An Integrated Bipolar Picture Fuzzy Decision Driven System to Scrutinize Food Waste Treatment Technology through Assorted Factor Analysis

Food Waste(FW)is a pressing environmental concern that affects every country globally.About one-third of the food that is produced ends up as waste,contributing to the carbon footprint.Hence,the FW must be properly treated to reduce environmental pollution.This study evaluates a few available Food Waste Treatment(FWT)technologies,such as anaerobic digestion,composting,landfill,and incineration,which are widely used.A Bipolar Picture Fuzzy Set(BPFS)is proposed to deal with the ambiguity and uncertainty that arise when converting a real-world problem to a mathematical model.A novel Criteria Importance Through Intercriteria Correlation-Stable Preference Ordering Towards Ideal Solution(CRITIC-SPOTIS)approach is developed to objectively analyze FWT selection based on thirteen criteria covering the industry’s technical,environmental,and entrepreneurial aspects.The CRITIC method is used for the objective analysis of the importance of each criterion in FWT selection.The SPOTIS method is adopted to rank the alternative hassle-free,following the criteria.The proposed model offers a rank reversal-free model,i.e.,the rank of the alternatives remains unaffected even after the addition or removal of an alternative.In addition,comparative and sensitivity analyses are performed to ensure the reliability and robustness of the proposed model and to validate the proposed result.

Inoculation of Chlorella and Food Waste Improves the Physio-Morphological Features of Red Pepper by Regulating Activating Antioxidant Defense System

Food waste is recognized as a valuable source for potential agricultural applications to supply organic matter and nutrients to arable soil.However,the information on the combined application of food waste and the plant growth-promoting bacterial strain,Chlorella,related to plant metabolic features and sodium chloride content in arable soil is limited.The present study was conducted to investigate the exogenous application of food waste along with Chlorella,which improved the physio-morphological features of red pepper.Our results revealed that this combination enhanced the organic matter in the soil,ultimately improving the fertility rate of the soil,and the physio-morphological features,such as chlorophyll a content(24.5±0.7),root(7.8±0.7)cm and shoot length(12.1±0.7)cm,fresh weight(2.1±0.05)g,dry weight(0.19±0.05)g,mineral contents,and hormonal concentration(ABA by up to 2 folds).The combined treatment also minimized free radicals via the activation of the intrinsic antioxidant series cascade and electrolyte leakage.Our findings showed that adding Chlorella and food wastes improved growth characteristics and can be used as a green bio-fertilizer for sustainable agriculture.

Nutrient Evaluation of Dining Center Food Waste and Comparison to Monogastric and Ruminant Feedstuffs

The objective of this study was to analyze the nutrient composition and variability of university dining hall food waste and compare it with common feedstuffs used in ruminant and monogastric diets. Food waste was categorized into two initial streams: mainstream (MS) from the serving line and vegetable preparation (VP) from the kitchen. Waste was collected from the Kramer Dining Center, Kansas State University, resulting in 30 daily samples. Waste was weighed and ground to homogenous particle size. Daily samples of MS and VP were analyzed for nutrient composition, where results were combined to calculate the nutrient profile of a hypothetical mixed food waste stream (MX) composited by total weight. Data were analyzed using R statistical software (v 4.2.2). Moisture and neutral detergent fiber (NDF) were greater in VP (P , while ether extract (EE) was less compared to MS and MX. Crude protein (CP) was greater (P < 0.05) in MS and MX streams compared to VP. The total digestible nutrients (TDN) and energy were greater in MS food waste than in MX, which was also greater than VP (P content, measured by standard deviation, was similar (P > 0.05) among streams for NDF, nitrogen-corrected neutral detergent fiber, acid detergent insoluble crude protein, CP, ash, lignin, and digestible and metabolizable energy. Dry matter and EE variation were greater (P < 0.05) in MS, whereas VP was less (P < 0.05) compared to MX. Standard deviation increased (P < 0.05) in MS and MX for neutral detergent insoluble crude protein, TDN, and gross energy when compared to VP. Despite having 70% - 80% moisture, dining hall food waste does have nutritive value and the potential to be included in ruminant and monogastric diets. Further research needs to be done to understand the value of including it in animal diets.

