminating of seawater concentrates of strontium radionuclides. This task is stated during treatment of liquid radioactive waste (LRW) streams at the Fukushima-1 NPP (Japan), where reverse osmosis concentrates constitute the main problem of localization of the aftermath of the disaster that occurred in 2011.

Hydrogen sulfide reformation in the presence of methane

This paper provides experimental investigation on the potential of hydrogen production from hydrogen sulfide and methane mixtures in nitrogen. The reformation of H2S in natural gas represents a viable alternative option for the treatment of acid gases extracted from gas wells that contains H2S, CH4 and N2 in the gases without their separation, using for example, the amine process to remove H2S. A laboratory-scale quartz reactor was used to investigate experimentally the effect of temperature and inlet stream composition on the production of hydrogen from a mixture of hydrogen sulfide and methane diluted in nitrogen. The results reveal the important role of reactor temperature on the decomposition of both hydrogen sulfide and methane as well as the production of hydrogen. The results also showed that the production of hydrogen increased dramatically at temperatures exceeding 1473K wherein the conversion of hydrogen sulfide is more significant. The methane was consumed at temperatures above 1373K. The conversion of hydrogen sulfide in presence of methane was higher than that in case of hydrogen sulfide only. The carbon disulfide formed during the reformation process increased with increase in temperature. These results provide favorable reactor operational conditions for the reformation of methane with hydrogen sulfide. These results also provide a viable alternative option for the treatment of various waste streams containing hydrogen sulfide to produce clean hydrogen and sulfur.

Methods for increasing the rate of anammox attachment in a sidestream deammonification MBBR.

Deammonification (partial nitritation-anammox) is a proven process for the treatment of high-nitrogen waste streams, but long startup time is a known drawback of this technology. In a deammonification moving bed biofilm reactor (MBBR), startup time could potentially be decreased by increasing the attachment rate of anammox bacteria (AMX) on virgin plastic media. Previous studies have shown that bacterial adhesion rates can be increased by surface modification or by the development of a preliminary biofilm. This is the first study on increasing AMX attachment rates in a deammonification MBBR using these methods. Experimental media consisted of three different wet-chemical surface treatments, and also media transferred from a full-scale mainstream fully nitrifying integrated fixed-film activated sludge (IFAS) reactor. Following startup of a full-scale deammonification reactor, the experimental media were placed in the full-scale reactor and removed for activity rate measurements and biomass testing after 1 and 2 months. The media transferred from the IFAS process exhibited a rapid increase in AMX activity rates (1.1 g/m(2)/day NH(4)(+) removal and 1.4 g/m(2)/day NO(2)(-) removal) as compared to the control (0.2 g/m(2)/day NH(4)(+) removal and 0.1 g/m(2)/day NO(2)(-) removal) after 1 month. Two out of three of the surface modifications resulted in significantly higher AMX activity than the control at 1 and 2 months. No nitrite oxidizing bacteria activity was detected in either the surface modified media or IFAS media batch tests. The results indicate that startup time of a deammonification MBBR could potentially be decreased through surface modification of the plastic media or through the transfer of media from a mature IFAS process.

A study of membrane distillation and crystallization for lithium recovery from high-concentrated aqueous solutions

Membrane distillation is emerging as an interesting solution to address the difficulties and limits of conventional pressure driven membrane processes to treat highly concentrated solutions. Mineral depletion, new environmental regulations and emerging opportunities emphasize the treatment of waste streams with extraordinary high concentrations. In this current study, comparative analysis of membrane crystallization in direct-contact, osmotic and vacuum configurations have been carried out with the aim to recover lithium chloride from aqueous solutions. To precipitate LiCl from single salt solutions, a concentration above 14M is required. The osmotic pressure associated with this concentrated solution is very high and its treatment is challenging for direct-contact membrane distillation and osmotic membrane distillation. The phenomena of osmotic pressure has been avoided by using vacuum membrane distillation. Only the application of vacuum membrane distillation, among the studied configurations, ensures the achievement of supersaturation required for crystallization. Moreover, studies on crystal morphology has been performed. Crystals can be recovered in cubic or orthorhombic polymorphic structures depending on the operative conditions. In general, this study provides an interesting comparative analysis of various membrane distillation configurations to treat highly concentrated solutions, which can contribute to the future integrated membrane desalination systems for simultaneously water, energy and minerals production.

