Ocean Disposal Research Articles

Screening-level risk assessment applied to dredging of polluted sediments from Guanabara Bay, Rio de Janeiro, Brazil

Guanabara Bay is characterized by predominant eutrophication and anoxic sediments with a mixture of pollutants. The risk prognosis associated with the dumping of its dredged sediments into the open ocean was addressed by our algorithm. Our algorithm could prioritize areas, characterize major processes related to dredging, measure the potential risk of sediments, and predict the effects of sediment mixing. The estimated risk of dredged sediment was >10-fold than that of ocean sediments. Among metals, mercury represented 50–90% of the total risk. The transfer of dredged material into the ocean or internal dumping in the bay requires a 1:10 dilution to mitigate the risk and bring the risk levels close to that in the EPA criteria, below which there is less likelihood of adverse effects to the biota, and a 1:100 dilution to maintain the original characteristics of the ocean disposal control area. Our algorithm indicator can be used in the design of both aquatic and continental disposal of dredged materials and their management.

Santos Sea Outfall Wastewater Dispersion Process: Physical Modeling Evaluation

ABSTRACT Alfredini, P.; Arasaki, E., and de Melo Bernardino, J.C., 2017. Santos sea outfall wastewater dispersion process: Physical modeling evaluation. To be environmentally sustainable, the ocean disposal of domestic sewage via a sea outfall must be carefully studied, such as previous modeling of waste-plume dispersion processes, for environmental impact assessments. A scale model, reproducing the Santos Bay and Estuary was calibrated at the Hydraulic Laboratory of Polytechnic School, University of Sao Paulo, Brazil. The complete modeling of this large estuarine system used numerical and scale models, which were all related to each other. Such an overall model, composed of individual hydraulic and numerical components, is called a hybrid model. It combines the advantages of both model components and adequate field survey measurements and is particularly important for simulating the plume dispersion process in Santos Bay. The goal hereby is to present a performance comparison of the outfall plume dispers...

Detecting, sourcing, and age-dating dredged sediments on the open shelf, southern California, using dead mollusk shells

Molluscan shell debris is an under-exploited means of detecting, sourcing, and age-dating dredged sediments in open-shelf settings. Backscatter features on the Southern California shelf are suggestive of dredged sediment hauled from San Diego Bay but deposited significantly inshore of the EPA-designated ocean disposal site. We find that 36% of all identifiable bivalve shells >2mm (44% of shells >4mm) in sediment samples from this 'short dump' area are from species known to live exclusively in the Bay; such shells are absent at reference sites of comparable water depth, indicating that their presence in the short-dump area signals non-compliant disposal rather than natural offshore transport or sea level rise. These sediments lack the shells of species that invaded California bays in the 1970s, suggesting that disposal preceded federal regulations. This inexpensive, low-tech method, with its protocol for rejecting alternative hypotheses, will be easy to adapt in other settings.

Metal accumulation in benthic invertebrates and sediments at the Kaohsiung Ocean Disposal Site, Taiwan

The distribution of metals (Hg, Pb, Cd, Cr, Cu, Zn, and Ni) in the sediments and in benthic invertebrates (arthropod, echinoderm, and mollusc) from the Kaohsiung Ocean Disposal Site (KODS) during 2014 was studied in terms of biota-sediment accumulation factor (BSAF). The mean concentration of metals in the sediments varied in the following order: Zn >> Cr > Cu > Ni > Pb > Hg > Cd. Results showed that the metal concentration in the sediments from the KODS was in agreement with that of other Asia harbors; there was no drastically high metal level in the Kaohsiung area. Results also showed that arthropod Acanthephyra species had accumulated high metal concentrations (e.g. 0.53, 3.02, 6.80, 53.24, 162.2, and 1.42 μg g−1 of Hg, Pb, Cd, Cu, Zn, and Ni, respectively), whereas mollusc Fusinus hyphalus had the lowest metal concentration. A positive correlation (p < 0.01) was observed between the concentration of Cr in the sediments and in arthropods. For all benthic invertebrates investigated, the BSAF of Cd and Hg were higher than 1.0. Especially the BSAF of Cd was remarkably high, e.g. for arthropods (30.0), echinoderms (38.7), and molluscs (42.2); whereas the BSAF of Pb, Cr, and Ni were low (BSAF << 1.0). According to the above results, benthic invertebrate of arthropods had a large metal accumulation capacity and thus could be suggested as the bioindicator of metal contamination of marine systems in further studies.