New Insights into Microplastic Contamination in Different Types of Leachates: Abundances, Characteristics, and Potential Sources

Municipal solid waste(MSW)is an important destination for abandoned plastics.During the waste disposal process,large plastic debris is broken down into microplastics(MPs)and released into the leachate.However,current research only focuses on landfill leachates,and the occurrence of MPs in other leachates has not been studied.Therefore,herein,the abundance and characteristics of MPs in three types of leachates,namely,landfill leachate,residual waste leachate,and household food waste leachate,were studied,all leachates were collected from the largest waste disposal center in China.The results showed that the average MP abundances in the different types of leachates ranged from(129±54)to(1288±184)MP particles per liter(particlesL1)and the household food waste leachate exhibited the highest MP abundance(p<0.05).Polyethylene(PE)and fragments were the dominant polymer type and shape in MPs,respectively.The characteristic polymer types of MPs in individual leachates were different.Furthermore,the conditional fragmentation model indicated that the landfilling process considerably affected the size distribution of MPs in leachates,leading to a higher percentage(>80%)of small MPs(20–100 lm)in landfill leachates compared to other leachates.To the best of our knowledge,this is the first study discussing the sources of MPs in different leachates,which is important for MP pollution control during MSW disposal.

Extraction, Production and Quality Evaluation of Margarine from Oil Extracted from Waste Biomass Peels of Avocado and Virgin Coconut Oil, Using Chitosan from Reared Shells as Preservative

The production and consumption of avocado pears generates tons of wastes, mainly the pear peels which are usually discarded, although they have been reported to contain important phyto-chemicals with biological activities. The adverse health effect associated with the consumption of saturated lipid based foods has ignited research on reformulation of lipid based foods to eliminate Trans Fatty Acids (TFAs). This study was thus aimed at the extraction and characterization of oil from Avocado Peels (APO) and evaluation of the quality of margarine produced from it. Five verities of pear were used for oil extraction by soxhlet method and physiochemical, oxidative, functional and antioxidant characterization was done. Margarines were formulated using a central composite design using oil blends of APO and Virgin Coconut Oil (VCO) with an oil ratio of 10:90, 40:60, 70:30 respectively, varied blending speed, blending time, and chitosan concentration. Samples were characterized and the effect of process parameters on the physiochemical and functional properties of the margarine studied. Optimized conditions were used to produce samples for sensory evaluation. Color, spreadability, aroma, taste and general acceptability was evaluated using ranking difference test. The results showed that the yield, density, and iodine values of APOs oils ranged from 14.91 ± 0.18 to 11.76 ± 0.46;0.93 ± 0.001 to 0.99 ± 0.1;46.63 ± 1.70 to 52.4 ± 0.63, their acid values, TBA and PV values ranged from 1.42 ± 0.39 to 1.97 ± 0.5;0.11 ± 0.002 to 0.18 ± 0.04;and 2.72 ± 0.14 to 4.43 ± 0.36 respectively, with Brogdon avocado peel variety having the overall best properties prepared blends of trans-free APO margarines showed that increase in APO ratio decreased melting point, increased oxidative stability and reduced moisture content of margarine samples. Chitosan addition leads to decrease moisture content and increase functional properties. VCO lead to increase in phenolic and flavonoid content of the margarines. Samples were spreadable and palatable with R20 being most palatable and the most accepted being R26 with a mean score of 7.07 ± 0.70. Decrease in color intensity increased acceptability. This study therefore demonstrated that avocado peel waste biomass can be valorized by using it as raw material for oil extraction, which can serve as good material for the production of trans-free margarines with good oxidative stability, functional and antioxidant properties.

High-solid Anaerobic Co-digestion of Food Waste and Rice Straw for Biogas Production

Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid（VS） concentration of more than 3 g VS · L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand（COD） and volatile fatty acids（VFAs） were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 m L· g V· S-1 · d-1 at a mass ratio（FW/RS） of 3 ： 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than monodigestions in higher organic loading system.

