Abstract: The present invention provides a reactor and process for the biological treatment of sewage, being transferred, by gravitational forces with a substantially constant flow rate (Q), through an array of successively alternating aerobic and anaerobic compartments (14, 16) for, respectively, aerobic and anaerobic degradation of biodegradable substances in said sewage, the compartments, which form part of the reactor of the invention, are separated by partition walls (50) and each has a top area (S), the passage of the sewage from an aerobic compartment (16) to its adjacent succeeding anaerobic compartment (14) is provided at the bottom of their common partition wall, while the transfer of sewage from an anaerobic compartment to its adjacent aerobic compartment is performed by means of gravity-caused flow over their common partition wall, whereby oxygen required for the aerobic treatment is dissolved into the sewage via an air-sewage interface at the top area of the anaerobic and aerobic compartments forming there

Abstract: A plastic bag for the collection of dirt, particularly dogs' excrement, off the ground, comprising a flat, envelope-like portion made of a yieldable sheet material with an open rim defining opposite, substantially straight lips extending one next to the other. Each lip is provided with a strip of a semi-rigid, bendable material. The respective ends of the strips are connected to each other to form a pair of hinges, such that the strips are flexed one away from the other by a pushing force applied thereagainst, the closed one against the other by a pulling force applied to the hinges.

Abstract: Described is a hand punch which can be constructed in a narrow compact form and of few and simple parts. It includes a narrow base formed with a plurality (e.g. two) punch pin openings in a straight line along the length of the base, a pair of lever arms pivotably mounted at opposite ends of the base on pivotal axes parallel to the width of the base, and punch pins received in openings in the lever arms and arranged such that a manual force applied to one of the lever arms to move same towards the base, also moves the other lever arm towards the base, and the plurality of punch pins through the openings in the base. The base is preferably constructed of a multi-leg channel member elongated in the direction of its length, the channel member having four spaced legs, the lower two of which define a compartment for receiving the paper chips, and the middle two of which define a slot for receiving the paper sheet to be punched.