Central Pollution Control Board

10.4 INDUSTRIAL POLLUTION CONTROL

10.4.1 Development of emission factors for cement industries

The studies were carried out in association with National Productivity Council, New Delhi. Emission factors are very useful tools for estimating air pollutants from sources.

The emission factors with and without APCDs evolved for various sections of a dry type cement plant are presented in table 10.1

Table 10.1: Emission Factor With and Without APCD For Dry Type Cement Manufacturing Industries

S. No.	Section	Sub Section	Emission Factors in Kg/T of Clinker Produced
S. No.	Section	Sub Section	Without APCD	With APCD
1.	Kiln	Kiln, Raw Mill & Clinker Cooler	94	0.98
2.	Grinding	Cement Mill & Coal Mill	257	0.21
3.	Others	Packing, Raw Mill Silo, Cement Mill Silo	7	0.01
Total			358	1.20

Similarly, the emission factors with and without APCDs evolved for various sections of a Wet type cement plant are presented in Table 10.2:

Table 10.2: Emission Factor With and Without APCD for Wet Type Cement
Manufacturing Industries

S. No.	Section	Sub Section	Emission Factors in Kg/T of Clinker Produced
S. No.	Section	Sub Section	Without APCD	With APCD
1.	Kiln	Kiln, Raw Mill & Clinker Cooler	174	0.20
2.	Grinding	Cement Mill & Coal Mill	123	0.02
3.	Others	Packing, Raw Mill Silo, Cement Mill Silo	6	0.03
Total			303	0.25

10.4.2 Assessment of requirement of bag filter vis-a-vis ESP in Thermal Power Plants

The continuous deterioration of coal quality with increase in ash content has affected the performance of ESPs. Realising the problem, some of the State Electricity Boards are planning to incorporate bag filter technologies to control the emission of particulate matter. In order to assess feasibility of installation of bag filter, a study has been initiated and indepth studies have been completed.

10.4.3 Description of alternate flyash disposal system for thermal power plant

Over the period number of alternate flyash disposal technologies have been developed and are successfully operating in developed countries. The dry ash disposal in the form of ash mound and dense phase ash disposal are few examples wherein land and water requirement ash disposal are very low in comparison to present conventional system. In order to promote these technologies in the country, a study on description of alternate flyash disposal system for thermal power plant including cost benefit assessment has been initiated in collaboration with IIT, Delhi and Flyash Mission. The study is likely to be completed by the year 2001-2002.

10.4.4 Development of Clean Technology for iron ore mines and development of Environmental Standards.

The main objectives of the study are as follows:

To describe clean technology for iron ore mining
To develop Environmental Standards for iron ore mines

During reporting period study is continued.

10.4.5 Assessment of Pollution Potential from Ship breaking activities

CPCB conducted the study through MECON, Ranchi. Two ship breaking sites namely Alang (Gujarat) and Kolkata, (West Bengal) were selected for indepth study. Report is being finalised.

10.4.6 Evaluation Of Technology For Treatment And Disposal Of Distillery Wastewater

The Central Pollution Control Board constituted an expert committee during the year 1998-1999 to evaluate the technology for treatment and disposal of distillery wastewater under the chairmanship of Prof. R.H. Siddiqui. The committee identified following technologies for detailed performance study:

Bio-methanation- followed by secondary biological treatment which may be aerobic or controlled application on land.
Composting.
Concentration and Incineration.
Composting and direct land application with or without Bio-methanation

The committee observed that inspite of the distillery industry being close to 100 year old, the proper and trouble free management of the distillery wastewater has not been possible. This is due to the fact that the treatment of the wastewater to an extent that would make it innocuous when disposed in the environment is difficult and costly.

The treatment of distillery wastewater to the extent that would make it safe to dispose in the environment has not been possible. In most cases, a partial treatment is given through primary biomethanation followed by an aerobic secondary treatment step, i.e. activated sludge process. The secondary effluent has to be diluted to meet the effluent standards for disposal on land for irrigation or in an inland surface water body.

The secondary aerobic process requires a high amount of energy input on a continuous basis, which is often not practical to cut the cost of treatment. This results in an inadequate treatment and environment degradation of the surroundings.