Economic, Regulatory and Social Aspects Related to Wastewater Ocean Disposal through Submarine Outfalls

Economic, Regulatory and Social Aspects Related to Wastewater Ocean Disposal through Submarine Outfalls

Радиоэкологические проблемы реабилитации арктических морей России

Some questions related to the Northern Sea Route status are considered in this paper. An analysis of radiation sources&#x0D; influence on environment, biota and human beings in the Arctic region has been carried out, and stages of this influence&#x0D; formation have been allocated. The world practice of ocean disposal is considered, and the information on nuclear and&#x0D; radiation hazardous objects dumped in the northwest Arctic seas has been submitted. The questions connected with lifting&#x0D; of the nuclear submarine K-27 dumped in the Kara Sea and the nuclear submarine “Komsomolets” sunken in the Norwegian&#x0D; Sea have been stated. Data on a modern radio ecological situation in places of dumped nuclear and radiation hazardous&#x0D; objects have been submitted. Such option of marine environment remediation as dumped/sunken objects lifting has been&#x0D; considered. An analysis of existing Russian technologies for lifting of the dumped/sunken objects has been carried out.&#x0D; The conclusions are drawn that the sunken and dumped objects containing spent nuclear fuel and radioactive waste, don´t&#x0D; constitute now real radio ecological danger to the population and environment, but they should be considered as sources of&#x0D; potential danger, whose scales and consequences will depend on protective barriers condition and mechanisms of further&#x0D; migration of radioactive materials in marine ecosystems. Regular complex surveys of the most potentially hazardous&#x0D; dumped/sunken objects’ status during joint international scientific and research expeditions should be a first step towards&#x0D; this problem solution.

Can irrigation with municipal wastewater conserve energy?

Can irrigation with municipal wastewater conserve energy?

Reduction in nitrogen oxides emissions by MILD combustion of dried sludge

Demands for the thermal treatment of sewage sludge are increasing due to the regulation of its ocean disposal and the desire to recover its potential energy. Because of the high nitrogen content in sewage sludge, one of the concerns about its combustion is a potential increase in NOx emissions. Although a number of studies have been conducted to reduce NOx emissions by combustion modifications, very few studies have addressed the combustion of dried sludge. In this study, a combustion technique called moderate or intense low oxygen dilution (MILD) was applied to the combustion of dried sludge with the goal of reducing NOx emissions. MILD combustion of dried sludge was tested using both our laboratory-scale vertical combustor with internal circulation and our horizontal cyclone combustor with external circulation. Tests were conducted to find suitable operating conditions and to demonstrate the stable MILD combustion of dried sludge. From these tests, fuel and air flow patterns were found to be an important factor in maintaining stable MILD combustion, and the horizontal cyclone combustor demonstrated excellent performance in the reduction of NOx emissions by the MILD combustion of dried sludge.

Environmental effects of sewage oceanic disposal by submarine outfalls: a review

Oceanic disposal systems of domestic sewage, or submarine sewage outfalls, have been historically used around the worldas a solution for urban effluents, in special due to economic aspects. However, release into the ocean, in shallow or deepwaters, may induce a set of negative environmental impacts, as eutrophication, toxic algal blooms, pathogenic microorganismsintroduction and contamination by chemical substances which are capable of causing toxic effects to the biotaand bioaccumulation. Thus, the release of untreated sewage into the sea does not constitute an adequate environmentalpractice; then, urban effluents should be treated in order to remove nutrients, contaminants and pathogenic organisms andavoid environmental degradation

