The purpose of this research is to quantify the potential of waste recycling in the form of participatory scenarios for separation from the source and to study the factors of minimization (reduction) of waste production in a district of Tehran. Amount of waste minimization was determined with considering a couple of citizens' participation scenarios. Source separation of valuable wastes including paper and cardboard, plastic, plastic bags, aluminum cans, bread, PET, waste metal and glass were considered in this procedure. Among 250 tons of generated dry waste within the district, 150 tons (60%) goes directly to landfill instead of getting recycled. Considering the successful experiences regarding the use of reverse vending machine (RVM) in recycling of beverage containers, this research takes RVM as a reasonable method to promote the recycling activities by citizens. In the 10% scenario, the participation for the separation of the total amount of daily materials is about 4,300 USD per day and in the 25% scenario, 10,800 USD of added value have been calculated. Also, for the participation of 10 and 25 percent during a month, 15 and 30 waste disposal services to the disposal and processing complex could get less.

Plastic usage increases year by year, and the growing trend is projected to continue. However as of 2017, only 9% of the 9 billion tons of plastic ever produced had been recycled leaving large amounts of plastics to contaminate the environment, resulting in important negative health and economic impacts. Curbing this trend is a major challenge that requires urgent and multifaceted action. Based on scientific and gray literature mainly published during the last 10 years, this review summarizes key solutions currently in use globally that have the potential to address at scale the plastic and microplastic contaminations from source to sea. They include technologies to control plastics in solid wastes (i.e. mechanical and chemical plastic recycling or incineration), in-stream (i.e. booms and clean-up boats, trash racks, and sea bins), and microplastics (i.e. stormwater, municipal wastewater and drinking water treatment), as well as general policy measures (i.e. measures to support the informal sector, bans, enforcement of levies, voluntary measures, extended producer responsibility, measures to enhance recycling and guidelines, standards and protocols to guide activities and interventions) to reduce use, reuse, and recycle plastics and microplastics in support of the technological options. The review discusses the effectiveness, capital expenditure, and operation and maintenance costs of the different technologies, the cost of implementation of policy measures, and the suitability of each solution under various conditions. This guidance is expected to help policymakers and practitioners address, in a sustainable and cost-efficient way, the plastic and microplastic management problem using technologies and policy instruments suitable in their local context.

Textile wastewater contains a huge amount of azo dyes and heavy metals and catastrophically deteriorates the agricultural field by affecting its phyisco-chemical/biological and nutritional properties when directly drained to agricultural lands without any treatment. Recently, biogenic copper nanoparticles (CuNPs) have gained considerable attention for photocatalytic degradation of wastewater pollutants owing to their unique physico-chemical and biological properties, low cost and environmental sustainability. The current study reports the synthesis of CuNPs by a native copper-resistant bacterial strain Escherichia sp. SINT7 and evaluation of the photocatalytic activity of the biogenic CuNPs for azo dye degradation and treatment of textile effluents. Scanning electron microscopy and transmission electron microscopy revealed the spherical shape of biogenic CuNPs with particle size ranging from 22.33 to 39 nm. Moreover, X-ray diffraction data revealed that the CuNPs have spherical crystalline shapes with an average particle size of 28.55 nm. FTIR spectra showed the presence of coating proteins involved in the stabilization of nanomaterial. Azo dye degradation assays indicated that CuNPs decolorized congo red (97.07%), malachite green (90.55%), direct blue-1 (88.42%) and reactive black-5 (83.61%) at a dye concentration of 25 mg L⁻¹ after 5 h of sunlight exposure. However, at 100 mg L⁻¹ dye concentration, the degradation percentage was found to be 83.90%, 31.08%, 62.32% and 76.84% for congo red, malachite green, direct blue-1 and reactive black-5, respectively. Treatment of textile effluents with CuNPs resulted in a significant reduction in pH, electrical conductivity, turbidity, total suspended solids, total dissolved solids, hardness, chlorides and sulfates as compared to the non-treated samples. Thus, the promising dye detoxification and textile effluent recycling efficiency of biogenic CuNPs may lead to the development of eco-friendly and cost-efficient process for large-scale wastewater treatment.

