BAC Filtration Examples in Full-Scale Drinking Water Treatment Plants - Activated Carbon for Water and Wastewater Treatment - page 317

Raw Water
Turbidity: ≥ 100 NTU
Ammonia: max. 5 mg/L
DOC: max. 5 mg/L
Pesticides: ≥ 5 µ g/L
(Atrazine, diuron etc.)

Ruhr River

Premixing Chamber
Preozonation

Flocculation and
Sedimentation

Main Ozonation

Biological Double
Layer Filtration

BAC Filtration

Infiltration for Artificial
Groundwater Recharge
Re-catchment
Safety Disinfection
by Chlorine

Finished Water
Turbidity: < 0.1 NTU
Ammonia: < 0.01 mg/L
DOC: 0.8-1 mg/L
Pesticides: below the limit
of quantification

Deacidification by
NaOH

Pumping and Distribution

Figure 10.1 Operation of the Styrum-West, Dohne, and Kettwig Water Works according to
the M ¨ lheim process(drawn based on Bundermann [5]).

filters. In contrast to the full-scale plant, no carbon reactivation was applied in the
pilot plant during 4 years operation. Pesticides were spiked into the influent of BAC
filtration where the concentrations varied between 2 and 10 m gL -1 .Eveninthe
absence of carbon reactivation the filter effluent still complied with standards and
guidelines: DOC was less than 2mg L -1 and AOX remained below 5 m gL -1 . After 4
years of spiking with 2 m gL -1 , still no pesticide breakthrough was observed in the
two-stage BAC filtration. For all the tested pesticides, the most consistent removal
was seen in the case of atrazine. It was concluded that a running time of 3 years
between two reactivations in the two-stage BAC filtration is achievable without
negatively affecting the finished water quality. Average DOC concentrations would
increase up to 1.2mg L -1 , from 1mg L -1 with running times of 2 years. After 4 years