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Pressure Washwater Treatment Demonstration Projects
New! CZM has released the A Guide to Selecting Pressure Washing Management Practices and Technologies: Supplement to the Massachusetts Clean Marina Guide (PDF, 1.4 MB), a comprehensive guide to pressure washing at marinas.
As part of a comprehensive effort to assist marinas in tackling the pressure washing issue, the Massachusetts Office of Coastal Zone Management (CZM) awarded $12,500 each to Cape Ann Marina in Gloucester and Arey's Pond Boatyard in Orleans for the installation of treatment systems that will remove pollutants from pressure washwater. Each of these facilities hosted a demonstration project that allowed the general public, marina operators, and state officials to view the funded systems. More details about the systems are included below.
Cape Ann Marina
Cape Ann Marina, a full service boatyard and marina in Gloucester, installed a pressure washwater collection and treatment system that discharges to the local sewage treatment plant. The system includes a reconstructed washpad with a trench drain for collection of the raw washwater. Large particles, paint chips, and biological growth settle on the washpad or in the trench drain. The trench drain overflows into a large underground tank where some smaller solids settle out of suspension. The first tank flows into a second settling tank, allowing for additional settling. Wastewater flows from the second tank into the treatment system, and from the treatment system into the sanitary sewer.
The system, manufactured by American Cleanway, Inc., is a chemical treatment system that is installed at many marinas across the country. As wastewater enters the system, the pH is adjusted up, and a chemical is added that causes coagulation of the pollutants. A second chemical is then added that cause the coagulated pollutants to clump together and settle out of solution. The liquid then goes into a settling tank with a conical bottom. Clean treated water drains off the tops of the tank into the local sewage system and the pollutant-laden sludge is drained from the bottom of the tank. The sludge is dewatered (dried) before disposing as solid waste (after determining that it is not hazardous).
This system works best when the wastewater is allowed to settle through a series of tanks before entering the treatment system. It is important to remove larger particulates before treatment. The system will be less likely to clog and will treat the wastewater more effectively if the settlable solids are removed.
Installation Cost Breakdown:
One additional requirement for the operation of this system is that a "certified operator" is required. The Massachusetts Department of Environmental Protection (MassDEP) designates any systems that treat wastewater for discharge as a "wastewater treatment plant." A person certified to operate the system must be present when discharging from such a system. The system is given a grade by MassDEP's certification board. This grade is based on the complexity of the system. The Cape Ann system was given an Industrial Grade 2, which means an operator certified at a Grade 2 or higher is required to operate the system.
Cape Ann Marina washes about 225 boats per season and the marina staff estimates that this generates about 400 gallons of wastewater per day in the fall, for a total of 18,000 gallons per year. CZM will continue to follow up with Cape Ann Marina regarding this system and to get operation and maintenance cost information.
Arey's Pond Boatyard
Arey's Pond Boatyard, a full-service marina, boatyard, and boatbuilder in Orleans, installed a closed-loop recycling washwater system at its inland storage facility in an industrial park in North Chatham. This system allowed Arey's Pond to move all its boat washing inland, away from the water. Previously, washing operations occurred less than 25 feet from the water's edge. The system includes a new washpad with a settling chamber for collection of the raw washwater. Large particles, paint chips, and biological growth settle on the washpad or in the chamber, which then overflows into a large double-walled underground tank where smaller solids settle out of suspension. Wastewater flows from this tank into the treatment system, and from the treatment system back into the pressure washer.
The system, manufactured by RGF Environmental Systems, Inc., is a physical treatment system that is installed at many marinas across the country. Wastewater enters the system and passes through one of four 50-micron bag filters, then passes through two 10-micron cartridge filters and a UV light/ozone chamber (for odor control). Clean treated water then goes back out to the pressure washer. When the pressure washer is not in use, the recycled water is recirculated through the UV/ozone chamber to control odor—a major concern for recycling systems.
This system is simply a physical filtration system, so there may be a periodic need to remove filtered washwater and add fresh water. Salts and other dissolved pollutants will build up over time that cannot be removed by this type of system. This system works best when the wastewater is allowed to settle before entering the filtration system. It is important to remove larger particulates before treatment. The system will be less likely to clog and will filter the wastewater more effectively if the settleable solids are removed.
Installation Cost Breakdown:
This system is a closed-loop recycling system and therefore requires no discharge permits. A licensed hauler will be hired to properly remove any wastewater that may need to be hauled offsite due to dissolved solids. The double-walled holding/settling tank will contain the majority of the recycled wastewater. MassDEP requires that storage/holding tanks go through a compliance certification. Although this tank is part of a wastewater treatment system, and technically not a storage tank, the marina operator was required by the town of Chatham to install a double walled tank and to complete the compliance certification.
Arey's Pond Boatyard washes about 150 small boats per season and the marina staff estimates that this generates about 25 gallons of wastewater per boat in the fall, for a total of 3,750 gallons of water used per year, most of it recycled. CZM will continue to follow up with Cape Ann Marina regarding this system and to get operation and maintenance cost information.
Unfortunately there are no easy answers for tackling this issue at boatyards in Massachusetts. In contrast to recycling washwater systems, all systems designed for discharge to the ground, sanitary sewer, or to coastal waters require significant investments in permitting, training, and operator certification (if staff qualified to get certified is available). Given this, recycling systems may be the answer. At a minimum, facilities should develop a system to collect the wastewater for treatment. For smaller boatyards that wash few boats, collecting all the washwater for offsite disposal may be the most cost-effective option.
Non-toxic bottom coatings are being developed and have showed varied success, but typically require more frequent and intensive maintenance and bottom cleaning. Results from European countries that have banned copper bottom paint may help direct boaters to better, less toxic product alternatives.
Regardless of the compliance difficulty and lack of effective, trouble-free paint alternatives, marinas must begin planning to move toward compliance. Many facilities have been performing boat washing operations in the same spots for years, most likely creating significant contamination issues. To eliminate further contamination, all washwater needs to be collected for treatment and/or disposal.
In addition to these demonstration projects, and recoginizing that the pressure washing information in the Massachusetts Clean Marina Guide was incomplete, CZM has developed a pressure-washing addendum to the guide. A Guide to Selecting Pressure Washing Management Practices and Technologies: Supplement to the Massachusetts Clean Marina Guide (PDF, 1.4 MB) provides guidance to marinas and boatyards about the proper handling and disposal of wastewater and solids generated when boat hulls are cleaned, including a review of relevant regulations, pressure washwater disposal options, and equipment that can be used to minimize impacts from pressure washing practices.
Please contact Robin Lacey, CZM's Marina Technical Assistance Specialist, if you have any questions about the demonstration projects, pressure-washing, or general environmental management questions related to clean marinas.