6 Drinking Water Supply Systems—Evolution Towards Efficiency
219
– replacing the sludge recirculation equipment;
– replacing the metallic parts, including the weir and the valves;
– providing electrical lifting devices for the mixers in the reaction chambers and a
pivoting crane at 360° for the lamellar modules.
Rehabilitation of the filtration station
Water filtration is a physical process of separating suspended and colloidal particles
from water by passing through a granular material (sand). The filters have the role
of lowering the settled water turbidity up to the limit of 1 NTU.
The filtration station at Gil˘ au WTP has 15 rapid double flow filter units each
having a surface of 60 m
2 , grouped into 3 filter lines. The 15 filters are located in
three different buildings.
The existing air system for the backwashing of filters (pipelines, fittings, air distributors, etc.) is physically and morally worn-out, with air leaks, which implies the
overworking of air compressors and, implicitly, their premature wear.
From the filtration station, the treated water is gravitationally transported to Cluj
area by two supply pipes of 1000 mm, respectively 1400 mm diameter.
The proposed improvement works for this stage of treatment are:
– replacing the hydraulic system in the pipe gallery up to the connection with the
washing pumps and the air blowers, with stainless steel pipes;
– replacing the existing valves in the pipe gallery, with electro-pneumatic actuators;
– replacing the float valves from both the inlet and outlet of the filters, as well as the
hydraulic pipe assembly in the filter unit;
– replacing the filter distributors with stainless steel distributors;
– providing an automatic level control system in the filters by installing ultrasonic
level sensors at each filter and automating the inlet and outlet valves in the filters;
– replacing the air system, including the air compressor;
– providing an automatic system for filter operation and backwashing and rehabilitation of the filter control panels;
– installing a dehumidification system in the filter room;
– providing a sand transportation system for the replacing or discharging of sand
from the filters, consisting of a configurable conveyor belt, a giraffe crane and a
sand pump.
– rehabilitation of the building.
Building a pre-oxidation station using chlorine dioxide
The provision of the pre-chlorination stage using chlorine dioxide will eliminate
large quantities of organic substances that may occur at certain times, avoiding the
formation of trihalomethanes.
For pre-chlorination at the Gil˘ au WTP, chlorine dioxide solution has to be prepared
on site from chlorine gas and sodium chlorite (NaClO 2 ). Gaseous chlorine can be
delivered by vacuum from the chlorine tanks storage room, which also supplies
chlorine gas for post-chlorination. The preparation of chlorine dioxide will be done
219
– replacing the sludge recirculation equipment;
– replacing the metallic parts, including the weir and the valves;
– providing electrical lifting devices for the mixers in the reaction chambers and a
pivoting crane at 360° for the lamellar modules.
Rehabilitation of the filtration station
Water filtration is a physical process of separating suspended and colloidal particles
from water by passing through a granular material (sand). The filters have the role
of lowering the settled water turbidity up to the limit of 1 NTU.
The filtration station at Gil˘ au WTP has 15 rapid double flow filter units each
having a surface of 60 m
2 , grouped into 3 filter lines. The 15 filters are located in
three different buildings.
The existing air system for the backwashing of filters (pipelines, fittings, air distributors, etc.) is physically and morally worn-out, with air leaks, which implies the
overworking of air compressors and, implicitly, their premature wear.
From the filtration station, the treated water is gravitationally transported to Cluj
area by two supply pipes of 1000 mm, respectively 1400 mm diameter.
The proposed improvement works for this stage of treatment are:
– replacing the hydraulic system in the pipe gallery up to the connection with the
washing pumps and the air blowers, with stainless steel pipes;
– replacing the existing valves in the pipe gallery, with electro-pneumatic actuators;
– replacing the float valves from both the inlet and outlet of the filters, as well as the
hydraulic pipe assembly in the filter unit;
– replacing the filter distributors with stainless steel distributors;
– providing an automatic level control system in the filters by installing ultrasonic
level sensors at each filter and automating the inlet and outlet valves in the filters;
– replacing the air system, including the air compressor;
– providing an automatic system for filter operation and backwashing and rehabilitation of the filter control panels;
– installing a dehumidification system in the filter room;
– providing a sand transportation system for the replacing or discharging of sand
from the filters, consisting of a configurable conveyor belt, a giraffe crane and a
sand pump.
– rehabilitation of the building.
Building a pre-oxidation station using chlorine dioxide
The provision of the pre-chlorination stage using chlorine dioxide will eliminate
large quantities of organic substances that may occur at certain times, avoiding the
formation of trihalomethanes.
For pre-chlorination at the Gil˘ au WTP, chlorine dioxide solution has to be prepared
on site from chlorine gas and sodium chlorite (NaClO 2 ). Gaseous chlorine can be
delivered by vacuum from the chlorine tanks storage room, which also supplies
chlorine gas for post-chlorination. The preparation of chlorine dioxide will be done