Eco-profiles of the
European Plastics Industry
SODIUM HYDROXIDE
A report by
I Boustead
for
PlasticsEurope
Data last calculated
March 2005
PlasticsEurope may be contacted at
Ave E van Nieuwenhuyse 4
Box 3
B-1160 Brussels
Telephone: 32-2-672-8259
Fax: 32-2-675-3935
CONTENTS
ELECTROLYSIS OF BRINE......
PRODUCT TREATMENT......
PARTITIONING......
Sodium chloride......
Water emissions......
Steam input to the chlorine cell......
HCl input to the chlorine cell......
NaOH input to the chlorine cell......
Sulphuric acid input......
Hydrogen emissions from the chlorine cell......
Chlorine emissions from the chlorine cell......
Electricity use in the chlorine cell......
ECO-PROFILE OF SODIUM HYDROXIDE......
ELECTROLYSIS OF BRINE
Over 90% of all industrial chlorine is produced by electrolysis, a process in which an electric current is passed through a brine solution. An important by-product of this process is sodium hydroxide. In its simplest form an electrolytic cell is as shown in Figure 1. Two plates, or electrodes, are inserted into a brine solution and connected to a DC power supply. The electrode connected to the negative terminal is called the cathode and the electrode connected to the positive terminal is called the anode. When the current passes, chlorine gas is liberated at the anode, hydrogen gas is liberated at the cathode and the electrolyte is gradually converted from sodium chloride to sodium hydroxide.
The net result of the reaction can be written as:
NaCl(aq) + H2O(l) = NaOH(aq) + ½H2(g) + ½Cl2(g)
All of the products of this reaction are marketable and so should be as pure as possible - hence one reason for the initial purification of the brine.
Quite apart from the poor energy efficiency of the simple cell, it possesses a number of other disadvantages which call for a more sophisticated design. Principal amongst these are:
(a) It is difficult to collect the hydrogen and chlorine gases,
(b) It is difficult to keep the hydrogen and chlorine gases apart. This could cause serious problems because they could react explosively with each other to form hydrogen chloride.
(c) The electrolyte is a mixture of sodium chloride and sodium hydroxide which would need further treatment to separate the marketable sodium hydroxide.
(d) Cells operate at elevated temperatures and hot sodium hydroxide solution will dissolve chlorine.
(e) The simple cell is not a continuous process.
(f) Once a significant proportion of the sodium chloride has been converted to the hydroxide, the cell is operating with dilute solutions of NaCl, which makes it inefficient.
Figure 1. Simple electrolytic cell.
One of the first methods employed to overcome some of these problems was the diaphragm cell shown schematically in Figure 2. It differs from the simple cell of Figure 1 in that the anode and cathode are separated by a permeable membrane (originally made from porous pot). The level of electrolyte in the anode chamber is maintained at a slightly higher level than that in the cathode chamber by allowing fresh brine to trickle in at the same rate as it runs out through the diaphragm. The net result is a continuous flow of electrolyte from anode to cathode chamber but the electrolytic reaction is identical to that in the simple cell.
The diaphragm cell overcomes most of the problems of the simple cell. Hydrogen and chlorine are produced in separate chambers, sodium hydroxide cannot diffuse into the anode chamber to react with the chlorine because of the continuous flow of brine through the diaphragm, the anode is presented with a constant concentration of sodium chloride so producing chlorine at a constant rate and, finally, the process is continuous.
Figure 2. Schematic diagram of a diaphragm cell.
From an operational viewpoint, the brine used in diaphragm cells must be carefully purified. It is especially important that the concentrations of Mg++ and Ca++ ions are minimised because the presence of sodium hydroxide will cause these two impurities to precipitate. This often occurs in the diaphragm itself and blocks the pores.
In modern diaphragm cells the diaphragm is usually made of asbestos, the cathode is usually a steel wire mesh and the anodes are usually titanium. The diaphragm will usually last 3 to 4 months before it needs replacement. The membrane cell is based on the same principle as the diaphragm cell but the membrane is usually based on cellulosic fibres.
