Microbially Induced Calcium Carbonate Precipitation as a Bioremediation Technique for Mining Waste.

Mining waste represents a global issue due to its potential of generating acidic or alkaline leachate with high concentrations of metals and metalloids (metal(loid)s). Microbial-induced calcium carbonate precipitation (MICP) is an engineering tool used for remediation. MICP, induced via biological activity, aims to precipitate calcium carbonate (CaCO3) or co-precipitate other metal carbonates (MCO3). MICP is a bio-geochemical remediation method that aims to immobilize or remove metal(loid)s via enzyme, redox, or photosynthetic metabolic pathways. Contaminants are removed directly through immobilization as mineral precipitates (CaCO3 or MCO3), or indirectly (via sorption, complexes, or inclusion into the crystal structure). Further, CaCO3 precipitates deposited on the surface or within the pore spaces of a solid matrix create a clogging effect to reduce contaminant leachate. Experimental research on MICP has shown its promise as a bioremediation technique for mining waste. Additional research is required to evaluate the long-term feasibility and potential by-products of MICP-treated/stabilized waste.

Preparation, characteristics, and performance of the microemulsion system in the removal of oil from beach sand.

Oil deposited on shoreline substrates has serious adverse effects on the coastal environment and can persist for a long time. In this study, a green and effective microemulsion (ME) derived from vegetable oil was developed as a washing fluid to remove stranded oil from beach sand. The pseudo-ternary phase diagrams of the castor oil/water (without or without NaCl)/Triton X-100/ethanol were constructed to determine ME regions, and they also demonstrated that the phase behaviors of ME systems were almost independent of salinity. ME-A and ME-B exhibited high oil removal performance, low surfactant residues, and economic benefits, which were determined to be the W/O microstructure. Under optimal operation conditions, the oil removal efficiencies for both ME systems were 84.3 % and 86.8 %, respectively. Moreover, the reusability evaluation showed that the ME system still had over 70 % oil removal rates, even though it was used six times, implying its sustainability and reliability.

Inhibited and Retarded Behavior by Ca2+ and Ca2+/OD Loading Rate on Ureolytic Bacteria in MICP Process.

The estimation of optical density (OD) with viable cells is challenging for engineering purposes. In this study, the OD conversion based on previous study was used. The inhibited and retarded behavior of the microbially induced carbonate precipitation (MICP) process was examined. The experimental results showed that high Ca2+ drastically influences the inhibited and retarded behavior on MICP processes. The analysis showed that the inhibition and retardation effects occurred when the Ca2+/OD loading rate exceeded 8.46 M. The critical value was equal to the proportional constant for obtaining carbonate precipitation rate (CPR) from OD. Due to this, the blending design of materials became possible, with no risk of inhibition. In conclusion, the inhibition and retardation of the MICP process are governed by the Ca2+ load and the linear standard line (LSL), which may be attributed to the capacity or tolerance of viable cells, i.e., CPR/OD = 8.46 M or Ca2+/OD = 8.46 M.

Removal of Nutrients from Water Using Biosurfactant Micellar-Enhanced Ultrafiltration.

The removal of NH4+, NO3-, and NH3- from wastewater can be difficult and expensive. Through physical, chemical, and biological processes, metals and nutrients can be extracted from wastewater. Very few scientific investigations have employed surfactants with high biodegradability, low toxicity, and suitability for ion removal from wastewater at different pH and salinity levels. This research employed a highly biodegradable biosurfactant generated from yeast (sophorolipid) through micellar-enhanced ultrafiltration (MEUF). MEUF improves nutrient removal efficiency and reduces costs by using less pressure than reverse osmosis (RO) and nanofiltration (NF). The biosurfactant can be recovered after the removal of nutrient- and ion-containing micelles from the filtration membrane. During the experiment, numerous variables, including temperature, pH, biosurfactant concentration, pollutant ions, etc., were evaluated. The highest amount of PO43- was eliminated at a pH of 6.0, which was reported at 94.9%. Maximum NO3- removal occurred at 45.0 °C (96.9%), while maximum NH4+ removal occurred at 25.0 mg/L (94.5%). Increasing TMP to 200 kPa produced the maximum membrane flow of 226 L/h/m2. The concentrations of the contaminating ion and sophorolipid were insignificant in the permeate, demonstrating the high potential of this approach.

An Overview on the Treatment of Oil Pollutants in Soil Using Synthetic and Biological Surfactant Foam and Nanoparticles.

