Discharge Regulations Research Articles

Predicting bilgewater emulsion stability by oil separation using image processing and machine learning

Bilgewater is a shipboard multi-component oily wastewater, combining numerous wastewater sources. A better understanding of bilgewater emulsions is required for proper wastewater management to meet discharge regulations. In this study, we developed 360 emulsion samples based on commonly used Navy cleaner data and previous bilgewater composition studies. Oil value (OV) was obtained from image analysis of oil/creaming layer and validated by oil separation (OS) which was experimentally determined using a gravimetric method. OV (%) showed good agreement with OS (%), indicating that a simple image-based parameter can be used for emulsion stability prediction model development. An ANOVA analysis was conducted of the five variables (Cleaner, Salinity, Suspended Solids [SS], pH, and Temperature) that significantly impacted estimates of OV, finding that the Cleaner, Salinity, and SS variables were statistically significant (p < 0.05), while pH and Temperature were not. In general, most cleaners showed improved oil separation with salt additions. Novel machine learning (ML)-based predictive models of both classification and regression for bilgewater emulsion stability were then developed using OV. For classification, the random forest (RF) classifiers achieved the most accurate prediction with F1-score of 0.8224, while in regression-based models the decision tree (DT) regressor showed the highest prediction of emulsion stability with the average mean absolute error (MAE) of 0.1611. Turbidity also showed a good emulsion prediction with RF regressor (MAE of 0.0559) and RF classifier (F1-score of 0.9338). One predictor variable removal test showed that Salinity, SS, and Temperature are the most impactful variables in the developed models. This is the first study to use image processing and machine learning for the prediction of oil separation for the application of bilgewater assessment within the marine sector.

Chemiluminescence quenching capacity as a surrogate for total organic carbon in wastewater

Total organic carbon (TOC) is a valuable indicator to evaluate the degree of organic pollution in wastewater. Real-time analysis of TOC in wastewater can allow the wastewater treatment plants to manage the treatment process efficiently, avoid violations of the discharge regulations, and eliminate overtreatment. However, traditional methods for TOC determination are time-consuming. Benefitting from the rapid generation of SO4•− in the iron(II)-activated peroxymonosulfate (Fe(II)/PMS) system and the high reactivity of SO4•− towards naproxen as a chemiluminescence (CL) probe, a surrogate for TOC based on the determination of CL quenching capacity (CLQC) of organics in the Fe(II)/PMS-naproxen system was developed. According to the derived equation by considering both non-fluorescent and fluorescent quenching, the CLQC of organics in the Fe(II)/PMS-naproxen system was highly dependent on their TOC, making it to be a potential surrogate for TOC. The interferences of ubiquitous inorganic ions in wastewater on the determination of CLQC were leveled by adjusting electrical conductivity and adding mercury ions. Finally, the feasibility of CLQC as a surrogate for TOC in two real wastewaters containing different concentrations of inorganic anions was confirmed. This work can provide a TOC value within several seconds by determining the CLQC of wastewater with Fe(II)/PMS-naproxen system.

Combined effects of river discharge regulation and estuarine morphological evolution on salinity dynamics in Yangtze Estuary, China

Salinity distributions and gradients within an estuary are of great socioeconomic and ecological importance. In this study, a well-validated and process-based hydrodynamic model (Delft3D) was applied to investigate the salinity distributions and variations in the Yangtze Estuary subject to river discharge regulation by the Three Gorges Reservoir and morphological evolution of the estuary. The results indicate that the regulation of river discharge is the controlling factor for salinity variations in the estuary. Following construction of the Three Gorges Reservoir, the salinity significantly decreased during the dry season and slightly increased during the flood season. The morphological evolution of the estuary induced spatial salinity variations and affected the salinity in the estuarine wetlands (the Jiuduansha Shoal and East Chongming Mudflat). The salinity in the Jiuduansha Shoal increased from 1998 to 2010, whereas it decreased from 2010 to 2018. During the period 1998 to 2018, the salinity in the East Chongming Mudflat exhibited an increasing trend. These findings provide implications for management of water resources and wetlands in the Yangtze and other similar estuaries.

