**4.1. Use of reagents**

**Radiological indices (Unit) Ra-eq (Bq/Kg) Dγr**

94 Advances in Petrochemicals

**3. Resources of NORM and TE-NORM**

enough radioactive potassium to set off radiation alarms.

**3.1. NORM and TE-NORM at the landfill**

**Table 7.** The average worldwide levels of the most common radiological indices

**(nGy/h)**

Activity level (Bq/Kg) 370 55 20 1

Earlier, we saw that many natural materials contain radioactivity. Some of these materials are used in manufacturing: clays and various minerals. In other cases, radioactive elements are used in manufacturing – not because of the radioactivity, but because of other chemical or physical properties. For example, thorium is radioactive, and it has a high melting temperature; for this reason, thorium is used in the manufacture of some welding electrodes, gas lantern mantles, and jet turbine blades. These products and the wastes from their manufacture will contain low levels of radioactivity. Many fossil fuels are associated with radioactivity; the geochemistry of uranium is such that it is often found in petroleum, natural gas, and coal deposits. The equipment used to extract and process these materials is often contaminated with NORM materials, especially with radium, which can be present in the scales and sludges from processing these materials. Although refined petroleum and natural gas products do not contain large levels of these nuclides, coal can; so, fly ash often contains elevated levels of radioactivity as well. In fact, when 90% or more of the coal is burned, all of the radioactivity is left in the remaining 10% that is ash. Thus, fly ash is considerably more radioactive than is the original coal. Uranium and thorium are fairly common in nature, and many minerals contain elevated levels of these radioactive elements and their decay series nuclides. In particular, minerals containing rare earth elements (such as monazite), titanium minerals, niobium ores, and some precious metal ores can be associated with elevated levels of radio‐ activity. When the minerals are processed, the metal is removed from the ore, and the radio‐ activity concentration in the remaining waste is even higher than in the original ore. In addition to all of these, anything that contains potassium will be somewhat radioactive because 1/100% of potassium is naturally radioactive. Potassium is found in many minerals, some forms of clay, and in many products – consumer and industrial both – so sometimes these items will also give high levels of radiation. Loads of bananas, kitty litter, and salt substitute all contain

Many industries produce wastes that might contain natural radionuclides, and most of these wastes end up at landfills, either hazardous or otherwise. The majority of TE-NORM sources waste arise from industrial processes. Most of the wastes obtained are produced in very large amounts with low activity. Improper disposal, recycling, and reuse of TE-NORM have led to

circumstances resulting in contamination and unnecessary public exposures.

**EADR (mSv/yr) for worker**

**EADR (mSv/yr) for Public**

> A water-bath heater from a gas production facility in North Sea (e.g., the Netherlands) has been used as a test for equipment in laboratory aimed at the in situ removal of TE-NORM. This is achieved by circulating an aqueous solution of commercially available scale dissolver through the contaminated equipment. For this purpose, some scale dissolvers which are widely used within exploration and production are commonly based on chelating chemistry and reportedly successfully applied in the dissolution of low specific activity scales [45]. For instance, application of scale dissolver reagents resulted in the rapid and complete removal of 226Ra and progeny-containing sulfate scales as well as 210Pb-containing sulfide scales from the head internals. These studies were performed using scale dissolver consisting of 15% v/v acetic acid and 1% v/v strongly oxidant, e.g., KMnO4. This reduced the total activity from 20 Bq/cm2 to 6 Bq/cm2 , the residual activity may be removed using 0.5 M citric acid. Also, scale dissolver solution containing 15% v/v acetic acid plus 1% v/v hydrogen peroxide was used to dissolve TE-NORM contaminated by overall activities of 2000 Bq (226Ra)/g and 600 Bq(2t0Pb)/g. This was followed by water flush. Generally, the application of a chemical scale dissolver can remove 95–99% of TE-NORM present in exploration and production facilities. On the other hand, radioactive scales containing 226Ra and its progeny, such as barium sulfate scales, are removed chemically using hydrochloric acid, and the dead acid is disposed as waste after appropriate radiometric checks [46].