One of the main commercial disadvantages of the diaphragm cell is the production of a mixture of sodium chloride and sodium hydroxide rather than pure sodium hydroxide. This problem is overcome in the mercury cell (sometimes called the amalgam cell) illustrated schematically in Figure 3.
This cell relies on the property of mercury, a liquid at room temperatures, to dissolve sodium metal to form an amalgam which remains liquid until the sodium concentration reaches 2.5wt%. In the mercury cell, mercury flows slowly across the steel base of the cell and electrical contact is made through the base. A stream of clean mercury is fed in at one end of the cell and liquid amalgam is extracted at the other. Similarly, saturated brine is fed into one end of the cell and depleted brine is extracted at the other; this maintains a constant concentration of brine within the cell.
This type of cell requires to additional external facilities; some means of decomposing the amalgam and some means of regenerating the brine.
The amalgam can be readily decomposed with hot water and since the process is separate from the electrolytic cell, the sodium hydroxide is pure and can be obtain at commercial concentrations at this stage. Furthermore, since the hydrogen liberated during the decomposition is outside of the electrolytic cell, there is no possibility of any reaction between hydrogen and chlorine.
Figure 3. Schematic diagram of a mercury cell. See text for explanation.
During passage through the cell, the brine concentration is reduced by 10%-15% of its initial value. The brine is regenerated by passing it through a suspension of solid sodium chloride. However, because of the continuous recycling, it is important that the resaturation plant also incorporates a further purification operation to prevent the build-up of impurities.
In the sample of producers examined in this report, 68% were operating mercury cells, 12% were operating diaphragm cells and the remaining 20% operated membrane cells. The mix of products also varied from one operator to another. Most producers manufactured chlorine, sodium hydroxide and hydrogen. One producer however made no chlorine; all of it was converted to sodium hypochlorite. The quantities of hydrogen recovered for further use was variable, ranging from one producers who vented the whole of the hydrogen output to the atmosphere to one producer who recovered almost the whole stoichiometric amount. All operators of mercury cells also produced sodium hypochlorite. Smaller quantities of hypochlorite were produced by the operators of membrane cells but very little hypochlorite was manufactured by the operators of diaphragm cells. The production of the different products by the various routes are summarised in Table 1.
Table 1.
Production of chlorine, sodium hydroxide, hydrogen and sodium hypochlorite in thousands of tonnes by the different production routes in the sample of plants examined. NaOH and NaOCl are expressed as 100% chemical and not as solution mass.
Production from plants operating: / Chlorine / Sodium hydroxide / Hydrogen / Sodium hypochloriteMercury cells / 5007 / 6386 / 189 / 374
Membrane cells / 1836 / 2045 / 51 / 125
Diaphragm cells / 949 / 1063 / 27 / 3
Totals / 7792 / 9494 / 267 / 502
PRODUCT TREATMENT
Most chlorine is dried using concentrated sulphuric acid and then compressed. A small proportion ( 5% of the sample examined) was liquefied.
Sodium hydroxide from mercury cells is usually produced as a 50% solution. That produced in both membrane and diaphragm cells is treated to remove residual sodium chloride and is concentrated. A small proportion ( 4% of the sample examined) produced solid sodium hydroxide.
None of the plants examined reported any treatment for the hydrogen produced. In many instances this hydrogen was burned in the steam plant to generate process steam and, occasionally, electricity for use in the electrolysis plant.
PARTITIONING
Sodium chloride
In the present work, sodium chloride has been partitioned between chlorine, sodium hydroxide and, where appropriate, sodium hypochlorite and hydrogen chloride on the basis of the stoichiometric demand. Any excess inputs of sodium chloride have been attributed to the relevant products in proportion to their stoichiometric demands.
