27CRDLWBMBALM-0001 - Dosing Specs.pdf

SECTION 02 10 00

CASEY LAKE WATER ALUM TREATMENT

PART 1: GENERAL

1.01 DESCRIPTION

A. The aluminum treatment project is to apply aluminum (both aluminum sulfate and sodium aluminate) to Casey Lake to inactivate sediment phosphorus and to reduce internal phosphorus loading. All Work included in this section shall be performed in accordance with the following paragraphs, the General Requirements set forth in these Specifications, and the provisions of the other Contract Documents.

B. Work covered by this section includes furnishing all supervision, labor, materials, and equipment required to supply, deliver, store, and apply aluminum (both aluminum sulfate and sodium aluminate) to Casey Lake, as shown on Sheets C000 and C101. The Contractor shall:

1. Furnish, deliver, store and apply liquid aluminum sulfate and liquid sodium aluminate (collectively referred to as aluminum) to Casey Lake to mitigate the internal release of phosphorus from the lake sediment.

2. Treat at appropriate weather, temperature, and flow conditions as directed by the Engineer.

3. Furnish, install, and remove all appropriate signage and buoys (if used) in a timely manner.

4. Restore all areas directly or indirectly disturbed by the Work.

5. All other Work required for a completion of the aluminum treatment as a project whole.

C. Access

Access to Casey Lake and application staging areas are located in the Archer’s Shelter Parking Area and Public Boat Launch. (C101 SITE PLAN)

Black Hawk County Conservation (BHCC) provided permission for the use of Casey Lake Public Boat Ramp as outlined in these specifications. All staging or operations that differ from those outlined in these specifications must be approved by BHCC.

D. Attachments

1. C000 COVER SHEET

2. C101 SITE PLAN

Exhibit 1: 27CRDLWBMBALM-0001

1.02 REFERENCES

A. AWWA B403-88 American Water Works Association Standard for Aluminum Sulfate.

B. AWWA B405-06 American Water Works Association Standard for Sodium Aluminate.

1.03 SEQUENCE OF WORK

1.04

A. Aluminum treatment shall not begin until chemical applicator (Contractor) is approved by the ENGINEER. Treatment is to occur between April 1, 2027 and May 15, 2027. Preferred application timing is Monday through Thursday with Friday application occurring if necessary.

B. The Contractor shall be responsible for all labor, aluminum sulfate and sodium aluminate, application equipment and arrangements for the timely delivery of aluminum sulfate and sodium aluminate required to complete the project. This shall include: a) GPS-linked computer system for barge (boat) guidance that is integrated with real-time bathymetric measurements and simultaneous chemical dosing control for both aluminum sulfate and sodium aluminate pumping rates, b) treatment barge (boat) with on-board chemical storage tanks, and c) boom applicator for even chemical distribution of chemicals.

C. Application of aluminum sulfate shall not occur if it can be reasonably expected that the surface temperature of Casey Lake will drop below 40º F within 24 hours after treatment completion. Once alum application is started the Contractor has seven (7) calendar days to complete the treatment to ensure application effectiveness.

SUBMITTALS

A. The Contractor shall submit certificate(s) indicating all materials meet requirements of these specifications before treatment occurs. The Contractor shall submit the item, applicable reference specification, class, type, manufacturer, and distributor. The Contractor shall also submit the results of aluminum sulfate and sodium aluminate lot testing of materials delivered to the site, including an analysis of the metals content of the material, before treatment.

B. The Contractor shall submit GPS coordinates and corresponding application rates and amounts of aluminum sulfate and sodium aluminate applied to the lake. This data shall be collected by the Contractor in real-time during the application and submitted to the Engineer on a daily basis.

C. The Contractor shall submit a Plan of Work for approval by the Engineer prior to the start of work. The Plan of work shall include, at a minimum, the following items:

1. Description of the temporary lakeshore chemical storage facilities including a spill prevention, control and contingency plan (SPCC Plan). Provide manufacturer’s model number and material type for aluminum sulfate and sodium aluminate storage tanks.

2. Method of chemical distribution documenting the computer control of chemical pumping rate into the lake based on application vessel speed, real-time GPS navigation, bathymetric measurements to ensure the dose in Table 1:

Table 1: Buffered Alum Treatment Dose

Waterbody Aluminum Sulfate (gal)

Sodium Aluminate (gal) Figure

Casey Lake Application 23,845 11,923 C101

3. Explanation of navigational guidance system detailing real-time GPS linked computer system for barge (boat) guidance and chemical metering control to ensure complete and uniform chemical coverage during application to the lake.

4. Explanation of application method, equipment, and chemical metering control to ensure complete and uniform chemical coverage during application to the three forebays.

5. Description of all backup systems to minimize down time.

6. Description of land-to-vessel chemical transfer method.

7. Anticipated treatment capacity (acre/hour or gallons/day).

8. Plan for adjusting application procedures or taking other steps to respond to unfavorable lake pH or other adverse occurrence during application.

1.05 BASIS FOR COMPENSATION

A. Compensation for all Work covered under this section of these Specifications shall be in accordance with the provisions set forth in Section 01 20 00, Price and Payment Procedures.

PART 2: PRODUCTS

2.01 CHEMICALS

A Aluminum Sulfate (Alum)

1. Liquid aluminum sulfate supplied shall meet the requirements of AWWA B403-

88. The liquid aluminum sulfate [Al2(SO4)3•14.3(H2O)] shall be of commercial grade appropriate for the application with an aluminum content of 4.4% Al+3 (Aluminum) by weight.

