The MBR Book: Principles and Applications of Membrane

230 The MBR Book
Table 5.8 Effluent characteristics, photographic production plant
Parameter Unit Design value
Mean flow (peak) MLD 0.84 (1.080[St1]) check
Temperature °C 37
pH – 7–8
COD concentration (load) mg/L (kg/day) 1800 (1512)
BOD concentration (load) mg/L (kg/day) 850 (714)
BOD/COD – 0.7
TSS concentration (load) mg/L (kg/day) 48 (40)
Total solids concentration (load) mg/L (kg/day) 79 (94)
TKN mg/L 35
NO � 3 -N (NO � 2 -N) mg/L 30 (25)
Total P concentration (load) mg/L (kg/day) 5 (4.2)
BOD/P ratio – 170
Ag concentration (load) mg/L (kg/day) 47 (40)
5.2.6.1 Fuji photographic production plant
The plant at Tilburg in the Netherlands is a photographic paper production plant,
owned by Fuji, discharging waste high in dissolved organic matter (Table 5.8). This
project was initiated in 1998 when a number of drivers combined to make the existing
management scheme untenable. Firstly, the province where the factory was based was
advocating reduced ground water usage. Trace chemicals discharged in the wastewater,
although not blacklisted at the time, were viewed as being onerous. Costs levied by the
municipality for wastewater treatment were increasing. Also, the temperature of the
water discharged in the summer months was close to the permitted limit of 30°C. There
was also a supplementary cost associated with silver recovery from one of the sludge
byproducts, this process being outsourced to a specialist company.
A cost benefit analysis revealed that for an estimated capital investment of €2.3
million for the recovery plant, savings in sludge treatment, energy and chemicals
(amounting to €600000/a), would provide a payback of �4 years. Additional savings
arising from reuse of reverse osmosis (RO) permeate from the recycling process
were estimated to reduce the payback time further to 2.5–3 years. It was on this
basis that piloting was initiated in 1998 using a 50 L/h sMBR pilot plant followed by
a 500 L/h plant in 1999, coupled with an RO pilot plant with a 400 L/h capacity. A
3-month pilot trial based on an iMBR pilot plant, estimated to further improve the
cost benefit by �100 k€/a in energy costs, was successfully conducted in 2002 by
the consultants for the project (Keppel Seghers) and led to the installation of the fullscale
plant.
Plant design The plant comprises an MBR-RO plant with a 0.75 mm pre-screen.
The biological treatment in the MBR consists of an aeration basin with separate denitrification
from which the sludge flows under gravity to the aeration basin (Fig.
5.18). Aeration is achieved using disc aerators powered by one or two air compressors
which are frequency-controlled to attain a target reactor DO level. A third basin
contains the membrane modules, comprising 12 stacks of 135 m 2 area, each fitted