RELIABILITY ACCEPTANCE TEST

Following completion of the FAT, the CONTRACTOR shall be allowed to proceed with the Reliability Acceptance Test (RAT) phase of testing.

DAFT C will be the first DAFT to undergo a RAT and the duration will be 45 days, for each subsequent DAFT a 21 day RAT will be required. CONTRACTOR shall be required to perform all work described under the RAT phase of commissioning for the number of days specified above, or until successful completion of the continuous 7 day operation

requirement, whichever is longer. Monitoring requirements and schedule for the 7 day continuous operating test are specified at the end of this RAT document.

If process acclimation and the 7 days of continuous operation requirement are completed in less than 21 or 45 calendar days, duration depending on which DAFT is undergoing the RAT, CONTRACTOR shall continue with work described under the RAT phase for the full duration of the calendar period.

If the process acclimation and the 7 days of continuous operation requirement is not

completed after full duration of the calendar period, CONTRACTOR shall continue to perform all work described under the RAT phase until the RAT has been accepted as complete, with no limit on the time period required to complete the RAT, and with no additional

compensation.

Reliability Acceptance Test (RAT) shall be performed on behalf of the CONTRACTOR by the Commissioning Coordinator after the FAT is completed and accepted.

Constraints: To the extent practical, during the RAT the plant shall be operated at average dry weather flow conditions during night time hours, and all abnormal, maximum and minimum flow conditions shall be tested during daylight hours.

Procedure: The DAFT sludge feed consists of waste sludge (WS), scum (S), and waste activated sludge (WAS). The sludge feed system must be operational before the DAFT process can be started. Each DAFT tank will be fully commissioned from start to finish before proceeding to the next DAFT. This schedule will be based on work sequencing as discussed in the Contract Documents.

The DAFT tank will be filled with secondary effluent to prepare for the startup. The water will be back fed from the secondary effluent piping into the pressurization piping as shown on the Contract Drawings. This will require the normally closed secondary effluent valve to be opened and all recycle pump suction valves to be closed. The secondary effluent will fill the recycle sumps and back feed into the submerged launder filling the DAFT tank. The water level should be maintained by the underflow weir gate located in the underflow box. The secondary effluent valve will be shut off once a DAFT liquid level elevation of 11.5’ has been reached.

Once the water level is maintained and the SE valve is shut off, one (1) saturation system consisting of a recycle pump and saturation tank will be started. A summary of the startup procedure is as follows. Detailed steps can be found in the startup activities table below.

1. Begin polymer batching 45 minutes prior to startup to allow proper aging 2. Startup the DAFT collector mechanism

3. Fully open back pressure control valve from top of DAFT tank 4. Startup air compressor system

6. Adjust air panel valves, pump discharge valve, saturation tank inlet valve and back pressure valve as needed to maintain optimum pressure of ~70 psi in the saturation tank and a well- balanced water level variation (always maintain level within magnetic indicator range) in the saturation tank

7. Begin feeding polymer to the polymer ring

Note: Contractor shall test the polymer feed pumps and flow meters per Polymer RAT requirements during the corresponding DAFT RAT. If the corresponding DAFT completed its RAT prior to polymer system commissioning the Contractor shall make arrangements to have the DAFT in operation for the purpose of the polymer feed pump and flowmeter testing.

8. Begin influent sludge flow to DAFT by opening the corresponding DAFT feed valve 9. Startup the TWAS pumps

All monitoring points (flows, pressures, etc.) should be checked and recorded on RAT daily process control data sheets by the CONTRACTOR during the commissioning period.

Prior to initiation of testing as specified on log sheets CONTRACTOR shall set up and perform a valve checklist to ensure equipment is ready to be tested. Checklist shall verify all procedures in the startup activity table have been performed.

Startup Activity

1.

Verify all required operational tests of mechanical and electrical systems have been successfully performed.

2.

Ensure the following slide gates and valves are in the proper position for operation of DAFT before startup:

A. DAFT feed sludge valves closed

B. Back Pressure valve (on top of DAFT tank) unit fully open C. Recycle pump suction and discharge valves closed D. Underflow box effluent gate is open

3.

Verify all valves are closed on the TWAS, saturation system, and polymer piping. 4.

