Gedrag van enkele gesubstitueerde benzenen, bestrijdingsmiddelen en complexvormers tijdens langzame zandfiltratie

A pilot plant study has been conducted to investigate the behaviour of organic micropollutants during slow sand filtration. The main goal of the study was to obtain information on the removal of some substituted benzenes, pesticides, synthetic complexing agents and AOX under the characteristic conditions of slow sand filtration practice. From the studied organic micropollutants a substantial removal of the following compounds has been found: - Substituted benzenes: p-dichlorobenzene (ca.80% decrease), o-dichlorobenzene 70%, nitrobenzene (70-80%) and p-chloronitrobenzene (60-80%). - Pesticides: 2,4-D (r.b.d.), MCPA (r.b.d.), Mecoprop (r.b.d), Fenoprop (60%) en TCA (50%). - Complexing agents: NTA (75-85%). No or only a slight decrease in concentrations has been observed for the following compounds: - Substituted benzenes: m-dichlorobenzene (20-40%), o-chloronitrobenzene (40%), 2,4-dichloroaniline (20-40%). - Pesticides: Atrazine (0%), Bentazon (0%). - Complexing agents: EDTA (0%). - AOX (10%). The study revealed that slow sand filtration is an effective drinking water treatment process for the removal of a number or organic micropollutants. A high removal of organic micropollutants can be expected especially in combination with anaerobic artificial recharge of river water in dunes, and in combination with activated carbon filtration, which could be less effective for the removal of high polar organic compounds.