Waste Processing

Solid waste from the decommissioning of coal-fired power plants collected from a power plant in Spain (Puertollano, Ciudad Real) was subjected to acid leaching tests in columns to evaluate the leachability of several valuable and toxic metals (Al, Ca, Fe, K, Mg, Na, Ti, V, Cr, Mn, Ni, and Zn). First, the contaminated waste, delivered by a national company, was chemically characterized. Second, column-leaching tests were conducted using two different acid solutions (nitric and sulfuric acid). The effect of the leaching agent concentration and time of leaching were examined. The results of column leaching tests showed that different concentrations of the acid solutions leached different proportions of Al, Fe, Mg, Mn, Ni, V, and Zn, which were leached by acid solutions from the solid waste sample. In general, use of sulfuric acid at pH 0.5 resulted in better leaching. Next, a comparison between three different configurations (one single stage without recirculation, one single stage wit...

The recovery of major components of bauxite residue by carbothermic reduction at 1550–1750 °C and subsequent slag leaching in a Na3CO3(aq) solution is studied. Iron recovers primarily to pig-iron and lime is added to tune the calcium aluminate slags towards the highly leachable mayenite phase. The concentration of aluminum in the leachate correlates well with the occurrence of mayenite and aluminum recoveries up to 50–60% are observed. However, slags with low CaO additions are vulnerable to gehlenite formation and display reduced leachabilities. Formation of an inhibiting layer of CaCO3(s) on the reaction surface of calcium-aluminate particles during leaching and immobilization of aluminum in CaTiO3(s) are also suggested to play important roles in limiting the aluminum leachability. Costs related to post-processing may be reduced by achieving disintegrating slags, a behavior which is observed for slags holding high γ- to β-Ca2SiO4 ratios. The disintegration is caused by the large vo...

We report the development of a process allowing the selective, sustainable recovery of Scandium (Sc) with 75% efficiency from Jamaican bauxite residue (red mud), a waste product from aluminum production. The process design is inspired by green chemistry principles and focuses on establishing highly selective process steps (sulfation, leaching, and precipitation) in order to minimize costs and waste produced. In addition to Scandium oxide, the chosen approach produces mixed rare earth oxides as a side product, thus isolating an average of 88% of all rare earth elements contained in red mud. Furthermore, in light of predicted supply shortages of the critical material Sc and the need to establish cost-effective bauxite residue remediation techniques, a systematic Monte Carlo-based economic performance assessment framework is developed in order to evaluate the economic prospects of the proposed process system in the presence of irreducible uncertainty.

Indian Railways is the largest public sector undertaking in India but suffers from a major problem of inefficient waste management system. This is a problem of dry and wet waste generated inside the running train and around the railway tracks resulting in unhygienic trains and unclean railway tracks. Everyday nearly 23 million people travel in 7000 passengers trains inIndia. The area around the railway track in India is about 16000 kms which has never been cleaned. It is estimated that approximately 6289 tons of plastic finds its way into India’s railway tracks every day. This enormous generation of waste is leading to undesirable health issues besides environmental pollution. In this backdrop, in this project a prototype technological modelis being developed which can help to solve this problem. A smart dustbin is placed in each compartment of all the bogies in a train wherein both the dry and wet waste are collected, segregated and crushed. With the help of the belt conveyor, this...

Sanitation is always regarded as a key of development intervention. Sanitation generally means to the provide facilities for disposal of human urine and fecal matter. It deals with maintenance of hygienic conditions through services such as collection and disposal of waste. Many diseases are because of lack of sanitation like diarrhea, dysentery, typhoid, malaria and dengue are the outcome of improper or lack of sanitation. INDIAN Railways, a fast profit making organization and operates as the most densely utilized train system in the world. Railways cover length and breadth of country through its rails. Sanitation in Indian Railways is a big threat to the image of Indian railways. Poor sanitation conditions are a setback to the progressing Railway sector. The existing toilet system in the coaches discharges excreta directly to the ground and on the railway tracks. The factors include unacceptable hygienic conditions, particularly on the railway stations, and damage to rails. A related socio economic problem is that of people residing near the railway stations, without access to toilet facilities, using tracks for open defecation. Open elimination of human excreta through railways, unhygienic toilets, blocked basins, uncleanliness in bogeys and along tracks are the causes that have compelled us to put a thought over sanitation in railways. This human waste on the railway tracks is the main cause of diseases spreading to nearby settlement areas along with delayed decomposition and contamination of water under bridges. This paper deals with a simple solution which will help in the collection of this waste and further process it to generate fertilizers and bio-gas which can be further used to generate electricity which will be sufficient for lightening purpose on railway stations and nearby household locality also.