The plight of Najafgarh drain in NCT of Delhi, India: assessment of the sources, statistical water quality evaluation, and fate of water pollutants.

The Najafgarh drain is the first major drain that joins the Yamuna River at Wazirabad in Delhi, India, and is known to contribute to the maximum pollution load to this river. The drain is originally an extension of the Sahibi River and was intentionally constructed as a canal to carry stormwater, but presently, it is carrying more of sewage, agricultural, and industrial effluents received through various small and large secondary drains. The present study has analyzed the water quality status of this interconnected system, i.e., the Najafgarh drain, its associated secondary drains, and the Yamuna River for physicochemical parameters (n = 16), microbiological parameter (n = 1), and heavy metal concentrations (n = 8). The analysis of the surface water samples collected during pre- and post-monsoon seasons showed that secondary drain discharges significantly impacted the water quality of the Najafgarh drain, which in turn affected the Yamuna River. Out of the eight selected secondary drains for this study, the Goyla dairy outlet came out as the most polluted site in terms of organic pollutants while the Basaidarapur drain was loaded with heavy metal contaminants. Statistical tools comprising hierarchical cluster analysis (HCA), Pearson's correlation, and principal component analysis (PCA) were further implemented on the water quality dataset for a better understanding of the possible sources of contamination for organic and inorganic pollutants in the selected sampling sites. The present study, thus, might help in providing key highlights to the policymakers for effective regulation and management of the point source discharges in Najafgarh drain, which will ultimately restrict its pollution loadings in Yamuna River, Delhi, and also help in the restoration of this important water body.

Modelling the benefits of urine source separation scenarios on wastewater treatment plants within an urban water basin.

Stringent discharge regulations are encouraging researchers to create innovative and sustainable wastewater treatment solutions. Urine source separation (USS) is among the potent approaches that may reduce nutrient peak loads in the influent wastewater and improve nutrient recovery. A phenomenological model was used to simulate dynamic influent properties and predict the advantages gained from implementing USS in an urban water basin. Several scenarios were investigated assuming different levels of deployment: at the entire city, or specifically in office buildings for men's urine only, or for both men and women employees. The results confirmed that all scenarios of urine source separation offered benefits at the treatment plant in terms of reducing nitrogen influent load. The economic benefits in terms of reducing energy consumption for nitrification and decreasing methanol addition for denitrification were quantified, and results confirmed environmental advantages gained from different USS scenarios. Despite larger advantages gained from a global USS rate in an entire city, implementation of a specific USS in office buildings would remain more feasible from a logistical perspective. A significant benefit in terms of reducing greenhouse gas emissions is demonstrated and this was especially due to the high level of N2O emissions avoided in nitrifying biological aerated filter.

Evaluation of Improved Bioremediation Strategy for the Treatment of Abattoir Wastewater using Bacillus licheniformis ZUL012

The abattoir generates a large volume and variety of biowastes, posing a high risk of environmental contamination, disease outbreaks, and contaminated food. The purpose of this research was to characterize and remediate abattoir wastewater (Aww). The physicochemical characterization of the Aww revealed high level of pollution which served as a baseline for monitoring treatment efficacy. The B. licheniformis ZUL012 isolated from textile wastewater was primed with H2O2 and used to remediate Aww waste water in the current study. This study revealed Aww high pollution level which necessitated a need for the Treatment with this bacterium resulted in a significant decrease in some of the waste water parameters tested. The induced cell reduced the parameters to 155 41 mg/L, 75 mg/L, 454 mg/L, 1750 mg/L, and 1000 mg/L, whereas the naive cell reduced them to 375 mg/L, 776 mg/L, and 3122 mg/L, respectively. This equates to an average reduction of 95 percent (COD), 95 percent (BOD5), 77 percent (TOC), and 71% (TDS) compared to raw wastewater. These novel strategies show that H2O2-induced B. licheniformis ZUL012 could be a viable hybrid-bioremediation option for reducing or transforming the pollutants present in Aww, thereby contributing to compliance with wastewater discharge regulations into bodies of water.

