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The use of microalgae and bacteria as a strategy for the startup of bioreactors for the treatment of industrial wastewater can be a sustainable and economically viable alternative. This technology model provides satisfactory results in the nitrification and denitrification process for nitrogen removal, organic matter removal, biomass growth, sedimentation, and byproducts recovery for added-value product production. The objective of this work was to evaluate the performance of microalgae and bacteria in their symbiotic process when used in the treatment of paper pulp industry wastewater. The experiment, lasting fourteen days, utilized four bioreactors with varying concentrations in mgVSS/L of microalgae to bacteria ratio (R1-100:100, R2-100:300, R3-100:500, R4-300:100) in the startup process. Regarding the sludge volumetric index (SVI), the results show that the R1 and R2 reactors developed SVI30/SVI10 biomass in the range of 85.57 ± 7.33% and 84.72 ± 8.19%, respectively. The lipid content in the biomass of reactors R1, R2, R3 e R4 was 13%, 7%, 19%, and 22%, respectively. This high oil content at the end of the batch, may be related to the nutritional stress that the species underwent during this feeding regime. In terms of chlorophyll, the bioreactor with an initial inoculation of 100:100 showed better symbiotic growth of microalgae and bacteria, allowing exponential growth of microalgae. The total chlorophyll value for this bioreactor was 801.46 ± 196.96 μg/L. Biological removal of nitrogen from wastewater from the paper pulp industry is a challenge due to the characteristics of the effluent, but the four reactors operated in a single batch obtained good nitrogen removal. Ammonia nitrogen removal performances were 91.55 ± 9.99%, 72.13 ± 19.18%, 64.04 ± 21.34%, and 86.15 ± 30.10% in R1, R2, R3, and R4, respectively. [Display omitted] • Microalgae and bacteria symbiotically initiated bioreactor start-up. • Initial inoculation concentrations were critical for photogranule development. • High total nitrogen removal efficiency in all bioreactor configurations. • Optimal setup boosts biomass and pigment. • Microalgae-bacteria consortium facilitated the production of valuable bioproducts. [ABSTRACT FROM AUTHOR]

Membrane distillation crystallization (MDC) is an emerging hybrid thermal membrane technology that synergizes membrane distillation (MD) and crystallization, which can achieve both freshwater and minerals recovery from high concentrated solutions. Due to the outstanding hydrophobic nature of the membranes, MDC has been widely used in numerous fields such as seawater desalination, valuable minerals recovery, industrial wastewater treatment and pharmaceutical applications, where the separation of dissolved solids is required. Despite the fact that MDC has shown great promise in producing both high-purity crystals and freshwater, most studies on MDC remain limited to laboratory scale, and industrializing MDC processes is currently impractical. This paper summarizes the current state of MDC research, focusing on the mechanisms of MDC, the controls for membrane distillation (MD), and the controls for crystallization. Additionally, this paper categorizes the obstacles hindering the industrialization of MDC into various aspects, including energy consumption, membrane wetting, flux reduction, crystal yield and purity, and crystallizer design. Furthermore, this study also indicates the direction for future development of the industrialization of MDC. [ABSTRACT FROM AUTHOR]

The environmental effects of the urban agglomeration planning policy (UAPP) are an exploration by rapidly developing China and a concern for countries seeking development and urban reform around the world. This paper takes the three regional urban agglomerations in the Yellow River Basin (YRB) as the research object and collects the panel data of 106 prefecture-level cities from 2006 to 2019 to study the reduction effects of UAPP on the industrial wastewater discharge (IWD). The empirical results from Difference-in-Differences models indicate that UAPP can significantly inhibit IWD. UAPP reduces IWD by promoting green innovation, and the development of service industries can strengthen this effect. UAPP shows a stronger IWD reduction effect in the northeast YRB than that in the southwest region. Compared to urban agglomerations with a single provincial jurisdiction, UAPP exerts stronger IWD reduction effects on urban agglomerations with multiple jurisdictions. Moreover, there exist spatial spillover effects of UAPP on IWD. These findings provide support and references for urban reform and the development of green cities in countries around the world, especially in developing countries. • Urban agglomeration planning policies can reduce industrial wastewater discharge. • Green innovation is the main intermediary factor. • Service industry development strengthens the discharge reduction effects. • The discharge reduction effects are stronger with multiple jurisdictions. • There exist spatial spillover effects of the discharge reduction effects. [ABSTRACT FROM AUTHOR]

