Removal of organochlorine pesticides from water using virgin and regenerated granular activated carbon

Abstract

Public water systems use granular activated carbon in order to eliminate pesticides. After saturation, the used activated carbon is regenerated and reused in order to reduce the costs of water production and minimize waste. In this study, the adsorption of 10 different chlorinated pesticides from water using columns packed with commercial virgin and regenerated granular activated carbon was simulated in order to compare their adsorption capacities for different chlorinated pesticides. The breakthrough curves showed that chlorinated pesticides from the group of hexachlorocyclohexane (HCH) were poorly adsorbed, followed by cyclodiens as averagely adsorbed and the derivatives of halogenated aromatic hydrocarbons (DDT) as strongly adsorbed. However, the adsorption capacity of regenerated granular activated carbon was considerably lower for tested pesticides compared to the virgin granular carbon. In addition, rinsing of the pesticides after the saturation point is a far more efficient process on regenerated carbon.

Postrojenja za pripremu vode u mnogim zemljama koriste granulisani aktivni ugalj za uklanjanje ostataka pesticida. Uobičajeno je da se aktivni ugalj regeneriše i ponovo koristi da bi se smanjili troškovi proizvodnje vode za piće i da bi se smanjila količina otpada. U ovom radu smo ispitivali adsorpciju organohlornih pesticida iz vodenog rastvora 10 različitih pesticida na kolonama ispunjenim komercijalnim svežim i regenerisanim granulisanim aktivnim ugljem. Utvrđene su adsorpcione sposobnosti granulisanog uglja za različite pesticide. Krive proboja na ovim kolonama pokazuju da se organohlorni pesticidi iz grupe heksahlorocikloheksana najslabije adsorbuju, zatim hlorovani ciklodieni, a najjače pesticidi iz grupe DDT. Utvrđeno je da je adsorpcioni kapacitet regenerisanog aktivnog uglja znatno manji od adsorpcionog kapaciteta svežeg aktivnog uglja, a ispiranje pesticida je mnogo efikasnije posle regeneracije.