Global demand for freshwater is rapidly escalating. It is highly essential to keep pace with the necessities of the increasing population. The effluents of wastewater are gradually identified as a reservoir of resources for energy generation and economic boom. Henceforth, most wastewater and sludge have great potential for reuse and recycling. The re-utilization and valorization of wastewater and sludge contribute to accomplishing sustainable development goals, combating water scarcity, and alleviating adverse environmental impacts of wastewater on the environmental components. The present article highlights the most novel approaches for wastewater treatment for the waste valorization of different industrial origins and the generation of value-added products and recovery of biopolymers, vitamins, enzymes, dyes, pigments, and phenolic compounds. We highlighted the life cycle assessment and techno-economic analysis. In addition, we have addressed a critical overview of the barriers to the large-scale application of resource recovery strategies and economic, environmental, and social concerns associated with using waste-derived products.

The assessment of tree biomass and its carbon (C) stock at the local and regional level is considered a crucial criterion for understanding the impact of changing environments on the global carbon cycle. In this context, we selected three sites in the western Himalayas, covering parts of Himachal Pradesh and north-eastern Haryana. Each study site experiences distinct climatic conditions, vegetation types, and elevations. We seek to elucidate the determinants of tree biomass and carbon stock across different forest types in the Western Himalayas. We found that temperate forests contributed the most biomass and carbon stock, with Cedrus deodara attaining the highest values of 782.6 ± 107.9 Mg/ha and 360 ± 49.7 Mg C/ha. In contrast, Quercus leucotrichophora mixed temperate had the lowest 286.6 ± 57.2 and 128.9 ± 25.7 Mg/C ha, respectively. Only a few species, such as Abies pindrow, Cedrus deodara, Quercus floribunda, and Quercus semecarpifolia, accounted for significant biomass and carbon stock. The lower elevation subtropical forests had the highest species richness (8–12 species) and stem density (558.3 ± 62.9 to 866.6 ± 57.7 trees/ha). Furthermore, tree diameter, total basal cover, and height emerged as the strongest predictors of biomass and C stock. The remaining variables showed no significant associations, including species diversity, climatic attributes and elevation. Thus, our study extended the assertion that vegetation composition and structural attributes, apart from climatic and topographic factors, are equally important in determining biomass and C stock in forest ecosystems. Our study indicated that the temperate forests in the western Himalayas possess significant carbon storage and climate change mitigation potential.

Assessing the effects of land use and land cover (LULC) on ecosystem service values (ESVs) is critical for public understanding and policymaking. This study evaluated the impacts of LULC dynamics on ESVs in Chandigarh city of India. The assessment of LULC changes was performed by analyzing the satellite imagery of the study area for the years 1990 and 2020 with different band combinations in ArcGIS (10.8 version software). In addition, we analyzed ecosystem services changes which were based on the LULC classes of the study area. Five LULC classes were identified in the present study area (Water bodies, forest and vegetation, built-up, agriculture and shrubland and open spaces). The results demonstrated (from 1990 to 2020) that the forest cover and agricultural areas decreased by 4.19% and 37.01%, respectively, whereas the built-up area substantially increased by 104.61%. Overall, ESV decreased by 2.54% from 1990 to 2020 due to rapid urbanization. The combination of LULC and ecosystem services valuation can increase our understanding of different issues of an urban ecosystem. Hence, we recommend the integration of LULC and ecosystem services valuation as a tool that could provide information to policymakers, urban planners and land managers for sustainable use in future.

Phosphorus (P) is a key limiting nutrient in subtropical forests and mixed forests with broadleaved species have been expected to stimulate P cycling, compared to pure conifer plantations. However, the mixture effect of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) and broadleaved species on rhizosphere soil and coniferous tree P dynamics is unclear. In our study, eight plots of a single species of a Chinese fir plantation (pure plantation, PP) and eight mixed plantations (mixed plantation, MP) with broadleaved tree species (Michelia macclurei Dandy in Hunan Province or Schima superba Gardn. et Champ. in Fujian Province) were selected in subtropical China. Six P fractions in the rhizosphere and bulk soils were analyzed by a modified Hedley P fractionation method. Phosphorus fractions and nitrogen (N) concentrations in different root orders, different age fresh needles and twigs, and needle and twig litter of Chinese fir were measured. Our results showed that available P, slowly released P, occluded P, and the total extractable P in rhizosphere soil were significantly higher in MP than PP (p < 0.05). In contrast, P and N concentrations in the transportive roots and two-year old needles were generally higher in PP than MP. Meanwhile, the slowly released P, occluded P, total extractable P, and residual P in rhizosphere soil were negatively correlated with P concentrations in young (absorptive and transportive roots, one- and two-year old needles) but not old tissues (storative roots, three-year old needles and litters). In conclusion, mixture may increase soil P availability through the rhizosphere effect, but can decrease P and N concentration of Chinese fir tissues by competition between Chinese fir and broadleaved species. Clearly, the mixture effect may differ in soil and plant nutrients, and this issue needs be taken into consideration when converting a pure conifer plantation into a mixed-species forest.