Formation of Struvite Crystals in a Simulated Food Waste Aerobic Composting Process

Bench-scale treatments with three mixtures of Mg and P salts, including K3PO4＋MgSO4, K2HPO4＋MgSO4, and KH2PO4＋MgSO4 as additives in a simulated food waste aerobic composting process, were conducted to test the magnesium ammonium phosphate（MAP） formation, and the compost products were analyzed by X-ray diffraction（XRD）, Scanning electron microscopy（SEM）, and Energy dispersive X-ray spectroscopy（EDS） analyses. The comparison results between XRD, SEM, and EDS analyses of MAPs in the dried compost and synthesized MAPs confirm the formation of MAP crystals in the simulated food waste aerobic composting process. The analysis of the compost also indicates that the addition of all the three mixtures of Mg and P salts in the aerobic composting process can increase nitrogen conservation and decrease nitrogen loss because of the formation of MAPs. The mechanism of MAP formation was verified as the reaction of ammonium（NH4＋） with magnesium（Mg^2＋） and phosphate[HnPO4^（3-n） , n=0, 1, and 2）.

Food Losses and Food Waste in the Context of Sustainable Development of the Food Sector

Globally, about one third of all food produced is wasted every year. Losses take place along the entire food chain and they need to be analyzed and monitored due to their impact on the development of the food sector. In addition to quantitative losses, irrational use of food contributes to the depletion of natural resources （water and energy） and poses a threat to the environment, constituting a barrier to sustainable development of the food sector. The aim of this study was to establish the causes and effects of food waste throughout the food supply chain and to propose mitigation measures. Identified causes of food waste can be divided into two groups. The first are those that lead to the fact that food cannot be consumed （e.g., inadequate conditions of agricultural production and interruption of the cold chain）. In the second, those that cause food cannot be sold （e.g., wrong label and wrong product weight）. Most of the identified causes of food waste can be avoided （e.g., by improving the conditions of production, storage, and transportation）. However, it is not possible to eliminate all potential errors leading to food waste. It is therefore necessary to consider what action to take to use food as intended. One way to reduce losses and food waste can be re-distributing to charity.

Effect of Food Waste Compost (FWC) and its Non-Aerated Fermented Extract (NFCE) on Seeds Germination and Plant Growth

The aim of this study was to investigate the effect of the food wastes compost (FWC) and its non-aerated fermented extract (NFCE) on seed germination and growth of tomato (Solanum lycopersicum L.), watercress (Nasturtium officinale), chili pepper (Capsicum annuum), peas (Pisum sativum L.), chickpea (Cicer arietinum) and beans (Vicia faba) under greenhouse conditions. The FWC and NFCE were physico-chemically and microbiologically characterized. The NFCE effect was evaluated on tomato, watercress, and chili pepper seeds germination and seedling growth. However, for leguminous, pea, chickpea and bean seedlings, the FWC amended soils and irrigated with NFCE were tested for plants growth. The results of FWC analyses revealed that FWC has neutral pH, low EC and C/N ratio, with fertilizing elements (N, P, K and Mg) and lack of phytotoxic effect. The NFCE was characterized by low EC and relatively high carbon content (COD = 9700 mg/l), and intense microbial activity, notably mesophilic bacteria. Therefore, in fermented compost extract, mesophilic bacteria were increased by 225, yeasts by 25 and molds by 10 times compared to those of the investigated compost. In greenhouse, the diluted NFCE increased significantly (p< 0.05) germination and growth of the tested seedlings. Used alone, the FWC amended soil or the NFCE irrigated soil, improved the growth of tested seedlings. The use of soil amended with compost and irrigated by fermented compost extract decreased significantly the growth of the same experimented seedlings. Therefore, the FWC and its fermented extract were a suitable substrate for germination and growth of the studied seeds.

Food packing: A case study of dining out in Beijing

the financial project supported by the State Key Program of the National Natural Science Foundation of China （71233007）

An Integrated Framework for Regional Assessment of Water, Energy, and Nutrients from Food Loss of Selected Crops in the Lower Fraser Valley, Canada

