Critical review of the OSPAR risk-based approach for offshore-produced water discharges.

The management of produced water (PW) discharges from offshore oil and gas installations in the North Atlantic is under the auspices of OSPAR (Oslo/Paris convention for Protection of the Marine Environment of the North-East Atlantic). In 2010, OSPAR introduced the risk-based approach (RBA) for PW management. The RBA includes a hazard assessment estimating PW ecotoxicity using two approaches: whole-effluent toxicity (WET) and substance-based (SB). Set against the framework of the WET and SB approach, we conducted a literature review on the magnitude and cause of PW ecotoxicity, respectively, and on the challenges of estimating these. A large variability in the reported magnitude of PW WET was found, with EC50 or LC50 values ranging from <1% to >100%, and a median of 11% (n = 301). Across the literature, metals, hydrocarbons, and production chemicals were identified as causing ecotoxicity. However, this review reveals how knowledge gaps on PW composition and high sample and species dependency of PW ecotoxicity make clear identification and generalization difficult. It also highlights how limitations regarding the availability and reliability of ecotoxicity data result in large uncertainties in the subsequent risk estimates, which is not adequately reflected in the RBA output (e.g., environmental impact factors). Thus, it is recommended to increase the focus on improving ecotoxicity data quality before further use in the RBA, and that WET should play a more pronounced role in the testing strategy. To increase the reliability of the SB approach, more attention should be paid to the actual composition of PW. Bioassay-directed chemical analysis, combining outcomes of WET and SB in toxicity identification evaluations, may hold the key to identifying drivers of ecotoxicity in PW. Finally, an uncertainty appraisal must be an integrated part of all reporting of risk estimates in the RBA, to avoid mitigation actions based on uncertainties rather than reliable ecotoxicity estimations. Integr Environ Assess Manag 2023;19:1172-1187. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

[Simulation of soil desiccation effects and production water footprint of apple orchards in different precipitation areas of the Loess Plateau, China]. / 黄土高原不同降水量区苹果园土壤干燥化效应及生产水足迹模.

To clarify the desiccation effect of deep soil and water footprint of crop production in two typical dry-farming apple orchards on the Loess Plateau of China, with Luochuan County in semi-humid region and Mizhi County in semi-arid region as two typical apple planting areas, we used the WinEPIC model to quantitatively simulate and analyze the variations of soil moisture from 0 to 15 m and water footprint of apple production during 1980-2020. The results showed that annual yield of mature orchards in Luochuan and Mizhi followed an "S" curve, with the average annual values being 24.64 and 18.42 t·hm-2, respectively. The average annual evapotranspirations of Luochuan and Mizhi were 623.82 and 458.97 mm, the average annual drought stress days of Luochuan and Mizhi were 20.4 and 52.73 days, and the water overconsumption were 167.94 and 121.15 mm, respectively. The available soil water contents in Luochuan and Mizhi showed a sharp decline from 1 to 25 years old and from 1 to 23 years old, respectively, with average annual soil desiccation rates being 64.6 and 68.03 mm·a-1, respectively. The dry layer of deep soil for the orchards of Luochuan and Mizhi appeared at the 13th and 7th years, and would be stable after 23 and 22 years, respectively. The formation and stability time of the soil dry layer in the area with high precipita-tion was later than that with low precipitation. Long-term soil moisture deficit would result in irreversible soil dry layer. Water footprint of apple production in Luochuan and Mizhi were low in the early stage and high in the later stage, with the average annual values being 0.187 and 0.194 m3·kg-1, respectively. Both apple yield and production water footprint were affected by precipitation. To ensure the sustainable and healthy development of apple industry, it was recommended that the optimal planting age of apple trees is about 23 years on the Loess Plateau where water sources is limited, and the maximum should not exceed 25 years.

A photobioreactor using Nannochloropsis oculata marine microalgae for removal of polycyclic aromatic hydrocarbons and sorption of metals in produced water.

The objective of the present work is to evaluate the potential of the removal of PAHs and metal sorption for the treatment of petroleum produced water using a photobioreactor system with Nannochloropsis oculata microalgae. A set of photobioreactors with different gradients of produced water concentration diluted in saline water was designed, establishing five gradients (v/v): 0, 25, 50, 75 and 100%. These concentrations were established to test the removal of PAHs. The microalgal growth was monitored daily, noting the adaptation of microalgae to the addition of produced water as a culture medium, with cell growth of 5.24 × 107 cells mL-1 from 25% (v/v), 4.09 × 107 cells mL-1 from 50% (v/v), 2.77 × 107 cells mL-1 from 75% (v/v), and 1.17 × 107 cells mL-1 from 100%. The total removal efficiency of PAHs in the produced water was 94%. Organic compounds such as naphthalene, benzo(a)pyrene, benzo(b)fluoranthene, and acenaphthylene showed higher removal percentages, between 89 and 99% efficiency in produced water. Iron and zinc were the metals detected in the water produced, and iron reduced from 1.57 ± 0.08 mg L-1 to <0.1 mg L-1 after 28 days of cultivation, whereas zinc increased by 0.23 ± 0.05 to 3.90 ± 0.46 mg L-1. The PAHs removal may have occurred in two ways, by intracellular bioaccumulation or biodegradation by oxidoreductase enzymes. 0.2 g of dry biomass with maximum extraction of oil obtained 3.07% and generation of 3.70% of protein was considered as value-added products for biodiesel and bioplastics.