Oil-contaminated soil is one of the most concerning problems due to its potential damage to human, animals, and the environment. Nanoparticles have effectively been used to degrade oil pollution in soil in the lab and in the field for a long time. In recent years, surfactant foam and nanoparticles have shown high removal of oil pollutants from contaminated soil. This review provides an overview on the remediation of oil pollutants in soil using nanoparticles, surfactant foams, and nanoparticle-stabilized surfactant foams. In particular, the fate and transport of oil compounds in the soil, the interaction of nanoparticles and surfactant foam, the removal mechanisms of nanoparticles and various surfactant foams, the effect of some factors (e.g., soil characteristics and amount, nanoparticle properties, surfactant concentration) on remediation efficiency, and some advantages and disadvantages of these methods are evaluated. Different nanoparticles and surfactant foam can be effectively utilized for treating oil compounds in contaminated soil. The treatment efficiency is dependent on many factors. Thus, optimizing these factors in each scenario is required to achieve a high remediation rate while not causing negative effects on humans, animals, and the environment. In the future, more research on the soil types, operating cost, posttreatment process, and recycling and reuse of surfactants and nanoparticles need to be conducted.

Remediation of oil-contaminated soil using Fe/Cu nanoparticles and biosurfactants.

Oil (or petroleum), consisting of a mixture of hydrocarbons, can leak from oil exploration, production, and use. Due to their complex mixture and interaction with the subsurface soil and water, they are hard to treat and can become a significant environmental concern. Rhamnolipid and sophorolipid biosurfactants, biologically produced surfactants, can be used to remove petroleum hydrocarbons. Nanoparticles have gained attention as promising materials for soil remediation. In this study, suspensions of Fe-Cu nanoparticles and biosurfactants were employed for the remediation of oil-contaminated soil. The results showed that these suspensions displayed a high oil removal rate from contaminated soil, which followed the first-order reaction. For batch experiments, the oil remediation efficiency was up to 84%. Optimum conditions to achieve the highest oil remediation performance included a rhamnolipid biosurfactant: nanoparticle ratio of 10:1 (wt%: wt%), pH 7, room temperature, and shaking speed of 60 rpm for 60 min. The remediation rate was improved by higher temperature and lower ionic strength. In the presence and absence of nanoparticles, rhamnolipid biosurfactant demonstrated a higher remediation efficiency than sophorolipid biosurfactant and ultraplex surfactant. The presence of other surfactants decreased the treatment productivity by 9-14% compared to using only rhamnolipid biosurfactant. Nanoparticles were reused with a remediation efficiency of 59% after three cycles by rhamnolipid biosurfactant. These results suggested that biosurfactants/Fe-Cu nanoparticle suspension showed promise for the remediation of oil-contaminated soil.

Surfactant-enhanced mobilization of persistent organic pollutants: Potential for soil and sediment remediation and unintended consequences.

This review aims to provide an overview of the sources and reactions of persistent organic pollutants (POPs) and surfactants in soil and sediments, the surfactant-enhanced solubilisation of POPs, and the unintended consequences of surfactant-induced remediation of soil and sediments contaminated with POPs. POPs include chemical compounds that are recalcitrant to natural degradation through photolytic, chemical, and biological processes in the environment. POPs are potentially toxic compounds mainly used in pesticides, solvents, pharmaceuticals, or industrial applications and pose a significant and persistent risk to the ecosystem and human health. Surfactants can serve as detergents, wetting and foaming compounds, emulsifiers, or dispersants, and have been used extensively to promote the solubilization of POPs and their subsequent removal from environmental matrices, including solid wastes, soil, and sediments. However, improper use of surfactants for remediation of POPs may lead to unintended consequences that include toxicity of surfactants to soil microorganisms and plants, and leaching of POPs, thereby resulting in groundwater contamination.

Utilization of a biosurfactant foam/nanoparticle mixture for treatment of oil pollutants in soil.

