3900-PM-BSDW0254f
Module 5
Rev. 2/2013
Date Prepared
Date Revised
PUBLIC WATER SUPPLY
MODULE 5 – SUSPENDED SOLIDS
CONTACT UNITS
Type of Units
Permit No.
(For Department Use Only)
Number of Units
Operating
Volume (Gal)
Total
A.
GENERAL FEATURES OF DESIGN (PWS Manual, Part II, Section IV, C.5.)
Have data been submitted from engineering studies, including pilot plant studies,
during periods of maximum variations in the raw water quality and flow, which
indicate the adequacy and suitability of the suspended solids contact units for
flocculation and sedimentation prior to filtration for turbidity and bacterial removal?
Yes
No
Yes
No
1. Are at least two units provided?
Yes
No
2. For surface waters which are difficult to treat, has provision been made for
either pretreatment or post-treatment by conventional methods?
Yes
No
3. Do the specifications include a complete list of maintenance tools,
accessories and necessary laboratory equipment?
Yes
No
4. Do the units provide for adequate piping with suitable sampling taps so
located as to permit the collection of samples of water and sludge from critical
areas of the units?
Yes
No
Yes
No
1. Is the flocculator motor adjustable?
Yes
No
2. Are all mixing devices employed, designed and constructed so as to control
depositing of solids in the mixing zone and to prevent floc destruction?
Yes
No
Yes
No
1. Is the size of sludge pipes at least 3 inches in diameter?
Yes
No
2. Is the piping so arranged as to facilitate cleaning?
Yes
No
3. Is the entrance to sludge withdrawal piping so designed as to prevent
clogging?
Yes
No
4. Are valves located outside the tank for accessibility?
Yes
No
B. INSTALLATION OF EQUIPMENT (PWS Manual, Part II, Section IV, C.5.a.)
Do the specifications require that the installation and initial operation of all
mechanical equipment be supervised by a representative of the manufacturer?
C. OPERATING EQUIPMENT (PWS Manual, Part II, Section IV, C.5.b.)
D. CHEMICAL FEED (PWS Manual, Part II, Section IV C.5.c.)
Are chemicals applied to the water at such points, and by such means, as to
assure satisfactory mixing of the chemicals with the water?
E.
F.
FLOCCULATION (SLOW MIXING) (PWS Manual, Part II, Section IV C.5.e.)
SLUDGE CONCENTRATORS (PWS Manual, Part II, Section IV, C.5.f.)
Does the equipment provide either internal or external concentrators?
G. SLUDGE WITHDRAWAL (PWS Manual, Part II, Section IV, C.5.g.)
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3900-PM-BSDW0254f
Module 5
Rev. 2/2013
Date Prepared
Date Revised
PUBLIC WATER SUPPLY
MODULE 5 – SUSPENDED SOLIDS
CONTACT UNITS (cont’d.)
Permit No.
(For Department Use Only)
H. UNIFORMITY OF FLOW (PWS Manual, Part II, Section IV, C.5.)
I.
1. Are the units designed to operate at the maximum uniform flow rate?
Yes
No
2. Are they adjustable to abrupt changes in flow?
Yes
No
Yes
No
CROSS-CONNECTIONS (PWS Manual, Part II, Section IV, C.5.h)
Does the installation exclude cross-connections?
J.
SUSPENDED SOLIDS
Section IV, C.5.j.)
CONTACT
SOFTENERS
(PWS
Manual,
Part II,
N/A
1. When used in the softening process, is the detention time, based on design
flow, at least 1 hour for groundwater sources or at least 2 hours for surface
water sources?
Yes
No
2. Is the total water loss 3 percent or less?
Yes
No
3. Is at least 5 percent by weight of the solids concentration of sludge bled to
waste?
Yes
No
4. Is the upflow rate no greater than 1.75 gallons per minute per square foot of
surface area at the slurry separation line?
Yes
No
K. SUSPENDED SOLIDS
Section IV, C.5.)
CONTACT
CLARIFIERS
(PWS
Manual,
Part II,
N/A
1. When used in the clarification process, is the settling detention time, based on
design flow rate, at least 2 hours?
Yes
No
2. Is the total water loss 5 percent or less?
Yes
No
3. Is at least 3 percent by weight of the solids concentration of sludge bled to
waste?
Yes
No
4. Is the upflow rate no greater than 1 gallon per minute per square foot of
surface area at the slurry separation line?
Yes
No
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