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NCAB Decisions 2009

11/2009 | 09/2009 | 07/2009 | 05/2009 | 03/2009 | 01/2009

 

Decisions of the National Coal Ash Board (NCAB) 11/2009

At the meeting of the National Coal Ash Board held in November 2009, it was decided to continue to advance and promote research and development on the following subject:

  • Environment – Assessment of public exposure to ionizing radiation from natural sources in Israel

These are the resolutions that were passed:

Assessment of public exposure to ionizing radiation from natural sources in Israel Building of a database and the development of assessment tools in the context of a research grant given to Lior Cahana, an M.Sc. student in nuclear engineering at Ben-Gurion University.
 
Brief overview
In the context of this study, the existing data will be collected, the missing data will be identified and the necessary measurements will be carried out to complement. A model will be developed to calculate the exposure of the public according to the specific living conditions in Israel. On the basis of the changes in the average radiation dose in Israel that have occurred in the past, the model will allow to assess the expected dose in the future due to expected changes in living or living environment conditions, including changes that may occur as a result of the use of coal ash in the construction industry in Israel.

Decisions of the National Coal Ash Board (NCAB) 9/2009

At the meeting of the National Coal Ash Board held in September 2009, it was decided to continue to advance and promote research and development on the following subjects:

  • Environment – Assessment of risks from leaching of pollutants from coal ash embankments
  • Environment – Forecasting trace elements in coal ash

These are the resolutions that were passed:

Assessment of risks from leaching of pollutants from coal ash embankments Assessment of risks from leaching of pollutants from coal ash embankments using the model of the Dutch ECN research institute.
 
Brief overview
The LeachXS-ORCHESTRA model developed by a group of researchers in the Dutch ECN research institute headed by Dr. Hans A. van der Sloot based on a very large number of different wastes, including coal ash, is intended to provide a quantitative assessment of a cumulative leaching over years (100) of trace elements (heavy metals and oxyanions), in consideration of the nature of the material and the environmental conditions to which it is exposed. The model serves as a testing tool by the working group for the development of European environmental standardization for the treatment of various kinds of wastes, including wastes that are resourced for various purposes, headed by Dr. van der Sloot. The risks assessment will be based on the running of the model with the data of Israeli ash.

The findings of the model and the assessment of the risks will be presented by Dr. van der Sloot at the international workshop on the environmental aspects of the use of coal ash to be held in December 2009.

Forecasting trace elements in coal ash Forecasting trace elements in coal ash dependent on the source of the coal and the features of the power station, using the model of the Dutch KEMA research institute.
 
Brief overview
KEMA, as a scientific-technological institute (owned by the Dutch Electric Corporation), which is a center that specializes in the environmental and health aspects of exposure to coal ash in its production and uses, developed a forecasting model, of KTM – KEMA Trace Model – that, based on a statistical analysis of the historic databases in the Dutch power stations, connects the content of trace elements in coal to their expected concentrations in the ash. The model helps the electric corporations in making decisions regarding the acquisition of coal in consideration of the final destination of the ash produced from it and its limitations as set by the various environmental authorities. The basket of coal sources in the Netherlands resembles that of Israel, as does the combustion technology used in the coal-fired power stations. The forecasting of trace elements will be carried out by Dr. Ruud Meij, a senior KEMA researcher, based on the data of the coal supplied to Israel.

The findings of the model will be presented by Dr. Ruud Meij at the international workshop on the environmental aspects of the use of coal ash to be held in December 2009.

Decisions of the National Coal Ash Board (NCAB) 7/2009

At the meeting of the National Coal Ash Board held in July 2009, it was decided to continue to advance and promote research and development on the following subject:

  • Environment – Environmental characterization (trace elements leaching) of Indonesian coal ash

These are the resolutions that were passed:

Environmental characterization (trace elements leaching) of Indonesian coal ash) Environmental characterization of Israeli coal ash in environmental terms (trace elements leaching), using the European method EN-PDT; carried out by Yoetz Deutsch of the Geological Survey of Israel.
 
Brief overview
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 permitted maximum values for concentrations of certain trace elements in ash leachates, as determined by the Ministry of Environmental Protection, following the recommendation of the professional-scientific committee of the National Coal Ash Board.

In accordance with this recommendation, the USEPA TCLP test method has been adopted, which was available for immediate implementation. This method suffers from essential disadvantages in its application to coal ash in the alkaline-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 real environmental conditions. The work is intended to characterize the ashes coming from the various coal sources in Israel with this method. In previous work, South African and Colombian ash were tested. Indonesian ash is different in a number of ways from the other sources of Israeli ash. The said test is intended to complete the characterization mapping of the types of ash available in Israel.

Decisions of the National Coal Ash Board (NCAB) 5/2009

At the meeting of the National Coal Ash Board held in May 2009, it was decided to continue to advance and promote research and development on the following subjects:

  • Agriculture – Continued observations of plants grown on a coal ash growth medium
  • Environment – Monitoring of water penetration in fly ash road embankments, fourth observation

These are the resolutions that were passed:

Continued observations of plants grown on a Bottom ash growth medium Control of vital parameters for the growth of plants on a bottom ash growth medium and monitoring of their development in research and commercial field experiments.
 
Brief overview
In the Jordan Valley – Gilgal – Research and Development Center – A comparative experiment involving the raising of peppers on various growth media (Bottom ash, tuff, perlite) in various types of receptacles (foam containers, cloth sleeves,). A multi-annual experiment begun in 2006 and planned to continue until 2011; funding of the experiment in cooperation with Fertilizers and Chemical Substances, Inc.

