The resent invention discloses geo-membrane applications having good processability, high stress crack resistance, good tensile properties and high impact toughness prepared with a bimodal medium density polyethylene resin. The apparatus has an inlet for receiving a contaminated gas having particulate matter, and for inducing a swirl to the contaminated gas. The closure element thus has the effect of a check valve. A partitioning key is also stored within the EEC.