Although there is no global shortage of food or water, food security has not been achieved, as human activity has turned these vital resources into “waste”. Wasted food not only loses valuable water resources but embedded calories of human energy and nutrients for healthy human populations. The Food and Agricultural Organization of the United Nations, in addressing these concerns, focuses on a global scale largely on an economic estimate of individual components of energy or water or nutrient loss. It is suggested that more information is required through local or regional assessments to provide better estimates, incorporating regional factors of the losses along the food supply chain. To address this suggestion, this study focused on an intensive agricultural and rapidly urbanizing region of Canada, the Lower Fraser Valley of British Columbia. Seven selected crops, including annual crops such as green peas, sweet corn and potato, and perennial crops that included three berry crops were assessed for their water, both constituent and virtual, as well as embedded energy, protein, and Vitamin C. Annual virtual water losses were higher for sprinkler than drip irrigation, ranging from 82 × 106 kg of water for strawberry to 7570 × 106 kg for blueberry. These high virtual water losses estimated along the food chain confirm the significance of food loss impacts on local water resources. Estimates of losses of food in kg were highest at the consumer level along the food chain and it was estimated that wasted food from the seven crops selected would have supplied the protein and caloric energy of over 33,000 men per year and Vitamin C of about 240,000 men per year. This assessment increases the awareness of food loss impacts from a regional perspective and provides a framework for future research on both environmental and nutritional implications of wasted food.

Comparing End-Use Potential for Industrial Food-Waste Sources

Approximately one quarter of the global edible food supply is wasted. The drivers of food waste can occur at any level between production, harvest, distribution, processing, and the consumer. While the drivers vary globally, the industrialized regions of North America, Europe, and Asia share similar situations; in each of these regions the largest loss of food waste occurs with the consumer, at approximately 51% of total waste generated. As a consequence, handling waste falls on municipal solid waste operations. In the United States, food waste constitutes 15% of the solid waste stream by weight, contributes 3.4 -107 t of carbon dioxide （CO2） equivalent emissions, and costs 1.9 billion USD in disposal fees. The levels of carbon, nutrients, and moisture in food waste make bioprocessing into higher value products an attractive method for mitigation. Opportunities include extraction of nutraceuticals and bioactive compounds, or conversion to a variety of volatile acids-including lactic, acetic, and propionic acids-that can be recovered and sold at a profit. The conversion of waste into volatile acids can be paired with bioen- ergy production, including hydrogen or biogas. This present review compares the potential for upgrading industrial food waste to either specialty products or methane. Higher value uses of industrial food waste could alleviate approximately 1.9-108 t of CO2 equivalent emissions. As an example, potato peel could be upgraded to lactic acid via fermentation to recover 5600 million USD per year, or could be converted to methane via anaerobic digestion, resulting in a revenue of 900 million USD per year. The potential value to be recovered is significant, and food-waste valorization will help to close the loop for various food industries.

Effects of Ultrasonic and Acid Pretreatment on Food Waste Disintegration and Volatile Fatty Acid Production

This study aims at investigating the effects of ultrasonic and acid pretreatment on food waste( FW)disintegration and volatile fatty acid( VFA) production. Single-factor experiments are carried out to obtain optimal conditions of individual ultrasonic and acid pretreatment,and response surface method( RSM) is applied to optimize the conditions of the combination of ultrasonic and acid( UA) pretreatment. Results show that the optimal acid,ultrasonic and UA pretreatments conditions are individual pH 2,individual ultrasonic energy density of 1. 0 W / mL and the combination of ultrasonic energy density1. 11 W / mL and pH 1. 43,respectively. Correspondingly,the maximum disintegration degrees( DD) of 46. 90%,57. 38% and68. 83%are obtained by acid,ultrasonic and UA pretreatments,respectively. After optimizing pretreatment conditions,batch experiments are operated to produce VFA from raw and pretreated FW under anaerobic fermentation process. Both the maximum VFA production( 976. 17 mg COD / gV S) and VFA / SCOD( 72. 89%) are obtained with ultrasonic pretreatment, followed by UA pretreatment, non-pretreatment and acid pretreatment,respectively. This observation demonstrates that a higher acidity on acid and UA pretreatments inhibits the generation of VFA. Results suggest that ultrasonic pretreatment is preferable to promote the disintegration degree of FW and VFA production.