High-efficiency nanophotocatalysts with large specific surface areas have a broad range of application prospects in the catalytic oxidation treatment of organic pollutants in wastewater. A chemical method was used to synthesize a TiO₂ nanophotocatalyst with a mesoporous structure upon which a rare earth metal (Nd) was deposited, namely Nd-TiO₂-SBA-15 (NTS). The prepared NTS was characterized using X-ray diffractometry, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectrometry. The photocatalytic mechanism was explored using scavenger experiments with photoinduced carriers combined with total organic carbon and UV–Vis measurements. At the same time, the kinetic properties of the NTS photocatalytic degradation of methyl orange (MO) were evaluated. The results showed that the deposition of TiO₂ nanoparticles on the surface of the SBA-15 molecular sieve did not change the mesoporous structure, and Nd was uniformly distributed on the surface of the nanophotocatalyst. The photogenerated holes of the NTS played an important role in the photocatalysis process. In addition, the synthesized NTS had good adaptability in the range of pH 2–10. At pH 4, the reaction rate constant (k) of the MO photocatalytic degradation by NTS was 0.011825 mg·(L·min)⁻¹, and the adsorption equilibrium constant (K) was 0.051359 L mg⁻¹. In addition, the photocatalytic degradation rate of MO by NTS remained above 70%, even when the NTS was recycled four times. The NTS showed a good performance after recycling. This work provides a good foundation for the large-scale application of NTS.

One of the most important reasons for the controversy over the development of nuclear energy is the proper disposal of spent fuel. Separation of actinide and lanthanide ions is an important part of safe long-term storage of radioactive waste. Herein, a three-dimensional (3D) graphene-based macrostructure (GOCS) was utilized to remove actinide thorium and lanthanide europium ions from aqueous solutions. The adsorption of Eu(III) and Th(IV) on the GOCS was evaluated as a function of adsorption time, solution pH, initial ion concentrations, and ionic strength. The experimentally determined maximum adsorption capacities of this GOCS for Eu(III) (pH 6.0) and Th(IV) (pH 3.0) are as high as 150 and 220 mg/g, respectively. By using Fourier transformation infrared (FT-IR), X-ray photoelectron (XPS), and extended X-ray absorption fine structure (EXAFS) spectroscopy, we concluded that the Eu(III) and Th(IV) adsorption was predominantly attributed to the inner-sphere coordination with various oxygen- and nitrogen-containing functional groups on GOCS surfaces. Our selective adsorption results demonstrate that the actinide and lanthanide ions can be effectively separated from transition metal ions. This study provides new clues to the overall recycling of actinide and lanthanide ions in radioactive environmental pollution treatments.

Rare earth element (REE) concentrations and patterns were measured in surface water, suspended particles (SP) and oysters from the Pearl River Estuary, China. During the rainy season of 2017, higher REE concentrations were found at the stations in the estuary (ΣREE = 0.06–0.42 μg L⁻¹) than those at the river mouths (referred to as ‘outlet’ stations, ΣREE = 0.001–0.14 μg L⁻¹). However, the reverse occurred in the dry season of 2016 (ΣREE = 0.07–0.16 μg L⁻¹ in the mid-estuary vs. 0.001–0.02 μg L⁻¹in the outlet stations). Elevated concentrations of Pr, Nd, Dy and Ho, relative to the other REEs were found in water in both seasons at most sampling locations. However, in some estuary stations, no anomalies were detected in the SP or in the oysters while some anomalies were seen in SP from the outlet stations. Significant correlations between REE concentrations in SP and oysters as well as between both total REE concentrations and the La/Yb ratio (reflecting enhanced accumulation of light REEs (LREEs)) in oysters indicate that, in the Pearl River Estuary, the dominant REE uptake pathway in oysters is from particles.The elevated concentrations of Pr, Nd, Dy and Ho, which are reported here for the first time suggest that elevated levels of these elements may result from REE recycling and other industrialized activities in this area of southern China. Specific REEs could be used to indicate emerging contamination by the modern REE industry; furthermore, REE anomalies and patterns may be suitable tools to track REE sources.

The Hooghly River (HR) estuary is the first deltaic off-shoot of the perennial and transboundary river, Ganga, India. HR receives industrial and domestic waste along with storm-water run-off from Kolkata city and the adjoining districts. Organic micropollutants (OMPs) have been collectively termed for plasticizers, pharmaceuticals and personal care products, which are extensively consumed and disposed in the waste streams. Hence emerging OMPs were investigated to obtain the first baseline data from the Hooghly riverine sediment (HRS) along urban and suburban transects using gas chromatography mass spectrometry (GC-MS). The concentration range of OMPs in the HRS varied between 3 and 519 ng/g for carbamazepine, 5–407 ng/g for non-steroidal anti-inflammatory drugs (NSAIDs), 2–26 ng/g for musk ketone, 2–84 ng/g for triclosan, 2–199 ng/g for bisphenol A (BPA), 2–422 ng/g for plasticizers (phthalic acid esters (PAEs) and bis (2-ethylhexyl) adipate (DEHA)) and 87–593 ng/g for parabens. Carbamazepine concentration in sediment was an useful marker for untreated wastewater in urban waterways. High concentrations of BPA and PAEs in the suburban industrial corridor together with significant correlation between these two type of OMPs (r2 = 0.5; p < 0.01) likely reflect a common source, possibly associated with the plastic and electronic scrap recycling industries. Among all the categories of OMPs, plasticizers seems to exhibit maximum screening level ecological risk through out the study area.