Studies on Production of Low-Cost Ceramic Membranes and Their Uses in Wastewater Treatment Processes

The need for water is increasing owing to the rapidly increasing world population, urbanization, industrialization, global climate changes, and intensive agricultural activities. While the importance of water is increasing day by day, the purification and reuse of water have become more and more essential. Reducing the pollutants at the source as much as possible and if it will be given to the receiving environment, giving the wastewater treatment in accordance with the current discharge regulations, are priority processes. Of the advanced separation methods, membrane separation technology is used to reduce water resource use and control environmental pollution and has advantages such as high separation efficiency, convenient operation, compact equipment, and energy-saving. Membranes are divided into two categories according to their structures: organic and inorganic membranes (or ceramic membranes). Compared to organic membranes, inorganic membranes have many advantages such as high thermal and chemical stability, good resistance to microbial erosion, easy regeneration and cleaning, high mechanical strength, and long-term stability in harsh conditions. The high cost of ceramic membranes is an important disadvantage. In recent years, it is seen that membrane production costs are reduced by using natural minerals such as kaolin, quartz, bauxite, diatomite, clay, limestone, dolomite, zeolite, and industrial wastes instead of the commonly used ceramic membrane raw materials. By using these raw materials, besides reducing the cost of ceramic membranes, it also contributes to lowering the temperatures required for their production. In this study, studies on ceramic membranes produced from industrial wastes (waste ash, sawdust, sewage sludge, construction and demolition wastes, waste diatomite, rice husk ash, sugarcane pulp ash, corn cob ash waste etc.) were examined.

Modeling and Analysis of Non-Linear Phenomena of Satellite Power System in Space Environment and Hazard-Risk Evaluations

With the aim to solve the problem of the non-linear phenomenon of the satellite power system under the influence of the space environment factors, which threatens the stability of the power system, in this paper, the abnormal charging and discharging of solar arrays and solar array drive assembly (SADA) induced by the space plasma environment and accidental events, such as debris impact, and the non-linear behaviors of the solar array and load during the Earth eclipse are modeled and analyzed. On this basis, the hazard risk evaluations of the above non-linear phenomena are carried out, and the weak links of the satellite power system in the space environment are identified. The results show that the unexpected energy of the solar array will increase the current stress and power loss of the power device, resulting in S3R over-regulation. An SADA arc fault will reduce the power supply capacity of the solar array, damage the shunt regulator, and affect the quality of the bus. The non-linear behavior of the solar array and load during the Earth eclipse may damage the battery charge and discharge regulator, seriously affecting the stability of the power system.

Ammonium removal and recovery from effluent of AnMBR treating real domestic wastewater using polymeric hydrogel

Anaerobic membrane bioreactor (AnMBR) technology has been considered promising to transform domestic wastewater (DWW) treatment as a net energy producer via bioenergy recovery. However, ammonium-nitrogen (NH4+-N) in DWW cannot be removed by anaerobic process, which raises the risk of eutrophication and prevents the wide-scale adoption of AnMBRs. This study proposed adsorption/desorption by poly (acrylic acid) (PAA) hydrogel as the post-treatment of AnMBRs to remove and recover NH4+-N, thus simultaneously promoting AnMBR technology and the circular economy. Batch experiment results showed that NH4+-N could be rapidly adsorbed by PAA hydrogels within 30 min with excellent maximum adsorption capacities of 110.6–120.8 mg N/L (10–50 °C). Furthermore, PAA hydrogels retained 81.1 % of NH4+-N adsorption capacity when treating AnMBR effluent, preliminarily suggesting their practical feasibility in complex water matrix. Thereafter, PAA hydrogels were packed into a bench-scale fixed-bed column. Up to 98.5% of NH4+-N in AnMBR effluent could be captured in the hydrogel column at the breakthrough point at flow rate of 0.5 mL/min, achieving a polished effluent concentration of <1.5 mg N/L and thus meeting the strictest discharge regulations. The hydrogel column could be regenerated for 10 adsorption/desorption cycles with an insignificant decline in adsorption capacity of ∼4.7%, highlighting its excellent reusability. More importantly, we for the first time proposed the strategic recirculation of 1 mol/l HCl solution as eluent and obtained an NH4+-N enrichment factor of ∼10 over four rounds of adsorption/desorption, demonstrating the promise of this strategy to concentrate NH4+-N as resources. The economic analysis based on our experimental results showed that PAA hydrogel-based adsorption/desorption process coupled with eluent recirculation has the potential to remove and recover NH4+-N from AnMBR effluent cost-effectively. Overall, this study could potentially expand the application of AnMBRs and foster innovations in sustainable wastewater treatment.

