Over the last few days, people have been asking "...what's that smell?"

Well, now we have an answer. The Portland Press Herald reported this morning that the foul odor is coming from Portland's East End Sewage Treatment Plant, and a perfect storm of high heat, humidity, and an $11 million ongoing upgrade to the facility is causing smells of raw sewage to waft over the greater Portland area.

The foul smell has been reported in the East End, on Munjoy Hill, throughout Bayside, Downtown, and even as far away as the SMCC campus in South Portland.

Several Portland residents have complained directly to the city, saying that the smell Monday night into Tuesday morning was "almost unbearable." Even our own concertgoers downtown complained of an offensive odor as they were leaving the Melanie Martinez show at the State Theatre on Monday night.

Plant officials say that the hot temperatures and humidity have increased smells, and that a massive renovation effort to fix the aging aeration systems has caused even more problems on top of that.

Portland officials have confirmed that the 36-year-old oxygen injection system can't pump enough clean air through the wastewater to eliminate the odors. According to the PPH, the facility treats about 20 million gallons of wastewater a day.