optionally have one or more vent openings 22 located at the top surface in one arrangement vents 22 are formed as convex deformations of upper mounting flange 18 as noted above baffle 10 is configured to prevent solids carried by density currents from flowing upwards and out of the clarifier tank however because of the downward sloping design of baffle surfaces 12 some solids may become trapped and produce a buildup of gases damaging baffle surfaces 12 and possibly reducing their functionality vents 22 allow these gases to escape to the surface without harming baffle 10 using the basic design as set forth above for baffle 10 and baffle surfaces 12 it has been found by the inventor that by implementing certain advantageous arrangements of baffle surfaces 12 including the deflection angle of baffle surfaces 12 from tank wall t the length of projection of the bottom of baffle surfaces 12 from tank wall t into the center of tank c and the position of baffle surfaces 12 at certain heights on tank wall t the relative concentration of solids in the effluent may be substantially reduces over the prior art designs the following description sets forth the salient features of the baffle 10 baffle surfaces 12 in those respects as shown in fig4 the schematic drawing identifies the measurements that define the size and positioning of baffle surfaces 12 it is noted that the desired minimum horizontal projection is ideally based on the following equation s where horizontal projection is in millimeters u03b1 16 7 millimeters per meter.