Long-time impact of a large dam on its downstream river’s morphology: determined by sediment characteristics, pollutants as a marker, and numerical modelling

Many river systems are regulated by dams, which causes an altered flow regime and sediment deficit in the downstream reach. The Rur dam (North Rhine-Westphalia, Germany), constructed from 1900 to 1959, serves as a model example of the impact of a large dam in a European low mountain area on downstream morphology. Today, a new equilibrium incorporates flow regulations, a deficit in suspended sediment supply, and an increased mean sediment diameter downstream of the dam. A hybrid examination of field measurements and numerical modelling shows that the sediment deficit and increased mean sediment diameters downstream of the Rur dam are superimposed by the lithostratigraphy and the sediment supply of tributaries. However, the discharge regulations lead to floodplain decoupling downstream of the dam. Furthermore, the Rur dam functions as a pollutant trap. Overall, more studies on the impact of damming on downstream reaches are needed to classify the impact depending on the river type for sustainable water management.

Aplication of the Method of Characteristics for Studying the Processes of Transformation of Flow Rates and Water Depths in the Derivation Channel of an HPP Under Discharge Regulation

Aplication of the Method of Characteristics for Studying the Processes of Transformation of Flow Rates and Water Depths in the Derivation Channel of an HPP Under Discharge Regulation

OPTIMIZATION STUDY OF GATE OPERATION RULE IN CIAWI DAM AS FLOOD CONTROL FUNCTION

The purpose of this research is to find out the effectiveness of operating gate on the design of flood routing and provide an alternative outlet operation gate for maximum flood reduction. The location of the research area is the Ciawi Dam watershed with an area of ​​88.50 km2, a river length of ±16.70 km and an average river slope of 5.60%. This research data is based on climatological data, low discharge data, flood hydrograph, and dam and reservoir engineering data. In addition, there are supporting data to perform calculations and analyzes, such as flood discharge data, elevation curve – reservoir volume and layout of the dam and its complementary buildings, existing operating patterns, and regional socio-economic data studies. The method used is to calculate flood routing of the capital flow curve at the outlet operation gate. The simulation is carried out using a design flood hydrograph so that optimal flood reduction can be determined by the outlet operation gate. Based on the results of the maximum reduction in the design of the reservoir operation dam design without utilizing the conduit gate as a flood control function, the researchers optimized the door operation pattern to increase the flood reduction capacity (optimization) of the Ciawi Dam. The result of the calculation and analysis is that the flood return period (Q25 th) is able to reduce flooding by 54.64%; flood return period (Q50 yr.) is able to reduce flooding by 45.21%; flood return period (Q100 yr.) is able to reduce flooding by 38.06%; flood return period (Q500 yr.) is able to reduce flooding by 38.50%; and the flood return period (Q1000 yr.) was able to reduce flooding by 33.22%. So, it can be concluded that by utilizing the bottom outlet gate as a flood discharge regulation, the benefits obtained are 42.27% (at Q 25 yrs.) from the pattern of dam operation without gate regulation.

Adsorption of persistent organic pollutants (POPs) from the aqueous environment by nano-adsorbents: A review

The intensification of urbanisation and industrial activities significantly exacerbates the distribution of toxic contaminations into the aqueous environment. Persistent organic pollutants (POPs) have received considerable attention in the past few decades because of their persistence, long-distance migration, potential bioaccumulation, latent toxicity for humans and wildlife. There is no doubt that POPs cause serious effects on the global ecosystem. Therefore, it is necessary to develop a simple, safe and sustainable approach to remove POPs from water bodies. Among other conventional techniques, the adsorption process has proven to be a more effective method for eliminating POPs and to a larger extent meet discharge regulations. Nanomaterials can effectively adsorb POPs from aqueous solutions. For most POPs, a >70% adsorptive removal efficiency was achieved. The major mechanisms for POPS uptake by nano-adsorbents includes electrostatic interaction, hydrophobic (van der Waals, π-π and electron donor-acceptor) interaction and hydrogen bonding. Nano-adsorbent can sustain a >90% POPs adsorptive removal for about 3 cycles and reuseable for up to 10 cycles. Challenges around adsorbent ecotoxicity and safe disposal were also discussed. The present review evaluated recent research outcomes on nanomaterials that are employed to remove POPs in water systems.