B Sodium Aluminate

1. Sodium aluminate supplied shall meet the requirements of AWWA B405-

06. The sodium aluminate [Na2Al204] shall be of commercial grade appropriate for the application with an aluminum content of 10.4% Al3+ (Aluminum) by weight.

C The aluminum solutions supplied under this standard shall contain no soluble mineral or organic substances in quantities capable of producing deleterious or injurious effects on public health or water quality.

PART 3: EXECUTION

3.01 DELIVERY, STORAGE AND HANDLING

A. The Contractor shall provide the name and location of the proposed chemical supplier with the Bid and will be responsible for all coordination with the aluminum supplier necessary to insure timely delivery to the project site. The Contractor shall confine all storage of equipment and materials within the Project Limits and otherwise in a safe, secure and environmentally sound manner. Conformance to these requirements shall be determined by the Contractor, subject to disapproval of the Engineer, whose failure to disapprove does not, however, constitute any shift of responsibility to properly handle equipment and materials from Contractor to Engineer. Tank Truck haul routes and site access shall be as directed by OWNER If gradual off-loading is required the Contractor shall be responsible for all demurrage charges.

B. The Contractor shall provide notice to Owner of delivery of equipment and materials seven days prior to the delivery date.

C. CONTRACTOR will be responsible for addressing any chemical spill or release in accordance with its spill prevention and contingency plan, and all laws and proper practices. CONTRACTOR will inform the Engineer of any such spill or release as soon as possible.

D. The Contractor shall maintain a copy of the spill prevention and spill contingency plan on site for the duration of the project.

3.02 UNFAVORABLE TREATMENT CONDITIONS

A. The ENGINEER will be responsible to monitor wind, water column temperature, and precipitation in order to make judgments about weather condition suitability for application. ENGINEER can make onsite determinations to pause the application if wind speeds exceed 15 mph and could force water mixing that might interfere with the application. If the application is paused, ENGINEER will determine when the application can resume based on suitable wind conditions.

B. Application of aluminum shall not occur if it can be reasonably expected (forecast) that a significant precipitation event (greater than 1.5 inch in 24 hours) shall occur during treatment or begin within 24 hours after treatment completion.

C. Application of aluminum shall not occur if the surface water temperature is below 40⁰ F.

D. Application of aluminum should only occur if the wind speeds at the surface of the lake are below 20 mph.

3.04 LOCATION OF WORK

A. Project Limits shall be the area equal to or greater than 5 feet water depth in Casey Lake and access areas indicated on C101.

B. The staging area is located at the Archer’s Shelter Parking Area and Public boat launch.

3.05 ALUMINUM APPLICATION

A. The Contractor shall be responsible for the purchase, delivery, scheduling, and application of the chemicals including all labor.

B. The Contractor shall be responsible for all staging area setup, security, cleanup, and restoration to its original condition. The Contractor shall meet all local and county requirements and take reasonable steps to minimize impacts on residents and lake users in noise, parking, safety, equipment and supply storage, smells, and general condition of the site.

C. The Contractor shall conduct the aluminum application utilizing a barge or similar vessel with an Engineer approved injection system that allows for uniform application of liquid aluminum. Aluminum application shall be made to the indicated areas of Casey Lake as shown on C101.

D. The Contractor shall ensure that the aluminum sulfate and sodium aluminate are applied at a ratio of 2:1 (2 gallons of aluminum sulfate for every 1 gallon of sodium aluminate). This ratio must be maintained to ensure that the pH in the lake water is maintained between 6 and 9. The application of the aluminum sulfate and sodium aluminate liquids must occur simultaneously using one boat (or system).

E. The Engineer estimates that the respective treatment rates will require a total material outlined in Table 1. It is Contractor’s responsibility to ensure that enough material is available to complete the Work in accordance with the dosing requirements stated herein.

F. The Contractor shall ensure that the aluminum sulfate and sodium aluminate are evenly distributed throughout the treatment area and that the appropriate dose is applied to the appropriate zones shown in C101.

G. The Engineer will monitor the ambient pH in Casey Lake during the aluminum treatment application. If at any time during treatment, the depth-averaged ambient pH in the lake falls below 6.5 or increases above 9 S.U., Contractor will stop the treatment. Treatment will not resume until authorized by the Engineer.

H. The Contractor shall conduct jar tests immediately prior to the start of the alum treatment and every morning before daily treatment begins to evaluate the effects of using the chemicals in lake water at the time of the treatment. Results of the treatment jar test will be used, if necessary, to adjust the application rate. Results will be shared with the Engineer and approval to proceed or a modification jointly agreed upon.

I. The aluminum treatment shall be made at a sufficient rate to ensure long term sediment phosphorus inactivation, as determined by the Engineer. Unless advised otherwise by the Engineer, the Contractor shall apply aluminum sulfate at a dose rate, Table 2:

Table 2: Buffered Alum Application Rate Waterbody Aluminum

Sulfate (gal/acre)

Sodium Aluminate (gal/acre)

Casey Lake Application 723 361

J. The Contractor will maintain ongoing communication with the Engineer and BHCC and will advise the Engineer on an ongoing basis as to application status, water pH readings, and all other conditions relevant to alum application and dosing. The Contractor shall keep daily records acceptable to the Engineer and available for review as a basis for and substantiation of payment. Daily logs shall minimally state the following:

a. Hours of aluminum application

b. The quantity of aluminum applied

c. The approximate acreage and volume treated

d. Approximate location (on map) of area treated

e. Summary of truck deliveries

f. Explanation of any downtime

K. The Contractor shall comply with all of the conditions of the permits.

**END OF SECTION**