Water emissions
Those water emissions associated with NaCl and its purification have been attributed to chlorine, sodium hydroxide and, where appropriate, sodium hypochlorite and hydrogen chloride on the basis of the quantities of sodium chloride attributed to each of these products. Water emissions, which could not be directly attributed to sodium chloride, e.g. mercury emissions, were partitioned between the products on a simple mass basis.
Steam input to the chlorine cell
In an earlier report,[1] the steam input to chlorine cells was all attributed to sodium hydroxide on the assumption that this was the primary reason for this input. From the present data, however, it is clear that this is not so. Many plants which reported separately the NaOH concentration stage also reported steam inputs to the cell itself. The steam input to the chlorine cell has therefore been partitioned across all products on a simple mass basis.
HCl input to the chlorine cell
Any HCl input to the cell electrolyte will be completely dissociated and will therefore provide an additional source of chloride ions in the electrolyte. It has therefore has been attributed to the production of chlorine.
NaOH input to the chlorine cell
Any NaOH input to the cell has been attributed solely to the production of NaOH on the assumption that it will be recovered along with the NaOH generated within the electrolytic process.
Sulphuric acid input
An input of 98% sulphuric acid is used for chlorine drying and so has all been attributed to the chlorine output.
Hydrogen emissions from the chlorine cell
Hydrogen emissions from the cell refer to the losses of hydrogen to the atmosphere. These emissions have therefore all been attributed to the production of hydrogen.
Chlorine emissions from the chlorine cell
Chlorine gas emissions from the cell refer to the loss of chlorine to the atmosphere. These emissions have therefore all been attributed to the production of chlorine.
Electricity use in the chlorine cell
The allocation of electricity to the different products from the chlorine cell has been the subject of much discussion over the years. Almost all methods that have been proposed have their proponents and opponents and no single method meets with universal approval. In the present work electricity input is partitioned over all marketable or usable products on a simple mass basis. This is the method that has traditionally been used in almost all work to date.
ECO-PROFILE OF SODIUM HYDROXIDE
The data given here refer to a concentrated solution of sodium hydroxide and refer to the mass of hydroxide, not the mass of solution. Table 2 shows the gross or cumulative energy to produce 1 kg of electrolytic hydrogen and Table 3 gives this same data expressed in terms of primary fuels. Table 4 shows the energy data expressed as masses of fuels. Table 5 shows the raw materials requirements and Table 6 shows the demand for water. Table 7 shows the gross air emissions and Table 8 shows the corresponding carbon dioxide equivalents of these air emissions. Table 9 shows the emissions to water. Table 10 shows the solid waste generated and Table 11 gives the solid waste in EU format.
Table 2