Risk Assessment and Ecotoxicology Limitations and Recommendations for Ocean Disposal of Mine Waste in the Coral Triangle

Risk Assessment and Ecotoxicology Limitations and Recommendations for Ocean Disposal of Mine Waste in the Coral Triangle

High-level techno-economic assessment of negative emissions technologies

This paper presents results from research conducted to provide a high level techno-economic and performance assessments of various emerging technologies for capturing CO2 from the air, directly and indirectly, on a life-cycle basis. The technologies assessed include ‘artificial trees’, the soda lime process, augmented ocean disposal, biochar and bio-energy with carbon capture and storage.These technologies are subjected to quantitative and qualitative analyses, based on the most recent peer reviewed data in the literature, to identify their potential performance as well as the technical and non-technical barriers to their adoption and scale up. Key findings for each technology are presented which seek to highlight the state of technological development and research needs, the anticipated life cycle capture cost in $/tCO2 based on their potential to deliver a 0.1ppm CO2 reduction per annum, policy requirements for scale up and, in light of these findings, the likely role that they will play in addressing climate change and broader environmental issues in the medium to long term.The key finding from the work is that the degree of scale-up required for negative emissions technologies to have a material impact on atmospheric emissions (i.e. at a ppm level) is probably unrealistic in less than 20 years. Therefore, emissions prevention efforts should remain the main focus in addressing climate change and the likely role for negative emissions technologies will be in augmenting a suite of mitigation measures targeting economically or practically difficult emissions.

Impacts of gold mine waste disposal on a tropical pelagic ecosystem

We used a comparative approach to investigate the impact of the disposal of gold mine tailings into the ocean near the Lihir mine (Niolam Island, Papua New Guinea). We found abundance and diversity of zooplankton, micronekton and pelagic fish to be similar or higher in the mine region compared to the reference site. We also found relatively high trace metal concentrations in lower trophic level groups, especially zooplankton, near the mine discharge, but few differences in tissue concentrations of micronekton, baitfish and pelagic fish between the two regions. Biomagnification of some trace metals by micronekton, and of mercury by fish was evident in both regions. We conclude that ocean mine waste disposal at Niolam Island has a local impact on the smaller and less mobile pelagic communities in terms of trace metal concentrations, but has little effect on the abundance and biodiversity of the local food web.

해양생태독성 평가용 표준시험생물로서 섬모충류 Mesodinium rubrum에 대한 연구

The mixotrophic marine ciliate Mesodinium rubrum possesses a highly modified algal endosymbiont as a nutrition source for the species. Accordingly, we assumed that the species can reflect the ecotoxicity on marine producer (as phytoplankton) and consumer (as zooplankton) both. A series of experiments were conducted to identify the potential of the species as a standard test species for marine ecotoxicological study. The comparison of species sensitivity on reference toxic materials was made using potassium dichromate for phytoplankton and copper chloride for zooplankton. The ciliate revealed the highest sensitivity on both reference materials among the seven test species including phytoplankton, benthic copepod and rotifer species. The toxicity end point of the species was 72hr-EC50=1.52 mg/L (as potassium dichromate) estimated by population growth inhibition (PGI), which is more sensitive than the most sensitive phytoplankton Skeletonema costatum (72hr-EC50=3.05 mg/L). As comparison to rotifer, it also revealed higher sensitivity on copper chloride; 72hr-EC50=0.38 mg/L for ciliate and 48hr-EC50=0.48 mg/L for rotifer. Also, the elutriate toxicity test of various ocean disposal wastes were conducted to identify the potential of ciliate toxicity test application using industrial waste sludges. The toxicity of leather processing waste sludge was highest on the ciliate, followed by dyeing waste sludge and dye production waste sludge as an increasing order of toxicity. 72h-EC50 of ciliate PGI test was 1.83% and that of S. costatum 3.84% for leather waste sludge which showed highest toxicity. The toxicity test results also revealed that the highest sensitivity was observed on ciliate species on ocean disposed sludge wastes. Also, ciliate toxicity test well discriminated the degree of toxicity between sludge sources; 72h-EC50 values were 1.83% for leather processing waste sludge, 16.75% for dye production waste sludge and 27.75% for textile production waste sludge. Even the laboratory culture methods of the species were not generally established yet, the species has high potential as the standard test species for marine toxicity test in terms of the dual reflection of phyto- and zooplankton toxicity from single test, sensitivity and test replicability.