The environmental legacies of metal mining are often dominated by large waste facilities, which can be sources of acid and metalliferous drainage, resulting in both local pollution and irreversible loss of some of the soluble minerals. Whether a material is treated as waste or ore depends on a wide variety of factors and circumstances. Three critical aspects-time, the extractive strategy and the economic context-are discussed in this paper. The authors argue that the fine line between waste and ore requires a mine waste management (MWM) hierarchy that properly considers waste as a potential future resource. This hierarchy exhibits four main levels: reduce, reprocess & stockpile, downcycle and dispose, which are illustrated by a review of both academic research and public data on industrial practices. The authors conclude that to generate the most successful outcomes the hierarchy must operate across all levels and is a core component of an overall mine sustainability framework.

Indian Railways is the largest public sector undertaking in India but suffers from a major problem of inefficient waste management system. This is a problem of dry and wet waste generated inside the running train and around the railway tracks resulting in unhygienic trains and unclean railway tracks. Everyday nearly 23 million people travel in 7000 passengers trains inIndia. The area around the railway track in India is about 16000 kms which has never been cleaned. It is estimated that approximately 6289 tons of plastic finds its way into India’s railway tracks every day. This enormous generation of waste is leading to undesirable health issues besides environmental pollution. In this backdrop, in this project a prototype technological modelis being developed which can help to solve this problem. A smart dustbin is placed in each compartment of all the bogies in a train wherein both the dry and wet waste are collected, segregated and crushed. With the help of the belt conveyor, this...

The environmental legacies of metal mining are often dominated by large waste facilities, which can be sources of acid and metalliferous drainage, resulting in both local pollution and irreversible loss of some of the soluble minerals. Whether a material is treated as waste or ore depends on a wide variety of factors and circumstances. Three critical aspects-time, the extractive strategy and the economic context-are discussed in this paper. The authors argue that the fine line between waste and ore requires a mine waste management (MWM) hierarchy that properly considers waste as a potential future resource. This hierarchy exhibits four main levels: reduce, reprocess & stockpile, downcycle and dispose, which are illustrated by a review of both academic research and public data on industrial practices. The authors conclude that to generate the most successful outcomes the hierarchy must operate across all levels and is a core component of an overall mine sustainability framework.

The combination of HCl-based dry digestion of bauxite residue and multi-stage circulation of the leach liquor was studied. The proposed processing technology allows to achieve a high selectivity for rare-earth elements with a limited co-dissolution of silica (< 5 wt%). The scandium concentration increased from 7 mg L-1 in stage 1 to 19 mg L-1 in stage 5, while the concentration of yttrium, lanthanum and neodymium increased from an average value of 7 mg L-1 in stage 1 to an average of 18 mg L-1 in stage 5, more than twice the concentration observed for single-stage leaching after dry digestion, and four times higher than the concentration achieved by a conventional direct acid leaching method. The water consumption was reduced by 60% in comparison to the conventional direct acid leaching method.status: publishe

The authors have proposed their own newly developed universal procedure for assessing waste and selecting methods of processing the waste for agricultural purposes. Increasingly more rigorous environmental legal regulations, especially pertaining to sustainability in agricultural and chemical production, were the most convincing motivation for such approach. The procedure is based on technological and environmental safety criteria. Special attention is devoted to the chemical processing of hazardous wastes into fertilizer products and the underlying reasons for such methodology. As opposed to physical and biochemical processes, in chemical processes the agents used completely change the chemical structure of the waste materials or at least that of some of their components. As a result, new phases are formed and the harmful properties of the initial material are eliminated. Prospects for the chemical processing of hazardous wastes are demonstrated using as an example the utilization ...

