type-4 - partial gravity system with pressure filterplanning, design, investigation, construction, erection, installation, completion testing and commissioning in all respect of entire units of arsenic cum iron removal plant (airp) of different capacities capable of removing arsenic & iron present in ground water in different concentration to acceptable limit as per latest bis code manual on basis of departmental process drawing (modified sujapur sadipur) along with 3 (three) years operation & maintenance after succesful completion of 3 (three) months trial run of augmentation of mahammadpur zone-i ground water supply scheme in lalgola block, under berhampore division-i, p.h.e. dte. (capacity-30.00 cum/hr.)