In this research, the potential application of Pistacia soft shell (PSS) was investigated as a novel bio-based flocculant for pulp and paper wastewater (PPWW) treatment. In line with this, after characterization of the PSS, the removal efficiencies of chemical oxygen demand (COD), turbidity and heavy metals (Cu2+ and Pb2+) from PPWW were investigated with different dosage of PSS. The results were compared with alum as a reference flocculant. In addition, the effect of pH adjustment on the flocculation-adsorption performance of PSS was studied under acidic and alkaline condition. Zeta potential, BET, FTIR and SEM as well as kinetics and isotherm analyses were conducted for mechanistic understanding. According to the results, PSS treatment could remove COD, turbidity, Cu2+ and Pb2+ up to 67%, 87%, 70% and 74%, respectively which were better than alum: 56%, 85%, 31% and 35%. It was observed that, pH adjustment significantly improved the performance of PSS treatment. Maximum removal efficiencies of 92%, 95%, 97% and 98% were achieved for COD, turbidity, Cu2+ and Pb2+, respectively, under optimal condition of using 2 g/L PSS at pH 9. The mechanism analysis revealed that the high removal efficiency of PSS is related to the dual flocculation-adsorption of bridging and sweeping mechanisms. The results of this study suggested PSS as a promising, sustainable and eco-friendly bio-based flocculant and adsorbent for industrial wastewater treatment. [Display omitted] • Pistacia soft sell can be used as a natural flocculant for wastewater treatment. • A removal of 67% and 87% were achieved for COD and turbidity, respectively. • 74% and 70% removal efficiencies were achieved for Pb2+ and Cu2+, respectively. • PH adjustment showed a synergy effect on Pistacia soft sell performance. • Optimum conditions were determined as Pistacia soft sell dosage of 2 g/L and pH 9. [ABSTRACT FROM AUTHOR]

Industrial wastewater discharge has increased manifolds over the last few decades. Efficient industrial wastewater treatment is mandatory to meet stringent discharge regulations. Biological treatment systems, such as the sequencing batch reactor (SBR) are generally employed for domestic wastewater treatment. However, low infrastructure and energy requirements, as well as low footprint, make SBR a prominent technique to treat industrial wastewater. In the present review, the feasibility of SBR to treat wastewater generated from industries, such as textile, pulp and paper, pharmaceutical, tannery, etc., has been discussed. The factors affecting the treatment efficacy of the SBR in terms of organics and nutrient removal have also been investigated. It has been observed that the SBR system is effective for industrial wastewater treatment as it is easy to operate, resistant to shock loads, and can retain high biomass concentrations. The modifications to the conventional SBR, such as sludge granulation, the addition of bio-film carriers, and the incorporation of adsorbents, salt-tolerant microbes, and coagulants have been discussed. Further, various novel combinations of SBR with the other advanced treatment technologies, such as Fenton, membrane-based process, and electrochemical process have shown enhanced removal of various conventional and recalcitrant pollutants. The current review also accentuates the sustainability aspects of SBR technology to treat industrial wastewater which may be beneficial for researchers and engineers working in this field. [Display omitted] • Presence of recalcitrant pollutants is the main concern in industrial effluents. • The potential of SBR for treating industrial wastewater is investigated. • Cyclic time, SRT, aeration rate, and OLR are the main influencing factors of SBR. • Modifications and recent advances enhanced the removal performance of SBR. • SBR is found to be more sustainable compared to other biological techniques. [ABSTRACT FROM AUTHOR]

From 2022, industrial wastewater discharge regulations in South Korea will replace chemical oxygen demand (COD Mn) with total organic carbon (TOC). A shift from COD Mn 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 COD Mn limits. Effluent COD Mn /TOC ratios (1.28 ± 0.64) found in our study were lower than the COD Mn /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 COD Mn /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 COD Mn 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, COD Mn 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. [Display omitted] • Hydrophobic and low MW neutral organic carbons were the most abundant in wastewater. • Humic substances in paper mill wastewater were often oxidized via COD Mn method. • Oil refinery wastewaters were biodegradable and COD Mn underestimated organic contents. • Effluent COD Mn /TOC ratio was lower than conversion coefficient and led to higher TOC. [ABSTRACT FROM AUTHOR]

Paint manufacturing industries produce wastewater containing high chemical oxygen demand and turbidity, besides organic matter, suspended solids, and heavy metals that cause enormous environmental damages. Safely treating this wastewater before being disposed to the natural water sources is essential for attaining the UN SDGs, particularly Goal 14: Life under water. Besides being efficient, wastewater treatment techniques must be sustainable – environmentally, economically, and ethically. While a few papers have reviewed specific treatment methods for certain pollutants, such as heavy metals, oils, and azo dyes from industrial wastewater, a comprehensive review of various treatment methods for all the pollutants of a particular industrial wastewater – paint industry – is lacking. This paper reviews the current treatment methods used for treating paint industry wastewater including the physicochemical, biological, and chemical treatment techniques. The physicochemical techniques produce large amount of sludge making it difficult for disposal while biological treatment techniques are difficult to maintain because of the uncertainties in the chemical compositions of the paint wastewater. Advanced oxidation processes are emerging as preferred methods among the chemical methods for reducing the toxicity of the various components of the paint wastewater with reduced sludge quantity. The review of various emerging techniques of paint industry wastewater treatments in this paper points to the need for paying greater attention to combining the oxidation and biological processes as they are emerging as sustainable methods for effective reduction of toxicity in paint wastewater while also reducing the sludge management challenges. [Display omitted] • Water pollution and environmental degradation due to industrial wastewater disposal is an increasing global challenge. • Reviews different treatment techniques developed to treat paint industry wastewater. • Advantages and disadvantages of various techniques. • Challenge to make the techniques efficient, sustainable, and economically viable. • Identifying the best methodology requires further investigations. [ABSTRACT FROM AUTHOR]