Drivers of dynamic evolution in provincial production water usage: perspective of regional relevance.

With the advancement of industrialization and urbanization, the issue of water shortage has become a bottleneck for China's economic development. Based on the structural decomposition analysis and multi-regional input-output tables of China in 2002 and 2012, this paper explores the drivers of the change in China's production water usage from the regional relevance perspective. Results show a significant increase in China's production water usage during the study period. The relationship between production water usage and per capita GDP shows an inverted U-shaped curve, and the economic scale by provinces has been improved, while the trend of production water usage differs. There are rapid increases in production water usage in economically developing provinces, while it is falling sharply in developed provinces. The crucial factors promoting its growth are changes in consumption level, population scale, and regional economic patterns. The technical effect is the most important factor in curbing the growth, followed by effects of final demand sectoral and distribution structure. The provinces and sectors with more production water usage shows higher technical and final demand effects. Therefore, it is necessary to promote water-saving activities, enhance the water-saving technical effect, and optimize final demand structure to promote economic growth with low-water usage.

Microbacterium algeriense sp. nov., a novel actinobacterium isolated from Algerian oil production waters.

A non-motile, straight-rod-shaped, Gram-stain-positive and facultative anaerobic bacterium (i.e., strain G1T) was isolated from production waters from an Algerian oilfield. Growth was observed in the presence of 0.3-3.5 % (w/v) NaCl, at 20-50 °C and at pH 6.0-9.0. Results of phylogenetic analyses based on 16S rRNA gene sequences showed that strain G1T belonged to the genus Microbacterium. Strain G1 T was closely related to Microbacterium oxydans (DSM 20578T) and Microbacterium maritypicum (DSM 12512T) with 99.8 % sequence similarity and to Microbacterium saperdae (DSM 20169T) with 99.6 % sequence similarity. Strain G1 T contained MK9, MK10, MK11, MK12 and MK13 as respiratory quinones, and phosphatidylglycerol, diphosphatidylglycerol and glycolipid as the major polar lipids. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0. The estimated DNA G+C content was 69.57 mol% based on its draft genome sequence. Genome annotation of strain G1T predicted the presence of 3511 genes, of which 3483 were protein-coding and 47 were tRNA genes. The DNA-DNA hybridization (DDH) and average nucleotide identity (ANI) values between strain G1T and M. oxydans (DSM 20578T) and M. maritypicum (DSM 12512T) were in both cases far below the respective species boundary thresholds (27.5 and 28.0 % for DDH; and 84.40 and 84.82% for ANI, respectively). Based on the data presented above, strain G1T was considered to represent a novel species for which the name Microbacterium algeriense is proposed with the type strain G1T (=DSM 109018T=LMG 31276T).

Microbial Culture in Minimal Medium With Oil Favors Enrichment of Biosurfactant Producing Genes.

The waste produced by petrochemical industries has a significant environmental impact. Biotechnological approaches offer promising alternatives for waste treatment in a sustainable and environment-friendly manner. Microbial consortia potentially clean up the wastes through degradation of hydrocarbons using biosurfactants as adjuvants. In this work, microbial consortia were obtained from a production water (PW) sample from a Brazilian oil reservoir using enrichment and selection approaches in the presence of oil as carbon source. A consortium was obtained using Bushnell-Haas (BH) mineral medium with petroleum. In parallel, another consortium was obtained in yeast extract peptone dextrose (YPD)-rich medium and was subsequently compared to the BH mineral medium with petroleum. Metagenomic sequencing of these microbial communities showed that the BH consortium was less diverse and predominantly composed of Brevibacillus genus members, while the YPD consortium was taxonomically more diverse. Functional annotation revealed that the BH consortium was enriched with genes involved in biosurfactant synthesis, while the YPD consortium presented higher abundance of hydrocarbon degradation genes. The comparison of these two consortia against consortia available in public databases confirmed the enrichment of biosurfactant genes in the BH consortium. Functional assays showed that the BH consortium exhibits high cellular hydrophobicity and formation of stable emulsions, suggesting that oil uptake by microorganisms might be favored by biosurfactants. In contrast, the YPD consortium was more efficient than the BH consortium in reducing interfacial tension. Despite the genetic differences between the consortia, analysis by a gas chromatography-flame ionization detector showed few significant differences regarding the hydrocarbon degradation rates. Specifically, the YPD consortium presented higher degradation rates of C12 to C14 alkanes, while the BH consortium showed a significant increase in the degradation of some polycyclic aromatic hydrocarbons (PAHs). These data suggest that the enrichment of biosurfactant genes in the BH consortium could promote efficient hydrocarbon degradation, despite its lower taxonomical diversity compared to the consortium enriched in YPD medium. Together, these results showed that cultivation in a minimal medium supplemented with oil was an efficient strategy in selecting biosurfactant-producing microorganisms and highlighted the biotechnological potential of these bacterial consortia in waste treatment and bioremediation of impacted areas.

