VPE 511: Environment and Environmental Hygiene (2+1)

DRAINAGE OF BUILDINGS

• To maintain sanitation in animal house one has to pay attention in drainage. The drainage system may conveniently be divided into three sections which all inter connected. That part inside and outside the building situated above ground level and leading to.
• The underground drain pipes and fittings in turn or connected to,
• The public sewer cesspool, septic tank or other means of disposal.
• The general principles of only drainage system
• The pipes should be made of non absorbent material and be laid with air and water tight joints.
• The drains should be laid in straight lines between points of access all changes of direction or gradient being open to inspection. All connections being on made that the incoming drain points in the direction of the flow of sewage.
• The drain should be laid to gradients which will ensure their being self cleaning.
• All inlets to fowl drain should be trapped.
• No drain should pass under buildings.
• All entrance to drains should be outside the building.
• There should be ample means of access for inspection.
• The drainage should be disconnected from the sewer or other outfall by means of a proper intercepting trap.
• The drainage system should be properly ventilated.
• It is desirable to provide a separate system of drains to take the rainwater in most cases.

Drain pipes

• Pipes for underground drains must possess strength to withstand the pressure of the super imposed soil and the weight and jar of traffic. Strength is also necessary to resist the internal pressure of gases. Drain pipes must have a smooth internal face so that the free passage of waste matter is not hindered. The internal surface must also resist the corrosion of liquids or gases.
• Pipes must be durable be able to withstand alternating temperatures, the action of chemicals and the friction of sand and other solid particles. Absolute impermeability to gases and water is an essential feature without which any drain pipe is not only useless but extremely dangerous as otherwise the surrounding soil would soon become the stoneware or fireclay pipes when well laid are always cleaner than iron drains and will in ordinary circumstances remain practically tight for long periods. On the other hand iron pipes will remain perfectly tight for long periods but do not remain for any length of time perfectly clean. Because of greater length of iron pipes fewer joints are required than with stoneware fireclay pipes.

Bends

• The drainage pipes must be laid in straight line if abrupt deviations from the straight are necessary bend are used. At the curve chokage is liable to occur the curved pipes are frequently provided with removable bolted covers.

Junctions

• Junctions at right angles are to be avoided for free flow. Junction should have inspection chambers and it is covered by lid which is securely bolted down. The optimum size of the pipe for livestock farm is 10-15 cm internal diameter.

Trap

• Is to prevent the gas escaping from the sewer to the house.
• Syphone trap
• The reliability of a trap depends primarily upon the depth to which the in-bent portion of the piping. An ideal trap effectively prevent sewer gases under ordinary circumstances from passing up the inlet pipes. It must be self cleansing.
• Dip stone, mason’s or built trap
• It is a receptacle built of brick. It is of the worst forms of traps. It is not self cleaning, allow to settle solids.
• Buchan’s Intercepting Syphon trap
• It is provided with an abrupt inlet and a gradual outlet, and the seal in this trap is very effective
• Gully trap
• In the drainage system the fluid alone pass into the drain and at the same time hold back the more solid portion. For this purpose gully traps are placed at the inlet of the drains, they are designed to catch and retain any solid matter.