Pilot-scale Field Study Research Articles

Pilot-scale field studies on activated microbial remediation of petroleum-contaminated soil.

Soil contamination by petroleum, including crude oil from various sources, is increasingly becoming a pressing global environmental concern, necessitating the exploration of innovative and sustainable remediation strategies. The present field-scale study developed a simple, cost-effective microbial remediation process for treating petroleum-contaminated soil. The soil treatment involves adding microbial activators to stimulate indigenous petroleum-degrading microorganisms, thereby enhancing the total petroleum hydrocarbons (TPH) degradation rate. The formulated microbial activator provided a growth-enhancing complex of nitrogen and phosphorus, trace elements, growth factors, biosurfactants, and soil pH regulators. The field trials, involving two 500 m3 soil samples with the initial TPH content of 5.01% and 2.15%, were reduced to 0.41% and 0.02% in 50 days, respectively, reaching the national standard for cultivated land category II. The treatment period was notably shorter than the commonly used composting and bioaugmentation methods (typically from 8 to 12 weeks). The results indicated that the activator could stimulate the functional microorganisms in the soil and reduce the phytotoxicity of the contaminated soil. After 40 days of treatment, the germination rate of rye seeds increased from 20 to 90%, indicating that the microbial activator could be effectively used for rapid on-site remediation of oil-contaminated soils.

Performance of constructed floating wetlands in a cold climate waste stabilization pond

Effectiveness of constructed floating wetlands (CFWs) is largely unknown for wastewater treatment in cold climates. An operational-scale CFW system was retrofitted into a municipal waste stabilization pond in Alberta, Canada. During the first year (Study I), insignificant performance was recorded for water quality parameters, although phyto-uptake of elements was evident. In Study II, doubling of the CFW area and addition of underneath aeration promoted plant uptake of elements, including nutrients and metals, following significant pollutant reduction in the water; 83 % of chemical oxygen demand, 80 % of carbonaceous biochemical oxygen demand, 67 % of total suspended solids, and 48 % of total Kjeldhal nitrogen. A mesocosm study, conducted in parallel to the pilot scale field study, confirmed the impact of both vegetation and aeration on water quality improvement. The phytoremediation potential was linked to accumulation within plant shoot and root biomass and was confirmed by mass balance. Bacterial community analyses reflected that heterotrophic nitrification, aerobic denitrification, complete denitrification, organic matter decomposition, and methylotrophy were dominant mechanisms in the CFW, likely resulting in successful transformation of organics and nutrients. CFWs appear to be a viable ecotechnology to treat municipal wastewater in Alberta; however, larger and aerated CFW systems are recommended to achieve maximum remediation. The study aligns with the United Nations Environment Program to scale up restoration of degraded ecosystems, and to improve conditions for water supply and biodiversity following recognition of 2021–2030 as the Decade on Ecosystem Restoration.

Mitigating fugitive methane emissions from closed landfills: A pilot-scale field study

Emissions from Canadian landfills account for 20 % of national greenhouse gas emissions, a portion of which occur as fugitive emissions. Depending on management factors, significant quantities of landfill gas are emitted during the operational phase and over several decades following landfill closure. Successful landfill reclamation developments depend on low-maintenance solutions to manage fugitive emissions. Designing passive methane oxidation biosystems (PMOBs) to complement landfill covers has become a promising complementary strategy. Achieving year-round methane oxidation in cold climates, requires specific conditions for survival of methanotrophic bacteria (responsible for methane oxidation), including optimal temperature, moisture and sufficient supply of O2 and CH4. The objective of this study was to design, construct and monitor a fully instrumented pilot-scale PMOB capable of abating fugitive methane emissions from a closed landfill in the city of Kitchener, Ontario, now a public park. Factors considered in the design include type of PMOB media, methane loading rates, hydraulic behaviour and ambient temperature. Methane oxidation efficiencies between 73 and 100 % were achieved during the monitoring period. The goal was to develop a long-term solution to mitigate fugitive methane emissions at this closed landfill. Successful mitigation will provide a low-maintenance, high impact technology that could be adopted by the municipality for abatement of CH4 emissions at other landfills under its management. The results will also be useful to landfill designers, operators, and regulatory bodies. Overall, the PMOB construction and monitoring results supported evidence that the designed PMOB was capable of abating most of the CH4 loading. The paper describes several steps taken to design, install and operate the PMOB.

