News

NCAB Decisions 2006

11/2006 | 09/2006 | 07/2006 | 05/2006 | 03/2006 | 01/2006

Decisions of the National Coal Ash Board (NCAB) 11/2006

At a meeting of the Coal Ash Board held on November 9, 2006, it was decided to promote research and development on the following subjects:

  • Agriculture – Growth media mixtures containing bottom ash
  • Infrastructures – The use of bottom ash to cover underground pipes

These are the resolutions that were passed:

Bottom ash as a growth medium A comparative study of the cultivation of spices in a growth medium based on bottom ash, compared to other media.
 
Brief description of work
A comparative study of the cultivation of leafy plants/spices on a growth medium containing coal ash and various concentrations of composted separated cattle manure, as opposed to beddings containing tuff in similar compost concentrations, will be carried out.The comparison will be carried out as above, as well as compared to a conventional soil mixture, while the beddings contain sewage sludge compost and composted separated cattle manure.

The site of the study: the Ein Shemer Ecological Hothouse as part of the final projects of high school students, under the supervision of hothouse instructors and Prof. Yona Chen of the Department of Soil and Water Sciences of the Faculty of Agriculture of the Hebrew University.

Coal Ash as a covering for underground pipes Experimental testing in a laboratory and in the field of the laying conditions of coal ash in various types of pipe coverings.
 
Brief description of work

An extensive survey of the literature carried out by Prof. Naftali Galili of the Civil Engineering Department of the Technion showed that bottom ash can be found in standard filling materials and consequently can be employed successfully in materials used to cover underground pipes of various kinds.

The experimental testing will include examination of the material’s mechanical features and its rigidity under various conditions of compaction in order to determine the appropriate compaction level for each type of pipe. Based on the findings of the laboratory tests, field experiments will be carried out at all stages of the work, from the digging to the final covering stage

Decisions of the National Coal Ash Board (NCAB) 09/2006

At a meeting of the Coal Ash Board held on September 7, 2006, it was decided to promote research and development on the following subjects:

  • Agriculture – Growth media mixtures containing bottom ash
  • Infrastructures -Stabilization of bike and hiking trails in Ayalon Park

These are the resolutions that were passed:

Bottom ash as a growth medium Expansion of experimentation and observations of plants cultivated on coarse coal ash growth medium
 
Brief description of work

The development of the use of coarse bottom ash as a growth medium for plants is currently in the interim stage, between proving feasibility and penetration into various applications in the industry. So far, growers of peppers and melons in the Arava area and growers of tomatoes in the Jordan Valley have been shown the advantages of the use of bottom ash through observations.

Stabilization of bicycle and hiking trails in Ayalon Park A feasibility study is moving ahead on a number of kilometers involving the stabilization of active recreation trails using bottom ash, as part of the development of the Ayalon Park.
 
Brief description of work

In the context of a preliminary experiment, a number of test segments were carried out in order to choose the preferred mixture to stabilize the bicycle and active recreation trails, out of a variety of materials (aggregates and stabilizers), including bottom ash as an aggregate and fly ash as a binder.

The mixtures in which bottom ash was used as an aggregate were found preferable to the others both in the service quality of the trails and their resistance to changes in weather, apparently due to the particle size distribution and ability to hold water.

At the advanced stage of the experiment, the stabilization of the trails containing coals ash and lime, in addition to the local soil, over a number of kilometers, will be examined. In this context, the effectiveness and quality of this work method and function of the trails over time will be explored.

Decisions of the National Coal Ash Board (NCAB) 07/2006

At a meeting of the Coal Ash Board held on July 6, 2006, it was decided to promote research and development on the following subjects:

  • Construction – Durability of concrete made with coal ash.
  • Environment – Environmental characterization (Heavy-metal leaching) of coal ash using the European method EN-PDT.

These are the resolutions that were passed:

Durability of concrete containing coal ash A probe into the possibility of increasing the efficiency coefficient of fly ash as an alternative to cement in concrete, while meeting the existing demands of the Concrete Law.
 
Brief description of work

Israeli Standard 466 – The Concrete Law, in its updated version, as recently determined, includes the possibility of replacing cement with fly ash at a proportion that expresses the contribution of the ash to the life span (durability) of concrete in the protection against the wear and tear caused by its exposure to the environment: the penetration of carbon dioxide generating carbonization, which impairs the concrete’s protection of its reinforcement and penetration of chlorides, which cause corrosion of the reinforcement. The alternative, at a defined proportion, is possible only in some parts of the country as set out in the standard.

