Project Experience

Project Scope

Techno as a subconsultant to Arcadis, provided Resident Engineering services at the Coney Island and Rockaway Wastewater Treatment Plants. This project consisted of Level 1 Step Feed Biological Nutrient Removal (BNR) Upgrades at both Wastewater Treatment Plants.

The following upgrades were implemented:

Coney Island WWTP

• Baffle Walls: Provide one per aeration tank pass, 16 total
• Mixers: Provide two mixers each in aeration tank passes A, B and C swing zones; three in aeration tank pass D swing zone; nine mixers per tank, 36 mixers total
• Froth Control:
  • Provide a combined surface wasting (SWAS) and froth collection and transfer system in the aeration tanks. Two SWAS/froth transfer pump stations (one each for the east and west battery aeration tanks) and common force main for transfer to the WAS wet well
  • Provide two tote based polymer systems for polymer makeup and addition to the plant effluent spray water system and RAS line serving the aeration tanks

Rockaway WWTP

• Installing concrete baffle walls and hyerbolic mixers to create axoxic zones in each pass of all four aeration tanks (16 total passes) 
• Remove and replace existing diffusers, local isolation valves, process air piping and concrete supports in all passes
• Replace existing process air distribution piping and local control valves; add new distribution piping and local isolation valves for new anoxic zones
• Install polymer storage and blending units within existing structure; tie into existing spray water and return activated sludge system
• Refurbish and startup existing spray water system with polymer addition
• Replace leaking gaskets on process air header pipe (limited to piping in the Air Distribution Building on the deck of the aeration tanks)
• Install blow-off valves on main blower air header
• Install one DO monitor per pass in oxic zones with local indication and readout in the Air Distribution Building
• Perform structural inspection and repairs on spalled concrete and expansion joints in all ATs where determined appropriate upon inspection and determination by the Resident Engineer