The maximum permissible level of bod (mg/l) in wastewater that is let into river is?
Answers
Micro Gram / Cubic meter (µg/m3)
Note : -(i) Annual arithmetic mean of 24- hourly / 8- hourly values shall be met 92% of the time in a year. However, 8% of the time it may exceed but not on two consecutive days.
(ii) In case of residential or commercial or industrial place falls within 500 metres of any dust generating sources, the National Ambient Air Quality Standards shall be made applicable.
(b) Frequency
(1) Air quality monitoring at a frequency of once in a fortnight (24 hourly sampling) at the identified locations near the dust generating sources.
(2) As a result of monthly monitoring, if it is found that the concentration of the pollutants is less than the 50% of the specified standards for three consecutive months, then the sampling frequency may be shifted to two days in a quarter year.
(3) In case the value has exceeded the specified standards, the air quality sampling shall be done twice in a week. If the results of four consecutive weeks indicate that the concentration of pollutants is within the specified standards, then fortnightly monitoring may be reverted to.
The levels of air quality which is an adequate with the margin of safety which is made to protect the public health of the common people and the vegetables and property.
Whenever and wherever the given amount of safety index when they two consecutive values exceeds the limit specified above for the respective standard category, it would be considered a large reason to institute regular and continuous monitoring and further investigations for the quality of the air.