A survey conducted by the City found no seagrass or oyster reefs on the bottom around the intake and discharge. As brown, pink, and white shrimp, along with blue crabs, redfish, and flounder spawn in the Gulf and make their way into the Bay, they are going to search for seagrass beds, oyster reefs, and marsh where they can hide and grow. Those places are not typically found in the Inner Harbor Ship Channel, nor are they located far below the water’s surface where the intake and discharge will be.

The facility will draw in seawater at very low speed – less than half a foot per second – allowing fish and other marine creatures to swim past. Special screens and intake structures will be used to prevent organisms from getting caught. The intake will be about 20 feet below the surface, below areas where the most vulnerable marine life in the Inner Harbor live, further reducing the impact on sensitive species.

No. The discharge going back into the Ship Channel after processing is called brine. It is actually seawater that is cleaner and more oxygenated than the seawater that is being taken in from the Ship Channel for desalination processing.

Sediment, algae, oils, and greases are removed from the water in the early stages of the treatment process and make up what is referred to as “sludge.” This material is not returned to the Ship Channel with the brine but is disposed of properly offsite.

A proven jet diffusion system that safely mixes the discharge water with ambient seawater will help to return the discharge back to the channel. This technology isn't experimental – it's been successfully used in similar facilities worldwide, including Perth, Australia, where a comparable plant has operated for nearly 20 years without negative environmental impacts.

Salt levels in the Bay can go from very fresh during floods to very salty during droughts. The plants and animals in the Bay are used to these wide swings in salt levels – a range as much as 20 parts per thousand (ppt) - and have great capacity to adapt to different salt levels. The brine resulting from the desalination process will be pushed back into the ship channel under pressure through a multiport diffuser. The force of the diffusion will allow the brine to be diluted to nearly the ambient salinity – to a difference of less than 1.5 ppt - of the ship channel water within 500 feet. Our review of the salinity tolerances of many of the recreationally and ecologically important fish and shellfish shows the salt levels expected in the dispersed brine will not impact marine life.

The City will conduct ongoing, real-time monitoring of salinity and dissolved oxygen, in addition to reporting of those levels at multiple stations around the discharge 4 times a year for 5 years. The City will also test the toxicity of the diluted brine four times a year for the first year.

No. During the desalination process, additional oxygen will be introduced into the water, so the brine will carry as much oxygen as it possibly can. Most of the oxygen-consuming matter that currently exist in the water of the Inner Harbor Ship Channel will also be removed during the treatment process.

CCW and their consultant Freese and Nichols has no cause for concern about the impact of Per- and Polyfluoroalkyl substances (PFAS) in the Inner Harbor Ship Channel. PFAS and other micro-contaminants have always been considered in the approach for designing the Inner Harbor Water Treatment Campus (IHWTC).

Some PFAS will remain in the discharge, however the PFAS concentration will be reduced due to removal from some of the treatment processes. PFAS constituents will return to ambient levels as a result of the jet diffusion technology that is being utilized for the discharge system.

PFAS sampling will be conducted as part of the pilot plant’s operations. The pilot is the best way to monitor and validate raw water PFAS levels and removal efficiencies of the pretreatment and reverse osmosis processes.

Once the full plant is operational, the City will conduct environmental monitoring at multiple stations near the discharge location.  This monitoring will include the collection of water quality samples four times per year and will include testing  of aquatic species.