Driving factors of water use change based on production and domestic dimensions in Jiangsu, China.

Water resource shortage has become a major bottleneck restricting the sustainable development of China's economy and society. Identifying the driving factors of water use is helpful to put forward suggestions of water-saving society construction. This paper takes Jiangsu province as example and adopts LMDI (Logarithmic Mean Divisia Index) method to decompose the driving factors of water use change. We find that the production intensity effect and the industrial structure effect are the two dominating factors that induce the decline of total water use. Economic development effect is the most important factor to promote the increase of total water use, and domestic intensity effect is the secondary factors except for 2000-2003 period. Population scale effect on the total water use is relatively weak. The domestic intensity effect is the primary factor to promote the increase of domestic water use; the urbanization effect is a secondary factor to promote the increase of domestic water use. Based on the research conclusions, the corresponding water-saving policy is put forward.

Numerical-ecotoxicological approach to assess potential risk associated with oilfield production chemicals discharged into the sea.

Several different chemical products are used on oil platforms to aid oil-water separation during the production process. These chemicals may enter into the sea by means of production water (PW), the main discharge derived from oil and gas offshore platforms. Consequently, toxic effects may occur in the marine environment, causing reductions in wildlife numbers, degrading ecosystem functions and threatening human health. For most of these chemicals, environmental toxicity and safety thresholds in marine ecosystems have not been fully investigated as yet. In this work, a numerical-ecotoxicological approach is proposed to assess the potential environmental risk associated with the discharge of five oilfield production chemicals (deoiler, scale inhibitor, corrosion inhibitor, catalyst, dehydrating agent) from a platform in the southern Adriatic Sea (Mediterranean Sea). Their concentrations in the seawater are numerically predicted, under different seasonal conditions, starting from the real concentrations used during the production process. The predicted concentrations are then evaluated in terms of possible toxic effects in order to assess the potential risk of oilfield production chemicals discharged into the sea.

Anaerobic biodegradation of partially hydrolyzed polyacrylamide in long-term methanogenic enrichment cultures from production water of oil reservoirs.

The increasing usage of partially hydrolyzed polyacrylamide (HPAM) in oilfields as a flooding agent to enhance oil recovery at so large quantities is an ecological hazard to the subsurface ecosystem due to persistence and inertness. Biodegradation of HPAM is a potentially promising strategy for dealing with this problem among many other methods available. To understand the responsible microorganisms and mechanism of HPAM biodegradation under anaerobic conditions, an enrichment culture from production waters of oil reservoirs were established with HPAM as the sole source of carbon and nitrogen incubated for over 328 days, and analyzed using both molecular microbiology and chemical characterization methods. Gel permeation chromatography, High-pressure liquid chromatography and Fourier-transformed infrared spectroscopy results indicated that, after 328 days of anaerobic incubation, some of the amide groups on HPAM were removed and released as ammonia/ammonium and carboxylic groups, while the carbon backbone of HPAM was converted to smaller polymeric fragments, including oligomers and various fatty acids. Based on these results, the biochemical process of anaerobic biodegradation of HPAM was proposed. The phylogenetic analysis of 16S rRNA gene sequences retrieved from the enrichments showed that Proteobacteria and Planctomycetes were the dominant bacteria in the culture with HPAM as the source of carbon and nitrogen, respectively. For archaea, Methanofollis was more abundant in the anaerobic enrichment. These results are helpful for understanding the process of HPAM biodegradation and provide significant insights to the fate of HPAM in subsurface environment and for possible bioremediation.

Growth Inhibition of Sulfate-Reducing Bacteria in Produced Water from the Petroleum Industry Using Essential Oils.

Strategies for the control of sulfate-reducing bacteria (SRB) in the oil industry involve the use of high concentrations of biocides, but these may induce bacterial resistance and/or be harmful to public health and the environment. Essential oils (EO) produced by plants inhibit the growth of different microorganisms and are a possible alternative for controlling SRB. We aimed to characterize the bacterial community of produced water obtained from a Brazilian petroleum facility using molecular methods, as well as to evaluate the antimicrobial activity of EO from different plants and their major components against Desulfovibrio alaskensis NCIMB 13491 and against SRB growth directly in the produced water. Denaturing gradient gel electrophoresis revealed the presence of the genera Pelobacter and Marinobacterium, Geotoga petraea, and the SRB Desulfoplanes formicivorans in our produced water samples. Sequencing of dsrA insert-containing clones confirmed the presence of sequences related to D. formicivorans. EO obtained from Citrus aurantifolia, Lippia alba LA44 and Cymbopogon citratus, as well as citral, linalool, eugenol and geraniol, greatly inhibited (minimum inhibitory concentration (MIC) = 78 µg/mL) the growth of D. alaskensis in a liquid medium. The same MIC was obtained directly in the produced water with EO from L. alba LA44 (containing 82% citral) and with pure citral. These findings may help to control detrimental bacteria in the oil industry.