Upgrade of Sewage Plant:
Facts
The Camphill Village site is not served by municipal sewer from the town of Copake. These services are obtained through an on-site central system consisting of a number of septic tanks and a remote cluster of seepage pits (so called dry-wells).
During an engineering review it was found that the existing wastewater treatment system was undersized using the current New York State Department of Environmental Conservation standards and the existing seepage pits are showing some signs of failure and also do not meet NYSDEC flow rate standards. This prompted the need to upgrade the existing wastewater treatment system to meet current state standards and requirements.
Objectives
There were many options available to improve the existing septic system. Each of these options has some benefit or drawback but after a thorough study of the options available the CHV Building and Maintenance group decided to install open sand-filters to upgrade the existing sewage system. As the name implies, open sand filters have their surface exposed for maintenance. The sand filter treats the wastewater by providing a media for beneficial bacteria to grown on. As the wastewater passes through the sand, the bacteria oxidize the organic matter in the water.
This decision was based on:
- environmental concerns-the quality of the effluent can be measured and appropriate action can be taken.
- low maintenance.
- proven reliability which was confirmed through site visits of as many as 6 open sand-filters in the area.
- economics
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Sand-filter pumping station |
Implementation
For a 15,000 GPD system, a total of 3,000 square feet of sand would be needed (5 GPD/SF loading rate). This would mean a total bed size of about 50 feet by 60 feet. For ease of operation and maintenance the system was split into two beds, each 25 feet by 60 feet.
The construction would consist of two concrete rectangles, 25 feet by 60 feet, sharing a common center wall. The height of the wall would be about 4 feet (2 feet set into the ground). The bed would have a distribution network on top of the bed and a collection network under the bed. The sand beds do not necessarily need to be covered, as most are not in New York State.
The existing septic tanks would be re-used and a new pump station with force main was installed to collect the septic and distribute it over each sand-filter bed when the pump station reached its high limit.
The sand-filters were completed and put into operation in the middle of the winter of 2008 with freezing weather conditions. Start-up and operations have been above expectation and the first laboratory tests show encouraging BOD improvements through the sand-filter from 71mg/L to 12mg/L.
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Sand filter beds with distribution pipes |
Click the links below to learn more about Camphill Village Environmental Initiatives.
• Underground Oil Tank Removal
• New Construction and Renovations
• Upgrade of Sewage Plant
• Fountain Hall Geo-Thermal System