Waste water treatment plant up and running

PALMER — The Palmer Waste Water Treatment Plant is up and running with the new moving bed biofilm reactor at their facility off of Inner Springer Road in Palmer. The new facility has yet to face its first test, Alaskan winter. Changing regulations from the Environmental Protection Agency placed the Palmer plant under a consent decree that changed the standards that the Palmer plant had to reach before dumping sewage into the Matanuska River, mainly due to the salmon spawning grounds located in the river.

The WWTP services 2,200 connections and treats 500,000 to 600,000 gallons of raw sewage each day. The Palmer WWTP is different than various other sewage treatment systems because cities and their landscapes are all different. The EPA did not only place these tightened regulations on Palmer, but made an example of the high ammonia levels.

“Ten years ago the EPA came and said well you’re actually discharging into a salmon spawning ground. Well that changed everything,” Palmer Department of Public Works Director Chris Nall said. “That changed our requirements for removal on just about everything, in particular the one we can’t get for most of the year is ammonia.”

Palmer had 18 months to get into compliance once the EPA set their decree in December of 2016. The reinforcing steel was laid in fall of 2017 and the construction finished this spring. It was tested in late June and came fully online in July. However, the new system is not without it’s kinks.

The MBBR is 24-30 feet deep and all sewage from the Greater Palmer Service Area is treated there. After going through the headworks building that filters most solids out of the raw sewage, it is transferred to the MBBR where hundreds of thousands of tiny ‘media’, (lego-looking circular webbed plastic pieces) grow bacteria or ‘bugs’ as the WWTP utilities Foreman Alycia Anderson calls them, that treat the sewage before entering the lagoons.

Three lagoons were built in the 1950’s that previously treated the raw sewage. The process would take about 30 days and gravity would filter out as much of the ammonia, TSS (Total Suspended Solids) and BOD (Biological Oxygen Demand) as possible before going through a Ultraviolet light and into the Matanuska River. Now the sewage enters the Headworks building, then goes into the MBBR before entering lagoon 2, then lagoon 3 and the UV building before exiting.

“July until mid January we have no problem meeting those limits,” Anderson said.

The tricky part about the standards set by the EPA are not in danger when the Salmon spawn in the fall. During the winter months, cold rises the ammonia level and bring the WWTP out of compliance. The Department of Public Works met with EPA officials and presented four options before the MBBR was chosen.

“We also have to monthly average limit of 8.6 milligrams per liter, in the months of July and August that drops down to 3.6 milligrams per liter with a monthly average of 1.7, which we have no problem meeting,” Anderson said.

Funding for the WWTP came from a variety of sources totaling $12 million dollars. The city of Palmer received a $3.6 million grant and a $4.8 million loan from the USDA, as well as a $5 million dollar bond. The city covered lagoons in 2012 to try to drop the ammonia level, which worked, but not well enough. The lagoons were dredged in 2015, removing 7 feet of sludge in some places in lagoon 1.

The WWTP requires only one full time staff to do testing, cleaning, and keep the facility running. Maintenance crews are also brought in for regular maintenance on machinery as well as emergency fixes. Staff will get an automated text, email, or phone call when something is wrong. The MBBR can automatically adjust itself based on BOD or ammonia levels, but any one of the lift stations that service the 2,200 connections can cause problems in delivering the sewage to the WWTP, which happened last week.

“There have been a lot of hiccups,” Nall said.

The $12 million dollar project features a new lab building that has not yet finished construction. The current lab is about the size of a conex storage container and features all of the samples and testing equipment required by the EPA. The winter months will show how well the new MBBR really works, as that is the time when temperatures drop and ammonia levels rise.