Aerial view of the Warren, Maine lagoon system. Photo courtesy of Woodard and Curran.

Lagoon Systems In Maine 

Systems In Maine

An Informational Resource for
Operators of Lagoon Systems

Mars Hill Wastewater Lagoon System - Mars Hill  Maine. Photo Courtesy of Wright-Pierce Engineers.
 Mission  |  Search  |  Acknowledgements  | Discussion Group |  Contact Us  | Links

Design & Operation
Lagoon Aeration
Tech Papers
Operation Articles
Lagoons In Maine
The Laboratory
Maine Lagoon News
Lagoon Biology

2003 Maine Wastewater Salary Survey as conducted by the Maine Wastewater Control Association

2003 Maine Wastewater Rate Survey conducted by the Maine Rural Water Association

Maine DEP Monthly
O & M Newsletter

Maine and WEF's
Operation Forum

Penobscot Watershed and Development of a TMDL 

EPA Binational Toxics

Maine Rural Water

Maine Wastewater
Operator Certification

Maine Is Technology

Maine Wastewater Control Association

Maine WasteWater Control Association

Wastewater Engineering


Carrabassett Valley Sanitary District
  Carrabassett Valley, Maine

aerated lagoons


Carrabassett Valley, Maine

CVSD Snowfields

Carrabassett Valley, Maine, well known for some of the best skiing in the Northeast, has placed itself on the map for another reason. Its wastewater authority has successfully put in place the first permanent system of its kind in the world to treat and dispose of wastewater by spraying effluent into snow.

     The Carrabassett Valley Sanitary District serves approximately 900 living units plus the commercial facilities, the equivalent of about 6,000 people. The 7 lagoons are earthen-berm construction with clay lining.  The aerated lagoon and each of the initial three storage lagoons are designed to hold 5.2 million gallons of sewage. Each backup lagoon is designed to hold 5.8 million gallons, giving a total volume of thirty-eight million gallons of which 33 million gallons is storage. The treated effluent is then pumped to a land-based disposal system comprised of a slow rate sprinkler irrigation system and freeze nucleation (snowmaking).

Carrabassett Valley, Maine

Two 125 horsepower vertical turbine pumps (300 gpm each) deliver effluent to the snow making towers

  The spray irrigation system is designed to empty the contents of the lagoons plus the associated summer wastewater flow and precipitation. Effluent is pumped to a forested disposal site, separate from the snowmaking site, at fifty thousand gallons per acre per week.

          Located in the western mountains of Maine, Carrabassett Valley has historically relied on spray irrigation for wastewater disposal of treated effluent during the summer. As soon as the Carrabassett Valley Sanitary District (District) was organized in 1993 to provide wastewater disposal services for the Sugarloaf Mountain Ski Resort and surrounding area, the Board of Trustees faced a shortage of lagoon storage space. Although their community is small, it increases to more than 10,000 during ski season, and the lagoons were full to nearly overflowing by the time the spray season began. Before the concept of spraying effluent into snow was ever discussed, plans called for construction of as many as 54 lagoons at a cost of $250,000 each and 26 spray irrigation areas, at a cost of $150,000 to $200,000 each, over 200 acres of wooded spray irrigation areas.

      This construction would take place on the treatment site property, located several miles from the access road to the Sugarloaf Mountain Ski Resort to accommodate projected build-out of the sewered area.

Carrabassett Valley, Maine

There are 2 two hundred horsepower air compressors capable of delivering 800 cfm @ 140 psi.

       Never entirely satisfied that the lagoon construction plan was the best approach, sanitary district trustees went looking for an alternate strategy.  A less costly and more practical approach to wastewater treatment and disposal by constructing snowmaking towers on the treatment site property instead of scores of lagoons was the new direction taken. A decade of environmental hurdles was about to begin in Carrabassett Valley.

 The primary stumbling block to be cleared was overcoming regulators' concerns about the fate of contaminants, surface runoff, and over saturation of the soil. Furthermore, without the Maine Department of Environmental Protection’s blessing, financing sources were wary. Woodard & Curran, selected as the newly organized Carrabassett Valley Sanitary District's engineer, analyzed the technology. This analysis turned out to be the critical step in allowing the project to move forward by explaining and resolving the issue of contaminant fate and transport. An explanation to Maine DEP why it worked by identifying the fundamental physical/chemical principles involved took place. This convinced them that making snow was, in fact, a viable treatment technology and cleared the way for license approval. The project has moved ahead smoothly ever since.

aerated lagoons

Snowmobile tracks cover the landscape. The machines are used by the operators to keep a watchful eye on the snowmaking process.

   Snow is made out of lagoon effluent throughout the winter and is spread out over a cleared, prepared site. Melting and disposal into the ground take place over the spring and early summer. This approach significantly reduces the storage volume required by applying effluent to the fields over the winter, when the influx of people to the ski resort results in the District's highest flows. The process is intended as a disposal method primarily, although the lagoon effluent receives additional treatment by means of the freeze/thaw process.

