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Delaware Engineering Letter — Village of Red Hook WWTP April 2025 Sewer Report

Meetings/Documents/wwtpb::wwtp_1952__b00
Attached document2025-04-01

wwCc~ i Delaware Engineering, D.P.C.

28 Madison Avenue Extension Albany, New York 12203

Tel: 518.452.1290 Fax: 518.452.1335

June 4, 2025

The Honorable Mayor Karen Smythe Village of Red Hook 7467 S Broadway,Red Hook, NY 12571

Subject: Village of Red Hook WWTP – April 2025 Sewer Report

Dear Mayor Smythe:

On Monday, March 31st, our office assumed operational responsibility for the Village's old and new wastewater treatment plants. Both facilities were found to be in a severely dysfunctional state, with inoperable equipment and treatment processes that were not meeting regulatory standards.

Several immediate actions were taken to begin restoring treatment capability. The old plant was taken offline, and all flow was diverted to the newer facility. To reduce hydraulic surges, the second and third EQ pumps were shut down, leaving only the first in operation. Aeration was increased to assist in building mixed liquor and suspended solids in the aeration basin. Temporary submersible pumps were deployed in the clarifiers to return activated sludge and support biological treatment.

The sand filtration system, which was completely fouled and producing no filtrate, underwent repeated backwashing to restore partial function. The UV disinfection system was cleaned, and the available functional bulbs were used to establish partial UV disinfection. To compensate for incomplete UV treatment, disinfection was supplemented using chlorination and dechlorination tablets.

Although gradual performance improvements were observed, the plant continued to fail to meet effluent permit limits due to the time required for full biological process recovery.

The following data is extracted from the DMR reports attached to this letter.

|Parameter|Units|Result Old Plant|Result New Plant|Limit| |---|---|---|---|---| |Average Day Flow|mgd|0|0.049|0.05| |TotalSuspended Solids (TSS)|mg/L|0|108|10| |Carbonaceous BOD5(5-Day)|mg/L|0|60|5| |Total Ammonia Nitrogen (as N)|mg/L|0|35.30|Note 1| |FecalColiform|MPN/100|0|2,503|200-400[2]| |Dissolved Oxygen|mg/L|0|6.11|7|

Notes:

  1. The limit for Total Ammonia Nitrogen (as N) is 0.98 mg/L from June 1[st] to October 31[st] and 1.81 mg/L from November 1[st] and May 31[st] .

  2. The limit for Fecal Coliform is regulated as 200 No./ 100m over a 30-Day geometric mean and 400 No./ 100m over a 7-Day geometric mean.

223 Main Street Goshen, New York 10924 845.615-9232

55 South Main Street Oneonta, New York 13820 607.432.8073

548 Broadway Monticello, New York 12701 854.791.7777

16 East Market Street Red Hook, NY 12571 518.452.1290

Delaware Engineering, D.P.C.

Please call me at 518-452-1290 if you have any questions.

Sincerely,

Roberto Flores, P.E.

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