Simplifying Treatment for Complex Waste Streams: Oil and Gas Produced Water and Fracturing Flowback Wastewater

Simplifying Treatment for Complex Waste Streams: Oil and Gas Produced Water and Fracturing Flowback Wastewater

Generation of PHB from Spent Sulfite Liquor Using Halophilic Microorganisms.

Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB.

Resource recovery from anaerobic digestate: struvite crystallisation versus ammonia stripping

The wide application of anaerobic digestion for the treatment of organic waste streams and high-loaded wastewater results in the production of high quantities of anaerobic effluents. Such effluents are characterised by high nutrient content, this is why struvite crystallisation and ammonia stripping have gained interest as routes to nitrogen and phosphorus recovery. Pros and cons of both technologies have been analysed in this paper. Ammonia stripping coupled with absorption proved to be a suitable technical solution for the recovery and valorisation of the nitrogen contained in waste streams. Laboratory-scale experiments result in more than 80% of ammonia recovery using this technique. However, since the crystallisation process can simultaneously remove and recover more than 90% P and N in stoichiometric ratio (according struvite formulation) from waste streams, it is considered the preferred technique. Both processes are environmentally friendly and cost-effective in large-scale facilities although economics slightly favour the struvite formation.

Waste to Energy – Energy Recovery of Green Bin Waste: Incineration/Biogas Comparison

This study presents how to determine marginal incinerator energy efficiencies. This concept should be applied in assessments of the treatment of specific waste streams to create a level playing field when comparing different technologies, for instance in life-cycle assessments. The marginal efficiencies depend on the technical level, the surrounding energy system, and the waste type/heating value. The concept of marginal efficiency is in this article applied to the treatment of green bin waste. The thermal treatment options considered are incineration and anaerobic digestion with biogas combustion in a reciprocating gas engine. The comparison is made only with regard to energy yield. The comparison is carried out for three different types of energy systems: power producing, combined heat and power, and combined heat and power with flue gas condensation. For a power-only energy system, the electrical efficiency of anaerobic digestion is found to be comparable to incineration. However, for an energy system with district heating as an option, the energy recovery of incineration is much higher than biogas. Furthermore, if the waste heat recovery technology flue gas condensation is used, the total efficiency of incineration is almost twice as high as the biogas technology, with the same boundary conditions applied. Although this study produces specific figures of energy recovery yields for a number of different scenarios for incineration and biogas production, the aim of the study is not a technology comparison as such. A proper technology comparison, including life-cycle assessments, should deal with many other issues than just energy recovery, for instance, other environmental factors, initial cost, operating and maintenance costs, and commercial aspects. However, this study does show that when undertaking such technology assessments, it is crucial to the results that: • Proper and relevant boundary conditions are applied: if district heating is possible, this changes results dramatically. Optimally, a specific site should form the basis for a comparison. • Energy recovery efficiencies must be linked to the actual waste steam considered. For green bin waste, this study has shown that margin efficiencies of up to 125 % can be achieved. This is much higher than efficiencies reported in the literature (95 %) [1•, 2•]. Therefore, one main conclusion is that efficiencies used for comparisons of technology must be waste-type (and calorific-value) specific to obtain reliable results in the comparisons.

Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment

Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl− ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl2/HClO/ClO−), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO− species led to the production of ClO3− and ClO4− ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment.

Characteristics of Potassium Acetate - Activated Coconut Shell Carbon

There is significant portion of agricultural wastes in the world posing environmental challenge; however, they could be converted into useful products like activated carbon. In this study, coconut shell based carbons were synthesized using chemical activation with potassium acetate (PAAC), potassium hydroxide (PHAC) and physical activation by CO2 (CSAC). The properties of potassium acetate-activated carbon were characterized and the results were compared with the other activation methods. The pyrolysis temperature of 700°C for 2h yielded 32% of char. The BET surface area and pore volume of PAAC are 622m2/g and 0.31cm3/g; while 369m2/g and 0.19cm3/g, and 1354m2/g and 0.61cm3/g were recorded for CSAC and PHAC, respectively. CSAC yielded lower surface area with approximately 88% micropores. On the other hand, PAAC yielded higher surface area with approximately 50% of both micropores and mesopores, whereby this heteroporous property would suffice for a wider range of application. From the Fourier Transform Infrared Spectroscopy analysis, hydroxyls, alkenes, carbonyls and aromatics functional groups were identified with more prominent peaks on the chemically activated porous carbons. From thermogravimetric analysis (TGA), lignin decomposition occurred in a wider temperature range (390-650°C). The properties of PAAC could offer a sustainable means for treatment of toxic waste streams.

