"The project has heavy sediment load in the runoff/drainage water due to construction impacts on the valley hillside. Typical runoff water has a turbidity of 150 Nephelometric Turbidity Units (NTU), but treated water has turbidity levels around 1-NTU...
...As soon as the pumped water enters the pipe, it has Chitosan (Liqui-Floc) added. The Chitosan causes the fine sediment particles to bind together and is subsequently removed with the sediment during sand filtration. Chitosan also removes phosphorous, heavy minerals, and oils from the water..."
"Flocculation works and works well In Washington State, developers and contractors have indicated that they would prefer to floc than to attempt to control runoff by conventional BMPs. By reducing or eliminating the conventional BMPs a large portion of the floc costs can be offset."
a General Use Designation for the CESF technology with the discharge of treated water to retention systems capable of infiltrating all storms to the ground and no discharge to surface water;
a General Use Designation for batch treatment of the CESF technology prior to discharge to surface water;
a Conditional Use Designation for discharge to surface water from a continuous system.
Sea-Tac Airport Comprehensive Development Plan Environmental Review
"The Chitosan polymer used in the stormwater treatment process is a natural derivative of chitin found in shellfish. It is very effective in removing suspended solids and turbidity form runoff and has been demonstrated to cause no harm to aquatic life in the receiving streams.
The Port would continue to use this and/or other advanced construction stormwater treatment for the Comprehensive Development Plan projects where necessary and appropriate. Several large-scale polymer systems have been successfully operated to treat runoff from the Third Runway construction."
The United States Army Corps of Engineers shut down all work in and near wetlands along SR 18 in April 2004 until it reached a settlement with WSDOT in July 2004. The provisions for WSDOT included:
...Paying a $50,000 civil penalty
...Not filling wetlands on the project site unless it had permission
...Performing additional wetland creation and enhancement to compensate for the damaged wetlands
...Implementing all recommendations in WSDOT's own report and submitting status reports on implementation efforts every six months for three years
...Assigning a replacement project engineer to carry out the terms of the settlement agreement
...An independent consultant with the authority to stop the work was to remain on the project for its duration. The Washington State Department of Ecology (WSDOE) also fined WSDOT and Atkinson $121,000 for clearing and filling eight wetlands and three wetland mitigation sites on the site without proper authorization and for performing work in two wetland mitigation sites after the WSDOE stop-work order
...Despite the setbacks, WSDOT and Atkinson returned to work determined to complete the project on a reworked schedule. Case credits the cooperative, team effort between the contractor and WSDOT for the success of the project that had such significant challenges to overcome
...For the stormwater, Case says WSDOT utilized a new technology that involves chitosan-enhanced sand filtration. This specialized additive uses natural materials from shrimp shells to enhance the filtration of water before it is returned to nearby water bodies
...Because of the proximity to salmon-bearing creeks and wetlands, it is imperative to control and manage the stormwater on this project," Case says. "This is relatively new, but it is not pioneering technology. We're seeing it used a lot more on construction sites these days."
...Case says the project turned out to be a success because of the collaborative efforts of WSDOT and Atkinson after the fines and punishments were handed down. "Basically, because of our team efforts with the contractor and the attention focused on our compliance with the permit requirements, we were able to re-establish good working relationships with permit agencies and maintain good working relationships with the contractors to get the job done," Case says.
Stormwater Magazine(Sept 2006)
"...The four-unit systems on this project have a theoretical capacity of 636 gpm, but backwash cycles result in an actual discharge rate in the range of 500 gpm. Programmable logic controllers, sampling equipment, backwash systems, remote monitoring, and allow the operation to be fairly simple once started and dialed in at the beginning of each day. Even with this automation, the chemical treatment subcontractor, Clear Water Compliance Services, still has full time staff on hand to proactively take manual turbidity, pH, residual chitosan, and arsenic samples; check for visible sheen; calibrate dosing; and document weekly performance...
...By October 2006, the Port of Seattle and HNTB will call for Clear Water Compliance Services to treat runoff from 376 acres through twelve CESF treatment systems with a total processing rate of 7200 gpm. In spite of the huge magnitude of the effort, we are confident that this will be another year that we can meet the challenge...
...In the case of stormwater treatment, this has not been a simple case of choosing the right BMP. The design goes beyond the one-size-fits-all guidelines in the local criteria by verifying with continuous models and validating that facilities match the specific contractor and client performance needs for the site. By anticipating the variability in contributing areas and setting performance guidelines such as maximum contributing area and minimum treatment rate, the contractors were able to understand the expectations and bid the project without surprises. This collaborative effort has been a great success for each of us involved in the project as well as the precious natural resources that inspire the work."