Start polymer batching of the permanent polymer system if polymer commissioning has been completed. Otherwise use the temporary polymer system for the purpose of conducting the DAFT RAT:

Note: Contractor shall test the polymer feed pumps and corresponding flowmeters per Polymer RAT requirements during the corresponding DAFT RAT if not already done so during the Polymer RAT.

5. Open SE valve and recycle sump isolation valve in order to back feed SE from pressurization piping into the submerged launder and fill DAFT tank

6. Startup the DAFT collector mechanism at 50% of full speed

8. Startup Saturation System

A. Fully open all valves on air panel except compressed air line B. Confirm back pressure valve is fully open

C. Open isolation valve on pump suction piping and allow SE to flow through the pump

D. Bleed air from the pump and suction piping

E. Open pump discharge valve and “bump” pump to charge line F. Close discharge valve

G. Start up the air compressor

H. Open compressed air valve on air panel. Confirm air compressor is producing a minimum air pressure of 100 psi and that the outlet PRV on the air panel is set to at least 70 psig

I. Bring saturator to operating pressure with compressed air J. Set nitrogen purge at _3_ cfm

K. Ensure water level in saturator is visible but at a low position

L. Start the pump and immediately open discharge valve (regulate if required for BEP)

M. Recirculation seal water flow to recycle pump will automatically initiate at this point.

N. Open saturator tank discharge isolation valve – regulate to maintain water level at mid-point

O. Observe pressure in saturation tank and adjust conditions to maintain a tank pressure of about 70 psi by gradually opening the back pressure valve to

decrease tank pressure and gradually closing the back pressure valve to increase tank pressure while continuing to gradually open the saturator tank discharge isolation valve

P. Be sure to check pump operating pressure (make sure in range of BEP). Note pump design flow and pressure is 1,344 gpm @ 178 feet. This will be an iterative process of closing the back pressure valve and opening the saturator discharge valve.

Q. Maintain the water level in the saturation tank within the low and high water levels as indicated by the magnetic level indicator by purging the nitrogen and setting the solenoid valve in Auto. It is important not to attempt to adjust the operating pressure while the water level is being depressed or raised.

R. Observe and verify that the saturation tank level is maintained. The solenoid valve should open and close at the specified set points and the water level should rise after the solenoid valve opens and drop after the solenoid valve closes. 9. Ensure polymer feed flow is flow paced based on the influent solids loading

10. Set polymer dilution water flow to 10 gpm on the pump skid rotameter

11. Open/Close valves as necessary to route the combined WAS/WS feed sludge to the DAFTs

12. Open corresponding DAFT feed sludge valves

13. Open TWAS pump suction and discharge valves. Startup the TWAS pump once float begins to collect in the TWAS sump if not already set in Auto mode

14. Begin sampling and monitoring the process control parameters (described in RAT Process Control Data Sheets) every 3-4 hours for the duration of the commissioning period.

7 Day Continuous Operating Test: After the startup activities have been successfully completed, determine whether facilities and equipment are operating satisfactorily in a steady state to allow start of 7-day test. Make adjustments as necessary before the start of the 7 day testing period.

1. Starting on Day 1 operate the DAFT at the annual average combined sludge flow of 1.54 MGD. Continue operating at this flow for all of Days 2, and 7 along with the night-shifts of Days 3, 4, 5, and 6. Flow adjustments can be achieved by throttling the motorized DAFT feed valve via CRISP. The entire DAFT system shall be performance tested by the Contractor to ensure correct operation as one complete functioning unit, including all DAFT related mechanical and electrical systems not limited to liquid and solids pumps, sludge collection systems, underflow gates, saturation systems, polymer systems, and foul air systems.

2. Float is collected from the DAFT tank liquid surface by the rotating DAFT basin sweep. The DAFT basin sweep is rotated in the DAFT tank by a variable speed drive. By adjusting the speed of the basin sweep and/or the run duration and frequency of the sweep operation the operator may control how quickly the float is removed from the DAFT tank water surface and therefore the thickness of the float layer. Basin sweep operation in combination with other aspects of the process such as polymer dosage and water level are used to optimize the DAFT operation Control Strategy: The DAFT basin sweep speed and run duration is selected by the operator to obtain the desired sludge thickness. It is expected that a changes in DAFT drive speed and run duration would be made only when there are significant changes in sludge flow. Verify all system components are functioning properly in both local and remote modes of operation.

