Title
Requisition Nos. REQ-0002565, REQ-0003295, REQ-0003302, REQ-0003341, REQ-0003401
Aluminum Sulphate
O&M
Body
Agenda of: April 23, 2025
Item No.: 2025-112
Amount: $19,771,178.90
TO: The Honorable
Board of Directors
Great Lakes Water Authority
FROM: Suzanne R. Coffey, P.E.
Chief Executive Officer
Great Lakes Water Authority
DATE: March 27, 2025
RE: Requisition Nos. REQ-0002565, REQ-0003295, REQ-0003302, REQ-0003341, REQ-0003401
Aluminum Sulphate
Vendor: Chemtrade Chemicals US LLC, PVS Nolwood Chemical, Inc.
Status: New Contract/PO
MOTION
Upon recommendation of Cheryl Porter, Chief Operating Officer - Water and Field Services, the Board of Directors (Board) of the Great Lakes Water Authority (GLWA), authorizes the Chief Executive Officer (CEO) to enter into REQ-0002565, REQ-0003295, REQ-0003302, REQ-0003341, REQ-0003401, “Aluminum Sulphate” with Chemtrade Chemicals US LLC, PVS Nolwood Chemical, Inc., at a cost not to exceed $19,771,178.90 for a duration of three (3) years and two (2) months; and authorizes the CEO to take such other action as may be necessary to accomplish the intent of this vote.
BACKGROUND
Aluminum sulfate (also referred to as liquid alum), when added to raw water, reacts with the alkalinity present in water and forms a gelatinous precipitate. The large particles of suspended matter in raw water can be removed by allowing them to settle out in a sedimentation basin. However, there are smaller particles in surface water that do not settle out within a reasonable time without some help to accelerate the process. These smaller particles, normally referred to as non-settleable solids, usually consist of a combination of biological organisms, bacteria, viruses, protozoan, color, organic matter and inorganic solids. The term turbidity is applied to all suspended matter in water. To effectively remove the suspended solids (turbidity), the size of the smaller particles needs to be increased. The difficulty with this is the particles to be removed are usually negatively charged. To bring these particles together, their charge is neutralized by adding chemicals with positively charged ions. The positive charges neutralize the negative charges and allow the particles to come together, forming larger particles that have better settling characteristics. This process of bringing the particles together is called coagulation and the chemical added is called coagulant. Alum is used as a coagulant at GLWA water treatment plants. This contract is for aluminum sulfate, liquid alum, to be delivered to GLWA’s five (5) water treatment plants upon request for the next 38 months beginning May 1, 2025.
JUSTIFICATION
Aluminum sulfate (liquid alum) is used by the five (5) water treatment plants as a coagulant, which binds together very fine suspended particles into larger particles that can be removed by settling and filtration. In this way, objectionable color and turbidity (cloudiness) are removed from the drinking water.
FINANCIAL PLAN IMPACT
Summary: The use of aluminum sulfate is anticipated as an ongoing component of the water treatment financial plan. The pricing for the proposed aluminum sulfate contract is in excess of what was anticipated during the budgeting process and the variance is due to increased volumes and therefore the maximum value of the cost exceeds the current financial plan. Potential positive variances of other chemicals as well as the use of this chemical may vary by year. Should this contract be exercised beyond the forecasted quantity, a budget amendment may be needed. First, offsetting other chemical treatment costs that may be reduced, then from other areas, and finally from the unallocated reserve.
Funding Source: Operations and Maintenance Budget (5910)
Cost Centers: Water Works Park WTP 882131
Springwells WTP 882141
Northeast WTP 882151
Southwest WTP 882161
Lake Huron WTP 882171
Expense Type: Chemicals - Aluminum Sulfate
Estimated Cost by Year and Related Forecast Variance:
Fiscal Year Amount
FY 2025 Budget (Prorated) $ 738,333.33
FY 2026 Budget 4,320,000.00
FY 2027 Forecast 4,332,000.00
FY 2028 Forecast 4,344,000.00
Total Financial Plan $13,734,333.33
Maximum Requisitions $19,771,178.90
Forecast Variance (Negative)/Positive ($ 6,036,845.57)
COMMITTEE REVIEW
This item was presented to the Operations and Resources Committee at its meeting on April 10, 2025. The Operations and Resources Committee unanimously recommended that the GLWA Board adopt the resolution as presented.
SHARED SERVICES IMPACT
This item does not impact the shared services agreement between GLWA and DWSD.