Oil contamination has become a primary environmental concern due to increased exploration, production, and use. When oil enters the soil, it may attach or adsorb to soil particles and stay in the soil for an extended period, contaminating the soil and surrounding areas. Nanoparticles have been widely used for the treatment of organic pollutants in the soil. Surfactant foam has effectively been employed to remediate various soil contaminants or recover oil compounds. In this research, a mixture of biosurfactant foam/nanoparticle was utilized for remediation of oil-contaminated soil. The results demonstrated that the biosurfactant/nanoparticle mixture and nitrogen gas formed high-quality and stable foams. The foam stability depended on the foam quality, biosurfactant concentration, and nanoparticle dosage. The pressure gradient change in the soil column relied on the flowrate (N2 gas + surfactant/nanoparticle mixture), foam quality, and biosurfactant concentration. The optimal conditions to obtain good quality and stable foams and high oil removal efficiency involved 1 vol% rhamnolipid, 1 wt% nanoparticle, and 1 mL/min flowrate. Biosurfactant foam/nanoparticle mixture was effectively used to remediate oil-contaminated soil, whereas the highest treatment efficiency was 67%, 59%, and 52% for rhamnolipid biosurfactant foam/nanoparticle, rhamnolipid biosurfactant/nanoparticle, and only rhamnolipid biosurfactant, respectively. The oil removal productivity decreased with the increase of flowrate due to the shorter contact time between the foam mixture and oil droplets. The breakthrough curves of oil pollutants in the soil column also suggested that the foam mixture's maximum oil treatment efficiency was higher than biosurfactant/nanoparticle suspension and only biosurfactant.

Development of a calcium alginate-cellulose nanocrystal-based coating to reduce the impact of oil spills on shorelines.

It is well known that oil stranded on shoreline substrates can be difficult to remove and cause serious environmental effects. To address this issue, a calcium alginate-cellulose nanocrystal (CA-CNC)-based coating with a unique surface structure and superhydrophobic properties was developed to reduce the extent of shoreline oiling. The results of batch washing test showed that not only did the introduction of CNC not reduce the oil removal efficiency; it also improved the environmental stability of the coating to resist the effects associated with seawater immersion and erosion (especially in the case of 0.4 wt% of CNC). The oil-repellent performance of the coated gravels implied that both oscillation time and oil concentration had almost no effects on the amount of adhered oil. Assessment of oiling prevention based on the laboratory shoreline tank simulator proved the coated gravel performed very well as more oil floated and less oil remained on substrates and penetrated into the subsurface. Biotoxicity analysis showed that the coating powders reduced impacts on the toxicity of the oil to algae at low doses. There is a good potential for the use of this CA-CNC based coating technique to improve shoreline oil spill response.

Incorporation of Optical Density into the Blending Design for a Biocement Solution.

The engineering practices for applying the microbial precipitation of carbonates require a design of the blending biocement solution (BCS). The BCS is usually blended with concentrated strains NO-A10, reaction media, such as urea and CaCl2, and a solvent, i.e., water or seawater. To characterize the BCS, the unknown microbial characteristics, such as the cell viability, are complex factors. Therefore, the optical density (OD) was redefined as Rcv OD*, in which OD* was the tentative OD of the BCS used and Rcv was the conversion rate concerning the cell viability. To determine Rcv values, a standard precipitation curve based on the precipitation rate at 24 h was determined. It was found that the curve was expressed by λ1 OD+ λ2 OD2, in which λ1 and λ2 were 8.46 M and -17.633 M, respectively. With this, the Rcv and OD values of unknown BCS were estimated from the results of precipitation tests using arbitrary OD* values. By extending the testing time, the second order term of OD or OD* was negligible. Accordingly, the precipitation amount is expressed as 8.46 OD, in which the OD can be estimated by precipitation tests using arbitrary OD* values of BCSs. Unless the Ca2+ value is dominant, the optimum blending of BCS can be determined by OD. Thus, it is concluded that the blending design of BCS is achieved using 8.46 OD, or 8.46 Rcv OD*, and the standard precipitation curve was defined in this study.

Feasibility of Pressure-Retarded Osmosis for Electricity Generation at Low Temperatures.

A membrane-based technique for production of pressure-retarded osmosis (PRO) is salinity gradient energy. This sustainable energy is formed by combining salt and fresh waters. The membrane of the PRO process has a significant effect on controlling the salinity gradient energy or osmotic energy generation. Membrane fouling and operating conditions such as temperature have an extreme influence on the efficiency of the PRO processes because of their roles in salt and water transportation through the PRO membranes. In this study, the temperature impact on the power density and the fouling of two industrial semi-permeable membranes in the PRO system was investigated using river and synthetic sea water. Based on the findings, the power densities were 17.1 and 14.2 W/m2 at 5 °C for flat sheet and hollow fiber membranes, respectively. This is the first time that research indicates that power density at low temperature is feasible for generating electricity using PRO processes. These results can be promising for regions with high PRO potential that experience low temperatures most of the year.

