![Figure 2 - Results of batch removal of arsenic [As(V)] with Connelly-GPM iron and calcareous sand (initial concentrations 50 to 22,000 μg/L) 500 j ................................................... O ppb As(V)..................... “Šk 400 Flow = 1.0 mL/mìn « 200 HRT = 6.0 minutes І 100 O V · — *](https://images.tandf.co.uk/common/jackets/crclarge/978156676/9781566766623.jpg "Figure 2 - Results of batch removal of arsenic [As(V)] with Connelly-GPM iron and calcareous sand (initial concentrations 50 to 22,000 μg/L) 500 j ................................................... O ppb As(V)..................... “Šk 400 Flow = 1.0 mL/mìn « 200 HRT = 6.0 minutes І 100 O V · — *")
ABSTRACT
T h e resu lts o f th e field experim en ts fo r th e fo u r co lu m n s are p re se n ted in F ig u re 5. T h e co n c en tra tio n o f arsen ic at th e co lum n effluen t is p lo tted as a fu n c tio n o f th e p o re vo lu m es o f w a te r th ro u g h th e colum n. T h e resu lts sh o w th a t th e C o n n e lly -G P M iro n filings rem o v ed all arsen ic from th e so lu tio n to less th an 1 p p b fo r th e en tire tw o m o n th period . T he J. T. B a k e r co lu m n s initially rem o v e d a b o u t 6 0 % o f th e arsen ic and a fte r 350 p o re vo lu m es rem o v ed arsen ic to less th a n 1 ppb from th e so lu tion . It is sp ecu la ted th a t th e J. T. B a k e r iron filings d id n o t rem o v e all a rsen ic from th e so lu tion in th e first 3 5 0 p o re vo lu m es d u e to lo w initial su rface a rea (20 tim es less th an th e C o n n e lly -G P M iron). A s c o rro s io n w as tak in g place , th e J. T. B ak er iron filings inc reased in su rface area, an d th e a rsen ic rem oval im proved .