Bauxite residue (red mud) with a high alumina content requires large amounts of fluxes during smelting, which increases the overall process cost, the energy consumption during smelting, and the acid consumption during slag leaching and decreases the throughput of bauxite residue in the smelting phase. Therefore, alumina was removed (or recovered) from bauxite residue by alkali roasting prior to smelting. The sample after alumina removal could be smelted at 1500°C without the need of adding any flux to obtain a clear slag-metal separation. After smelting, the slag was leached with acids (HCl, H 2 SO 4 , or HNO 3). The recovery yields of the rare-earth elements (REEs), except scandium, drastically decreased in the low-alumina slags, compared to the original bauxite residue. These poorer recovery yields are due to the formation of a perovskite (CaTiO 3) phase, which binds REEs except scandium. CaTiO 3 is a stable phase and does not dissolve in acids under normal conditions. Therefore, slag was quenched to suppress the CaTiO 3 formation. The REEs and titanium could also be dissolved in acidic solutions at 25°C by quenching the molten slag. Removal of alumina from bauxite residue by alkali roasting with sodium carbonate requires high temperatures ([900°C). Therefore, sodium carbonate was replaced with sodium hydroxide to decrease the energy consumption by decreasing the roasting temperature (\500°C).

Indian Railways was being roundly criticized for creating an environment hazard by discharging toilet waste on tracks. IR coaches have toilet system that has hole on the floor through which human feces and urine is flushed directly on railway tracks. Various types of environment friendly Green toilets have put on outfields trials by Indian Railways to overcome this problem. Controlled Discharge Toilet System (CDTS), Bio-toilet developed by Indian Railways engineers and DRDO biotechnologists, development of Zero Discharge Toilet System (ZDTS) by IIT Kanpur and Research Development and Standards Organization (RDSO) Lucknow, are some efforts in this direction. These technologies are more expensive due to inherent complexities, disposal problem at yards (ZDTS) and requirement of extra infrastructure at the terminal. FFEM approach not only solves these problems but also convert toilet waste into energy which can be utilized further in lighting at platforms or some other useful purposes.

About 40 million tonnes of municipal waste is generated in India every year. The waste management scenario continues to be grim, even though there have been some commendable initiatives by scattered municipalities, individuals, groups and NGOs. As of ...

The authors have proposed their own newly developed universal procedure for assessing waste and selecting methods of processing the waste for agricultural purposes. Increasingly more rigorous environmental legal regulations, especially pertaining to sustainability in agricultural and chemical production, were the most convincing motivation for such approach. The procedure is based on technological and environmental safety criteria. Special attention is devoted to the chemical processing of hazardous wastes into fertilizer products and the underlying reasons for such methodology. As opposed to physical and biochemical processes, in chemical processes the agents used completely change the chemical structure of the waste materials or at least that of some of their components. As a result, new phases are formed and the harmful properties of the initial material are eliminated. Prospects for the chemical processing of hazardous wastes are demonstrated using as an example the utilization ...

The main goal of the study performed in this paper is the improvement of disposal and processing of technogenic wastes with high nonferrous metals content. In particular, the peculiarities of the copper recovery process from technogenic raw materials by using a hydrocarbonylation method are considered. A substantiation of the real possibility of selective copper recovery from polycomponent solutions, formed as a result of technogenic raw materials repulping or leaching, is adduced. At that, the primary reagent is carbon monoxide and the duration of the process cycle is not to exceed 10 hours at low specific power consumption and the high purity of product copper.

The main purpose of the work was to determine the methods of mining enterprises
wastewater secondary treatment from nitrogenous compounds. The chemical analysis
of wastewater was carried out, and substances with exceeding concentrations were
established. The accumulating power of indigenous species of higher aquatic
vegetation has been estimated. The absorption regularities of nitrates of duckweed
(Lemna minor) in solutions with different concentrations were determined. The
expediency of duckweed cultivating with the aim of phytoremediation has been
proved.

The main goal of the study performed in this paper is the improvement of disposal
and processing of technogenic wastes with high nonferrous metals content. In
particular, the peculiarities of the copper recovery process from technogenic raw
materials by using a hydrocarbonylation method are considered. A substantiation of
the real possibility of selective copper recovery from polycomponent solutions,
formed as a result of technogenic raw materials repulping or leaching, is adduced. At
that, the primary reagent is carbon monoxide and the duration of the process cycle is
not to exceed 10 hours at low specific power consumption and the high purity of
product copper.

