Asingle source of bod causes an oxygen sag curve with a minimum downstream do equal to 6.0 mg/l. if the bod of the waste is doubled (without increasing the waste flow rate), what would be the new minimum downstream do? in both cases assume that the initial oxygen deficit just below the source is zero and the saturated value of do is 10 mg/l. (note that when the initial deficit is zero, the deficit at any point is proportional to the initial bod)

Determine the time of the day and month of the year at which the peak sensible cooling load occurs for a top floor, north-eastern corner room of an office building in durban for the following conditions: floor area: 8 x 8 x 3 m east and north walls: 115 mm face brick (outside), 20 mm air space, 115 mm ordinary brick (inside) with 15 mm plaster roof construction: suspended plasterboard ceiling, 450 mm air space, 150 mm concrete, 75mm screed, waterproofing no heat transfer across other surfaces window area 3x 1,5 m high in north wall only. ordinary glass with venetian blinds. lights and occupants : from 07: 00 to 18: 00 average light density: 25 w/m2 number of occupants : 5 seated, light office work room temperature 24°c