 Another key to the process is making snow as soon as freezing weather starts. This way the snow pack develops before the ground freezes. Then, in the spring, when warm weather starts the melting process, the treated effluent (melted water) infiltrates into the unfrozen ground with minimal runoff. It is not uncommon to see mounds of snow still melting in July.

After the systems first year of operation (28,000,000 gals. of effluent turned into snow), the District Trustees voted to increase the operational effectiveness by adding three additional snowmaking towers and a 750 kW diesel generator. This reduced the power costs from $20,000 a month to $18,000 annually (based upon costs of  $0.50 /gal. of diesel fuel).

District Superintendent Dave Keith checks the nozzles atop the snow gun tower

District Superintendent Dave Keith checks the nozzles atop the snow gun tower

The 1,000 horsepower generator powers 2 two hundred horsepower air compressors capable of delivering 800 cfm @ 140 psi. Two 125 horsepower vertical turbine pumps (300 gpm each) deliver effluent via buried 6-inch welded steel pipe to the eleven 40-foot high  snowmaking towers. Normal snowmaking operations of 1,000 hours per year (42 days) are required to turn the stored lagoon effluent into man-made snow. Facility Superintendent David Keith describes optimum snowmaking conditions as “cold and windy”.

This two hundred and fifty thousand dollar ($250K) upgrade improved the ability to more evenly distribute snow across the cleared application area and reduced operating costs by approximately fifty thousand dollars ($50K) annually with savings from in-house power generation and reduced site maintenance. Design, equipment purchases, and planning were performed in-house at a considerable savings.  


Carrabassett Valley, Maine

A view from the bottom  

In 1997, CVSD recognized weaknesses in the snowmaking process control system. The Trustees approved a further expenditure from the remaining balance of construction funds to upgrade the snowmaking system from a PC based control system to a PC/PLC based I/O system. The revised system is SCADA technology that allows centrally based control, monitoring and reporting (operator interface software) at the main control building. This allowed communications locally to PLCs (processors and I/O with system programs) within the control building and with the facility’s in-house power generation system, at the snowmaking distribution vault and the District’ s sewage pumping station. To further enhance the system, both the District Superintendent and Plant Operator have remote access and control of the operating system via home-based personal computers.    

Carrabassett Valley, Maine

  The addition of snowmaking technology has the potential to more than double the capacity of Carrabassett Valley's existing facilities without needing any additional storage lagoons and within the existing 60 acres of land application area. This effluent disposal project has relieved the District's concerns for a long time to come.


Carrabassett Valley Sanitary District - Operational Snap Shot
In-House Three Phase Power Generation

  Gallons Processed Hours Operated Gallons
Fuel Usage Gallons Fuel $$/Gal KWH Generated $$
$$/Gallon Snowmaking
Dec-99 3,234,562 100 32,546.6 3,994 0.50 53,230 0.0375 0.0006
Jan-00 6,939,425 202 34,353.6 8,298 0.50 108,033 0.0384 0.0006
Feb-00 2,666,652 79 33,755.1 3,292 0.50 42,116 0.0391 0.0006
Mar-00 581,246 15 38,749.7 579 0.50 8387 0.0345 0.0005
Dec-00 2,287,716 74 30,915.1 3,063 0.50 38,904 0.0394 0.0007
Jan-01 5,036,128 146 34,494.0 5,986 1.17 75,392 0.0929 0.0014
Feb-01 3,026,193 87 34,783.8 3,489 1.25 45,469 0.0959 0.0014
Totals   703   28,701        
    Average 34,199.57     0.0540   $0.00083



Lagoon Specifications

aearted lagoons






Storage 1

Storage 1

Storage 1


5.2 MG

5.2 MG

5.2 MG

5.2 MG

5.8 MG

5.8 MG

5.8 MG


Coarse Bubble







Comments: Lagoons operate at 9.0 feet of depth. 
Total lagoon area - 18 acres or 780,00 sq. ft.



System Information

aearted lagoons


Design Flow

Licensed to Discharge 40 MG/Year 
to Spray Irrigation and 56 MG/Year

Actual Flow

0.10 to 0.40 MGD (highest in winter)

Discharge To

Land Application

Year Built


Design Engineers

James Sewall Co.     Upgrade -  Woodard and Curran

Septage Received


Collector System

12 miles gravity sewer, 1 pump station , 280 manholes

Staff Size

2 Full Time

Number of Users

Year round 100 users. Winter peaks to 4,000 people

Billing Software

Uses GIS for collection system maintenance

Back to Lagoons in Maine



aerated lagoons


  Copyright 2003 |  Home | Site Map                                          

Search  |  Contact Us  | Links