Remediation of zinc-contaminated groundwater by iron oxide in situ adsorption barriers – From lab to the field

Heavy metals such as zinc cannot be degraded by microorganisms and form long contaminant plumes in groundwater. Conventional methods for remediating heavy metal-contaminated sites are for example excavation and pump-and-treat, which is expensive and requires very long operation times. This induced interest in new technologies such as in situ adsorption barriers for immobilization of heavy metal contamination. In this study, we present steps and criteria from laboratory tests to field studies, which are necessary for a successful implementation of an in situ adsorption barrier for immobilizing zinc. Groundwater and sediment samples from a contaminated site were brought to the lab, where the adsorption of zinc to Goethite nanoparticles was studied in batch and in flow-through systems mimicking field conditions. The Goethite nanoparticles revealed an in situ adsorption capacity of approximately 23 mg Zn per g Goethite. Transport experiments in sediment columns indicated an expected radius of influence of at least 2.8 m for the injection of Goethite nanoparticles. These findings were validated in a pilot-scale field study, where an in situ adsorption barrier of ca. 11 m × 6 m × 4 m was implemented in a zinc-contaminated aquifer. The injected nanoparticles were irreversibly deposited at the desired location within <24 h, and were not dislocated with the groundwater flow. Despite a constantly increasing inflow of zinc to the barrier and the short contact time between Goethite and zinc in the barrier, the dissolved zinc was effectively immobilized for ca. 90 days. Then, the zinc concentrations increased slowly downstream of the barrier, but the barrier still retained most of the zinc from the inflowing groundwater. The study demonstrated the applicability of Goethite nanoparticles to immobilize heavy metals in situ and highlights the criteria for upscaling laboratory-based determinants to field-scale.

Water–energy nexus in Central Asia's lift irrigation schemes: Multi-level linkages

Separating downstream agriculture from upstream hydropower in transboundary river basins complicates water management at the national level. The shift from hydropower to thermal power supply increases the competition for water between agriculture and energy generation, accelerates depletion of fossil energy resources, and increases greenhouse gas emissions. Because of the competition for scarce water between agriculture and energy generation, brackish groundwater irrigation has been explored as an option to cover the water deficit in Central Asia's lift irrigation zones. This study examines the combination of aquifer storage and recovery with drip irrigation to improve brackish groundwater quality in the Karshi Main Canal zone. In this zone, a cascade of sequential pump stations is used to lift water from the transboundary Amudarya River. The method used to evaluate the technology is a pilot-scale field study. The results show that wide-scale adoption of the technology can produce significant water (24%) and energy savings (19%), as well as reduced saline flows and emissions of greenhouse gases.

Pilot-scale field study for vanadium removal from mining-influenced waters using an iron-based sorbent

This study investigated the removal of vanadium from mining waters at a closed mine site (Mustavaara, Finland) using granular ferric oxyhydroxide (CFH-12) on pilot scale. Two filter systems, pilot A and pilot B, were placed in different streams, where the influent in pilot A contained a higher and very variable vanadium concentration (6.46–99.1 mg/L), while the pilot B treated influent had lower vanadium concentrations (0.443–2.33 mg/L). The operation periods were 51 days for pilot A and 127 days for pilot B. Water quality analyses revealed that vanadium was efficiently captured in the filter system in both pilots. X-ray fluorescence analysis revealed that the filter beds were not fully saturated with vanadium. X-ray photoelectron spectroscopy confirmed that oxidised vanadium (5+) existed in the used CFH-12 and the carbon content in the used material had increased due to the adsorbed organic compounds. For comparison, lab-scale coagulation experiments were conducted using ferric sulphate for the influent of pilot A (the sampled batch contained 15.9 mg/L V). The optimum coagulant dosage was 350 mg/L (>93% vanadium removal) at the original pH (7.8–7.9) of the influent, whereas the required coagulant amount decreased when the influent pH was adjusted to 4.6–4.8.