Gross energy required to produce 1 kg of sodium hydroxide. (Totals may not agree because of rounding)
Fuel type / Fuel prod'n / Energy content / Energy use / Feedstock / Total& delivery / of delivered / in / energy / energy
energy / fuel / transport
(MJ) / (MJ) / (MJ) / (MJ) / (MJ)
Electricity / 7.81 / 4.05 / 0.07 / - / 11.93
Oil fuels / 0.15 / 1.11 / 0.03 / <0.01 / 1.29
Other fuels / 0.39 / 8.11 / 0.03 / 0.29 / 8.82
Totals / 8.35 / 13.27 / 0.13 / 0.29 / 22.04
Table 3
Gross primary fuels required to produce 1 kg of sodium hydroxide. (Totals may not agree because of rounding)
Fuel type / Fuel prod'n / Energy content / Fuel use / Feedstock / Total& delivery / of delivered / in / energy / energy
energy / fuel / transport
(MJ) / (MJ) / (MJ) / (MJ) / (MJ)
Coal / 1.63 / 2.02 / <0.01 / 0.23 / 3.88
Oil / 0.72 / 1.44 / 0.12 / <0.01 / 2.27
Gas / 1.53 / 7.44 / <0.01 / <0.01 / 8.98
Hydro / 0.57 / 0.43 / <0.01 / - / 1.00
Nuclear / 3.67 / 1.81 / <0.01 / - / 5.48
Lignite / <0.01 / <0.01 / <0.01 / - / <0.01
Wood / <0.01 / <0.01 / <0.01 / 0.06 / 0.06
Sulphur / <0.01 / <0.01 / <0.01 / 0.01 / 0.01
Biomass (solid) / 0.04 / 0.03 / <0.01 / <0.01 / 0.07
Hydrogen / <0.01 / 0.48 / <0.01 / - / 0.48
Recovered energy / <0.01 / -0.45 / <0.01 / - / -0.45
Unspecified / <0.01 / <0.01 / <0.01 / - / <0.01
Peat / 0.01 / 0.01 / <0.01 / - / 0.01
Geothermal / 0.06 / 0.03 / <0.01 / - / 0.08
Solar / <0.01 / <0.01 / <0.01 / - / <0.01
Wave/tidal / <0.01 / <0.01 / <0.01 / - / <0.01
Biomass (liquid/gas) / 0.02 / 0.01 / <0.01 / - / 0.03
Industrial waste / 0.02 / 0.01 / <0.01 / - / 0.03
Municipal Waste / 0.05 / 0.02 / <0.01 / - / 0.07
Wind / 0.02 / 0.01 / <0.01 / - / 0.03
Totals / 8.35 / 13.27 / 0.13 / 0.29 / 22.04
Table 4
Gross primary fuels used to produce 1 kg of sodium hydroxide expressed as mass.
Fuel type / Input in mgCrude oil / 50000
Gas/condensate / 170000
Coal / 140000
Metallurgical coal / 32
Lignite / 12
Peat / 1600
Wood / 6300
Table 5
Gross raw materials required to produce 1 kg of sodium hydroxide.
Raw material / Input in mgAir / 22000
Animal matter / <1
Barytes / 31
Bauxite / <1
Bentonite / <1
Biomass (including water) / 11000
Calcium sulphate (CaSO4) / <1
Chalk (CaCO3) / <1
Clay / <1
Cr / <1
Cu / <1
Dolomite / 1
Fe / 80
Feldspar / <1
Ferromanganese / <1
Fluorspar / <1
Granite / <1
Gravel / <1
Hg / 2
Limestone (CaCO3) / 11000
Mg / <1
N2 / 710
Ni / <1
O2 / 2
Olivine / 1
Pb / 1
Phosphate as P2O5 / <1
Potassium chloride (KCl) / 2
Quartz (SiO2) / <1
Rutile / <1
S (bonded) / <1
S (elemental) / 1400
Sand (SiO2) / 81
Shale / <1
Sodium chloride (NaCl) / 990000
Sodium nitrate (NaNO3) / <1
Talc / <1
Unspecified / <1
Zn / <1
Table 6
Gross water consumption required for the production of 1 kg of sodium hydroxide. (Totals may not agree because of rounding)
Source / Use for / Use for / Totalsprocessing / cooling
(mg) / (mg) / (mg)
Public supply / 430000 / - / 430000
River canal / 6 / 640 / 640
Sea / 34 / 550 / 580
Well / <1 / <1 / <1
Unspecified / 3000000 / 6600000 / 9600000
Totals / 3400000 / 6600000 / 10000000
Table 7
Gross air emissions associated with the production of 1 kg of sodium hydroxide. (Totals may not agree because of rounding)
Emission / From / From / From / From / From / From / Totalsfuel prod'n / fuel use / transport / process / biomass / fugitive