Exploring the use of alginate hydrogel coating as a new initiative for emergent shoreline oiling prevention.

Marine oil spills are often reported as a result of activities associated with oil exploration, production and transportation. The spilled oil may reach the shoreline, and then the stranded oil can persist for a long time, exerting many negative effects on coastal ecosystems. Conventional shoreline cleanup methods cannot effectively remove the oil residues from affected areas and are very expensive. Therefore, the use of alginate hydrogel coatings was proposed as a new initiative for emergent shoreline oiling prevention. The alginate hydrogel-coated gravels showed high surface roughness, as well as remarkable water wetting and low-oil-adhesion properties. There was a low oil adhesion on the coated gravels in the continuous test with oil/water emulsion flow, indicating the excellent oil-repellent properties of the coated substrate. The results of batch oil-repellent tests showed that independent of the kind or weathering degree of the oil used, oil can be easily washed out from the coated gravels. The coated gravels had good environmental stability and the slightly partial de-crosslinking of alginate structure would not reduce the oil repellence performance. Moreover, the performance of the alginate hydrogel-coated gravel was further proved with a laboratory shoreline tank simulator, in which more stranded oil floated to the water surface and less oil remained on gravels and entered into subsurface. This proposed oiling prevention method can be used not only for shorelines but also for coastal piers, seaports, and solid manmade shorelines. The coating material is derived from the biomass in the ocean and can be degraded under natural conditions. This study may provide a unique direction for the future development of green oil spill control strategy.

Sustainable Remediation of Contaminated Soil Using Biosurfactants.

Selection of the most appropriate remediation technology must coincide with the environmental characteristics of the site. The risk to human health and the environment at the site must be reduced, and not be transferred to another site. Biosurfactants have the potential as remediation agents due to their biodegradability, low toxicity, and effectiveness. Selection of biosurfactants should be based on pollutant characteristics and properties, treatment capacity, costs, regulatory requirements, and time constraints. Moreover, understanding of the mechanisms of interaction between biosurfactants and contaminants can assist in selection of the appropriate biosurfactants for sustainable remediation. Enhanced sustainability of the remediation process by biosurfactants can be achieved through the use of renewable or waste substrates, in situ production of biosurfactants, and greener production and recovery processes for biosurfactants. Future research needs are identified.

Start-up of oxygen-limited autotrophic partial nitrification-anammox process for treatment of nitrite-free wastewater in a single-stage hybrid bioreactor.

This study presents effective ammonium removal from nitrite-free ammonium-rich synthetic wastewater through combined partial nitrification (PN) and anammox processes in a multi-zone hybrid airlift bioreactor (BioCAST). Removal efficiencies of ammonia-nitrogen and total nitrogen up to 85.6% and 81.2%, respectively, were achieved shortly after the start-up of bioreactor treating the nitrite-free ammonium-rich synthetic wastewater with ammonium concentrations of 10-350 mg/L. The hybrid (containing suspended and attached biomass) and multi-zone design of the bioreactor with different dissolved oxygen levels, along with the inoculation with anammox-containing sludge were the main factors in the successful start-up of the bioreactor. Nitrate accumulation problem due to the fast growth of nitrite-oxidizing bacteria in the bioreactor was controlled by two operating strategies including lowering the HRT from 4 days to 2 days and controlling the dissolved oxygen concentration in the aerobic zone of the bioreactor between 0.9 and 1.2 mg/L. Moreover, the 16S rRNA gene analysis confirmed that the partial nitrification of ammonia to nitrite occurred by Nitrosomonas sp. primarily in the suspended biomass in the aerobic zone, while the conversion of nitrite to N2 occurred by Candidatus Brocadia species in the anoxic zone. This study showed the effective removal of ammonium from a nitrite-free wastewater by providing a proper HRT, controlling the DO concentration between 0.9 and 1.2 mg/L in the aerobic zone, and preventing biomass loss using both suspended and attached microbial cultures in different zones of the bioreactor.

Filtration for improving surface water quality of a eutrophic lake.

