Tender for Annual operation and maintenance of sand filter, disinfection system and valve operation at Paharganj, Ram Nagar water complex, MSRR, DLT, Lahori gate Thompson Road near PF- 16, RPSF water complex in the section of SSE/W/NDLS under DEN/Works (for 8 months) & Annual operation and maintenance of sand filter, disinfection system and valve operation at DLI water complex in the section of SSE/W/DLI under DEN/Works (for one year) in the jursidictiono of Sr. DEN-III