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File #: 2020-1028    Version: 1 Name:
Type: Consent Status: Passed
File created: 4/8/2020 In control: BOARD OF DIRECTORS
On agenda: 4/22/2020 Final action: 4/22/2020
Title: PLANT NO. 2 TRICKLING FILTER SOLIDS RETURN SECONDARY SLUDGE PUMP REPAIR
Sponsors: Rob Thompson
Attachments: 1. Agenda Report
FROM: James D. Herberg, General Manager
Originator: Rob Thompson, Assistant General Manager

SUBJECT:

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PLANT NO. 2 TRICKLING FILTER SOLIDS RETURN SECONDARY SLUDGE PUMP REPAIR
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GENERAL MANAGER'S RECOMMENDATION

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RECOMMENDATION:

A. Approve a sole source purchase order contract for the repair of ten (10) Return Secondary Sludge pumps at the Plant No. 2 Trickling Filter Clarifiers, for a total amount not to exceed $194,234, plus applicable shipping and taxes, to Vaughan's Industrial Repair Co., Inc.; and

B. Approve a contingency of $19,424 (10%).
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BACKGROUND

The trickling filter process is one of two secondary treatment processes at the Orange County Sanitation District's (Sanitation District) Plant No. 2 that remove suspended and dissolved organic material using microorganisms, enabling the Sanitation District to meet ocean discharge permit limits. The other secondary treatment process is pure oxygen activated sludge. The trickling filter process consists of six trickling filter clarifiers, each uses two return secondary sludge (RSS) pumps. The purpose of these pumps is to return the secondary sludge to the solids contact aeration basins to reduce the biochemical oxygen demand of the influent.

RELEVANT STANDARDS

* 24/7/365 treatment plant reliability
* Comply with environmental permit requirements
* Maintain a proactive asset management program

PROBLEM

The RSS pumps are experiencing lower shaft seal failures. Two of the twelve units have been removed, disassembled, diagnosed, and repaired. The other ten pumps are experiencing the same failure symptoms of reduced pumping efficiency which is expected to eventually lead to premature pump failure. It was determined that these pumps need to be rebuilt with higher-grade 660 bronze bushings in order to minimize future corrosion.

PROPOSED SOLUTION

Rebuild the remaining 10 RSS pumps, two pumps at a time, at the Plant No. 2 Trickling Filter Clarifier Pump Ro...

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