Response to "Comment on 'A Pilot-Scale Field Study: In Situ Treatment of PCB-Impacted Sediments with Bioamended Activated Carbon'".

Response to "Comment on 'A Pilot-Scale Field Study: In Situ Treatment of PCB-Impacted Sediments with Bioamended Activated Carbon'".

Comment on "A Pilot-Scale Field Study: In Situ Treatment of PCB-Impacted Sediments with Bioamended Activated Carbon".

Comment on "A Pilot-Scale Field Study: In Situ Treatment of PCB-Impacted Sediments with Bioamended Activated Carbon".

A Pilot-Scale Field Study: In Situ Treatment of PCB-Impacted Sediments with Bioamended Activated Carbon.

A combined approach involving microbial bioaugmentation and enhanced sorption was demonstrated to be effective for in situ treatment of polychlorinated biphenyls (PCBs). A pilot study was conducted for 409 days on PCB impacted sediments in four 400 m2 plots located in a watershed drainage pond in Quantico, VA. Treatments with activated carbon (AC) agglomerate bioamended with PCB dechlorinating and oxidizing bacteria decreased the PCB concentration in the top 7.5 cm by up to 52% and the aqueous concentrations of tri- to nonachlorobiphenyl PCB congeners by as much as 95%. Coplanar congeners decreased by up to 80% in sediment and were undetectable in the porewater. There was no significant decrease in PCB concentrations in non-bioamended plots with or without AC. All homologue groups decreased in bioamended sediment and porewater, indicating that both anaerobic dechlorination and aerobic degradation occurred concurrently. The titer of the bioamendments based on quantitative PCR of functional marker genes decreased but were still detectable after 409 days, whereas indigenous microbial diversity was not significantly different between sites, time points, or depths, indicating that bioaugmentation and the addition of activated carbon did not significantly alter total microbial diversity. In situ treatment of PCBs using an AC agglomerate as a delivery system for bioamendments is particularly well-suited for environmentally sensitive sites where there is a need to reduce exposure of the aquatic food web to sediment-bound PCBs with minimal disruption to the environment.

Application of native phosphate solubilizing bacteria for the use of cheap organic and inorganic phosphate source in agricultural practise of Capsicum annum (Chili) - A pilot scale field study

Abstract Soluble phosphorus (P) is one of the vital macronutrients for plant growth. Native phosphate solubilizing bacteria (PSB) from rhizosphere soil of Capsicum annum was isolated and the phosphate solubilizing efficiency was evaluated in the presence of Egg Shell, Tea powder, Animal bone waste (ETB), Rock phosphate (RP) for the chili plant as an alternative fertilizer, instead of chemical fertilizer with the reference of Triple Super Phosphate (TSP) as control. Potential PSB were used as the inoculum for rhizosphere soil with ETB and RP. Growth and yield parameters were recorded to determine the efficiency of PSB with the alternative P source. The study results showed that the selected PSB effectively increase the growth and yield when inoculating PSB along with ETB and RP.

A Pilot Scale Field Study of Using Phosphate Solubilizing Bacterial Native Microflora for the Use of Cheap Organic and Inorganic Phosphate Source for the Agriculture Practice of Solanum melongena Linn. (Eggplant)

Abstract Phosphorus is an essential element that regulates protein synthesis in a plant. This study is to isolate phosphate solubilizing bacteria (PSB) from rhizosphere soil of eggplant as well as to evaluate the solubilization efficacy and the effectiveness of those strains. The plant parameters results showed the highest mean shoot length of S. melongena in PSB strain with ETB application (77.1cm), PSB with TSP (69.9cm), PSB with RP (66.5cm), and PSB without fertilizer (48.8cm). The identical trends were observed in mean weight of fruits (206.6g, 122.6g, 117.9g and 8.1g); the mean length of fruits (32.7cm, 21.4cm, 19.8cm and 2.6cm) and chlorophyll content (8.2mg/g, 7.4mg/g, 4.9mg/g and 4.3mg/g). So, it can be concluded that ETP with PSB strain tends to solubilize organic P in the alternative P source as good as TSP and they also can be used as an alternative to phosphate fertilizer.