When the effluent is applied on land, it should be done on a scientific basis and a strict control should be exercised in regard to the treatment and dilution of the treated wastewater and its application rate, otherwise it results in an irrepairable adverse effect on soil and groundwater. Many a times availability of sufficient land for disposal through irrigation becomes a bottle-neck. Under such circumstances the industry disposes undiluted waste on a limited area resulting in soil degradation and groundwater pollution.

When the treated spent wash is disposed in inland surface waters, the requirement of the dilution water is twice as much as that required for disposal on land to meet the effluent BOD standard. Though no standards are prescribed for inorganic dissolved salts for such disposal, this may also result in an increase in the salinity of the receiving water body, particularly in the low flow season.

Considering the problems in the treatment and disposal of the wastewater on land for irrigation or in surface water, namely, large power requirement for the second stage aerobic treatment, use of fresh water for dilution, non-availability of sufficient land and adverse effects on the receiving stream or land, the other alternatives, composting, controlled once a year land application, estuarine and marine disposal, seem to be more promising. Concentration and incineration with energy recovery would be the ideal solution. However, the technology is yet to be proven on field scale.

Many industries do not opt for composting assuming that a suitable filler material would not be available from nearby sources at a `reasonable' cost. A detailed analysis of costs, economic as well as environmental, must be made before anaerobic and aerobic treatment, dilution and disposal on land or inland watercourse is preferred over composting.

For industries located on coastline, disposal by dilution seems to be the ideal solution. However, this should be done only after biomethanation and recovery of energy and ensuring adequate dilution in the receiving water body in a limited mixing zone.

Where existing industries are having problems in suitably disposing the waste on land or in inland water bodies, they should be encouraged to adopt a combination of technologies to minimise the problem.

Each of the alternatives discussed above can go wrong if a site specific waste management and monitoring programme is not implemented. The results of monitoring must be reviewed periodically and the management plan may be modified, if necessary.

Recommendation

The treatment of distillery wastewater to the extent that would make it safe to dispose in the environment has not been possible. In most cases, a partial treatment is given through primary biomethanation followed by an aerobic secondary treatment step, such as the activated sludge process. The secondary effluent has to be diluted to meet the effluent standards for disposal on land for irrigation or in an inland surface water body.

Primary treatment through biomethanation and energy recover, for which proven technology is available, has been used extensively by distilleries. It may be an integral part of any treatment scheme other than concentration and incineration.

The secondary aerobic process requires high amount of energy input on a continuous basis, which is often not practiced to reduce the cost of treatment. This results in an inadequate treatment and environmental degradation of the surroundings.

When the effluent is applied on land, it should be done on a scientific basis and a strict control should be exercised in regard to the treatment and dilution of the treated wastewater and its application rate, otherwise it results in an irreparable adverse effect on soil and groundwater. Many a time availability of sufficient land for disposal through irrigation becomes a bottle-neck. Under such circumstances the industry disposes undiluted water on a limited area resulting in soil degradation and groundwater pollution.

When the treated spent wash is disposed in inland surface waters, the requirement of the dilution water is twice as much as that required for disposal on land to meet the effluent BOD standard. Though no standards are prescribed for inorganic dissolved salts for such disposal, this may also result in an increase in the salinity of the receiving water body, particularly in the low flow season.

Further, while dilution may allow meeting of the effluent standard for BOD, the problem of colour would still persist. As no economically feasible technology is available for colour removal, no permission may be given for setting up new distilleries or expansion of existing distilleries, which discharge into inland surface water. The existing industries, which are discharging into inland surface waters should be made to adopt an alternative treatment and disposal scheme.

Considering the problems in the treatment and disposal of the wastewater on land for irrigation or in surface water, namely, large power requirement for the second stage aerobic treatment, use of fresh water for dilution, non-availability of sufficient land and adverse effects on the receiving stream or land , the other alternatives, composting, controlled one a year land application, estuarine and marine disposal, seem to be more promising. Concentration and incineration with energy recovery would be the ideal solution. However, the technology is yet be proven on field scale. In order to encourage its adoption by distilleries, the committee feels that the Government may provide financial assistance for its development.

Each of the alternatives discussed above can go wrong if a site specific waste management and monitoring programme is not implemented. The results of monitoring must be reviewed periodically and the management plan may be modified, if necessary.