MIDDLETOWN — After a decade of wrangling and more than $20 million spent on construction and engineering, the City of Middletown’s new water treatment plant is on the verge of its grand unveiling.

The system went online in late March; the city is still doing a little final tinkering.

Why does Middletown need to filter its water?

The city draws its water from open reservoirs, some of which are susceptible to algal blooms, others, to relatively high levels of iron and manganese — metals that can cause discoloration and unpleasant flavors. Open water supplies are more vulnerable to microorganisms — viruses, bacteria, cryptosporidium and giardia. The plant is set up with multiple disinfection methods to cope with that — filtration, chemical disinfection and ultraviolet light — and there are redundancies built into each just in case a problem crops up.

Public Works Commissioner Jacob Tawil said the plant also includes tanks and equipment to add fluoride to the water.

City to fluoridate water

The Common Council approved fluoridation in 2003, but the actual implementation had to wait for this new plant. The city will run a legal notice to advise the public when fluoridation will start, Tawil said.

The city is still wrangling with its aging water mains, and is working on a plan to replace at least some of the transmission lines.

The city is also replacing the master meter at the plant, which should — finally — give an accurate measure of how much water the city actually uses.