The Vered model farm in Kadesh Barnea – Comparative observations of the raising of cherry tomatoes on various growth media (local sand, coal ash, tuff, perlite) using different packing methods (open trenches, disconnected trenches, cloth sleeves, buckets). The experiment began in 2007 and the observations in 2008, slated to continue until 2010.

Vineyard in Sde Boker – Comparative observation of reinforcement of local loess soil with ash medium using two methods (underground, covering). The observation began in 2008 and is slated to continue until 2010 and also includes examination of the heavy metal content in grapes for the purpose of national licensing of Food and Nutrition Services for multi-annual edible crops.

Monitoring of water penetration in fly ash road embankments, fourth observation Examination of changes in rate of water penetration in road embankments constructed of fly ash, as a result of chemical processes that occur over time; carried out by Prof. Rami Keren of the Institute of Soil, Water and Environmental Sciences, The Volcani Center for Agricultural Research.
 
Brief overview
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 dissolution 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. Initial tests on the Jisr-a-Zarka embankment indicate the tendency of a well compacted 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, it has been decided to conduct repeated infiltration tests through repeated observations over a number of years of the ash road embankment from the earliest stages of its construction.

The tests are being carried out by Prof. Rami Keren on Section 19 of Highway 6 after completion of the embankment. So far, three observations have been carried out: The first one, which reflect the starting point, were carried out in the summer of 2005 upon completion of the paving, and the following ones were carried out in 2006-2007. The findings of the tests point to a clear reduction in the permeability of the ash, however the sealing process has not yet been completed after two years.

Decisions of the National Coal Ash Board (NCAB) 3/2009

At the meeting of the National Coal Ash Board held in March 2009, it was decided to continue to advance and promote research and development on the following subject:

  • Environment – The monitoring of trace elements in runoff water from fly ash embankments

These are the resolutions that were passed:

Monitoring of trace elements in runoff water from fly ash embankments Study of the source for the relatively high concentration of boron in the cover soil of a fly ash embankment, carried out by Dr. Meny Ben-Hur of the Institute of Soil, Water and Environmental Sciences, The Volcani Center for Agricultural Research.
 
Brief overview
The fly ash embankment on the access road to the northern entrance to Jisr-a-Zarka was built ten years ago and has served since then as a monitoring and test site for the environmental behavior of fly ash, processed in accordance with the conditions of the paving specifications and represents a structural nucleus in a road embankment.

The monitoring of runoff water carried out in the winter of 2008 confirmed the assessments that had been consolidated as a result of the multi-year monitoring that fly ash implemented as moistened and compacted structural filler in road embankments and infrastructure behaves like an inert monolith to the environment in terms of the criteria for European standards.

Nevertheless, the concentration of boron was found to be relatively high (although still low in absolute terms) in the runoff water of the coal ash section, in comparison to the runoff in a control section of natural filler soil. The 2009 monitoring is intended to contend with the question of the source of the excessive boron in the coal ash section. It should be noted that this question is of scientific interest only, and is of no practical environmental significance since the concentration of the boron found in the runoff water is negligible. However, due to its unique properties, the boron is interesting as an indicator for the study of the mechanisms of the leaching of the elements from the ash in general. This additional information will further bolster understanding of the processes that occur in the contact between the coal ash embankments and the environment.

Decisions of the National Coal Ash Board (NCAB) 1/2009

At the meeting of the National Coal Ash Board held in January 2009, it was decided to continue to advance and promote research and development on the following subject:

  • Environment – The impact of coal ash on radon exhalation from concrete

These are the resolutions that were passed:

The impact of coal ash on radon exhalation from concrete A survey of the professional literature regarding the exposure to radiation from building products and a study on the impact of adding coal ash to concrete on its radon exhalation, are carried out by scientists from the National Building Research Institute – Faculty of Civil and Environmental Engineering, Technion, Haifa (Prof. Kosta Kovler, Prof. Rachel Becker) and the Radiation Safety Division, Soreq Nuclear Research Center (Dr. Jan Koch, Gustavo Haquin).
 
Brief overview
A number of studies throughout the world have shown that adding coal ash to concretes does not increase the coefficient of radon exhalation, as may be expected due to the increase in the activity concentration of 226Ra in the product, and may even reduce it. The main reason for the reduction may be due to the encapsulation of the radon in the vitreous ash particles, which are formed at high temperatures prevailing during the combustion of coal. Another reason is the change that the ash causes in the micro-structure of the concrete as a result of the pozzolanic reaction that occurs between the ash and one of the hydration products of the hydration of the Portland cement – calcium hydroxide / hydrated lime. This dense structure prevents the “escape” of the radon atoms into the cement pores. In addition, it is possible, as reported in the literature, that the rate of radon emission in products containing coal ash is significantly reduced over time, as a function of the environmental humidity.
  1. A literature survey in the following areas:
    • The exhalation of radon from construction products containing coal ash
    • Methods to measure radon exhalation in the laboratory.
    • Regulations dealing with the activity concentrations of radionuclides from natural sources in construction materials and products.
  2. Radon exhalation from concrete that contains coal ash:
    • Radon exhalation from concrete samples and from protected spaces in dwellings will be measured (this examination will be held in the laboratories at Soreq NRC as well as abroad, in Holland).

The study is held in cooperation with the Planning and Engineering Administration at the Ministry of Housing and Construction.