Sustainable Autarky of Food-Energy-Water

Meeting the demand for food, energy, and water to sustain the worldwide growth of urban population is a major challenge. Several recent reports have concluded that one approach to overcome this challenge is to recover and recycle resources within the food-energywater (FEW) nexus in urban settings. Urban wastewaters (UWW) are now being recognized as a resource, rich in nutrients and energy, rather than a waste stream that has to be treated and disposed of at the expense of significant energy input and associated environmental emissions. Reclaiming reusable water, nutrients, and energy from UWWs can contribute to autarky of FEW nexus and render the wastewater management process sustainable and potentially profitable. This paper presents a novel approach to treat UWW with the potential for high recovery of energy, nutrients, and water from UWW for use in food crop production. This approach entails cultivation of energy-rich algal biomass in primary-settled UWW followed by extraction of biocrude and nutrients from the algal biomass by hydrothermal liquefaction. A fraction of the recovered nutrients is recycled to boost biomass production while the rest can be stockpiled for use as fertilizer. Results from a pilot scale field study conducted at a local wastewater treatment plant confirmed that the algal system can achieve &gt;80% removal of organic carbon, ammoniacal-nitrogen, and phosphates in UWW, meeting the respective discharge standards in a single step, with a batch process time of three days.

Water Quality Improvements in Soil Aquifer Treatment (SAT) Simulated Soil Columns

Artificial recharge of Aquifers with treated wastewater is one of the most promising techniques for its reuse. Usually laboratory and pilot scale field studies are conducted for investigating the feasibility of wastewater recharge for any aquifer. The addition of sand to the local soil can improve the performance of the Soil Aquifer Treatment (SAT) process. Thus, a laboratory study was conducted to investigate the effect of sand amendment with local Sandy Clay Loam (SCL) texture soil collected from Anna University Sewage Treatment Plant (STP), Chennai, India. Four 35 cm long PVC soil columns were fabricated and were filled with 5 % (R5), 10 % (R10), 15 % (R15) and 20 % (R20) sand amended soil. The experiments were run simultaneously for a period of ten cycles with 3 days wet/4 days dry cycles. Water samples were collected at the outlet of the columns and analysed for TDS, ammonia, nitrite and nitrates. The removal of ammonia was through nitrification process which was found to be a dominant removal mechanism of nitrogen. When reduction performance achieved with different sand amendment columns were compared, it could be seen that R10 column yielded with least nitrate value of 0.69 and 1.57 mg/l after 1st and 3rd wetting day.

Defluoridation by Al-based coagulation and adsorption: Species transformation of aluminum and fluoride

The species transformation of Al and fluoride in fluoride removal by Al-based coagulation and adsorption is far from being well-characterized. This study used batch- and pilot-scale experiments to compare the fluoride removal efficiency and species transformation of Al and fluoride in Al coagulation with that in Al precipitate (AlOxHy) adsorption. Al coagulation showed superior removal of fluoride compared to AlOxHy adsorption. In the coagulation process, the formation of complexed fluoride (Com-F) occurred, and Com-F concentrations increased with elevated Al dose, i.e., lowered pH. At initial pH of 8.6, free fluoride (Free-F) dominated in the adsorption system even at the high AlOxHy dose of 200mg Al/L whereas at pH<7.0, Com-F was the dominant species in both systems. Fluoride had an influence on Al3+ hydrolysis and favored the transformation of Al3+ and Al–F complexes to Al–F precipitates, and the removal of fluoride by coagulation was improved thereafter. Fluoride also promoted the dissolution of AlOxHy, the extent of which was more significant at lowered pH from 7.0 to 4.0 and at elevated ratios of fluoride to Al from 0.15 to 2.45. The formation of Al–F complexes impaired fluoride removal by adsorption. A pilot-scale field study also indicated that coagulation showed higher efficiency than adsorption in the removal of fluoride. The average ratios of Com-F to total fluoride were 0.14:1 and 0.04:1, respectively, in coagulation and adsorption processes.