The current study aims to examine the possibility of increasing the replacement coefficient and the expansion of its application, at appropriate proportions to all areas.

Environmental characterization of coal ash Characterization of Israeli fly ashes in terms of metals leaching using the European PDT method.
 
Brief description of work

The application of coal ash in its various uses in the areas of civil engineering – construction, paving and various infrastructures, conditioned on meeting the criterion of “usable” ash – the list of maximum values permitted for concentrations of metal trace elements in in ash leachates, as determined by the Ministry of Environmental Protection, following the recommendation of the professional-scientific committee of the Coal Ash Board.

In accordance with this recommendation, the TCLP examination method of the USEPA has been adopted, which was accessible for immediate implementation. This method suffers from essential disadvantages in its application to coal ash in the base-neutral environment typical in Israel. The consolidation of the European EN-PDT method (pH Dependence Test) has recently been completed, and it better reflects the expected behavior of the coal ash in its exposure to the environment under real conditions. The work is intended to characterize the various ashes coming from the various sources in Israel with this method.

Decisions of the National Coal Ash Board (NCAB) 05/2006

At a meeting of the Coal Ash Board held on May 11 2006, it was decided to promote research and development on the following subjects:

  • Environment – Chemical and mineral changes in the fly ash in road embankments
  • Environment – Infiltration of water in fly ash road embankments over time
  • Agriculture – Betterment of land for agricultural purposes with help of fly ash
  • Industry – Exploitation of bottom ash as alternative to sand in asphalt mix

These are the resolutions that were passed:

Chemical and mineralogical changes in the ash A follow-up drill in Jasr-el-Zarka coal ash embankment will carried out by a research team from the Geological Survey Institution headed by Yoetz Deutsch, under the supervision of Dr. Yaacov Natan.
 
Brief description of work

The fly-ash embankment on the Jasr-el-Zarka road serves, in accordance with the instructions of the Ministry of Environmental Protection, as a monitoring site for the behavior of fly ash in road embankments and their possible long-term impact on the quality of the water table.

A multi-annual follow up of mineralogical and chemical changes occurring in the fly ash of the road embankment makes it possible to monitor the changes in the quality of the groundwater in long-term processes and to establish the hypothesis regarding the non-leaching of pollutants in conditions of road paving. The vertical migration of polluting chemical elements in significant concentrations is an indicator of possible pollution, whereas chemical and mineral stability minimizes the likelihood of potential pollution.

The permeability of the road embankment to water A probe of the changes in the water infiltration rate in a road embankment made of fly ash because of long-term chemical process – second year observation.
 
Brief description of work

The environmental conditions for the use of fly ash in the paving of roads and similar uses have been determined in the strict case assumption of a maximum mass of pollutants in the ash, their leaching from the ash embankment, immediate passage through the ground and accumulation in the groundwater at the full quantitative potential of the ash found in the embankment. This assumption, which according to all the experts is manifestly unreasonable, is unavoidable in the state of current knowledge and the absence of an understanding of the processes and of appropriate measuring instruments.

The early tests on the Jasr-el-Zarka embankment indicate the tendency of a tightly compressed fly-ash embankment to become sealed over time to the passage of water through it. In order to establish these findings and assess the speed of the sealing process so that they can be used when determining reasonable environmental conditions for the paving with ash, infiltration tests will be conducted through repeated observations over a number of years of ash embankments of a road from the earliest stages of its construction.

Betterment of soil for agriculture with fly ash An examination of the structural changes in soil designated for agriculture by means of amending physical and chemical properties with the use of the active properties contained in fly ash. Field experiment stage.
 
Brief description of work

International research points to a possible contribution from fly ash to improve the physical properties of soil, for example, to increase the fertility of sandy soil by improving its water-holding properties; prevention of crust formation, erosion, water runoff and cracking of loess soil; prevention of cracking in heavy soil.

The purpose of the study is to examine the potential uses of coal ash as an additive to agricultural soil, and to define in detailed experiments the optimal ways to implement those uses that have been proved in preliminary studies as having high implementation feasibility. In addition to the agronomical and economic aspects, emphasis was placed on the environmental aspects, since they are of considerable importance in determining the implementability of the agricultural uses.

Fine bottom ash in asphalt mixture A field study of paving with asphalt mix containing fine bottom ash as a substitute to fine limestone aggregate.
 
