140) When there is no recirculation of sewage, then recirculation factor is

141) For the same solid content, if the quantity of sludge with moisture content of 98% is X, then the quantity of sludge with moisture content of 96% will be

142) A pipe which is installed in the house drainage to preserve the water seal of traps is called

143) The pipe which is used to carry the discharge from sanitary fittings like bath rooms, kitchens etc. is called

144) The gas from sludge digestion tank is mainly composed of