Grit Separation Module Performance and Influencing Factors for Grit Removal Efficiency from Activated Sludge

In wastewater treatment plants, grit accumulation reduces the ratio of volatile suspended solids/total suspended solids (i.e., reduces biomass in activated sludge), and therefore impairs the efficiency of wastewater treatment. A grit separation module was developed to reduce grit accumulation in such wastewater treatment systems, and a pilot scale field study was conducted at a full-scale wastewater treatment plant in Chongqing, China. The results suggest that feed pressure (working pressure) and outlet ratio (the ratio between the underflow outlet and overflow outlet diameter) were the most important control parameter and structural parameter, respectively. Grit separation efficiency was satisfactory when the feed pressure was controlled between 0.15 and 0.175 MPa and the outlet ratio K was between 0.4 and 0.6. The greatest grit separation efficiency was obtained at a cone angle of 20°, an overflow outlet diameter of 22 mm, an underflow outlet diameter of 13 mm, and a feed pressure of 0.175 MPa. Under these conditions 48% of the grit contained in feed sludge was recovered in the underflow stream with a split rate of 0.17, suggesting that the grit can efficiently be separated from activated sludge by the module presented in this study.

Fate and movement of selenium from drainage sediments disposed onto soil with and without vegetation

Disposal options for salty and selenium-laden agricultural drainage sediments are needed to protect the agricultural ecosystem in Central California. Thus, a 7-year pilot-scale field study evaluated the effects of disposing Se-laden drainage sediment onto soil that was planted with either salado grass (Sporobolus airoides ‘salado’) or cordgrass (Spartina patens ‘Flageo’), or on soil left bare with and without irrigation. Significant decreases in salinity and water-extractable and total soil Se concentrations were observed in all treatments to a depth 30 cm, while water extractable Se and salinity increased most significantly between 30 and 60 cm. Total yields increased over time for both species, while plant Se concentrations were ≈10 and 12 mg kg−1 DM for salado and cordgrass, respectively. The results show that Se and soluble salts disposed of as Se-laden drainage sediment onto light textured soils will significantly migrate to lower depths with or without vegetation.

Mercury emission and plant uptake of trace elements during early stage of soil amendment using flue gas desulfurization materials

A pilot-scale field study was carried out to investigate the distribution of Hg and other selected elements (i.e., As, B, and Se), i.e., emission to ambient air, uptake by surface vegetation, and/or rainfall infiltration, after flue gas desulfurization (FGD) material is applied to soil. Three FGD materials collected from two power plants were used. Our results show Hg released into the air and uptake in grass from all FGD material-treated soils were all higher (P < 0.1) than the amounts observed from untreated soil. Hg in the soil amended with the FGD material collected from a natural oxidation wet scrubber (i.e., SNO) was more readily released to air compared to the other two FGD materials collected from the synthetic gypsum dewatering vacuum belt (i.e., AFO-gypsum) and the waste water treatment plant (i.e., AFO-CPS) of a forced oxidation FGD system. No Hg was detected in the leachates collected during the only 3-hour, 1-inch rainfall event that occurred throughout the 4-week testing period. For every kilogram of FGD material applied to soil, AFO-CPS released the highest amount of Hg, B, and Se, followed by SNO, and AFO gypsum. Based on the same energy production rate, the land application of SNO FGD material from Plant S released higher amounts of Hg and B into ambient air and/or grass than the amounts released when AFO-gypsum from Plant A was used. Using FGD material with lower concentration levels of Hg and other elements of concern does not necessary post a lower environmental risk. In addition, this study demonstrates that considering only the amounts of trace elements uptake in surface vegetation may under estimate the overall release of the trace elements from FGD material-amended soils. It also shows, under the same soil amendment conditions, the mobility of trace elements varies when FGD materials produced from different processes are used. Implications This study evaluated environmental impact associated with land application of FGD material by considering the overall mass balance of an element in a life cycle starting from coal combustion process to the stage of land application. The approach allows the relative significance of trace element release potential among different FGD materials, as well as the distribution of trace elements in different release pathways (i.e., air emission, uptake in grass, and soil leachate), to be compared based on different environmental management schemes.

