Cultivating microalgae in wastewater for biomass production, pollutant removal, and atmospheric carbon mitigation; a review.

Biowaste-to-bioplastic (polyhydroxyalkanoates): Conversion technologies, strategies, challenges, and perspective

Hydrothermal carbonization (HTC) of wet solid wastes has been pointed out as an eco-friendly, flexible and highly efficient technology for the sustainable valorization of multiple sourced wastes. In this review paper, most recent studies on hydrochars (solid residue of the HTC process) production, characterization and application for wastewaters treatment was summarized and deeply discussed. The role of initial feedstock source nature and characteristics as well as the HTC experimental conditions including the temperature, the residence time and the pH media was assessed. Physical and chemical activation methods including the use of oxygen, steam, microwave, acids, alkaline, organics and salty solutions for the improvement of the physicochemical properties of the produced hydrochars are compared. The efficiency of these raw/modified hydrochars along with the involved mechanisms during organic (dyes) and mineral pollutants (heavy metals and nutrients) removal from aqueous solutions is also reviewed. Finally, this paper addresses the main challenges and also demonstrates insights on new directions for hydrochars research and development in the future.

/pdf/hydrochars-production-characterization-and-application-for-4yjipo2af8.pdf

Hydrochars production, characterization and application for wastewater treatment: A review

The quest for a chemical surfactant substitute has been fuelled by increased environmental awareness. The benefits that biosurfactants present like biodegradability, and biocompatibility over their chemical and synthetic counterparts has contributed immensely to their popularity and use in various industries such as petrochemicals, mining, metallurgy, agrochemicals, fertilizers, beverages, cosmetics, etc. With the growing demand for biosurfactants, researchers are looking for low-cost waste materials to use them as substrates, which will lower the manufacturing costs while providing waste management services as an add-on benefit. The use of low-cost substrates will significantly reduce the cost of producing biosurfactants. This paper discusses the use of various feedstocks in the production of biosurfactants, which not only reduces the cost of waste treatment but also provides an opportunity to profit from the sale of the biosurfactant. Furthermore, it includes state-of-the-art information about employing municipal solid waste as a sustainable feedstock for biosurfactant production, which has not been simultaneously covered in many published literatures on biosurfactant production from different feedstocks. It also addresses the myriad of other issues associated with the processing of biosurfactants, as well as the methods used to address these issues and perspectives, which will move society towards cleaner production.

/pdf/a-critical-review-on-various-feedstocks-as-sustainable-2uzuelf7u5.pdf

A critical review on various feedstocks as sustainable substrates for biosurfactants production: a way towards cleaner production.

A review on treatment of petroleum refinery and petrochemical plant wastewater: A special emphasis on constructed wetlands

Background Demand of dairy products is increasing in different countries, which results in the development of the dairy industry and increases in the generation of wastes. The main wastes generated are whey, dairy sludges and wastewater (processing, cleaning and sanitary). They have high nutrient concentration, biological oxygen demand (BOD), chemical oxygen demand (COD) and organic and inorganic contents. Furthermore, they can contain different sterilizing agents and a wide range of acid and alkaline detergents. Pollution due to dairy industry affects the air, soil and water quality. Scope and approach This review aims to describe the different methods used by the dairy industry to treat wastes, highlighting their effects on quality and efficiency removal of the pollution. Especially, it focusses on biotechnological alternatives to utilize the dairy wastes. Key findings and conclusions Physico-chemical, biological, and biotechnological methods can be used for treatment of dairy wastewaters. The physico-chemical treatment is used for reduction of milk fat and protein colloids, but it has the disadvantages of the high cost of the reagents and limited removal of COD. Biological treatments are used to remove organic material from dairy waste, however, the formation of sludge during aerobic biodegradation is a disadvantage. Aerobic and anaerobic process treatments can be used together in order to reach the effluents discharge limits for dairy wastewater. Biotechnological processes are the most recent alternatives, and can result in important products to the industries, such as whey-derived products, bioplastics, biofuels, bioenergy, organic acids, bioactive peptides, enzymes, among others.

Treatment and utilization of dairy industrial waste: A review

Whey is a by-product formed during the milk coagulation process in the manufacture of cheese, casein, or similar dairy products. Its composition, rich in water, lactose, protein, and minerals, shows nutritional quality and high potential for use as an input for both the food and bioprocessing industries, in the preparation of dairy products, ethanol and biogas manufacture, and other products. However, the generation of excessive volume of whey in the dairy manufacturing processes and its rapid perishing can set challenges in the use of this by-product, requiring investments in refrigeration, processing, and transportation. Such difficulties lead to less useful uses of this input, such as supplementation of animal feed and soil irrigation, and even its disposal as waste, causing economic and environmental disadvantages. Thus the valorization of whey, as well as investment in research and technology, are fundamental advances for the expansion of activities of the global dairy industry. This chapter presents an overview of the characteristics of whey, its main destinations, and processing to obtain it, aiming to valorize this by-product of the cheese industry.

Whey: generation, recovery, and use of a relevant by-product

Corporate environmental management has emerged as a global trend in the face of sustainable development and more stringent environmental regulations. Industries from different sectors have adapted this new scenario, including the dairy sector. Dairy production is an industrial activity with high consumption of natural resources, with great potential to generate impacts on the environment. In this context, the dairy sector has adopted environmental management instruments aimed at improving the environmental performance associated with the production process. Among the instruments, Cleaner Production (CP) strives for production process efficiency, reducing the use of natural resources and minimizing the environmental impacts associated with the industrial processes, leading to environmental, economic, and social gains. Thus this study aims to present s the CP instrument and the methodology necessary for its implementation. Based on the dairy industry production process the main environmental aspects and environmental impacts are highlighted. To control the consumption of energy and water, other inputs, waste generation, emissions, and effluents discharges, the dairy industries have adopted opportunities for using CP aimed at minimizing the environmental impacts. Such measures include the reduction of water and energy consumption, pollutants in wastewater and effluents, and gaseous pollutant emissions, as well as the use of cleaner fuels and the use of whey in the production of other dairy products (recycling). Finally, some opportunities are suggested for CP in the dairy industries.

Simone Maria Ribas Vendramel

Papers

Treatment and utilization of dairy industrial waste: A review

Whey: generation, recovery, and use of a relevant by-product

Environmental aspects in dairy processing