Specifications Part 1 - Water Supply, Sewerage and Tube Well Works

(opening) at the top, the diameter increasing uniformly towards the bottom forstability.14.13.5 The shaft shall be provided with a Crowell or fitted with a wire ground at thetop.14.14 Cleaning/Maintenance of Sewers :-14.14.1 Sewer inspections and maintenance should be planned. The whole seweragesystems should be marked on a plan and divided into sections and areas,which are placed under a maintenance gang. The maintenance gangpreferably consists of a supervisor or mate with at least 6 skilled sewer men.The area under each gang will depend on the size of the sewer, depth to whichit is laid, the spacing of manholes, the condition of sewer line (whethersurcharged or not) whether cleaning is being done by manual labour or bymechanical sewer machines etc. In case, house gully traps are to bemaintained, special gang of one or two persons who will clean these trapsregularly in a phased or planned manner is necessary.14.14.2 The work of each sewer maintenance gang would consists of the following.14.14.2.1 Check manhole condition for deposition of silt, flow, new connections done,damaged walls or steps, manhole covers, clogged vertical pipes in dropmanholes etc. While the cleaning of the manhole, pipes etc., will be undertakenby the gang, repairs etc. may be reported to be handled by a separateconstruction gang of mason and helpers. It is preferable that the repair gangcomes out on the work when the sewer cleaning or maintenance gang isworking, so that brick bats, debris mortar etc., which fall in the manhole areremoved there and then. This will cause a major blockage if the same isallowed to flow into the sewer line, which usually occurs when repairs are doneseparately. In such cases, a couple of sewer men should be deputed to cleanthe manhole of the debris immediately after repair work is completed.14.14.2.2 Check the sewer line between two successive manholes for silting and flowconditions and remove the deposited silt and.14.14.2.3 Check for any harmful and extraneous matter entering into the sewer line sothat further investigation for the cause and location can be determined.14.14.2.4 Check air release valves in rising or force mains, sluice gates or stoppage inthe sewer lines, overflow arrangements etc.14.14.2.5 A record of daily work done by the gang, and also a record of work done on thesewer lines should be maintained so that chronic trouble spots may beinvestigated and remedial action taken.14.15 Sewer Cleaning Equipment and Procedures :-14.15.1 Sewer cleaning works require usual implements like pick axes, manholeguards, tripod stands, danger flags, lanterns, batteries, safety lamps, leadUrban Administration & Development Department Page 169