Brief description of work

The use of the fine component (smaller than 2-3 millimeters) of bottom ash as an alternative to fine aggregates (graded sand, gravel), which represent about 35% of the standard asphalt blend, should offer an industrial alternative with a positive added value for the fine “residue” (about 70%) left behind after filtering the coarse bottom ash designated for agricultural uses. In certain respects, the blends containing the fine component of bottom ash provide lower values than the dolomite blend. On the other hand, the blends of fine component of bottom ash achieve higher strength values.

While the fine component of bottom ash has a relative economic disadvantage due to the close proximity of most of the asphalt plants to the source of the replaced raw material in the quarries themselves, certain plants located outside the quarries can serve as an attractive target that can compete with agricultural applications and unlike them, is characterized by stability and consistency.

Decisions of the National Coal Ash Board (NCAB) 03/2006

At a meeting of the National Coal Ash Board (NCAB) held on March 3, 2006, it was decided to advance research and development in the area of:

Agriculture – Coal ash medium to grow plants and animals.

The details of the decision follow:

Testing for pollutants and radionuclide content Analysis of concentrations of heavy-metal and radioactive elements in edible plants and animal tissue grown on media containing bottom ash.
 
Brief description of work

The National Coal Ash Board (NCAB) is working on the development of the use of various size fragments of bottom ash as an agricultural medium for the growth of plants and as litter for animals. In order to meet the requirements of the National Food Services, the National Coal Ash Board (NCAB) will conduct tests on the heavy-metal and radionuclide content in the edible plant and animal products grown on these media (fruit, vegetables and spices; dairy and beef and chicken) to show that they meet accepted health standard levels (food pollutants).

Decisions of the National Coal Ash Board (NCAB) 01/2006

At a meeting of the National Coal Ash Board (NCAB) held on January 5, 2006, it was decided to advance research and development in the area of:

  • Basic research – Characterization of amorphous matter in coal ash.
  • Agriculture – Bottom ash media and sewage sludge compost.
  • Infrastructures – Potential in bottom ash as a covering for flexible water, sewage and drainage pipes.
  • Environment – Seepage of water into ground from road embankments constructed from fly ash.

These are the resolutions that were passed:

Characterization of amorphous matter in coal ash An exploratory study to investigate the chemical and physical processes having significant environmental and engineering implications for the applications of coal ash, will be carried out by a student of the Israel Geological Institute, under the supervision of Dr. Yaacov Nathan.
 
Brief description of work
Many phenomena in the behavior of coal ash in exposure to various environments, which are of environmental and engineering significance, have their source in the properties of the amorphous matter, which represents 40-80% of the ash. A study of the mineral composition of the amorphous phase can help to understand these processes and to develop physical-chemical models for the optimization of the ash in its various uses.
Mixtures of bottom ash and sewage sludge in growth media A study of the growth of plants on a mixed medium made up of coarse and fine bottom ash and sewage sludge compost conducted in the Ein Shemer Ecological Greenhouse, under the coordination of Inbal Hagiladi.
 
Brief description of work

The research program includes growing tarragon, a perennial aromatic herb that has not yet been grown on coal ash media. The study will explore different media with varying compositions – Matza’it (coarse ash), Ripudit (fine ash), separated cow sewage and human sewage sludge and test them for various agricultural, chemical and health properties.

Potential of the use of bottom ash in the covering of flexible underground pipes The creation of a knowledge base to write specifications for the use of coal ash as a covering for underground facilities, carried out by Prof. Naphtali Galili of the Technion.
 
Brief description of work
This development seeks to address the rising price of sand, especially in the north of the country, caused by the exhaustion of the final reserves available in the southern coastal region. The study will survey the knowledge available in the world, characterize the ash and determine principles for use in accordance with accepted standards.
Seepage from road embankments constructed from fly ash A study of the infiltration of water from road embankments carried out by Prof. Rami Keren of the Volcani Center, in order to establish environmental guidelines for paving with coal ash and the effect on the existing processes.
 
Brief description of work

The environmental conditions for the use of fly ash in the paving of roads and similar uses have been determined in the strict case assumption of a maximum mass of pollutants in the ash, their leaching from the ash embankment, immediate passage through the ground and accumulation in the groundwater at the full quantitative potential of the ash found in the embankment. This assumption, which according to all the experts is manifestly unreasonable, is unavoidable in the state of current knowledge and the absence of an understanding of the processes and of appropriate measuring instruments. To complete the study of how fly ash behaves in an aqueous environment, infiltration tests will be conducted through repeated observations over a number of years of ash embankments of a road from the earliest stages of its construction.