Algal blooms and the presence of cyanotoxins in surface water restrict the public from accessing lakes and beaches for drinking and recreational activities. An effort was taken in this on-site study to improve the surface water quality of a eutrophic lake, which has been under a swimming advisory for many years. A floating filtration unit with non-woven geotextiles as a sole filter media was tested for removing algae, nutrients, and suspended solids from overlying water under different lake conditions. Three non-woven geotextiles of different pore sizes were examined in different combinations and lake water quality was monitored for different physico-chemical, biological parameters. A YSI-EXO2 multiparameter probe was used for continuous online water quality monitoring during filtration. Depending on the initial water quality, excellent removal efficiency was observed as follows: 85-98% turbidity, 98-100% total suspended solids (TSS), 57-88% total phosphorus (TP), 33-66% chemical oxygen demand (COD) and 80-96% chlorophyll a (Chl. a.). The filtered lake water quality satisfied the norm set for oligotrophic lakes for TP and Chl. a. Results from this on-site study are very promising, showing the potential applicability of geotextile filtration as an ecologically attractive technique to improve the surface water quality of small aquatic bodies.

Pilot-scale application of a single-stage hybrid airlift BioCAST bioreactor for treatment of ammonium from nitrite-limited wastewater by a partial nitrification/anammox process.

This paper presents the treatment of a nitrite-limited wastewater by partial nitrification/anammox process under different dissolved oxygen (DO) concentrations of < 1.2 mg/L, < 0.5 mg/L, and 0 mg/L, and at temperatures of 35 to 27 °C in a pilot-scale single-stage hybrid bioreactor (BioCAST). The effect of operational parameters on microbial community structure and composition has also been investigated during the 1-year experimental period. Ammonium removal efficiencies of 73 ± 19% at 35-32 °C and 87 ± 9% at 29-27 °C were obtained from a synthetic nitrite-limited wastewater with ammonium concentration of 350-500 mg/L (175-250 g m-3 d-1). The adaptation of bacteria to a lower temperature (27 °C) and lower free ammonia concentrations at 27 °C was showed to be key factors leading to the optimal nitrite production by aerobic ammonium-oxidizing bacteria (AOB). No nitrite accumulation was observed due to the effective distribution and transfer of nitrite produced by the AOB in the aerobic zone to the microaerophilic/anoxic zones. The fast enrichment of Candidatus species in the suspended biomass in the anoxic zone at temperatures of 35-30 °C and in the attached biofilm in the microaerophilic zone (DO < 0.5 mg/L) at 29-27 °C suggests that the growth media (e.g., suspended biomass vs attached biofilm) had a minor effect on the diversity of microbial community in this bioreactor. This study supports the effective treatment of nitrite-limited wastewater with ammonium concentrations of < 500 mg/L by partial nitrification/anammox process at 35-27 °C in a single-stage hybrid bioreactor by adjusting the DO concentration to < 0.5 mg/L and by providing longer retention times for aerobic (AOB) and anammox bacteria in the biofilm, which resulted in the long-term suppression of nitrite-oxidizing bacteria (NOB).

An eco-friendly method for heavy metal removal from mine tailings.

One of the serious environmental problems that society is facing today is mine tailings. These byproducts of the process of extraction of valuable elements from ores are a source of pollution and a threat to the environment. For example, mine tailings from past mining activities at Giant Mines, Yellowknife, are deposited in chambers, stopes, and tailing ponds close to the shores of The Great Slave Lake. One of the environmentally friendly approaches for removing heavy metals from these contaminated tailing is by using biosurfactants during the process of soil washing. The objective of this present study is to investigate the effect of sophorolipid (SL) concentration, the volume of washing solution per gram of medium, pH, and temperature on the efficiency of sophorolipids in removing heavy metals from mine tailings. It was found that the efficiency of the sophorolipids depends on its concentration, and is greatly affected by changes in pH, and temperature. The results of this experiment show that increasing the temperature from 15 to 23 °C, while using sophorolipids, resulted in an increase in the removal of iron, copper, and arsenic from the mine tailing specimen, from 0.25, 2.1, and 8.6 to 0.4, 3.3, and 11.7%. At the same time, increasing the temperature of deionized water (DIW) from 15 to 23 °C led to an increase in the removal of iron, copper, and arsenic from 0.03, 0.9, and 1.8 to 0.04, 1.1, and 2.1%, respectively. By increasing temperature from 23 to 35 °C, when using sophorolipids, 22% reduction in the removal of arsenic was observed. At the same time while using DI water as the washing solution, increasing temperature from 23 to 35 °C resulted in 6.2% increase in arsenic removal. The results from this present study indicate that sophorolipids are promising agents for replacing synthetic surfactants in the removal of arsenic and other heavy metals from soil and mine tailings.