Evaluations of the Sensory Quality Indices and Freshness Assessment of Nile Tilapia Oreochromis niloticus Fillets Fed Recycled Food Waste Materials

This study was designed to evaluate the sensory quality indices, freshness assessment and safety of eating Nile tilapia fed recycled food waste materials [food industry waste （FIW） and soy sauce waste （SSW）] for 32 weeks using K values, IMP content and microbial viable cell count. Five experimental diets were formulated at 0% and 20%-22% inclusion level of recycled food wastes. The diets were designated as D 1： 0% of recycled food waste, D2： 20% inclusion of FIW, D3： 20% inclusion of FIW and SSW, D4： 20% inclusion of FIW and tryptophan, and D5： 22% inclusion of SSW. The result from the body composition shows that D I had higher carcass protein, while D3 had the highest lipid content and there was no significant difference in the carcass moisture and ash contents among all treatments. The results of microbial viable cell counts showed that no significant differences were observed among the dietary treatments and all the fish fed experimental diets still remained fresh four days after refrigerated storage at 5 ~C. In addition, no significant differences were noted among the K value concentrations of all the fish fed the experimental diets. From the result of this study, we concluded that using 20% inclusion of recycled food waste materials （FIW and SSW） in the diet of tilapia had no negative effect on the flesh of the fish; hence, recycled food waste could be a good alternative ingredient to aquaculture.

Anaerobic Digestion of Food Waste Using UASB Sludge from a Poultry Slaughterhouse as Inoculum

In 2010, Brazil endorsed a new national policy of solid wastes, which has a very ambitious target to close up all the dumping areas and to manage adequately all the municipal solid waste, disposing in landfills only the refuse of treated municipal solid waste after 2019. Food waste is the largest representative of organic waste produced in Brazilian municipalities, which can produce both fertilizer and biogas through anaerobic digestion （AD） process, reducing in both cases greenhouse gases emissions. AD assays of some samples of restaurant food wastes were performed in batch laboratory, 500 mL reactors for determination of optimized start-up conditions. The tests were conducted in triplicate, using anaerobic sludge from a poultry slaughterhouse wastewater treatment as inoculum to start up the anaerobic biodigestors. The effect of three different substrates to inoculum mixing ratios 10：90 （S1）, 20：80 （S2） and 30：70 （S3） was evaluated. The food waste used as substrate was previously homogenized and submitted to aerobic mechanical mixing for four days before it was fed in the reactors in anaerobic conditions at the mentioned proportions with the inoculum. The reactors were maintained at 35 ℃ and under mechanical mixing at 60 rpm. The methane production was monitored until its stabilization. Results showed that S1 presented the best performance during the initial 12 d, when it totalized 526 NmLCH4/gVSsubstrate.

Temperature Effect on Biogas Reaction from Food Waste

Food waste has developed as an alternative for the production of renewable fuels such as biogas from AD （anaerobic digestion）. In relation to the biogas production rate, digester temperature setting is one of the very important factors for digester operation, especially in low temperature countries. In this study, the effect of digester temperature on biogas and methane production efficiency in the AD of food waste was evaluated. The two-stage anaerobic digestion has a total reactor volume of 60 L （acid reactor volume was 30 L and methane reactor volume was 30 L）. They were incubated at mesophilic and thermophilic conditions for 25 days to determine temperature profiles for the AD process. The results of the laboratory-scale experiment show that maximum biogas production occurred at 55 ℃ （38.14 L of biogas） for a period of 11 days when compared to other temperatures. Second best was at 50 ℃ （37.44 L of biogas） for a period of 12 days, followed by 40 ℃ （35.36 L of biogas） for a period of 15 days. Thermophilic temperatures will be used in further studies to examine scaling up of the process.

Food Waste Management in Luxury Hotels-Best Practices and Limitations

Hospitality industry and hotels are considered to waste a lot of food.This research aims to focus on food waste management in luxury hotels by investigating three luxury hotels in Budapest(Hungary).The investigation focuses on qualitative methods,eleven interviews and observations were made from September to December 2018.Results show that in luxury hotels the main challenge is to ensure the correct balance between 5*experience and minimizing food waste.It was found that kitchen,breakfast open-buffet and staff canteen are among the leading causes of food waste,generating even higher food waste compared to conferences,banquets,orála carte options.While a broad range of practices exist that are believed to minimize the food waste of buffets,most of the luxury hotels are only implementing a small ratio of such practices and are only in the beginning of the planning phase to expand their practices in this regard.

