Disposal of wastewater often results in high nutrient loading into aquatic environments, which may lead to favorable conditions for undesirable phytoplankton blooms. Microalgae are efficient in removing nitrogen, phosphorus, and toxic metals from wastewater under controlled environments. If key nutrients in the wastewater stream can be used to grow microalgae for biofuel production, the nutrients can be removed, thus significantly reducing the risk of harmful phytoplankton overgrowth. This review paper summarizes the major nutrient components of different wastewater streams, the mechanisms of algal nutrient uptake, nutrient removal performance of various species of microalgae when cultured in wastewater, and current microalgae production systems. Finally, new algae cultivation technologies applicable for biofuel production and nutrient recovery in polluted water bodies are discussed.

Nutrient recovery from wastewater streams by microalgae: Status and prospects

Production and harvesting of microalgae for wastewater treatment, biofuels, and bioproducts

Increasing environmental awareness coupled with more stringent regulation standards has triggered various industries to challenge themselves in seeking appropriate wastewater treatment technologies. Coagulation–flocculation process is regarded as one of the most important and widely used treatment processes of industrial wastewaters due to its simplicity and effectiveness. This paper provides a critical review on recent studies of coagulation–flocculation treatment processes of various industrial wastewaters. The limitations and challenges for the coagulation–flocculation process such as the toxicity and health hazard posed by inorganic coagulants, production of large amount of toxic sludge, ineffectiveness in removing heavy metals and emerging contaminants, increase in effluent color, inefficient pollutant removal using natural coagulants, and complexity of scaling up procedure are presented. In addition, an overview on the influence of process parameters on treatment efficiency is included in this revie...

Recent Advancement of Coagulation–Flocculation and Its Application in Wastewater Treatment

Application of membrane bioreactor technology in treating high strength industrial wastewater: a performance review.

Membrane bioreactor: Applications and limitations in treating high strength industrial wastewater

Biological Treatment of Tannery Wastewater - A Review

In this study, aerobic digestion of tannery industry wastewater was carried out using mixed culture obtained from common effluent treatment plant treating tannery wastewater. The effect of pH, temperature, inoculum concentration, agitation speed and initial substrate concentration on the reduction of organic matters were found. The optimum conditions for COD reduction was found to be pH 7 (60%), temperature 30C (61%), inoculum concentration 2% (61%), agitation speed 150rpm (65%) and initial substrate concentration 1560 mg COD/L (74%). Kinetics studies were carried by using Monod model, First order, Diffusional model and Singh model. From the results it was found that the Monod model suits well for the degradation of tannery wastewater using mixed microbial consortium. Keywords—Tannery, Wastewater, Biological treatment, Aerobic, Mixed culture, Kinetics.

Kinetics Studies on Biological Treatment of Tannery Wastewater Using Mixed Culture

Among the industries generating hyper saline effluents, tanneries are prominent in India. Hyper saline wastewater is difficult to treat by conventional biological treatment methods. Salt-tolerant microbes can adapt to these conditions and degrade the organics in hyper saline wastewater. In this study, the performance of a bench scale aerobic sequencing batch reactor (SBR) was investigated to treat the tannery wastewater by the salt-tolerant bacterial strains namely Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and Styphylococcus aureus. The study was carried out under different operating conditions by changing the hydraulic retention time, organic loading rate and initial substrate concentration. From the results it was found that a maximum COD reduction of 90.4% and colour removal of 78.6% was attained. From this study it was found that the salt-tolerant microorganisms could improve the reduction efficiency of COD and colour of the tannery wastewater.

/pdf/aerobic-digestion-of-tannery-wastewater-in-a-sequential-bjxomli95b.pdf

Aerobic digestion of tannery wastewater in a sequential batch reactor by salt-tolerant bacterial strains

Any wastewater treatment system must have a complete model to provide a tool for predicting the system’s performance and to serve as the foundation for regulating the process’s operation. This would save running expenses while also examining the stability of the environmental bal - ance. This process is challenging and reaches a high degree of non-linearity due to the presence of bio- organic elements that are difficult to define using mechanistic techniques. Predicting plant operating characteristics using standard experimental approaches is time consuming and difficult, making it difficult to regulate such operations effectively. Using a radial function neural network, a research was successfully simulated to analyse the performance of sequential batch reactors on a lab scale. The information gathered is used in a neural network to treat tannery waste water in a sequential batch reactor. Degradation of organic compounds is represented in this method by a trained neural network. The degradation investigations used different dilutions such as 25%, 50%, 75%, and 100% for an initial substrate concentration of 6,240 mg COD/L and at different hydraulic retention times (5, 4, 3, and 2 d). The neural network-based model is thought to have been effective in establishing the system’s properties with high precision. This research uses an artificial neural network (ANN) modelling technique to obtain the knowledge base of a genuine SBR, which is then used as a process model.

/pdf/artificial-neural-network-based-modeling-for-the-degradation-18bt3jlv.pdf

Artificial neural network based modeling for the degradation of tannery wastewater in sequential batch reactor

The sequential batch reactor (SBR) technology is being applied in a large number of treatment processes owing to the operational flexibility it offers. SBR’s capability to carry flow equalization, biological processes, and secondary clarification within a single reactor by differing the time period of different phases and duration of aeration proves it a flexible process for wastewater treatment. In this study SBR was employed to treat the tannery industry wastewater for removing colour. The phase of the SBR was observed over a period of 50 d. Statistical based experiments were performed for optimizing the parameters viz., pH, temperature, inoculum’s concentrations, agitation speed and initial concentration of the substrates on the treatment of wastewater from tanneries by the mixed culture derived from the tannery common effluent treatment plant sludge, in a batch reactor under aerobic condition. At the optimized conditions, experiments were performed by salt tolerant microorganisms such as Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and Staphylococcus aureus at various organic loading rate (OLR) by varying tannery wastewater concentration and hydraulic retention time (HRT) for colour removal. A maximum decolouriza- tion 94% was obtained in SBR with the OLR 0.312 kg COD/m 3 d, HRT 5 d for the substrate’s initial concentration of 1,560 mg COD/L.

G. Durai

Papers

Biological Treatment of Tannery Wastewater - A Review

Kinetics Studies on Biological Treatment of Tannery Wastewater Using Mixed Culture

Aerobic digestion of tannery wastewater in a sequential batch reactor by salt-tolerant bacterial strains

Artificial neural network based modeling for the degradation of tannery wastewater in sequential batch reactor

Colour removal of tannery wastewater using salt tolerant microorganisms in a sequential batch reactor