A comprehensive review on bio-hydrogen production from brewery industrial wastewater and its treatment methodologies

The brewing process for beer extraction often produces a maximum quantity of wastewater and solid waste materials. It needs to be properly discarded in a cost-effective and safe mode to reach the standard discharge regulations laid down by governmental agencies to conserve human/animal life in the environment. It is clearly understood that ten litres of potable water were required for brewing a litre of beer. Furthermore, brewery wastewater, effluent obtained in enormous quantities from agriculture-based industries and its treatment technique can be merged with energy generation strategies as in the case of biogas formation, effluent rich in either Hydrogen (H2) or methane (CH4) content. Thus, the methane production via anaerobic co-digestion of such brewing waste is well recognised. In contrast, biosynthesis of H2 has been analysed for certain agro-based wastewaters but has obtained less focus in the case of brewing water. Hence, the in-depth review presents sources for a generation and complete decomposition of the brewing water, enlightening the recent research concerning methane production by anaerobic digestion. Also highlighted are the optimum conditions for H2 generation from wastewater sources emanating due to agriculture. This article highlights the complete analysis of current trends in brewing wastewater treatment techniques and their potential benefits for reuse based on recent findings. The key issues have also been addressed for brewing wastewater treatment and its reuse strategy, highlighting future social benefits recommendations.

Assessment of the Wetland Ecosystem Services Status and Their Uses in the Barotse Flood Plains of Zambezi Sub Basin, Zambia

The Zambezi River Basin system and wetlands in particular, have a high ecosystem services and economic value to large number to people the study aim was to assess the status of ecosystem services and their benefits in the wetlands of Barotse Flood plains (BFP). The study utilized both secondary and primary data sources. Primary data was collected using interview schedule, key informant’s interviews, Participatory rural appraisal and field observations. Simple random sampling was used to select proportional respondents from 9 district that are found study area. The wetland ecosystem services that were identified in BFP are: Provisioning which include water, fish, wild game, fruits, edible plants, reeds, sedge, pasture, thatching grass, sand and clay soil, and medicinal plants. Regulation; climate regulation (temperature and precipitation), ground water discharge and river flow regulation. Cultural; traditional ceremonies, sacred places and recreation. Support services; soil formation, alluvial and organic matter. The study found that the ecosystem services were affected by socio-ecological factors in the BFP that led to declining of ecosystem services in general. The Pearson coefficient correlation showed that there is a significant relationship of 0.930** at 0.01 level between socio-ecological factors and declined ecosystem services in BFP. The study recommended strategies such as the government, local leadership and other stakeholders to embark on protection and conservation of BFP since it is a recognized and designated Ramsar heritage site. Government also to embark on formulating new policies on ecosystem services management in the wetlands and to fully implement the already existing policies.

Is polycyclic aromatic hydrocarbon concentration significantly underestimated in scrubber effluent discharge?

