The World Bank published its occupational health and safety guidelines in 1988. Most of the effluent, ambient air, and stack emissions guidelines have been updated, and new World Bank standards will be formally published in December, 1996. The following is a draft summary of these, based on MESAS's understanding and is meant to be an indicative, not authoritative, discussion of the World Bank's occupational and health guidelines.
The new World Bank guidelines cover many more issues and industry catagories than listed here, and a complete understanding will only be had by referring to the new guidelines when they are issued in December, 1996. For more information, visit the World Bank's Public Information Center or the Environmental Management for Power Development page supported by the World Bank and other sponsors.
Thermal Power Station Stack Emissions
The World Bank guidelines are the minimum standards for Bank funded projects, unless the environmental standards of the host country are more stringent. Any World Bank funded project must comply with the host country's environmental standards. The host country environmental standards, as well as the World Bank standards, should be clearly detailed, in comparison to the project designed emissions, in the environmental impact assessment. The environmental impact assessment should also include air dispersion modelling to assess project impacts on ambient air quality.
| Parameter | Maximum Value | Comments |
| pH | 6 to 9 | |
| Total Suspended Solids (TSS) | 50 mg/l | |
| Oil & Grease | 10 mg/l | |
| Total Residual Chlorine | 0.2 mg/l | Chlorine shock dosing preferred, See footnote 1. |
| Chromium (Total) | 0.5 mg/l | |
| Chromium (Hexavalent) | 0.1 mg/l | |
| Copper | 0.5 mg/l | |
| Iron | 1.0 mg/l | |
| Nickel | 0.5 mg/l | |
| Zinc | 1.9 mg/l | |
| Temperature Increase | 3o | See footnote 2 below. |
| Ambient Air: | ||
| Particulate Matter | 50 ug/m3 | Annual Average, PM10 |
| 80 ug/m3 | Total Suspended Particulates | |
| 200 ug/m3 | "Emergency Trigger Value," 24 hour average. See footnote 3 below. | |
| Sulfur Dioxide | 80 ug/m3 | Annual Average |
| 300 ug/m3 | "Emergency Trigger Value," 24 hour average. See footnote 3 below. | |
| Nitrogen Oxides | 100 ug/m3 | Annual Average |
| 200 ug/m3 | "Emergency Trigger Value," 24 hour average. See footnote 3 below. | |
| Stack Emissions: | ||
| Particulate Matter | 50 mg/Nm3 | Removal Efficiency of 99.9% if standard not achievable. |
| Nitrogen Oxides | Coal: 750 mg/Nm3 (260 ng/J or 360 ppm) | At least 95% of the time that the plant or unit are operating. |
| Oil: 460 mg/Nm3 (130 ng/J or 225 ppm) | See footnote 4 for assumptions. | |
| Gas: 320 mg/Nm3 (86 ng/J or 155 ppm) | ||
| Sulfur Dioxide | Less than 0.20 tons/day per MWe, for the first 1,000 MWe, plus 0.10 tons/day for each add'l. MWe | Concentration not to exceed 2,000 mg/Nm.3 |
1 Chlorine shocking may be preferable; that is, dosing at high levels for a few seconds at intervals, rather than continuous low level release. The maximum value is 2 mg/l for up to 2 hours, not to be repeated more often than once in 24 hours. The maximum allowable 24 hour average is 0.2 mg/l. The same limits apply to bromine and fluorine.
2Less than or equal to 3oC at the edge of the mixing zone, or where the mixing zone is not defined, 100 m from the point of discharge, when there are no sensitieve ecosystems within this distance.
3Good airshed managementshould encompass establishment of an emergency response plan during plant operation, to be put into effect when one or more emer-gency trigger values of air pollution are exceeded.
4 Assumptions - Coal: flue gas dry 6 % excess O2, assumes 350 Nm3 /GJ; Oil: flue gas dry 3 % excess O2, assumes 280 Nm3/GJ; Gas: flue gas dry 3 % excess O2, assumes 270 Nm3/GJ
For combined cycle units, the maximum NOx emission level is:
Gas: 86ng/J (or 50 ppm@ 15 % Oxygen)
Oil (except diesel) 130 ng/J (or 76 ppm @ 15 % Oxygen)
Where nitrogen concentration of the fuel is greater than 0.015 %, an NOx emission allowance can be computed based on the following:
| Nitrogen Content (weight %) | Correction Factor |
| 0.015 to 0.1 | 0.04 N |
| 0.1 to 0.25 | 0.004 + 0.0067 (N - 0.1) |
| > 0.25 | 0.005 |
There may be some cases where cost effective NOx controls may not be technically feasible. Exceptions to the NOx emission requirements are accept-able provided it can be shown that: 1) the alternative emission level will not result in ambient conditions which have a significant impact on human health and the environment for the entire duration of the project; and 2) cost-effective techniques such as low NOx burners, low excess air, water or steam injection, and reburning are not feasible.
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