PC SP WWT info 24100.pdf

Port Crescent State Park – Wastewater Collection System

Water Flow and Treatment System Narrative

Introduction

The park sewer system collects wastewater from two bathroom/shower buildings, one cabin bathroom, a dump and fill transfer station, a campground office, and 12 full hook-up campsites. Wastewater from these locations is collected into a system with two submersible pump lift stations, one of which collects water from the north end of the campground, pumps into a gravity fed sewer line to the secondary lift station at the south end of the campground. The secondary station also receives flow from all other campground locations previously listed. Raw sewage from the pump station is then pumped to the wastewater treatment facility across the highway and adjacent to the park headquarters. Raw sewage travels via a 4-inch diameter cement asbestos force main and discharges to 4-inch diameter ductile iron force main at the treatment site. Flow then enters an in-line comminutor, or grinder, inside the Control

Building. The comminutor, or grinder, is a device that grinds up large solids in the raw sewage to make it pass more easily through the rest of the treatment processes.

Following the grinder, the sewage passes through raw sewage flow measurement device before entering the aeration tank. This device is a magnetic flow meter that measures the flow rate through the influent pipe and the total volume of flow that has passed through the pipe.

After the sewage passes through the magnetic flow meter, the sewage continues to the aeration tank. The sewage is accumulated, mixed, and treated in the tank with air that is injected into the sewage through diffusers in the bottom of the tank. These diffusers are attached to the air supply piping which is fastened to the concrete tank base slab.

Two positive displacement blowers, located in the Control Building, compress air and discharge to the air supply piping for mixing and treatment of the sewage. The dissolved oxygen provided by the blowers provides both the energy for the treatment process to occur and helps to minimize odors. The air bubbles provide mixing as they rise through the sewage in the tank. This will keep most of the solids in the sewage suspended within the tank contents and help prevent accumulation of solids in the bottom of the tank.

Once the aeration tank is filled, the sewage overflows by gravity to two (2) facultative lagoons, first into cell #1 and then through an equalization pipe into cell #2. The treated sewage is seasonally discharged to the Ahearn Drain during two three-month periods; Spring period is March-May, and Fall period is October-December. The Ahearn Drain discharges into the Old branch of the Pinnebog River.

North Lift Station Collection

The North lift station is directly adjacent to the East Toilet Building at the north end of the Port

Crescent Campground. This station has two submersible pumps that push water into a gravity fed sewer line that runs to the south end of the campground and into a secondary lift station pit. The north lift station collects water from the East Toilet Building and the full amenity cabin which is directly adjacent to the lift station and the toilet building. The sewer lines for the toilet building and cabin tie together and then lead to a catch basin and then into the lift station. The catch basin is in line to collect sand and other large material that settles out, and is emptied each season by an outside contractor.

The material emptied from the basin is not disposed of or treated by the owners of the facility.

The East toilet building consists of two full sized restrooms, a family bathroom, and six showers.

There is a total of 7 toilets, 2 urinals, and 7 showers in this building. There is also a dishwashing station on the outside of the building, and two maintenance pipe alleys with a mop sink in each, the larger of which has a water softener that backwashes 1 time per day. This building is in operation from April until

October each season and is not operational from November to March during which time wells are shut off, pipes are drained, and the building is winterized.

The full amenity cabin has a kitchen and a full bathroom. There is one sink in the kitchen, and in the bathroom there is a sink, toilet, and shower. This cabin is also only operational from April to October and gets shut down and winterized along with the shower building.

Once the water is pumped from the lift station it flows through a 4-inch gravity sewer line to the secondary lift station at the south end of the campground. There are 3 man-hole access points between the two stations.

South Lift Station Collection

The south lift station collection system is located at the south side of the campground near the campground office. This station receives water from the entire campground and pumps the water through a 4-inch cement asbestos force main to the treatment site across the highway.

The West Toilet Building’s sewer line connects to the line that runs from the North lift station.

The West building consists of 2 restrooms, one family bathroom, and 10 showers. There are 7 toilets total, and 11 showers in total, with an additional mop sink in the maintenance room.

There is also a catch basin at this location to catch sediments, and just like with the East Toilet

Building, this pit is pumped out by an outside contractor and the material is not treated by this facility.

The sanitation station and camp office also flow into this lift station. The sanitation station has one sewer port and the campground office has one toilet and one sink. There is also a full hookup campsite that connects to the lift station and this is located directly adjacent to the station.

Treatment Site

Flow from the force main enters an in-line grinder inside the Control Building. The comminutor, or grinder, is a device that grinds up large solids in the raw sewage to make it pass more easily through the rest of the treatment processes. There is a bypass around the grinder for maintenance reasons.

The water then flows into the aeration tank – there is a tank bypass straight to the lagoons, but this is always closed. The Aeration tank is meant to fill and stay full continuously aerating after the water level exceeds the height of the aeration blowers. Once the level within the tank reaches capacity there is a gravity overflow to which it flows into 2 facultative lagoons. There is also a secondary overflow about one foot above the other in the tank.

The water flows from the tank to the 2 lagoons where it treats throughout the season. There are valves that control the flow to each so the operator can make the tank flow to either one or both lagoons. The lagoons are also linked together by an equalization pipe with a valve that can be used to isolate the lagoons.

To discharge, each cell has three pipes that lead to the Ahearn Drain at different levels – the two lower ones are utilized during discharge drawdown based on pond depth, and the top is an overflow pipe. There is no emergency shutoff on the overflow pipe – the water in the ponds reaches this level, it travels directly into the Ahearn Drain. There is a bypass around the flow meter and flow basin for maintenance.

Treatment Facility History

In 2000, the Michigan Department of Environmental Quality (MDEQ) issued Surface Water

Discharge Permit No. MIG589000 and Certificate of Coverage No. MIG5890352, allowing the discharge of up to 2.6 million gallons per year of treated sanitary sewage seasonally to the Ahearn

Drain. The Drain is situated to the north of the existing lagoons and discharges to Lake Huron.

The Central Wastewater Treatment Facility was constructed in 2003. Major upgrades to the system include the installation of a new lift station on the south side of the campground in the spring of

2022. Otherwise there have been no others. No known major improvements to the treatment site.

Future Improvements

Plans for improvement include liner and repair in cell #1 and liner analysis of cell #2 during the

2024 season. The park campground is slated to be closed during the entirety of this season for other infrastructure upgrades – during this time the 12 full-hookup sites mentioned will be added, the gravity line from the North to South lift stations will be replaced, and the catch basin at the West Toilet Building will be added. We are also looking into the addition of chemical additives to lower wastewater phosphorous levels.

Port Crescent State Park Wastewater Treatment System Flow Diagram

Well #1

East R/S Cabin

North Li Sta on

Well #2

Well #3

Well #4

Water distribu on building

West R/S Camp Office Sanita on Sta on Full Hookup Site

South Li Sta on

Cell #1 Cell #2

Ahearn Drain Aera on

Tank Flow Basin

Building inflows from wells do not necessarily match ou lows to collec on system. We have many outdoor spigots and jug fillers that u lize either French drains, or empty directly onto the ground.