The environment is continuously affected by constant addition of pollution waste material and other hazardous product. It is essential that environment should be protected and maintains to make safe for living. Use of smart toilet or green toilet should help the cause of achieving the goal of environment safety. The First Rake with bio-toilets developed with DRDO is running in Bundelkhand Express since 18th January -2011. DRDO is constantly trying to make improvements in EFT to reduce the pollution and make travelling in railways more comfortable .This project deals with an ECO FRIENDLY TOILET system. It is developed to solve three problems in eco-friendly toilet. This eco-friendly toilet will be in accordance with DRDO (Defence research & Development organization) rules and regulation. Improvement is to be needed in railway bogies to reduce the pollution and deposition of waste material. The system is developed while considering the railway passenger. The problem of space availability, cost, odour and quantity of water is solved in this project. This problem is solved by merging two EFT tanks and it is also used for disable person as well as common passenger in railway bogies many other improvements.

The environment is continuously affected by constant addition of pollution waste material and other hazardous product. It is essential that environment should be protected and maintains to make safe for living. Use of smart toilet or green toilet should help the cause of achieving the goal of environment safety. The First Rake with bio-toilets developed with DRDO is running in Bundelkhand Express since 18th January -2011. DRDO is constantly trying to make improvements in EFT to reduce the pollution and make travelling in railways more comfortable .This project deals with an ECO FRIENDLY TOILET system. It is developed to solve three problems in eco-friendly toilet. This eco-friendly toilet will be in accordance with DRDO (Defence research & Development organization) rules and regulation. Improvement is to be needed in railway bogies to reduce the pollution and deposition of waste material. The system is developed while considering the railway passenger. The problem of space availability, cost, odour and quantity of water is solved in this project. This problem is solved by merging two EFT tanks and it is also used for disable person as well as common passenger in railway bogies many other improvements.

This paper presents the methodology for design and fabrication of human waste disposal system for Indian railway with the related search. The study specifies factors influencing the human waste disposal and recommends a number of design options for human waste disposal system for Indian railway. These are based on a systematic study of the human waste disposal system and testing of a prototype model of it. For which we consider literatures reviews & some of them are explained.

Nagpur is the largest city in central India (2001 Census) and the second capital of the
state of Maharashtra. Nagpur’s population is 2,420,000; and is 13th largest urban
conglomeration in India and 114th largest city in world. It ranks as 143rd largest urban
area in world in terms of population. With 7 platforms, Nagpur is a world class station,
and all the trains stop here for minimum 15 minutes. It caters to daily around 182 trains.
Daily around 1, 50,000 passengers use this station for boarding various local, passenger,
express trains. Considering huge passenger coverage by the IR one can easily predict the
daily consumption of water during the travel by the passenger. Even we estimate that
only 20 % of the passengers are using the PET bottles i.e. 30 thousands of drinking water
bottles are consumed daily by the travelers. After the use most of passengers throw away
the PET bottles which are littered in the tracks and on the platforms and subsequently
swept out and either burnt or thrown on the side of the track by the safaiwalas. This paper
aims at investigating the role of reverse logistic for effective distribution and recycling of
waste of PET bottles at Nagpur Railway Station so that this waste can turn it to be a
profitable business model for the Indian railway.

The paper presents the problems related to the use of asbestos and the asbestos containing materials as well as the methods of the neutralization of the waste asbestos developed after enforcing the limitations and bans on this material. A new method elaborated by the authors consists in the digestion of the asbestos wastes in a strongly acidic environment of the phosphoric acid with such a concentration of hydrogen ions that it assures maintaining all the originating phosphates in the soluble form. Thus, all phosphates, mainly calcium and magnesium ones, can easily be separated from the solid residue and processed to other products. After the neutralization with calcium hydroxide or calcium carbonate the solution can be processed to fodder phosphates (MCP or DCP type) or to phosphate fertilizers – triple superphosphate (TSP) or to dicalcium phosphate. The chemical analyses as well as the microscopic observations carried out, showed that no asbestos fibers were present in the liquid ...