(mg) / (mg) / (mg) / (mg) / (mg) / (mg) / (mg)
dust (PM10) / 350 / 83 / 2 / 110 / - / - / 540
CO / 740 / 150 / 23 / 1 / - / - / 910
CO2 / 440000 / 680000 / 3800 / 570 / -5800 / - / 1100000
SOX as SO2 / 2900 / 1900 / 34 / <1 / - / - / 4800
H2S / <1 / - / <1 / <1 / - / - / <1
mercaptan / <1 / <1 / <1 / <1 / - / - / <1
NOX as NO2 / 1300 / 1700 / 34 / 10 / - / - / 3000
NH3 / <1 / - / <1 / <1 / - / - / <1
Cl2 / <1 / <1 / <1 / <1 / - / - / <1
HCl / 46 / 13 / <1 / <1 / - / - / 59
F2 / <1 / <1 / <1 / <1 / - / - / <1
HF / 2 / <1 / <1 / <1 / - / - / 2
hydrocarbons not specified elsewhere / 510 / 110 / 10 / <1 / - / <1 / 640
aldehyde (-CHO) / <1 / - / <1 / <1 / - / - / <1
organics / <1 / <1 / <1 / <1 / - / - / <1
Pb+compounds as Pb / <1 / <1 / <1 / <1 / - / - / <1
Hg+compounds as Hg / <1 / - / <1 / <1 / - / - / <1
metals not specified elsewhere / 1 / 1 / <1 / <1 / - / - / 2
H2SO4 / <1 / - / <1 / <1 / - / - / <1
N2O / <1 / <1 / <1 / <1 / - / - / <1
H2 / 28 / <1 / <1 / 260 / - / - / 290
dichloroethane (DCE) C2H4Cl2 / <1 / - / <1 / <1 / - / <1 / <1
vinyl chloride monomer (VCM) / <1 / - / <1 / <1 / - / <1 / <1
CFC/HCFC/HFC not specified elsewhere / <1 / - / <1 / <1 / - / - / <1
organo-chlorine not specified elsewhere / <1 / - / <1 / <1 / - / - / <1
HCN / <1 / - / <1 / <1 / - / - / <1
CH4 / 11000 / 230 / <1 / 65 / - / <1 / 12000
aromatic HC not specified elsewhere / <1 / - / <1 / <1 / - / <1 / <1
polycyclic hydrocarbons (PAH) / <1 / <1 / <1 / <1 / - / - / <1
NMVOC / <1 / - / <1 / <1 / - / - / <1
CS2 / <1 / - / <1 / <1 / - / - / <1
methylene chloride CH2Cl2 / <1 / - / <1 / <1 / - / - / <1
Cu+compounds as Cu / <1 / <1 / <1 / <1 / - / - / <1
As+compounds as As / - / - / - / <1 / - / - / <1
Cd+compounds as Cd / <1 / - / <1 / <1 / - / - / <1
Ag+compounds as Ag / - / - / - / <1 / - / - / <1
Zn+compounds as Zn / <1 / - / <1 / <1 / - / - / <1
Cr+compounds as Cr / <1 / <1 / <1 / <1 / - / - / <1
Se+compounds as Se / - / - / - / <1 / - / - / <1
Ni+compounds as Ni / <1 / <1 / <1 / <1 / - / - / <1
Sb+compounds as Sb / - / - / <1 / <1 / - / - / <1
ethylene C2H4 / - / - / <1 / <1 / - / - / <1
oxygen / - / - / - / <1 / - / - / <1
asbestos / - / - / - / <1 / - / - / <1
dioxin/furan as Teq / - / - / - / <1 / - / - / <1
benzene C6H6 / - / - / - / <1 / - / <1 / <1
toluene C7H8 / - / - / - / <1 / - / <1 / <1
xylenes C8H10 / - / - / - / <1 / - / <1 / <1
ethylbenzene C8H10 / - / - / - / <1 / - / <1 / <1
styrene / - / - / - / <1 / - / <1 / <1
propylene / - / - / - / <1 / - / - / <1
Table 8
Carbon dioxide equivalents corresponding to the gross air emissions for the production of 1 kg of sodium hydroxide. (Totals may not agree because of rounding)
Type / From / From / From / From / From / From / Totalsfuel prod'n / fuel use / transport / process / biomass / fugitive
(mg) / (mg) / (mg) / (mg) / (mg) / (mg) / (mg)
20 year equiv / 1200000 / 700000 / 3900 / 4600 / -5800 / <1 / 1900000
100 year equiv / 710000 / 690000 / 3900 / 2100 / -5800 / <1 / 1400000
500 year equiv / 530000 / 680000 / 3900 / 1000 / -5800 / <1 / 1200000
Table 9
Gross emissions to water arising from the production of 1 kg of sodium hydroxide. (Totals may not agree because of rounding).