The amount of industrial pollution entering the environment and its impact on living organisms is an ongoing concern. At the same time, due to an increasing awareness, new methods of wastewater treatment are being explored that are not only effective but also environmentally acceptable. Meeting environmental standards for permitted concentrations is a necessity, but investigating the effects of wastewater on living organisms is also an important issue. In this paper, the influence of metal ions (Fe(III), Cr(III), Ni(II), Cu(II)) in industrial wastewater from electropolishing of stainless steel on Daphnia magna has been investigated. Daphnids have been exposed to wastewater both before and after treatment (Ca(OH) 2 precipitation, sorption with peat). Immobilisation in a 48-h acute toxicity test and EC 50 has been determined. In the case of studied industrial wastewater, the organic content (expressed as total organic carbon) of the effluent has a positive impact in terms of the survival of D. magna and increases the range of heavy metal concentrations tolerated by them. The application of a two-stage process with Ca(OH) 2 neutralisation followed by sorption with peat allows for the removal of almost 100% of metal ions from the wastewater. The reduction obtained ensured a limited impact on D. magna and a decrease in immobilisation to less than 10%. Proper execution of the wastewater treatment process ensures a reduction of its negative impact on living organisms. • Influence of industrial electropolishing wastewater on D. magna has been investigated. • Ca(OH)2 treatment and sorption with peat from a health resort in Poland were used. • Two-stage treatment removed almost 100% of Fe, Cr, Ni and Cu ions from wastewater. • The reduction in concentration resulted in a decrease in D.magna immobilisation to <10%. • Reduced toxicity has mitigated the environmental impact of wastewater. [ABSTRACT FROM AUTHOR]

The mechanism between financial agglomeration and environmental pollution is an important concern for both academia and policymaking. The main objective of this paper is to study the nonlinear impacts of financial agglomeration on environmental pollution. A theoretical framework was first constructed based on the scale effect, structure effect, and technology innovation effect of financial agglomeration and a Copeland-Taylor endogenous growth model. Using the panel data of 281 Chinese prefectural-level cities from 2003 to 2019, a panel threshold regression model was introduced to estimate the nonlinear association between financial agglomeration and environmental pollution. Industrial smoke (dust) emissions and industrial wastewater discharge were adopted to quantify current environmental pollution in China. The results show that financial agglomeration had a significant effect on improving the environment characterized by gradient thresholds; also notable is that 68.64% of the cities crossed the threshold value, entering the decelerating phase of financial agglomeration inhibiting environmental pollution. Both upgrading industrial structure and enhancing marketization could reduce environmental pollution, whereas increasing human capital, environmental regulation, and energy consumption had a deteriorating effect. The three channels for financial agglomeration to reduce environmental pollution were revealed to be financial scale, financial structure, and financial technology innovation. Our findings provide strong evidence for policymaking in sustainable development. [Display omitted] • Financial agglomeration (FA) is a crucial way to improve environment pollution (EP). • We built the theoretical framework of FA and EP based on the Copeland-Taylor model. • We tested the nonlinear impacts of FA on EP using the panel threshold model. • We revealed the transmission mechanism between FA and EP. [ABSTRACT FROM AUTHOR]

This research paper concentrates on the removal of heavy metal from wastewater which was produced from an electroplating industry. Here, the Dissolved Air Flotation (DAF) treatment process is carried out to remove toxic metals such as chromium, cadmium, nickel, lead, and copper using Sodium Dodecyl Sulfate (SDS) as a collector. The best-optimized conditions for the maximum removal of all the metal ions about 97.39% was achieved at pH 8, contact time of 60 min, surfactant dosage of 0.2 g, and the pressure of 137.89 kPa. At optimized conditions, the treated water consists of 2.71 mg/L of chromium, 1.13 mg/L of cadmium, 10.24 mg/L of nickel, 0.06 mg/L of lead, and 1.14 mg/L of copper. The used surfactant SDS was found as an environmentally friendly compound as prescribed by the Environmental Protection Agency. It is inferred that the flotation kinetics that manifests the rate of recovery and time for all the metal ions follow first-order kinetics. Further, the removal rate constant (k) increases with decreasing the initial metal ion concentration. Overall, the result of this work propounds that the DAF process plays as a promising technique to eliminate noxious pollutants from the wastewater. [Display omitted] • Removal of heavy metals from Electroplating industrial wastewater was carried out using dissolved air flotation. • Sodium Dodecyl Sulfate was used as a surfactant. • Flotation kinetics establishing the relationship between time and concentration. • Pollutants removal relies on the formation of bubbles and proper collector used. • Scale-up of the system for industrial wastewater treatment is advisable as they act as a promising technology. [ABSTRACT FROM AUTHOR]