Relative risk assessment of cruise ships biosolids disposal alternatives

A relative risk assessment of biosolids disposal alternatives for cruise ships is presented in this paper. The area of study encompasses islands and marine waters of the Caribbean Sea. The objective was to evaluate relative human health and ecological risks of (a) dewatering/incineration, (b) landing the solids for disposal, considering that in some countries land-disposed solids might be discharged in the near-shore environment untreated, and (c) deep ocean disposal. Input to the Bayesian assessment consisted of professional judgment based on available literature and modeling information, data on constituent concentrations in cruise ship biosolids, and simulations of constituent concentrations in Caribbean waters assuming ocean disposal. Results indicate that human health and ecological risks associated with land disposal and shallow ocean disposal are higher than those of the deep ocean disposal and incineration. For incineration, predicted ecological impacts were lower relative to deep ocean disposal before considering potential impacts of carbon emissions.

Scoping the effective marine environmental assessment of dredging and ocean disposal of coastal sediments in Korea

The application of scoping is reviewed to improve the efficiency and rationality of the marine environmental impact assessment system applied to the dredging of coastal sediments and the oceanic disposal of dredged material in Korea. Both the impact levels and those items requiring assessment vary in response to differing goals of the coastal activities involved and also to changes in the characteristics of different marine environments. As a consequence, different assessment fields need to be emphasized for evaluation of the impact that both dredging and dumping might have on the sites involved. The status of current assessment procedures is examined and its problems are diagnosed. Following a survey of interested parties and a review of case studies of the oceanic disposal of dredged sediment in other countries, checklists of core assessment items are proposed as part of a revamped review process, along with improvements to the assessment system.

Environmental and economical assessment of sewage sludge compost application on soil and plants in a landfill

Composting of sewage sludge is one of the most suitable solutions for managing and recycling such waste. With the aim to decrease ocean disposal and increase recycling, composting of sewage sludge and its application to reclaimed soil in landfills were studied, including measurements of various parameters for composting and feasibility study. Pot experiments with three tree species ( Quercus acutissima, Liriodendron tulipifera, and Betula schmidtii) were performed to evaluate the effects of compost treatments on the soil properties and tree growth responses. Sewage sludge compost improved soil characteristics such as moisture, organic matter, N content, and respiration. It also improved soil porosity and bulk density. The leaf biomass and tree physiological parameters such as the chlorophyll contents and photosynthesis rates increased after the compost treatments. Heavy metal accumulation in the soil after the treatments was lower than the Ecological Soil Screening Levels (Eco-SSLs) for plants set by the US Environmental Protection Agency (EPA). Further, heavy metal accumulation in the leaves was insignificant compared with that of the control. Recycling sewage sludge compost as fertilizer will generate economical profits. Therefore, the use of sewage sludge compost as a soil conditioner in landfills would be an efficient and cost-effective method to restore the fertility of reclaimed soil and an environment-friendly solution for disposal problems.

An analysis of liquid CO2 drop formation with and without hydrate formation in static mixers

AbstractThe formation process of CO2 drops in various types of Kenics Static Mixers was analyzed from the perspective of energy dissipation in the mixer, focusing on the formation of drop surfaces. Experimental studies on CO2 drop formation were conducted under varying temperatures, pressure, and flow rates, with and without hydrate formation. Analysis of the CO2 drop size and distribution at several locations within the static mixer was conducted, as of pressure drop in the mixer, to determine dissipation energies. In all the experimental conditions, by considering the surface energy for hydrate formation, the energy required for the formation of CO2 drops correlated well with total energy dissipation by mixer flow, which is represented by a pressure drop along the mixer. This process has important applications to the formation of liquid CO2 for ocean disposal as a countermeasure to global warming. © 2010 American Institute of Chemical Engineers AIChE J, 2010