Water, Energy and Nutrient Losses from Food Wastage of Selected Crops in Three Agro-Climatic Zones in British Columbia, Canada

Food waste is a growing global concern. Data on the factors and magnitude are largely global estimates, thus local studies aid in providing information on the impacts of food waste. Three important agro-climatic zones in British Columbia and nine common crops, both annual and perennial, were selected to evaluate the environmental and nutritional implications of local food waste. Using Canadian estimates of total food waste, the constituent water, caloric content, protein, vitamin C, phosphorus and potassium wasted by each crop were estimated. Regionally, the total production and losses were the highest in the Lower Fraser Valley which had high production of potatoes and blueberries, followed by the Okanagan, with grapes and apples, and Vancouver Island, with potatoes. Virtual water was estimated by the BC Agriculture Water Calculator and used to assess the soil and climatic factors impacting the local water demand. Although soil texture seemed to influence water demand, the agro-climatic zone was the main factor controlling the water demand and the corresponding amount of water wasted. Dry agro-climatic zones had annual virtual water up to two times higher for the same crop and soil texture. Lower water demand crops, finer soils and more efficient irrigation systems were more congruent with water stress scenarios. Total losses for each region were based on conservative estimates and would have supplied the caloric energy and protein for over 40,000 adults, and vitamin C for over 300,000 adults for one year. Additionally, the total N, P and K wasted accounted for up to 32, 2 and 13 kg/ha respectively for common fertilizers used in British Columbia. This study confirmed the significance of food waste impacts on local water demand, human nutrition and soil management based on regional data for representative crops.

Design Biogas Production from Mixed Napier Pak Chong I/Food Waste at Thermophilic Temperature by Anaerobic Digestion in Cow Dung and Chicken Dung

AD （anaerobic digestion） is a beneficial and efficient technique for the treatment of agricultural wastes, food wastes and wastes water to produce renewable energy. Solid agricultural are potential renewable energy resoures. Biogas production by co-digestion of mixed Napier Pak Chong I and food waste at thermophilic temperature using anaerobic digestion in cow dung and chicken dung as the seed inoculums were investigated. The total reactor volume of the co-digester reactor was 7.94 m^3, which was equipped with pump, and it was operated continuously for the 20 days as a pilot scale at 50 ℃. The Napier Pak Chong I was cut into 2 mm sections, and the initial VS （volatile solids） was 30%. The initial VS of food waste were 70%. Two pilot-scale digesters filled with Napier Pak Chong I and food waste, which both digesters contained 476 kg of Napier Pak Chong I mixed 305 L of food waste, and 1305 L of water. There were carried out to investigate the optimum C/N （carbon to nitrogen） ratio for effective biogas production. The slurry raw materials provided sufficient buffering capacity to maintain appropriate pH values （between 7.0 and 8.0）. Digester I was designed for 1.98 m^3 of cow dung as the seed inoculum while digester II was designed to establish 1.98 m^3 of chicken dung as the seed inoculum. Gas detector performs analysis gas production. The m^3/day in digester I and 1.86 m^3/day from digester II, resulting in added, respectively. Biogas production in digester I was directly experimental results indicate that total biogas production was 2.19 specific methane yields of 1.26 m^3 CH4/kgVS and 1.07 m^3 CH4/kgVS correlated with temperature.

Hydrothermal carbonization pretreatment makes a remarkable difference in activation of rice and lettuce in food waste

Cooked rice and the vegetables like lettuce are common kitchen waste,which are carbonaceous materials and have the potential as feedstock for the production of activated carbon.Cooking is similar to hydrothermal treatment(HTC),which might impact the subsequent activation of kitchen waste.In this study,the HTC of lettuce,rice,or their mixture and the activation of the resulting hydrochars were conducted.The results indicated that cross-polymerization between the N-containing organics from lettuce and the sugar derivatives from rice took place in their co-HTC,which significantly increased the hydrochar yield.Activation of the hydrochar from the coHTC generated the AC with a yield of 2 times that from direct activation of mixed lettuce/rice.However,the coHTC facilitated aromatization,reducing reactivity with K2C2O4in activation and producing the AC with main micropores and low specific surface area.Activation of the hydrochar from HTC of rice followed the above trend,while that from lettuce was the opposite.The organics in lettuce were thermally unstable and could not undergo sufficient aromatization.The activation of hydrochar from HTC of lettuce thus generated the AC with the lowest yield,but the highest specific surface area(1684.9 m2/g),abundant mesopores,and superior capability for adsorption of tetracycline.However,the environmental impacts and energy consumption for the production of AC from the hydrochar of lettuce were higher than that from hydrochar of co-HTC.