Arsenic Species Transformation and Transportation in Arsenic Removal by Fe-Mn Binary Oxide–Coated Diatomite: Pilot-Scale Field Study

The removal of arsenic (As) by iron (Fe)-manganese (Mn) binary oxide-coated diatomite (FMBO-diatomite) and the transformation and transportation of As, Fe, and Mn in a fixed-bed reactor were investigated in this pilot-scale field study (arsenite [AsdIII] = 50-80 mu g/L, arsenate [AsdV] = 40-60 mu g/L). Before regeneration, the effluent As(tot) was reduced to less than 10 mu g= L with no residual As(III). FMBO-diatomite exhibited elevated adsorptive capability of As after in situ regenerations with breakthrough bed volumes increasing from 550 to 760 bed volumes after three cycles of operation. The residual concentrations of As(III) and As(V) at different layers along the adsorption column indicated the oxidation of As(III) and the As transportation during the filter layer. Additionally, FMBO-diatomite could efficiently remove the turbidity, Fe and Mn in influents, without causing secondary pollution. Acid dilution analysis showed more Fe content and less Mn content after three cycles through the FMBO-diatomite upper layer. This was attributable to the oxidation of As(III) and Fe(II) by manganese dioxide (MnO(2)) within FMBO and the transportation of Mn(II) thereafter. The backwashing procedure led to a size classification of adsorbents. However, the FMBO-diatomite also showed increased size diameter after three cycles of operation because of the in situ regeneration. DOI: 10.1061/(ASCE)EE.1943-7870.0000432. (C) 2011 American Society of Civil Engineers.

Is Phycovolatilization of Heavy Metals a Probable (or Possible) Physiological Phenomenon? An In Situ Pilot‐Scale Study at a Leather‐Processing Chemical Industry

Using algae to treat industrial effluents containing heavy metals presents an alternative to the current practice of using other biosorbents and physical and chemical methods. In this study, effluent from a leather-processing chemical industry in Ranipet, Tamil Nadu, India, was treated for the removal of heavy metals using the microalga, Chlorella vulgaris, which was isolated from the effluent itself. The objectives of this study were to (1) assess the mass balance of a model parameter, lead, in laboratory conditions and estimate the lead adsorption capabilities of the microalga and (2) conduct pilot-scale studies for the removal of heavy metals, using the microalga, from the effluent and the solid waste accumulated over the years generated by conventional treatment methods. The results of the study show that after 8 hours, Chlorella vulgaris exhibited a better adsorption capacity under sunlight compared to laboratory conditions (i.e., 30.6 mg/g dry weight vs 10.5 mg/g dry weight, respectively). Similarly, reduction of heavy metals and mass balance in pilot-scale field studies conducted in a high-rate algal pond showed that the microalga, apart from adsorption, complexation, and entrapment mechanisms, is likely to possess phycovolatilization capability probably via biotransformation processes.

Application of phycoremediation technology in the treatment of wastewater from a leather-processing chemical manufacturing facility

Phycoremediation is the use of algae for the removal or biotransformation of pollutants from wastewater. Employing this technology in the treatment of industrial effluents presents an alternative to the current practice of using conventional methods, including physical and chemical methods. In the present study, the effluent from a leather-processing chemical manufacturing facility, situated at Ranipet, Tamil Nadu, India, was treated using the microalga, Chlorella vulgaris, which was isolated from the effluent itself. The objective of this study was to treat the effluent as well as ETP (effluent treatment plant) solid waste by phycoremediation (pilot-scale field study as well as laboratory study) and to analyse the physico-chemical parameters before and after treatment. The results obtained showed that Chlorella vulgaris exhibited appreciable nutrient scavenging properties under both laboratory and field conditions, although phycoremediation carried out in sunlight (field study) gave better results. Moreover, the growth of Chlorella vulgaris was faster under field conditions.Keywords: Phycoremediation, microalgae, Chlorella vulgaris, effluent, ETP solid