A novel process for food waste recycling: A hydrophobic liquid mulching film preparation.

Appropriate and effective recycling of food waste (FW) has become increasingly significant with the promotion of garbage classification in China. In this study, a novel and green process was developed to recycle FW to prepare a biodegradable composite liquid mulching film (LMF) through crosslinking with sodium alginate (SA). The solid phase of FW was obtained as the raw material after hydrothermal pretreatment to remove pathogens and salts, and to improve the reactivity of active components at a moderate temperature. The prepared LMF had a hydrophobic surface and compact structure due to the lipid in FW and the acetalization reaction and hydrogen bonds among SA, glutaraldehyde and multi-active components of FW, resulting in enhanced water vapor barrier properties. The minimum water vapor permeability of the prepared LMF reached (8.23 ± 0.05) ✕ 10-12 g cm/(cm2·s·Pa) with 1.82 wt % of plasticizer, 0.74 wt% of crosslinker and a mass ratio of HTP-FW to SA of 3.56:1. The prepared LMF showed good mechanical properties and could maintain its integrity after spraying it on the soil surface for 31 days. In addition, it could effectively prevent the loss of soil moisture and heat, promote the seed germination of Chinese cabbage and achieve 89.14% of weight loss after burying in the soil for 27 days. This study provides a high value-added route to convert the FW to a hydrophobic LMF with superior properties, which addresses not only the problem of food waste but also the pollution of plastic mulching film.

[Strategies of nutrients control in lakes based on ecoregions of lakes in China].

In order to better reduce lake eutrophication, based on five ecoregions of lakes, the relationships of total nitrogen (TN), total phosphorus (TP), and TN/TP ratio with chlorophyll-a (Chl-a) in 100 lakes were discussed, furthermore, strategies of nutrient control were proposed respectively. Results showed that among the five ecoregions, the lake eutrophication level was the lowest in Dongbei ecoregion and the highest in Huabei ecoregion, but the eutrophication level in lakes of all the five ecoregions is increasing in recent years. Algal growth in lakes of Dongbei and Huabei ecoregions was limited by phosphorus, while it was simultaneously limited by nitogen and phosphorus in lakes of other three ecoregions (Zhongdongbu, Yungui and Mengxin). In lakes with TN/TP < 10, significant correlation between Chl-a concentration and TN was found in lakes of the five ecoregions except for Huabei ecoregion, and significant correlation between Chl-a concentration and TP was found in lakes of Dongbei and Mengxin ecoregions. In lakes with TN/TP > 17, significant correlation between Chl-a concentration and TP was found in lakes of the five ecoregions except for Mengxin ecoregion, and significant correlation between Chl-a concentration and TN was found in lakes of Zhongdongbu, Yungui and Mengxin ecoregions. In lakes with 10 < TN/TP < 17, no significant correlation between Chl-a and TN (or TP) was found in lakes of all ecoregions except for Zhongdongbu ecoregion where Chl-a concentration was significantly affected by TN. As for strategies of nutrient control and reduction in the five ecoregions, lakes of Huabei ecoregion should adopt TP control in priority, and in Dongbei ecoregion, TP and TN should be controlled simultaneously in lakes with TN/TP < 10, while other lakes should focus on TP control. Lakes in other three ecoregions (Zhongdongbu, Mengxin and Yungui) should control TP and TN simultaneously.

[Influence of additive on characteristic of slag during the process of melting fly ash from municipal solid waste incinerator].

A kind of compound additive was studied and prepared in the paper, which associated with many functions. Using typical fly ash of Shanghai and Fuzhou, We studied the effect of the additive on evaporation rate, flowing temperature, fixed rate of heavy metals and its leaching characteristics in melting slag in the process of melting fly ash. The result showed that the flowing temperature and the evaporation rate of fly ash could be respectively reduced approximately 150 degrees C and 10% - 20% by adding 10% additive, and the fixed rate of heavy metals Cu and Pb increased 10% - 20%, especially Zn, which could increase 40%. The amount of leaching heavy metals in melting slag were both under corresponding standard limits using either national toxicity leaching methods or TCLP of EPA.