**5. Conclusions**

The wastes derived from rapeseed cultivation and production of oil and biodiesel are of interest in the context of circular economy. According to the reviewed literature, there exists valorization options for each rapeseed waste (stems, stalks, leaves, hulls, meal/cake). Major applications of these wastes include the use as cover crop for agricultural residues (stems and leaves) and animal feed for rapeseed meal. Rapeseed wastes contain valuable constituents and nutrients, making them of relevant nutritional and economic importance. Protein, pectin and polyphenols can be extracted from stems, leaves and meal. Besides the use of animal feed, the RS meal has great potential for obtaining high-value products for human consumption.

A less popular valorization option is the use of rapeseed waste as adsorbents for wastewater treatment. The literature survey presented in this chapter has revealed the existence of sufficient RS-derived adsorbents that have a stable structure and proved significant organic and inorganic removal efficiencies. However, many studies were done in batch operation, at laboratory scale. Very few researchers reported the use of fixed-bed column and/or real wastewater containing the target pollutants. Practical application of RS waste can sometimes be difficult. For example, RS meal forms a slurry when in sufficient contact time with water, which leads to difficult separation of phases or column clogging. This problem ca be tackled by mixing the biosorbent with some inert material (e.g., ceramic rings) or immobilization in a matrix (e.g. alginate). The use of stalks or husks is another solution, due to their lower protein content. In any case, chemical or thermal modification of natural RS waste can be also an alternative, especially when a higher sorption capacity is desired. Regeneration of the adsorbent and its subsequent use in a new sorption cycle is also possible. The exhausted adsorbent can be valorized as substrate for microbial growth, biochar or biofuel production.

#### **Acknowledgements**

This study was supported by a grant of the Romanian Ministry of Research and Innovation, CCCDI-UEFISCDI, project number 26PCCDI/01.03.2018, "*Integrated and sustainable processes for environmental clean-up, wastewater reuse and waste valorisation*" (SUSTENVPRO), within PNCDI III.

**157**

**Author details**

and Carmen Paduraru

Irina Morosanu, Carmen Teodosiu\*, Lavinia Tofan, Daniela Fighir

"Gheorghe Asachi" Technical University of Iasi, Iasi, Romania

\*Address all correspondence to: cteo@ch.tuiasi.ro

provided the original work is properly cited.

Department of Environmental Engineering and Management, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Valorization of Rapeseed Waste Biomass in Sorption Processes for Wastewater Treatment*

*DOI: http://dx.doi.org/10.5772/intechopen.94942*

*Valorization of Rapeseed Waste Biomass in Sorption Processes for Wastewater Treatment DOI: http://dx.doi.org/10.5772/intechopen.94942*
