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Protein Polysaccharide Biopolymers (PPBs) Technology Evaluation for Renourished Beach Erosion Control
Frank A. Ocaña1; Amine Dahmani2; Rodolfo Pinzón1; Daniel Ceballos1 and Ismael Mariño-Tapia3
1 Marcost de México SA de CV. Calle 10 No. 305B, Col. Benito Juárez Oriente, 97178, Mérida, Yucatán, México.
2 SAMARCEL LLC, Storrs, CT and SESI Consulting Engineers, Pine Brook, NJ 3 Centro de Investigación y de Estudios Avanzados (CINVESTAV). Antigua carretera a Progreso Km 6, Cordemex, Loma Bonita Xcumpich, 97310 Mérida, Yucatán, México.
Two main strategies have traditionally been used to control beach erosion, namely hard stabilization such as wave-breakers, groins and seawalls, and soft stabilization such as beach renourishment. Hard stabilization structures are not always the preferred solution because they impact beach aesthetics and interfere with natural ecosystems by inducing more sand erosion and threatening nesting grounds of native shoreline species. Soft stabilization methods typically have a lower environmental impact. Beach renourishment may be used as a stand-alone technology or combined with other soft technologies such as sandtainers, geotubes, artificial reefs and dune restoration. In the field of geotechnical engineering, natural biopolymers such as polysaccharides have been used for soil stabilization. Although polysacharrides can directly enhance cohesion of soils, they can also enhance microorganism-induced production of extracellular polymeric substances that augment soil cohesion. In addition, certain vegetable proteins may also enhance sediment cohesion. Based on these principles, SAMARCEL developed various PPB formulations that can be used for sand cap stabilization on contaminated sediment and for erosion control of natural and renourished beaches. One PPB formulation, SandFirst (SF), was tested in the upper Yucatan peninsula (Mexico) on a previously renourished beach. Beach profiles and sand accretion/erosion were monitored for an SF-treated beach section (85 m) and compared to two similar untreated beach sections (controls) located on both sides of the SF-treated beach. Beach profiles were measured on a monthly basis to assess the effectiveness of the PPB treatment in controlling beach erosion. The results indicated that beach width increased in the SF-treated section. On the other hand, the control sections displayed continued erosion. Moreover, the erosion/accretion rate in the treated section was +0.06 m3/m, whereas in the non-treated section the rate was -4.04 m3/m, which is consistent with reported erosion data in neighboring coastal areas. Our findings suggest that using PPBs may be a promising ecofriendly method for enhancing renourished beach retention. The presentation will include results from laboratory testing, ecotoxicity testing and field testing.
Contact information:
Frank A. Ocaña: franko@marcost.com; Rodolfo Pinzón: rodolfopinzon@marcost.com; Daniel Ceballos: danielceballos@marcost.com
Ismael Mariño-Tapia: imarino@cinvestav.mx
Amine Dahmani: amine@samarcel.com; ad@sesi.org
Sand Cap Stabilization and Sediment Resuspension Mitigation Optimization Using Innovative Protein Polysaccharide Biopolymers (PPBs)
Amine Dahmani (ad@sesi.org) and Fuad Dahan
(SESI Consulting Engineers, Pine Brook, NJ, USA)
Faiyha Qweider, Connor Ligeikis, Jennifer Mulqueen,
Christos Bagtzoglou and Rachel Albino (UCONN, Storrs, CT, USA)
Richard Beach (GZA, Philadelphia, PA)
Sean Damon and Elizabeth Anzinger (Langan, Doylestown, PA, USA)
There are increasing concerns regarding the potential environmental impact of dredging PAH-, PCBs- or metals-contaminated sediments and the resulting resuspended sediments. The concern with dredging resuspension is not just the increase of suspended solids in the water column but also the release of contaminants from pore water and desorption of the contaminants from the resuspended sediment particles into the water. An in-situ technology that uses PPB amendments has been developed by Dr. Dahmani and SESI to minimize dredging-related resuspended sediment. The amendments can also be used to render sand-based isolation capping of sediment more stable.
Testing was conducted at the University of Connecticut (UCONN) to assess the cohesion-enhancing properties of PPB amendments by measuring direct shear strength (ASTM D3080) of treated sand. Testing was also conducted on sediment from a tidally influenced shallow creek system in southern New Jersey to assess PPB treatment effectiveness in reducing the turbidity and total suspended solids (TSS) of sediment/water mixtures. Finally, aquatic toxicity testing was conducted to assess toxicity of the PPB amendments. The tests (EPA-821-R-02-012) were performed using Ceriodaphnia dubia and Pimephales promelas as freshwater species, and Mysidopsis bahia and Menidia beryllina as saltwater species.
The results of the sand cap treatment demonstrated an increase in shear strength (ASTM D3080) and a 5 to 10-fold increase in cohesion of sand treated with PPBs (0.5% and 1% dosage by weight, respectively) when compared to untreated sand. The tests were conducted on sand cured at 35 deg.C for 24 hrs. This indicates that the treatment could enhance erosion resistance of sand caps. The experiments conducted with the sediment from a tidally influenced shallow creek system showed that reductions of 76% in turbidity and 87% in TSS were achieved for the PPB-treated sand as compared to the control tests. This indicates that PPB treatment could be used to stabilize sediment in-situ or minimize sediment resuspension during dredging operations. Finally, the aquatic toxicity results indicate that the PPB treatment passed the acute toxicity tests (> 90% survival). Additional testing results will be presented to assess the effect of dosage on sand cohesion and aquatic toxicity.
Contact Information:
Amine Dahmani: ad@sesi.org; Fuad Dahan: fd@sesi.org
Faiyha Qweider: faiyha.qweider@uconn.edu; Connor Ligeikis: connor.ligeikis@uconn.edu; Jennifer Mulqueen: Jennifer.mulqueen@uconn.edu; christos.bagtzoglou@uconn.edu; Rachel Albino: Rachel.albino@uconn.edu
Rick Beach: Richard.Beach@gza.com
Sean Damon: sdamon@langan.com; Elizabeth Anzinger: eanzinger@langan.com
