
The pilot plant was configured to simulate as closely as possible the process train selection of a full-scale system. The pilot plant was designed for a maximum nominal throughput of 500 litres per day. The treatment offered by the pilot plant was to take place over a maximum of 4 steps, namely;
The frame holding these vessels was constructed of 2 wrap around
100 x 50mm stainless steel box section. Centrally placed in the
frame was a bedplate to mount the Forward Feed Pump, Backwash Pump
and Air-Scour Blower. Externally mounted on the frame was the Ozone
Generator, The Control Panel / distribution panel and the system
fascia / mimic.
The system was configured to be operated manually with respect to
all filtering and washing sequences. However certain safeguards
were incorporated such as low flow protection and overload cut outs
on electrical loads. Flow through the system was controlled via a
manually adjusted needle valve downstream and a variable area
(Rotameter type) flowmeter on the inlet, this flowmeter was also
fitted with a reed switch and magnetized float to give a low flow
alarm contact. Refer to Figure 2 for details of the plant fascia
mimic.
TK1 was configured to be backwashed using a combined air scour and
backwash regime and consisted of a mono media sand of 0.7 to 1.4mm
size. TK3 was configured for separate air and water backwashing
with a high water upflow of the order of 30m/hr. media was sand
identical to TK1 with a top layer of coarse filter anthracite. TK4
was configured for a water only wash, however a scour connection
was provided as some types and grades of carbon will withstand and
require air scouring.