tender for disinfectioning, cleaning and desilting of ugr at sec 23 rohini bps in ac 07, cleaning of underground sump, over head r.c.c. tank (independent staging) including disposal of slit and rubbish, all as per direction of engineer-in-charge. the cleaning shall consist following operations:- (i)tank shall be emptied of water by pumping & bottom shall be cleaned of silt and other deposits. (ii) entire surface area of the sump shall then scrubbed thoroughly with wire brush etc. and pressure washed with water. (iii) chlorination of rcc internal surface by liquid chlorine. (iv) the treated surface shall be dried using air jetting and all loose particles shall be removal from the surface. (v) finally the surface shall be treated with ultraviolet radiation etc.