Results are presented on the use of ozone to decolorize textile dye solutions. The results describe the rates of reaction and the stoichiometry for the use of ozone to decolorize a simulated wastewater containing a bisazo acid dye (Acid Red 158). These rates of reaction are not sensitive to pH and are only mildly affected by temperature. The effects of a combination of an uncolored organic compound on the rates of reaction were investigated because if ozone reacts preferentially with uncolored compounds, its use might not be economical. Guar gum used in the textile industry as an aid in dyeing carpets increases the consumption of ozone by 20-60% for the conditions studied and has a small effect on the reaction rate. The competition found is not severe enough to make ozone treatment uneconomical.

The performance of a membrane bioreactor treating wastewater from a metal transformation industry was compared with the ultrafiltration system at the mill. Toxicity analysis using the microtox and algal tests on the untreated and treated effluents from both systems showed a 130 fold reduction in toxicity due to the ultrafiltration step and a further 10 fold reduction due to the biological step. This resulted in a biomass which must be disposed of as a hazardous waste. In comparison with the present situation, the overall quantity of hazardous waste was reduced by a factor of 3 due to the combination of the bioreactor and the ultrafilters.

The Netherlands has been joined by Norway the USSR and Algeria as the important suppliers of natural gas to Western Europe. Supply and demand are in balance until the mid nineties after which there will be a widening supply gap. Additional supplies are likely to come from the Soviet Union, Algeria and Nigeria. Costs will rise significantly as more remote sources of supply are used. Western European gas distributors continue to arrange future supplies with long term contracts linked to the cost of petroleum products.