Moving from recycling to waste prevention: A review of barriers and enables.

Current European waste policy does not mainly aim to treat waste streams but rather place in the foreground of interest the complete supply chain of a product. Waste prevention and re-use do have the highest priority and they take effect before the end-of-life phase of a product or a material is reached. Recycling only takes the third place whereas recovery and disposal represent the least favourable options. Recycling can help to decrease the consumption of primary resources but it does not tackle the causes but only the symptoms. In principle, recycling processes require energy and will generate side streams (i.e. waste). Furthermore, there are insuperable barriers and the practice is far from 100% recycling. The philosophy of waste prevention and re-use is completely different since they really tackle the causes. It is self-evident that a decrease of waste will also decrease the consumption of resources, energy and money to process the waste. However, even if European legislation is proceeding in the right direction, a clear decrease in waste generation did not occur up to now. Unfortunately, waste generation represents a positive factor of economic growth. Basically, waste generation is a huge business and numerous stakeholders are not interested to reduce waste. More sophisticated incentives are required to decouple economic growth from waste generation.

Microbial diversity in innovative mesophilic/thermophilic temperature-phased anaerobic digestion of sludge.

Anaerobic digestion (AD) is one of the few sustainable technologies that both produce energy and treat waste streams. Driven by a complex and diverse community of microbes, AD may be affected by different factors, many of which also influence the composition and activity of the microbial community. In this study, the biodiversity of microbial populations in innovative mesophilic/thermophilic temperature-phased AD of sludge was evaluated by means of fluorescence in situ hybridization (FISH). The increase of digestion temperature drastically affected the microbial composition and selected specialized biomass. Hydrogenotrophic Methanobacteriales and the protein fermentative bacterium Coprothermobacter spp. were identified in the thermophilic anaerobic biomass. Shannon-Weaver diversity (H') and evenness (E) indices were calculated using FISH data. Species richness was lower under thermophilic conditions compared with the values estimated in mesophilic samples, and it was flanked by similar trend of the evenness indicating that thermophilic communities may be therefore more susceptible to sudden changes and less prompt to adapting to operative variations.

Investigation of Microalgae Co-Cultures for Nutrient Recovery and Algal BiomassProduction from Dairy Manure

<abstract> <bold><sc>Abstract. </sc></bold>Treatment of waste streams using algae can minimize eutrophication by removing inorganic nutrients while producing biomass which can be used for biofuels, animal feed, and fertilizer production. While there are many studies that report the growth of individual algal strains in different media, there are relatively few studies that examine the performance of algae coculture. The objective of this research was to determine the growth parameters and nutrient sequestration profiles of Chlorella vulgaris, Scenedesmus dimorphus, and their coculture in wastewater from a dairy facility at two dilutions (10% and 25%). Average specific growth rates (and biomass concentrations) the S. dimorphus, C. vulgaris, and their coculture were 0.263 d^-1 (0.290±0.059 g/L), 0.063 d^-1 (0.145±0.011 g/L), and 0.250 d^-1 (0.400±0.060 g/L) d^-1 at 10% manure, and 0.232 d^-1 (0.543±0.149 g/L), 0.234 d^-1 (0.364±0.113 g/L), and 0.289 d^-1(0.612±0.255 g/L) at 25% manure, respectively. Based on the results it was evident that the strains S. dimorphus and C. vulgaris have different capacities for accumulation of biomass production (S. dimorphus is higher), lipid accumulation (S. dimorphus is higher), chlorophyll (C. vulgaris is higher), total suspended solids (TSS) (C. vulgaris is higher), and volatile suspended solids (VSS) (S. dimorphus is higher). It was found that mixed coculture had higher biomass growth, specific growth rate, and removal efficiency of nitrogen, phosphorous, and TSS for the 25% dairy wastewater. The results were similar for 10% dairy wastewater except for the specific growth rate and nitrogen removal efficiency which were higher for the S. dimorphus monoculture. These capacities can be leveraged in mixed coculture to achieve higher treatment efficiencies compared to monocultures. The results can inform managers of agricultural and municipal wastewater facilities as they make decisions about whether to include algal technology in future upgrades and expansion.

