Valved manifold and system suitable for introducing one or more additives into a fluid stream

A manifold comprises a conduit for conveying a fluid stream, a plurality of nozzles, and a plurality of valves. Each nozzle is connected to a corresponding port in the conduit, and each valve is connected to a corresponding nozzle. The ports can be disposed at discrete locations on two or more transverse planes of the conduit and such that no longitudinal, diametrical plane of the conduit passing through the center point of any one of the ports is coplanar with a longitudinal, diametrical plane of the conduit passing through the center point of a longitudinally adjacent port. Alternatively, the ports can be disposed at discrete locations on the conduit such that no longitudinal, diametrical plane of the conduit passing through the center point of any one of the ports is coplanar with a longitudinal, diametrical plane of the conduit passing through the center point of any other port.