Occurrence of synthetic musks in Korean sewage sludges

Six polycyclic musks (PCMs) and five nitro musks (NMs) were analyzed in dewatered sludge samples from 13 municipal, 4 livestock and 1 pharmaceutical wastewater treatment plants (WWTPs) in South Korea. 1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyran (HHCB; Galaxolide ®, Abbalide ®), and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN; Tonalide ®, Fixolide ®) were the two predominant PCMs in the sludge samples, at concentrations ranging from 0.52 to 82.0 mg/kg dry weight (dw) and 0.12 to 28.8 mg/kg (dw), respectively, suggesting the extensive use of these two PCMs in South Korea. Hierarchical cluster analysis (HCA) revealed the different usage patterns of PCMs between livestock cultivating farm and household. The levels of HHCB and AHTN in the effluent discharged from the WWTPs were lower than the threshold effect levels derived for fish, suggesting low potential risks to aquatic organisms. Nevertheless, the calculated discharge of synthetic musks (SMs) from sludge in each target WWTP ranged from 36 to 10,961 g/d. These results indicate the necessity of conducting monitoring studies in marine ecosystems due to ocean disposal of sludge, particularly focused on the two prevailing PCMs.

Multicriteria decision analysis to assess options for managing contaminated sediments: Application to Southern Busan Harbor, South Korea

Many years of untreated effluent discharge from residential areas, a shipyard, a marina, and a large fish market resulted in substantial contamination of bottom sediment in Southern Busan Harbor, South Korea. Contaminants in these sediments include heavy metals and organic compounds. Newly introduced regulations for ocean disposal of dredged material in South Korea pose significant challenges, because the previous practice of offshore disposal of contaminated dredged material was no longer possible after August 2008. The South Korean government has mandated that such sediments be assessed in a way that identifies the most appropriate dredged material management alternative, addressing environmental, social, and cost objectives. An approach using multicriteria decision analysis (MCDA) in combination with comparative risk assessment was used as a systematic and transparent framework for prioritizing several dredged sediment management alternatives. We illustrate how MCDA can recognize the multiple goals of contaminated sediment management. Values used in weighting decision criteria were derived from surveys of stakeholders who were sediment management professionals, business owners, or government decision makers. The results of the analysis showed that land reclamation was the preferred alternative among cement-lock, sediment washing, 3 contained aquatic disposal alternatives (one in combination with a hopper dredge), geotextile tubes, solidification, and land reclamation after solidification treatment. Land reclamation was the preferred alternative, which performed well across all MCDA objectives, because of the availability of a near-shore confined disposal facility within a reasonable distance from the dredging area.

A decision‐analysis approach for contaminated dredged material management in South Korea

To meet London Protocol requirements, South Korea is preparing to reduce the need for disposal of dredged material at sea. The new requirements controlling ocean disposal of dredged material pose significant challenges to the South Korean government, because the previous practice of offshore disposal of contaminated dredged material is no longer permitted. Hence, other alternatives for treating and disposing of contaminated dredged material are being evaluated and selected for implementation. A new management and decision approach is therefore needed for regulators and implementers to show what information and what decision-making processes were used to make the decision, to increase administrative transparency for such projects in the public domain. To address this need, an iterative approach was developed for dredged material management that includes the essential elements of process, people, and tools needed for successful environmental decision making. The approach has 6 steps: problem definition, developing objectives and criteria, identifying alternatives, performing the evaluation, comparing alternatives, and selecting the preferred alternative. The primary objective of the approach is to provide a systematic means of exploring contaminated dredged material management alternatives in South Korea using criteria that integrate risk with economic and stakeholder value information. The approach incorporates the desired decision-making attributes of transparency, comparative analysis, and inclusion of public input. Although it was developed for South Korea, the approach can be applied in any situation in which dredged material management alternatives are being considered to manage contaminated sediment risks.