3. The recycle pump corresponding to the DAFT system being tested shall be operated across a range of flows after the initial saturation system adjustments are made as described above. Standby recycle pumps designed to feed the DAFT being commissioned shall also be tested for no less than 25% of the time during the 7 day continuous operating test. The recycle pumps have been selected for a design flow of 1,344 gpm to provide a saturation tank

pressure of 70 psig. Higher tank pressures and hence lower recycle flows can be achieved by gradually closing the back pressure valve if this is desired for producing better sludge

thickening capabilities. The same principal applies to reducing saturation tank pressure which is achieved by gradually opening the back pressure valve and fully opening all isolation valves in the system. Saturation tank pressures should be operated between 65 and 75 psig to find optimum sludge thickening conditions. Once the optimum setting has been found the recycle pumps should be held at a constant flowrate and pressure while keeping as close as possible to the pump’s best efficiency point, as determined by the selected pump curve. Peak air flow into the saturation system is designed for 45 scfm. This parameter shall be adjusted via the air control panel to provide the necessary air saturation. Verify all components of the saturation system are functioning properly in both local and remote modes of operation.

4. The lead and lag TWAS pumps corresponding to the DAFT system being tested shall be run based on the preset control strategy programmed into the PLC. The lead pump will start after the level in the TWAS sump reaches a predetermined setpoint. The TWAS pumps are positive displacement constant speed units each with a capacity of 345 gpm. For the purpose of the RAT each of the two pumps corresponding to the DAFT being commissioned will be tested to verify proper operation and flow capacity. This may require alternating the lead and lag designations of each pump to ensure adequate testing of each unit. In addition, one pump each from two TWAS sumps (two pumps total) shall be operated concurrently to monitor flow

5. The underflow weir gate shall control the liquid level in the DAFT tank. Liquid level in the DAFT is determined by the DAFT tank bubbler panel. Ensure correct operation of the

pneumatically operated weir gate through its entire range of motion. The weir gate should then be set at the elevation which results in accumulation of float at a depth of six inches above the leading edge of the beach. This set point should be further adjusted based on optimum liquid level as determined by sludge thickness testing.

6. During the day-shift of Days 3, 4, 5, and 6 the DAFT will be operated at design peak day flow of 2.03 MGD. The Contractor shall make arrangements with Sanitation District O&M to achieve peak flow conditions. This may require taking other DAFTs offline to compensate for the increased flows. The entire sludge remover mechanism shall be performance tested by the Contractor. At the peak design solids loading the collectors shall be operated to maintain a constant float level. If the sludge builds up faster than it can be removed at maximum collector speed, the test shall be considered a failure and the Contractor will be required to remedy the problem. The DAFT unit manufacturer shall then provide advice on the proper adjustments to the equipment as necessary to achieve the specified performance requirements and goals.

Adjustments shall include influent feedwell weir elevations, depth of submergence of float collection skimmers, collector speed, number of float collectors in service, number of saturation tanks in service, underflow weir gate level and back pressure control valve settings along with all other adjustments referenced in this document and the contract documents. Contractor shall demonstrate these adjustments along with all other adjustments and requirements as described herein and in the contract documents.

Power Loss Simulation Testing:

Power loss simulation testing shall be conducted after the conclusion of the 7 day continuous operating test but before the RAT calendar period expires.

Note: All non-DAFT system loads at the MCC shall be locked out prior to power loss simulation testing.

1. Turn off feeder breaker for DAFT MCC at switchgear SWGR-BC. Monitor to confirm that status signals from the DAFT system are available at the SCADA powered by the UPS. 2. Turn on feeder breaker for DAFT MCC at switchgear SWGR-BC. Monitor to confirm that

status and alarm signals are reset and ready to operate.

RAT Process Control Data Sheet Notes

Based on the anticipated average and peak WAS concentrations and flows, the following are anticipated process conditions with one DAFT tank on-line:

 WAS Concentration ~ 3,300 – 3,700 mg/L

 WAS flow ~ 1,069 – 1,409 gpm

 Pressurized flow ~ 953 – 1,430 gpm

 Hydraulic loading ~0.9 – 1.2 gpm/ft2

 Solids Loading ~ 18 – 27 lb/ft2d

 Polymer Dosage ~ 7 - 14 lb/dry ton

TSS samples will be collected and used to calibrate the TSS meters and process control. CONTRACTOR shall have TSS meter rep on site to calibrate TSS meters.

RAT ISSUES LOG