Germany has introduced a number of technologies, by which by products are used. The various technologies as well as their different by-products are given as below :
| Technology | By-products/Reuse |
| 1. Limestone Scrubbing | Gypsum |
| 2. Spray Dry Scrubbing | Mostly consists of CaSo3 & CaSo4 |
| 3. Walther Process | Pulverized Ammonium Sulphate |
| 4. Wellman Lord Process | Elemental Sulphur |
| 5. Dry Additive Process | Flyash, CaCO3, CaSO4, CaO |
| 6. Activated Carbon Process | Processing of SO2 rich gas to Sulphuric Acid |
| 7. Desonox Process | Sulphuric Acid |
The reuse of flyash from thermal power plants, re-utilization of by-pass kiln dust in cement industry, utilization of cement kiln dust in wet process cement kilns etc. have been elaborated in the report.
The techno-economic as well as techno-commercial aspects of the industrial air pollution control technologies for different air pollution control equipments/systems in use are discussed in detail giving advantages and disadvantages of individual systems and presenting a “Quick Comparison Guide for several air pollution control systems”. Economics of clean air, estimates of incremental costs of removing pollutants from the existing and new sources, cost of air pollution control and its advantages, comparison of air pollution control equipments and their costs, economical / commercial feasibility for various industries are also given.
The industrial costs of air pollution on account of disease, damage to health, material damage are elaborated, because their indirect costs also have an impact on the overall pollution costs which need to be minimized.
The last chapter points to the preconditions imposed for the erection and operation of the emitting plants, measuring and monitoring their emissions, time availability of gas cleaning systems to maintain the standards. It also contains concepts for the industry incentives as laid down by the Environmental Protection agency (EPA), USA action plan as chalked out by the Ministry of Environment and Forests main issues involved in air pollution and action plan for the control of various industries under study individually as well as a “Suggestive Action Plan” to control industrial pollution.
Suggestive Action Plan may be:
1. Approach to prevention of pollution rather than its control.
2. To integrate environmental considerations into decision making at all levels.
3. To ensure adherence to Public Insurance Bill passed by the Parliament.
4. Environmental courts to be set up to provide for speedy dispensation of compensation to the victims of environmental hazards.
5. Environmental Act, 1986 to be amended to widen its scope for implementation.
6. A realistic time limit should be given to fulfill consent conditions.
7. Power interruptions and voltage fluctuations, even for short durations affects the continuity of the pollution control measures and the efficiency of the systems. Proper consideration must be given to this aspect.
8. Availability of good quality coal should be assured as high ash content coal lowers the efficiency of equipments like ESP’s.
9. The standards based on initial raw water characteristics such as TDS and ambient air quality specifications should as far as possible be flexible and location wise.
10. A phased programme of implementation of standards be adopted for different industries.
11. The penalties for not achieving and adhering to the laid standards should be proportionate to the deviations.
12. Pollution awaress creating programmes may be tailored and given wide publicity.
13. training programmes may be organised quite oftenly.
A quick Review of Technologies from various countries and widely used, alongwith their special features is summarized in the Table in following pages.