The authors have proposed their own newly developed universal procedure for assessing
waste and selecting methods of processing the waste for agricultural purposes.
Increasingly more rigorous environmental legal regulations, especially pertaining to sustainability
in agricultural and chemical production, were the most convincing motivation for such
approach. The procedure is based on technological and environmental safety criteria. Special
attention is devoted to the chemical processing of hazardous wastes into fertilizer products
and the underlying reasons for such methodology. As opposed to physical and biochemical
processes, in chemical processes the agents used completely change the chemical structure
of the waste materials or at least that of some of their components. As a result, new phases
are formed and the harmful properties of the initial material are eliminated. Prospects for the
chemical processing of hazardous wastes are demonstrated using as an example the utilization
of asbestos wastes. There are vast amounts of asbestos materials installed in industrial,
communal, and service facilities. Landfill asbestos waste disposal is the common practice,
but this does not solve properly the problem of environmental hazard. The proposed utilization
concept consists in destroying asbestos with a phosphoric acid solution in a two-stage
process. The obtained suspension is then filtered, and the solution of phosphates containing
an excess of phosphoric acid is subsequently neutralized with lime and processed into phosphate
fertilizers of TSP (triple superphosphate) or DCP (dicalcium phosphate) type.
Experiments showed that the process yielded asbestos-free products which did not contain
any respirable fibers. Comparative immunological tests showed that the products did not
cause any degeneration of human lung cells exposed to them, as opposed to the original asbestos,
which had a highly damaging effect on the cells.

This paper undertakes study of two railway
coach repair workshops located in South India
involved in periodical overhauling of broad
gauge passenger coaches. This paper covers a
period of five years from 2007 to 2011 and
takes into account the production, energy input
and related environmental impact for both the
workshops. The study revealed that the specific
energy consumption per coach overhauling
of larger workshop was 553 kWh which was
less compared to the smaller one at 700 kWh
due to better utilization of its assets and as
such its carbon foot print is lower. The trend
analysis shows that electricity is the major form
of energy for both the workshops with relative
share of 40%. Both the workshops have taken
numerous steps to reduce the energy
consumption over a period of time and thereby
the overall cost of energy is reducing inspite of
the increase in the energy costs by distribution
companies. The combined energy
consumption of both the workshops during
2011 was 16016 GJ. As there are 45 such
workshops, it is felt that the new technologies
adopted by these shops can be easily replicated
for a better global environment. The major
areas of concern in the workshops are the
aged transformer welding plants and the
centralized air distribution systems with dated
technology. The major hazardous waste
handled by the coach workshops are lead acid
batteries, lead based enamel paints, nonferrous
scrap, lubricating oil and grease which
are sold out by way of auction by stores
department to authorized recyclers who are
registered with CPCB and state PCB and
comply with HW Management rules

Indian Railways (IR) is one of the largest and busiest rail networks in the world and an
important mode of public transportation in the country. Since their inception 154 years
ago, the Railways have contributed significantly to India’s transport needs and economic
growth. Today, Indian Railways ranks among the top five national railway systems in
terms of size and scale and is poised to emerge as a world class railway system. IR
carried 17 million passengers daily over its network spread over 63,327 route
kilometers. Considering huge passenger coverage by the IR one can easily predict the
daily consumption of water during the travel by the passenger. Even we estimate that
only 20 % of the passengers are using the PET bottles i.e. 34 lacks of drinking water
bottles are consumed daily by the travelers. After the use most of passengers throw away
the PET bottles which are littered in the tracks and on the platforms and subsequently
swept out and either burnt or thrown on the side of the track by the safaiwalas. This
research work aims at investigating the role of reverse logistic for effective distribution
and recycling of waste of PET bottles in Indian Railway so that this waste can turn it to
be a profitable business model for the Indian railway.

Indian Railways (IR) is one of the largest and busiest rail networks in the world and an
important mode of public transportation in the country. Since their inception 154 years
ago, the Railways have contributed significantly to India’s transport needs and economic
growth. Today, Indian Railways ranks among the top five national railway systems in
terms of size and scale and is poised to emerge as a world class railway system. IR
carried 17 million passengers daily over its network spread over 63,327 route
kilometers. Considering huge passenger coverage by the IR one can easily predict the
daily consumption of water during the travel by the passenger. Even we estimate that
only 20 % of the passengers are using the PET bottles i.e. 34 lacks of drinking water
bottles are consumed daily by the travelers. After the use most of passengers throw away
the PET bottles which are littered in the tracks and on the platforms and subsequently
swept out and either burnt or thrown on the side of the track by the safaiwalas. This
research work aims at investigating the role of reverse logistic for effective distribution
and recycling of waste of PET bottles in Indian Railway so that this waste can turn it to
be a profitable business model for the Indian railway.