Copper on chitosan: a recyclable heterogeneous catalyst for azide–alkyne cycloaddition reactions in water

Conventional biological wastewater treatment processes are energy-intensive endeavors that yield little or no recovered resources and often require significant external chemical inputs. However, with embedded energy in both organic carbon and nutrients (N, P), wastewater has the potential for substantial energy recovery from a low-value (or no-value) feedstock. A paradigm shift is thus now underway that is transforming our understanding of necessary energy inputs, and potential energy or resource outputs, from wastewater treatment, and energy neutral or even energy positive treatment is increasingly emphasized in practice. As two energy sources in domestic wastewater, we argue that the most suitable way to maximize energy recovery from wastewater treatment is to separate carbon and nutrient (particularly N) removal processes. Innovative anaerobic treatment technologies and bioelectrochemical processes are now being developed as high efficiency methods for energy recovery from waste COD. Recently, energy savings or even generation from N removal has become a hotspot of research and development activity, and nitritation–anammox, the newly developed CANDO process, and microalgae cultivation are considered promising techniques. In this paper, we critically review these five emerging low energy or energy positive bioprocesses for sustainable wastewater treatment, with a particular focus on energy optimization in management of nitrogenous oxygen demand. Taken together, these technologies are now charting a path towards to a new paradigm of resource and energy recovery from wastewater.

Towards energy neutral wastewater treatment: methodology and state of the art

Today, heavy metal pollution is of prime concern from the environmental point of view. Among the heavy metals, manganese is a very common contaminant of wastewater and ground water, as it is a significant raw material for industry. This paper reviews various technologies that have been used to treat manganese containing wastewater and ground water, such as chemical precipitation, coagulation, flotation, ion-exchange, oxidation/filtration, electrochemical treatment, adsorption, and membrane filtration. Recovery of manganese is also very imperative due to its economical and environmental aspects.

A review of technologies for manganese removal from wastewaters

Enzymatic conversions of chitin and its soluble, partially deacetylated derivative chitosan are of great interest. Firstly, chitin metabolism is an important process in fungi, insects and crustaceans. Secondly, such enzymatic conversions may be used to transform an abundant biomass to useful products such as bioactive chito-oligosaccharides. Enzymes acting on chitin and chitosan are abundant in nature. Here we review current knowledge on the structure and function of enzymes involved in the conversion of these polymeric substrates: chitinases (glycoside hydrolase families 18 & 19), chitosanases (glycoside hydrolase families 8, 46, 75 & 80) and chitin deacetylases (carbohydrate esterase family 4).

Structure and function of enzymes acting on chitin and chitosan

Wei-Min Ni

Papers

The effect of Cu(II) stress on the activity, performance and recovery on the Anaerobic Ammonium-Oxidizing (Anammox) process

Towards simultaneously removing nitrogen and sulfur by a novel process: Anammox and autotrophic desulfurization–denitrification (AADD)

Removal of Mn(II) and Zn(II) ions from flue gas desulfurization wastewater with water-soluble chitosan

The influences of temperature, salt and calcium concentration on the performance of anaerobic ammonium oxidation (anammox) process

Evaluation of the efficacy and regulation measures of the anammox process under salty conditions