Digester #2 Rag Screening
Project Number: WW2021-23
Problem or Opportunity: Digester #2 was placed in service in 2009 and has operated continuously since that time. As it is a closed system, cleaning is not possible. Typical digester operation will result in an accumulation of rags, plastics, hair, etc. for which cleaning will be required every 8 to 10 years. In December, 2020, a dramatic increase in the rag content in the digested sludge being processed was noted. Clogging of pumps, piping, and
dewatering equipment severely compromised operation. In an attempt to defer digester cleaning, it was determined that a de- ragging of the digester contents would be beneficial.
Assets Included: OWAM ID 782
Condition Score: N/A
Criticality Score: N/A
Recommended Solution: External filtration of digester sludge contents to remove rags, hair, plastics, etc. with filtered solids being returned to the digester.
Measurable Benefits: Reduction in clogs during digested sludge processing.
Basis of
Recommendation:
Numerous pump, piping, and equipment blockages
Assumptions/Risks: De-ragging operation success measurement cannot be directly measured. Reduction of clogs and blockages will determine success of this project.
Primary Driver: Observed clogs in equipment, piping, etc.
Cost Estimate: $33,138
Method of Delivery: Subcontractor equipment
Replacement of Belt Filter Press Inline Sludge Feed Grinder (Muffin Monster)
Project Number: WW2021-24
Problem or Opportunity: Existing inline grinder had been determined as unnecessary.
Recent increase in appearance of rags and debris in belt filter press sludge feed indicates the need for a replacement grinder Assets Included: OWAM ID 630
Condition Score: 5
Criticality Score: 2
Recommended Solution: Replacement in kind of grinder (known commercially as a Muffin Monster)
Measurable Benefits: Reduction in belt press operational interruptions due to clogs from rags and debris
Basis of
Recommendation:
Grinder is an industry standard for reduction of clogging materials. It will replace a failed grinder of a similar design Assumptions/Risks: It is assumed that the grinder will substantially reduce the quantity of interruptions in belt press operation
Primary Driver: Observed clogs from rags, plastics, hair, etc. in the belt press sludge feed flow (digester output)
Cost Estimate: $12,312
Method of Delivery: Equipment vendor
Repair of Damaged Holding Tank Pump
Project Number: WW2021-25
Problem or Opportunity: Rental pump was damaged when pumping sludge from the North Holding Tank. Investigation indicated that the damage was caused by a bolt entrained in the sludge flow stream Assets Included: N/A (rental pump)
Condition Score: N/A
Criticality Score: N/A
Recommended Solution: Repair pump
Measurable Benefits: Repair of pump to prevent excess charges from rental company Basis of
Recommendation:
Observed damage to pump internal mechanicals
Assumptions/Risks: Damage to pump was caused when in use at Rialto WWTP Primary Driver: Pump repairs required
Cost Estimate: $14,800
Method of Delivery: Equipment vendor
Removal of Accumulated Sludge
Project Number: WW2021-26
Problem or Opportunity: Disruption in sludge dewatering operation resulting in pump, piping, and equipment clogs due to rags and debris in sludge being drawn from the digester resulted in the need to divert sludge flow to abandoned tankage in Plants 1 and 2. Existing dewatering equipment lacks the time and capacity required to dispose of the accumulated material. This project will rent the required dewatering equipment.
Assets Included: N/A
Condition Score: N/A
Criticality Score: N/A
Recommended Solution: Rental of required dewatering equipment and associated support
Measurable Benefits: Removal of accumulated sludge which can result in odors and/or vector attraction
Basis of
Recommendation:
Collection of quotes, negotiation of contract pricing
Assumptions/Risks: Contractor to be engaged has a proven record of performance Primary Driver: Required removal of accumulated sludge
Cost Estimate: $124,999
Method of Delivery: Subcontractor