Environmental pollution associated with the discharge of textile industries is becoming a global concern. There is an imperative need for developing efficient, environmentally friendly, and cost-effective techniques for treating the wastewater containing dyes. Bioremediation of dyes is a fascinating approach to treat the textile effluents as it offers many advantages over the conventional treatment techniques. This review critically evaluates the latest advancements in applications of bioremediation techniques for the removal of various dyes from wastewater. The applications of various microorganisms such as bacteria, algae, fungi, yeast, and enzymes for the uptake of dyes are portrayed in detail. The current advancements in the bioremediation of textile effluents, research opportunities, challenges, and future outlook are emphasized. It also highlights the progress in bioremediation of dyes using bioreactors and microbial fuel cells. This review is beneficial in understanding the current status of bioremediation in water purification and accelerating the research focusing the role of bioremediation in water purification applications in future.

Bioremediation of dyes: Current status and prospects

Efficiency of bacteria and bacterial assisted phytoremediation of heavy metals: An update.

Recent progress in integrated fixed-film activated sludge process for wastewater treatment: A review.

Production of renewable energy is one of the prime focuses of modern research and industry. Anaerobic digestion (AD), as a mean for biogas production, is hence the fastest growing segment within the waste management industry. AD is a naturally occurring series of microbial processes, encompassing the breakdown of organic materials, ensuring energy recovery with the reduction of greenhouse emissions and facilitating a sustainable development of energy supply from waste. Nevertheless, the efficacy of AD may drastically reduce due to problems such as substrate diversity, ammonia inhibition, microbial flora washout, low methane yield, feedstock purity, etc. In this review, we cater to these problems that lead towards process instability and inefficiency through the applications of various synthetic, biological and nanomaterials. Different support materials tend to enhance biogas production by facilitating the microbial growth, via electron transfer, avoiding toxic concentrations of ammonia, biofilm/anaerobic granular sludge formation, nutrient supplements, H2S removal, CO2 sequestration and bio-augmentation. This review focuses on the unique features of support materials and their role in microbial and substrate dynamics as the reinforcement strategies in AD biogas production.

Applications of materials as additives in anaerobic digestion technology

In the last 3 years alone, over 10,000 publications have appeared on the topic of dye removal, including over 300 reviews. Thus, the topic is very relevant, although there are few articles on the practical applications on an industrial scale of the results obtained in research laboratories. Therefore, in this review, we focus on advanced oxidation methods integrated with biological methods, widely recognized as highly efficient treatments for recalcitrant wastewater, that have the best chance of industrial application. It is extremely important to know all the phenomena and mechanisms that occur during the process of removing dyestuffs and the products of their degradation from wastewater to prevent their penetration into drinking water sources. Therefore, particular attention is paid to understanding the mechanisms of both chemical and biological degradation of dyes, and the kinetics of these processes, which are important from a design point of view, as well as the performance and implementation of these operations on a larger scale.

https://www.mdpi.com/1420-3049/26/4/870/pdf

Recent Achievements in Dyes Removal Focused on Advanced Oxidation Processes Integrated with Biological Methods

Anaerobic treatment of wastewater is a viable alternative to aerobic treatment with the advantage of low net energy requirement and less sludge production. Successful establishment of a two-stage anaerobic treatment process resulted in better performance and improved tolerance to perturbations in operating conditions such as high organic loading rate and higher methane production. In this study we have reported process development, microbial enrichment and validation of performance of a two-stage anaerobic packed-bed reactor comprising of an acidogenic reactor followed by a methanogenic reactor, each containing porous polyvinyl alcohol (PVA)-gel beads as biofilm carrier, harboring different consortia of microorganisms for treating wastewater at mesophilic temperature. The stage-separated reactor system demonstrated chemical oxygen demand (COD) removal efficiency up to 89% with overall methane productivity of 0.08 L methane/(L reactor.d). During steady-state operation, the acidogenic reactor produced an effluent with concentration ratio of propionic acid to acetic acid as low as 0.2, which indicated the stability of the reactor system against environmental shock-related failure. During an event of deliberately imposed low-temperature shock period of 60 days, the COD removal efficiency decreased from 89% at steady-state to as low as 33% with concomitant decline in methanogenic productivity. The predominance in microbial community changed from steady-state characteristics of Gram positive to Gram negative during the temperature shock. After the shock was withdrawn, the reactor system regained its original performance within 28 days; the Gram positive bacteria also switched back to the predominance.

Anaerobic treatment of wastewater using a two-stage packed-bed reactor containing polyvinyl alcohol gel beads as biofilm carrier

Greenhouse gases emission control in WWTS via potential operational strategies: A critical review.

In the present study, an integrated fixed-film activated sludge (IFAS) bioreactor was subjected to dissimilar intermittent aeration (IA) cyclic operations, and its effects were investigated on extracellular polymeric substances (EPS) production, sludge characteristics, and specific power consumption. A total of three IA cycles (IA1, 150 min aeration on and 30 min off; IA2, 120 min aeration on and 60 min off; IA3, 90 min aeration on and 60 min off) were evaluated in the present IFAS reactor. Specific EPS production (mg/g of suspended solids) was found to be following the increasing trend with respect to the non-aeration to aeration time ratio, whereas, the sludge production followed the reverse trend. The amount of bound EPS was observed to be much higher (6–10 times) than soluble microbial product (SMP) in each intermittent aeration phase. During all the investigated IA cycles, the pilot was observed to be significantly affected in terms of biomass characteristics, which was also confirmed by increasing trends of sludge volume index (SVI) and filamentous index (FI) values. In-situ monitoring and measurement of reactor operation parameters such as pH, oxidation reduction potential (ORP), and dissolved oxygen (DO) was also done in all IA cycles. A maximum of 27.05% reduction in electrical energy was observed in highest non-aeration period cycle.

Effect of intermittent aeration cycles on EPS production and sludge characteristics in a field scale IFAS reactor

The present study is based on the investigation of process kinetics of a two-phase anaerobic packed-bed biofilm reactor (AnPBR) with PVA gel beads as biocarrier treating synthetic wastewater-containing molasses. During the steady-state conditions, the reactor system was attributed to 89% of COD removal efficiency. For the comparison of substrate loading removal rate with the prediction of Grau’s second-order model and Stover–Kincannon substrate removal model, AnPBR reactor was run under different hydraulic retention times (HRT) and organic loads. The experimental data obtained from the steady-state conditions showed that Stover–Kincannon model and Grau’s second-order model were the most appropriate models for the proper description of the reactor. Both the Grau’s second-order model and Stover–Kincannon model gave very high correlation coefficients of 98.36% and 98.37%, respectively, for the overall reactor system. Thus, both of these models can be used efficiently for the prediction of behavior and to design the AnPBR reactors.

Performance Evaluation and Substrate Removal Kinetics of an Anaerobic Packed-Bed Biofilm Reactor

This study aimed at evaluating the Moringa oleifera (M. oleifera) seed powder for treatment of segregated (dye rich, DR; and starch rich, SR) and mixed wastewater (AM) streams of a textile industry. Two different sizes (

Siddhartha Pandey

Papers

Anaerobic treatment of wastewater using a two-stage packed-bed reactor containing polyvinyl alcohol gel beads as biofilm carrier

Greenhouse gases emission control in WWTS via potential operational strategies: A critical review.

Effect of intermittent aeration cycles on EPS production and sludge characteristics in a field scale IFAS reactor

Performance Evaluation and Substrate Removal Kinetics of an Anaerobic Packed-Bed Biofilm Reactor

Parametric and kinetic investigations on segregated and mixed textile effluent streams using Moringa oleifera seed powders of different sizes