Evaluation of heavy metal ions removal from acidic waste water streams

This study presents some purification processes of acidic waste streams including such heavy metals as Cu(II), Zn(II) and Ni(II) in the low and adjusted pH range as well as high NaCl concentrations, which are typical industrial conditions. A novel approach to the assembly of previously used processes skips the step of pH adjustment of the treated waste streams, which further reduces maintenance costs of waste streams. The study was conducted using macroporous ion exchange resins based on the polystyrene–divinylbenzene matrix: Lewatit TP 207 and Lewatit TP 208 – the chelating ion exchangers with the iminodiacetate functional groups and the medium base anion exchange resin Lewatit MonoPlus MP 64 with the quaternary ammonium and tertiary amine functional groups. Ion exchangers are characterized by high resistance to osmotic shock. The macroporous structure provides an ideal diffusion of Cu(II), Zn(II) and Ni(II), allowing the efficient exhaustion and regeneration. Beside the commercial form, Lewatit TP 207 and Lewatit TP 208 were used in the mono- and disodium forms.

Waste Problem and Management in Insular and Isolated Systems. Case Study in the Canary Islands (Spain)

The municipal waste management is becoming increasingly important in regional policies. While, on one hand there are currently high rates of recycling, it is also true that waste production grows exponentially. Waste management is a difficult task, but in the case of island territories is very complex, being isolated and limited territories. Also the need to establish a plan for restoration of degraded areas, as landfills must be considered. Given the continuous increase in the amount of waste managed, waste is one of the biggest problems facing environmental management in the Canaries. In small and limited spaces such as islands, even taking into account the increased capacity of waste recovery is where it has the greatest sense premise that “the best waste is not produced”. The Canary Islands lie with the challenge of developing a management model that solves the collection and treatment of new waste streams according to the EU, national and regional legislation. It has to be taken into account its character as an island with an important tourist population, which, although not considered legal population, is generating waste.

Removal of pesticide in agricultural runoff using granular-activated carbon: a simulation study using a fixed-bed column approach

The use of pesticide and its subsequent release to the environment is a major concern for modern society as concerns over environmental pollution associated with toxic emission are recognized due to contaminants present in pesticide (particularly malathion). Adsorption process using activated carbon is among the most effective techniques for the removal of pesticides in the treatment of various waste streams. The adsorption of pesticide containing malathion in agricultural runoff was investigated using granular-activated carbon (GAC) as the adsorbent; GAC made of coconut, and palm shells were used and their effectiveness in retaining the pesticide is discussed. A fixed-bed column test was performed to simulate the actual condition of adsorption in a continuous manner in a filtration process. Different flow rates were used to evaluate their effects on the column performance, where different breakthrough curves were obtained. The Adam–Bohart breakthrough curve equation was used to predict the breakthrough curve and to obtain the adsorption capacity of pesticide on GAC. The results showed that the Adam–Bohart equation fitted the experimental data well, and the use of a bed of GAC as the adsorbent in the set up showed high capacity in retaining the pesticide present in the aqueous solution, achieving removal efficiency at the rate of 71.4 and 82.9% for palm shell activated carbon and coconut shell activated carbon, respectively. Our results indicate that the use of GAC through adsorption process shows exceptional promise as a means for treating problematic pesticide in agricultural runoff.

Rural African renewable fuels and fridges: cassava waste for bioethanol, with stillage mixed with manure for biogas digestion for application with dual‐fuel absorption refrigeration

AbstractThe growth and processing of cassava (Manihot esculenta) in Africa produces a range of waste streams which are proving problematic due to their current mismanagement. Although a range of technical solutions exists to convert these waste streams into valuable products, there has been very little progress made in applying these solutions. This review provides a broad picture of the cassava waste issue in the context of African agriculture and bioprocessing. As an outcome of the review process the authors propose a simple and scalable two‐step process that biologically converts the waste streams into valuable products. The first step in the process is fermentation and distillation of the cassava waste to produce ethanol. The second step is the anaerobic digestion of the fermentation byproducts with other waste streams, including animal manure and human excrement, to produce biogas and biological fertilizers. Despite the scalability of this system, the focus of this review is the development of a conceptual system for rural smallholders to achieve multiple beneficial outcomes including treatment of multiple troublesome waste streams, production of a liquid biofuel, the provision of refrigeration through biogas powered absorption chillers, and the co‐production of organic fertilizers. © 2013 Society of Chemical Industry and John Wiley &amp; Sons, Ltd