Label
DPU052025DIGESTERTANKCLEANING
Water Reclamation
Mike Schreidah (x2607)
Revised
Title
Authorizing the Mayor to enter into a contract with Denali Water Solutions, LLC for the emergency tank cleaning at the Bay View Water Reclamation Plant; authorizing the Mayor to accept bids and award contacts for related services necessary for the completion of the Digester No. 8 tank cleaning project; authorizing the appropriation and expenditure of an amount not to exceed $1,000,000 from the Sanitary Sewer Replacement Fund for said project; and declaring an emergency.
Body
SUMMARY & BACKGROUND:
The Bay View Water Reclamation Plant (Plant) includes a sludge digestion treatment process in the Solids Handling area. Primary and secondary thickened sludges are mixed in the Sludge Equalization Tank, which is referred to as Digester No. 8, before the mixed sludge is pumped into the anaerobic digesters for a biological and digestion treatment. Digester #8 is about 85 feet in diameter and 30 feet deep and holds a capacity of 1.2 million gallons. The Division of Water Reclamation (Division) has recently experienced operational problems with this digester as Operations were not able to pump the required volume of mixed sludge from it to feed the anaerobic digesters. This continued on for days, which caused a disruption in the entire digestion treatment process. The sludge transfer pumps were discovered not to be the problem as they were able to pump into the nearby Digester No. 7. This left one possible culprit, which is Digester No. 8 and the suction sludge piping to the sludge transfer pumps. The Division declared the problem as an emergency and received the permission to solicit informal bids from qualified and experienced companies in this field.
The Division contacted Denali, Synagro and Merrill Brothers for cost estimates, but only Denali responded with a detailed cost proposal to clean the tank and perform related services, such as removing the draft tube mixers from t...
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