With the wide-scale use of exhaust gas cleaning systems (scrubbers) by ships and the associated scrubber washwater discharge, there is growing concern regarding the risk of the marine environment posed by scrubber washwater, especially for the organic contaminants “Polycyclic Aromatic Hydrocarbons (PAHs)” which is a toxic washwater pollutant component. The detection of PAHs in scrubber effluent has been conducted widely by two different methods: the Gas Chromatography-Mass Spectrometry (GC-MS) method of labs and the fluorescent method by online PAHs sensors. Unfortunately, the current lab analysis only focuses on the EPA 16 PAHs rather than any other derivatives, resulting a knowledge gap between accurate estimating the actual concentrations of PAHs in the onboard scrubber effluents to onboard PAHs monitoring. This gap leads to controversial opinion on scrubber effluent environmental impact as well as ambiguity in “sulphur cap” regulation implements. In this study, we conducted a scrubber effluent sampling program on three ships, and the lab analysis indicated that alkylated derivatives of naphthalene, phenanthrene, and fluorene clearly dominate in all PAHs of the scrubber effluent. However, since current PAHs monitoring devices survey/approval solely report the content of the EPA 16 PAHs from lab report, the overlooked alkylated PAHs may lead to a significant underestimation (up to 30 times lower) of total PAHs concentration in scrubber effluent. Consequently, the overall marine environment risk of scrubber effluent could be substantially underestimated considering alkylated PAHs are often reported more toxic than their parent PAHs. This study may trig re-examinations of PAHs monitoring methods and lead to an understanding that the present discharge regulations require an overhaul.

Analysis of Legislative Changes in the Regulation of Surface Wastewater Discharges to Water Bodies

The paper considers the features of the transition to a new system of rationing of surface wastewater discharges. The basic legislative requirements are given, the required degree of purification is calculated, which ensures the achievement of technological standards. The possible lists of substances for goals calculating the specifications of permissible dump are given. The necessity of entering additional information into technical standards for the ensure system of rationing of surface wastewater discharges at the design and construction stage is substantiated.

On the issue of normalization of maximal permissible input of suspended matter into water bodies

B Analysis of the currently used system of normalization of the suspended substances (SS) input into water bodies has shown that it is based only on fishery norms of maximal permissible concentration set in laboratory conditions for neutral SS. The detailed analysis has demonstrated that SS can contain organic and non-organic ingredients with not only mechanical impact on hydrocoles but with the impact upon hydro/chemical characteristics of water bodies due to transformation because of the inter-water body processes influence. Besides, they act as carriers of the adsorbed pollutants including high-toxic ones, as well as initiators of bottom sediments (sources of secondary pollution) formation. A number of authors who deal with ecosystem impact of suspended substances and consider chemically neutral SS have proposed regulation of discharge based on the pollutants’ impact on fish families according to the results of long-time observations of the fish behavior under the neutral suspended substances’ impact. Analysis of the current situation demonstrates that now there is practically no aggregated assessment of the suspended substances impact on the water bodies’ status. There is only differentiated estimation of the impact of only the one class of suspended substances ("chemically neutral") though it is quite inadequate in respect of the current situation. In fact, there is practically no well-grounded norms of suspended substances discharge to water bodies to take into account the whole spectrum of the SS impact upon water bodies.

A shift from chemical oxygen demand to total organic carbon for stringent industrial wastewater regulations: Utilization of organic matter characteristics

From 2022, industrial wastewater discharge regulations in South Korea will replace chemical oxygen demand (CODMn) with total organic carbon (TOC). A shift from CODMn to TOC is a pioneering change in protecting water bodies from organic contaminants. However, several industries are struggling to meet these TOC requirements even though their effluents met the CODMn limits. Effluent CODMn/TOC ratios (1.28 ± 0.64) found in our study were lower than the CODMn/TOC coefficients (1.33–1.80) suggested by the Ministry of Environment in South Korea. Aliphatic and particulate organic matter contents in effluents likely influenced the CODMn/TOC ratio. Regardless of the industrial category, dissolved organic carbon often consists of low molecular weight neutrals, hydrophobic organic carbon, and protein-like substances in raw and treated industrial wastewaters. The present study also revealed that TOC and CODMn represented different organic matter fractions in the paper mill and oil refinery wastewater, whereas the industrial park wastewater showed similar dissolved organic matter characteristics. Specifically, CODMn was effective in the determination of humic content in paper mill wastewater but was underestimated in oil refinery wastewater. Additionally, only paper mill effluents exceeded the TOC requirements (4 of 6 samples) and required an additional post-treatment process owing to higher organic loads.

Legal regulation of wastewater discharge in the Russian Federation from the point of view of environmental safety

Legal regulation of wastewater discharge in the Russian Federation from the point of view of environmental safety