Selection of an appropriate management strategy for contaminated sediment: A case study at a shallow contaminated harbour in Quebec, Canada.

Harbours, as strategic places in tourism and transportation, are exposed to many sources of contamination. Assessing the quality of harbours sediment by guidelines and regulations does not reflect the actual level of contamination and the risk posed to aquatic ecosystems. Selection of an appropriate management technique for contaminated sediments in those strategic locations is crucial for the aquatic environment. The purpose of this study is to show that insufficient information, provided by sediment quality guidelines (SQGs) to identify the actual contaminants, could lead to a destructive or potentially ineffective decision for risk reduction in contaminated harbours. A comprehensive evaluation on physicochemical characteristics of sediment and water samples of a shallow harbour in St. Lawrence River was performed. Results of trace metal fractionation and risk assessment indicated that Cd and Pb were the contaminants that could pose a threat to aquatic ecosystem, although the SQG outcomes implied that Cu and Zn may cause an adverse effect on the benthic organisms. The results of multivariate statistical analysis demonstrated that the locations in the vicinity of the maintenance area contained the most contaminated sediment samples and require appropriate management. Antifouling paint particles and probably the runoff entering the harbour were the main sources of pollution. Among the diverse range of management strategies, the resuspension technique is suggested as a viable alternative in this specific case for shallow locations with contaminated sediments. A suitable management strategy could reduce the cost of remediation process by identifying the actual contaminated spots and also reduce the risk of remobilization of trace metals.

Acidification of In-Storage-Psychrophilic-Anaerobic-Digestion (ISPAD) process to reduce ammonia volatilization: Model development and validation.

In-Storage-Psychrophilic-Anaerobic-Digestion (ISPAD) is an ambient temperature treatment system for wastewaters stored for over 100days under temperate climates, which produces a nitrogen rich digestate susceptible to ammonia (NH3) volatilization. Present acidification techniques reducing NH3 volatilization are not only expensive and with secondary environmental effects, but do not apply to ISPAD relying on batch-to-batch inoculation. The objectives of this study were to identify and validate sequential organic loading (OL) strategies producing imbalances in acidogen and methanogen growth, acidifying ISPAD content one week before emptying to a pH of 6, while also preserving the inoculation potential. This acidification process is challenging as wastewaters often offer a high buffering capacity and ISPAD operational practices foster low microbial populations. A model simulating the ISPAD pH regime was used to optimize 3 different sequential OLs to decrease the ISPAD pH to 6.0. All 3 strategies were compared in terms of biogas production, volatile fatty acid (VFA) concentration, microbial activity, glucose consumption, and pH decrease. Laboratory validation of the model outputs confirmed that a sequential OL of 13kg glucose/m(3) of ISPAD content over 4days could indeed reduce the pH to 6.0. Such OL competes feasibly with present acidification techniques. Nevertheless, more research is required to explain the 3-day lag between the model results and the experimental data.

Effect of the resuspension technique on distribution of the heavy metals in sediment and suspended particulate matter.

Harbour areas play important roles in the economy worldwide. Human activities, however, in those areas, generate contamination, which mostly accumulates in sediments. On the other hand, harbour areas have been facing deposition of significant amounts of sediment each year. As a consequence, shallowness and accumulation of contaminants in sediment become challenging issues in harbours. Among the various management options for remediation of contaminated sediments in harbours, resuspension technique was introduced as a new approach to address those issues. The concept of the resuspension method is that finer sediments have a greater tendency to adsorb the contamination. Therefore, removing the finer sediments instead of dredging the whole contaminated area is the main goal of the resuspension technique. The objective of this paper was to evaluate the effect of the resuspension method on reducing the concentration of contamination and distribution of heavy metals in sediment and suspended particulate matter. The resuspension method was successful in reducing the concentration of seven selected heavy metals (Cr, Ni, Cu, Zn, As, Cd and Pb) by removing just 4% of the contaminated sediment. The contamination intensity in the sediment, presented by geoaccumulation index, was reduced for Cd and Pb as the main contaminants by 26 and 28 percent and the rest of the selected heavy metals returned to the natural level. The results of the sequential extraction tests and enrichment factor implied that the resuspension technique is capable of decreasing the risk of remobilization of heavy metals in the aquatic ecosystem.