Emission / From / From / From / From / Totalsfuel prod'n / fuel use / transport / process
(mg) / (mg) / (mg) / (mg) / (mg)
COD / 1 / - / <1 / 3 / 5
BOD / <1 / - / <1 / <1 / <1
Pb+compounds as Pb / <1 / - / <1 / <1 / <1
Fe+compounds as Fe / <1 / - / <1 / <1 / <1
Na+compounds as Na / <1 / - / <1 / 23000 / 23000
acid as H+ / 1 / - / <1 / 1 / 3
NO3- / <1 / - / <1 / <1 / <1
Hg+compounds as Hg / <1 / - / <1 / <1 / <1
metals not specified elsewhere / <1 / - / <1 / 6 / 7
ammonium compounds as NH4+ / 1 / - / <1 / 1 / 2
Cl- / <1 / - / <1 / 32000 / 32000
CN- / <1 / - / <1 / <1 / <1
F- / <1 / - / <1 / <1 / <1
S+sulphides as S / <1 / - / <1 / <1 / <1
dissolved organics (non-hydrocarbon) / <1 / - / <1 / <1 / <1
suspended solids / 34 / - / 4 / 3400 / 3400
detergent/oil / <1 / - / <1 / <1 / <1
hydrocarbons not specified elsewhere / <1 / <1 / <1 / <1 / <1
organo-chlorine not specified elsewhere / <1 / - / <1 / 17 / 17
dissolved chlorine / <1 / - / <1 / <1 / <1
phenols / <1 / - / <1 / <1 / <1
dissolved solids not specified elsewhere / <1 / - / <1 / 16000 / 16000
P+compounds as P / <1 / - / <1 / 3 / 3
other nitrogen as N / <1 / - / <1 / 3 / 4
other organics not specified elsewhere / <1 / - / <1 / <1 / <1
SO4-- / <1 / - / <1 / 4700 / 4700
dichloroethane (DCE) / <1 / - / <1 / <1 / <1
vinyl chloride monomer (VCM) / <1 / - / <1 / <1 / <1
K+compounds as K / <1 / - / <1 / <1 / <1
Ca+compounds as Ca / <1 / - / <1 / 100 / 100
Mg+compounds as Mg / <1 / - / <1 / <1 / <1
Cr+compounds as Cr / <1 / - / <1 / <1 / <1
ClO3-- / <1 / - / <1 / 280 / 280
BrO3-- / <1 / - / <1 / <1 / <1
TOC / <1 / - / <1 / 1 / 1
AOX / <1 / - / <1 / <1 / <1
Al+compounds as Al / <1 / - / <1 / <1 / <1
Zn+compounds as Zn / <1 / - / <1 / <1 / <1
Cu+compounds as Cu / <1 / - / <1 / 1 / 1
Ni+compounds as Ni / <1 / - / <1 / 1 / 1
CO3-- / - / - / <1 / 150 / 150
As+compounds as As / - / - / <1 / <1 / <1
Cd+compounds as Cd / - / - / <1 / <1 / <1
Mn+compounds as Mn / - / - / <1 / <1 / <1
organo-tin as Sn / - / - / <1 / <1 / <1
Sr+compounds as Sr / - / - / <1 / <1 / <1
organo-silicon / - / - / - / <1 / <1
benzene / - / - / - / <1 / <1
dioxin/furan as Teq / - / - / <1 / <1 / <1
Table 10
Gross solid waste associated with the production of 1 kg of sodium hydroxide. (Totals may not agree because of rounding)
Emission / From / From / From / From / Totalsfuel prod'n / fuel use / transport / process
(mg) / (mg) / (mg) / (mg) / (mg)
Plastic containers / <1 / - / <1 / <1 / <1
Paper / <1 / - / <1 / <1 / <1
Plastics / <1 / - / <1 / 1100 / 1100
Metals / <1 / - / <1 / <1 / <1
Putrescibles / <1 / - / <1 / <1 / <1
Unspecified refuse / 600 / - / <1 / <1 / 600
Mineral waste / 25 / - / 38 / 6800 / 6900
Slags & ash / 8600 / 1300 / 15 / 2800 / 13000
