Benchmarking biochar with activated carbon for immobilizing leachable PAH and heterocyclic PAH in contaminated soils.

Remediation of residually contaminated soils remains a widespread problem. Biochar can immobilize polycyclic aromatic hydrocarbons (PAH). However, studies on its ability to immobilize PAH and N, S, and O substituted PAH (hetero-PAH) in real soils, and benchmarking with commercial activated carbon are missing. Here, we compared the ability of pristine biochar (BC), steam-activated biochar (SABC), and commercial activated carbon (AC) to immobilize PAH and hetero-PAH. The three carbons were tested on soils from four different contaminated sites in Austria. Different amendment rates (w/w) of the carbons were investigated (BC: 1.0, 2.5, and 5%; SABC: 0.5, 1.0, and 2.0%; AC: 1%) in batch experiments to cover meaningful ranges in relation to their performance. SABC performed better than AC, removing at least 80% PAH with the lowest application rate of 0.5%, and achieving a complete removal at an application rate of 1.0%. BC performed slightly worse but still acceptable in residually contaminated soils (40 and 100% removal at 1 and 5% amendment, respectively). The ability of BC and SABC to immobilize PAH decreased as the PAH-molar volume increased. PAH with three or more rings were preferentially removed by AC compared to SABC or BC. This can be explained by the difference in pore size distribution of the carbons which could limit the accessibility of PAH and hetero-PAH to reach sorption sites for π- π electron donor-acceptor interactions, which drive PAH and hetero-PAH sorption to carbons. Column percolation tests confirmed the results obtained in batch tests, indicating, that decisions for soil remediation can be derived from simpler batch experiments. In soil samples with 1% BC, a reduction of over 90% in the total concentration of PAH in the leached water was observed. Overall, BC and SABC were demonstrated to be valid substitutes for AC for stabilizing residually contaminated soils.

Quantification and mapping of fish waste in retail trade and restaurant sector: Experience in Emilia-Romagna, Italy.

The circular economy approach imposes the complete recovery of components, materials and energy from waste. Many active compounds with biomedical and nutraceutical applications can be extracted by Fish Waste (FW), but few are the operating industrial plants. Quantification and mapping of the potential FW availability along the entire fish value-chain is crucial in fostering its actual valorisation. Apart at industrial processing, in the distribution segment the estimation of FW availability is absent. This paper aimed to quantify and locate FW generated by point sources such as supermarkets, fishmongers and restaurants as well as to establish the diffuse domestic FW production in a 4,5M inhabitants region. The study provides an exportable method and indications for comparable worldwide areas. A simplified valorisation scenario for equivalent biomethane production is also presented. Direct interviews and indirect approach based on fish consumption have been adopted and compared. Large supermarkets and medium-large restaurants are the main FW producers (239 and 125 kg/week, respectively) followed medium-large fishmongers and medium supermarkets (63 and 86 kg/week, respectively). In the investigated region the larger FW point sources are supermarkets (average 3000 Mg/y), while fishmongers are the smaller (average 750 Mg/y). Restaurants (average 1400 Mg/y) show the wider range of variability between 460 and 8000 Mg/y. The indirect methodology reveals that domestic FW production ranges from 2376 to 3961 Mg/y. Per capita estimations of FW ranged from 0.5 - 3 kg/y. The economic value of FW (biomethanation route) is 68 EUR/Mg. A qualification as "highly potential waste" would promote FW valorization.

Exploitable fish waste and stranded beach debris in the Emilia-Romagna Region (Italy).

Within Circular Economy principles, this paper analyses and estimates exploitable marine residues, such as fish waste and stranded debris in beaches and their potential valorisation scenarios. The Emilia-Romagna Region (Italy) has been chosen as a case study. Based on the sold fish, about 200 Mg/year of fish waste are produced at the five major fish markets of the Region. Including all regional fish processing plants and retail trade, the estimated availability of fish waste increases up to 30,000 Mg/year. Stranded beach debris collected by mechanical cleaning operations are currently deposited in landfill. About 63,000 Mg/year of sieved debris are collected each year, out of which the recoverable fractions consist of 19,000 Mg/year of organic material, 8,000 Mg/year of shells and 5,200 Mg/year of stones. Classification and valorisation routes for these residual biomasses are proposed and their applicability to other regions discussed. In order to investigate the possible use in anaerobic digestion plants and the effects on biogas production, Biochemical Methane Potential (BMP) assays have been carried out with fish waste samples and with organic material found in marine debris. Salt content in driftwood has been quantified to assess its potential use in Combined Heat and Power (CHP) plants. Proposed valorisation routes for shells and stones include the production of calcium carbonate (cement industry, wastewater treatment and mulching) and the application in building industry, respectively.