Use of constructed wetlands to prevent overloading of wastewater treatment plants.

The fluctuation in the number of people in tourist areas affects the wastewater quality and quantity. Constructed wetlands (CWs) aim to simulate physical, chemical, and biological processes occurring in natural environments for wastewater treatment and are considered a sustainable system. The current study aimed at evaluating the effectiveness of in-vessel CWs for supporting the wastewaters treatment plants in periods of overloading. Such approach can be quickly implementable, economic, and the CWs can be fast regenerated in the framework of sustainable good practices. Three pilot scale CWs were prepared in as many containers layering 10 cm of gravel, 60 cm of sand and 10 cm of gravel, and placing pieces of giant reed rhizomes in the upper layers. The bottom of each CW had a tap, and CWs were irrigated with a real municipal sewage three times a week. Before each new irrigation, the tap was opened, and the effluent collected for determining gross parameters, elemental composition, and contaminants of emerging concern (CECs). CWs significantly reduced almost all gross parameters considered and half the CECs, except for a couple of metabolites of corresponding parental compounds. With regards to the potentially toxic elements, all reduced their concentration from the influents to the effluents. The results of this study were promising and highlighted good efficiency of constructed wetlands as pre-treatment of real municipal sewage to reduce the overloading of the wastewater treatment plant.

Effects of different pioneer and exotic species on the changes of degraded soils.

Soil degradation resulting from deforestation contributes to a dramatic decline in soil quality whose restoration must go through reforestation with pioneer species. We investigated the effects of cypress and black locust, pioneer but exotic species, on soil chemical properties and microbial and enzymatic activities of two marginal soils. The sampling sites were Lama Giulia and Locone lake in the Murge plateau of the Apulia Region, Italy. The soils at Lama Giulia presented a silty loam texture, while at Locone Lake site were sandy, and most likely due to the different texture, the former exhibited higher organic C, N, P and micronutrients contents than Locone Lake under black locust reforestation, despite the latter was reforested earlier. In addition, the higher microbial entropy and turnover of Locone Lake's soils suggested a less conservative soil state than Lama Giulia's soils. The effects of black locust reforestation at Lama Giulia on almost all soil parameters considered did not differ from those of the corresponding pasture, confirming the more conservative soil state in that site and suggesting that the time of reforestation was not enough to get differences between the reforested and not reforested soil. The soils reforested with cypress showed the significantly highest SOC, N, dissolved organic C and microbial biomass C content. In addition, it presented also the numerically largest dehydrogenase, phosphatase and ß-glucosidase activities, soluble carbohydrates, and phenolic compounds content. These results may be ascribed to the longer litter deposition occurred in cypress soils.

Reuse of Wasted Bread as Soil Amendment: Bioprocessing, Effects on Alkaline Soil and Escarole (Cichorium endivia) Production.

In an era characterized by land degradation, climate change, and a growing population, ensuring high-yield productions with limited resources is of utmost importance. In this context, the use of novel soil amendments and the exploitation of plant growth-promoting microorganisms potential are considered promising tools for developing a more sustainable primary production. This study aimed at investigating the potential of bread, which represents a large portion of the global food waste, to be used as an organic soil amendment. A bioprocessed wasted bread, obtained by an enzymatic treatment coupled with fermentation, together with unprocessed wasted bread were used as amendments in a pot trial. An integrated analytical plan aimed at assessing (i) the modification of the physicochemical properties of a typical Mediterranean alkaline agricultural soil, and (ii) the plant growth-promoting effect on escarole (Cichorium endivia var. Cuartana), used as indicator crop, was carried out. Compared to the unamended soils, the use of biomasses raised the soil organic carbon content (up to 37%) and total nitrogen content (up to 40%). Moreover, the lower pH and the higher organic acid content, especially in bioprocessed wasted bread, determined a major availability of Mn, Fe, and Cu in amended soils. The escaroles from pots amended with raw and bioprocessed bread had a number of leaves, 1.7- and 1.4-fold higher than plants cultivated on unamended pots, respectively, showing no apparent phytotoxicity and thus confirming the possible re-utilization of such residual biomasses as agriculture amendments.