"Over the one-year operating test period, a total volume of 17,295,000 gallons of stormwater was treated at an average flow rate of 500 gallons per minute. Field analyses were performed for turbidity, conductivity, temperature, and residual chitosan in both the influent and effluent stormwater. Laboratory tests were performed for phosphorus, toxicity to rainbow trout (acute 96-hour whole-effluent toxicity), and toxicity to Daphnia magna (acute 48-hour whole-effluent toxicity). An in situ flow-through rainbow trout test was also performed by a professional consultant...
...The treatment system reduced turbidity on average by 98.4% with a standard deviation of 1.29% and a coefficient of variation of 0.013...
...every effluent turbidity value was less than the turbidity limit set by the State of Washington (10 NTU)...
...Of the 253 samples of effluent that were field-tested for residual chitosan, all had less than 0.1 milligram per liter residual chitosan...
...In each test, all fish survived (100% survival). Rainbow trout have been determined to be the most sensitive species to chitosan."
"Water quality discharge standards for construction sites in Washington State are tightening and the regulatory hammer is a new NPDES Stormwater Permit for Construction Activities that will regulate the turbidity of water discharged to streams, lakes and bays...
...The Olhava Site Development Project located in Poulsbo, Washington is a mixed use, 250-acre construction project building retail stores, a university extension and residential homes...
...The majority of the site, however, drains to a federally-protected salmon stream called Dogfish Creek which subsequently drains to Liberty Bay in Puget Sound. Dogfish Creek is home to several endangered salmon species that use the lower reaches of the creek as a spawning ground. For this reason, a lot of attention has been focused on the construction project to prevent the release of sediment to the highly sensitive salmon spawning ground...
...Scarsella Brothers investigated several treatment technologies as soon as it became apparent that normal erosion and sediment control Best Management Practices (BMPs) would not be sufficient to control stormwater quality to the degree required...
...Scarsella Brothers contracted with Clear Water Compliance Services of Lynnwood, Washington to build and operate the stormwater treatment system...
...The Washington State Department of Ecology set a discharge standard of 10 NTU because of the sensitivity of the receiving water...
...the turbidity of the treated effluent never exceeded 10 NTU and, in fact, averaged 4.76 NTU with an average influent turbidity of 38.5 NTU for an average treatment efficiency of 81.6 percent. The enhanced sand filtration systems are capable of higher percentage of turbidity reduction, frequently better than 95%, but this system was designed to meet the discharge requirements of the site...
...The recently (Washington State) approved stormwater treatment technology has proven to be effective in reducing the turbidity of collected stormwater at the Olhava project meeting state-mandated discharge standards."
"As a result of Clear Water's excellent performance during the overall site construction, any problems resulting from close oversight by regulatory authorities or from possible third-party actions resulting from site construction or erosion control activities were eliminated. Because of the certainty in discharge compliance resulting from Clear Waters performance, Olhava Associates (owners of the Olhava Development) required that Clear Water be retained for stormwater treatment services during both the Wal-Mart and Home Depot site construction...
Clear Water's performance has been outstanding and their service more than paid for itself by eliminating any possible stormwater discharge concerns arising from our project. We will utilize their services again, and can recommend their performance to anyone involved in site construction activities."
Ferguson Construction, Inc.
"The Costco project in Woodinville was perhaps the most difficult encountered due to extremely poor soil conditions, the presences of historic contamination on the site from past industrial activity, the sensitivity of a nearby creek, and the close attention being paid to the project by a local environmental activist group..."
"We were, however, able to complete the project without a single water quality violation..."
"In summary, we are pleased to express our highest endorsement and recommendation of Clear Water Compliance Services, Inc."
There are several things about Clear Water that impressed us. The company is very service oriented and effectively communicated the planned procedure to accomplish the task at hand. You put together a timeline showing all of the activities leading up to achieving the project goals. Clear Water maintained good communication with Geomatrix and was able to rapidly adjust schedules and procedures to changing site conditions. Geomatrix and our client were particularly pleased with the serious and thorough way in which Clear Water treated the health and safety aspects of the project.
The project was completed on time and within our expectations for project cost. Finishing on-time was critical for the remote location and limited site access that develops during winter conditions are 7,500 feet in the Sierras.
"The project had experienced problems with stormwater quality and stormwater issues were a significant distraction on this project before Clear Water was brought under contract. After discussing and interviewing a number of other stormwater treatment service providers, Clear Water was selected on the basis of their in house technical expertise and extensive experience in employing CESF treatment systems. Since they have been on site, there have not been any significant problems with stormwater quality and no violations of discharge criteria. The working relationship between Ecology, WSDOT and the contractors has improved."
The Associated General Contractors of America (AGC), the voice of the construction industry, is an organization of qualified construction contractors and industry related companies dedicated to skill, integrity, and responsibility.
The International Erosion Control Association (IECA) is the world's oldest and largest association devoted entirely to helping members solve the problems caused by erosion and its byproductsediment. Founded in 1972, IECA is a non-profit organization that serves as the premier global resource for the prevention and control of erosion.
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