Mixed industrial / -990 / - / 1 / 380 / -610
Regulated chemicals / 730 / - / <1 / 200 / 930
Unregulated chemicals / 560 / - / <1 / 2200 / 2700
Construction waste / <1 / - / <1 / <1 / <1
Waste to incinerator / <1 / - / <1 / <1 / <1
Inert chemical / <1 / - / <1 / 780 / 780
Wood waste / <1 / - / <1 / 130 / 130
Wooden pallets / <1 / - / <1 / <1 / <1
Waste to recycling / <1 / - / <1 / <1 / <1
Waste returned to mine / 26000 / - / 1 / 6 / 26000
Tailings / 1 / - / 1 / 7 / 9
Municipal solid waste / -6600 / - / - / <1 / -6600
Note: Negative values correspond to consumption of waste e.g. recycling or use in electricity generation.
Table 11
Gross solid waste in EU format associated with the production of 1 kg of sodium hydroxide. Entries marked with an asterisk (*) are considered hazardous as defined by EU Directive 91/689/EEC
Emission / Totals(mg)
010101 metallic min'l excav'n waste / 350
010102 non-metal min'l excav'n waste / 27000
010306 non 010304/010305 tailings / 2
010308 non-010307 powdery wastes / 2
010399 unspecified met. min'l wastes / 98
010408 non-010407 gravel/crushed rock / 76
010410 non-010407 powdery wastes / <1
010411 non-010407 potash/rock salt / 3400
010499 unsp'd non-met. waste / 1
010505*oil-bearing drilling mud/waste / 710
010508 non-010504/010505 chloride mud / 560
010599 unspecified drilling mud/waste / 600
020107 wastes from forestry / 130
050106*oil ind. oily maint'e sludges / <1
050107*oil industry acid tars / <1
050199 unspecified oil industry waste / 22
050699 coal pyrolysis unsp'd waste / 29
060101*H2SO4/H2SO3 MFSU waste / <1
060102*HCl MFSU waste / <1
060106*other acidic MFSU waste / <1
060199 unsp'd acid MFSU waste / <1
060204*NaOH/KOH MFSU waste / <1
060299 unsp'd base MFSU waste / 2
060313*h. metal salt/sol'n MFSU waste / 3100
060314 other salt/sol'n MFSU waste / <1
060399 unsp'd salt/sol'n MFSU waste / 1100
060404*Hg MSFU waste / 7
060405*other h. metal MFSU waste / 1
060499 unsp'd metallic MFSU waste / 720
060602*dangerous sulphide MFSU waste / <1
060603 non-060602 sulphide MFSU waste / 3
060701*halogen electrol. asbestos waste / 220
060702*Cl pr. activated C waste / <1
060703*BaSO4 sludge with Hg / 6
060704*halogen pr. acids and sol'ns / 1300
060799 unsp'd halogen pr. waste / 700
061002*N ind. dangerous sub. waste / <1
061099 unsp'd N industry waste / <1
070101*organic chem. aqueous washes / <1
070103*org. halogenated solv'ts/washes / <1
070107*hal'd still bottoms/residues / <1
070108*other still bottoms/residues / <1
070111*org. chem. dan. eff. sludge / <1
070112 non-070111 effluent sludge / <1
070199 unsp'd organic chem. waste / <1
070204*polymer ind. other washes / <1
070207*polymer ind. hal'd still waste / <1
continued over …..