Food waste has a high energy potential that can be converted into useful energy in the form of methane via anaerobic digestion. Biochemical Methane Potential assays (BMPs) were conducted to quantify the impacts on methane production of different ratios of food waste. Anaerobic digester sludge (ADS) was used as the inoculum, and BMPs were performed at food waste:inoculum ratios of 0.42, 1.42, and 3.0g chemical oxygen demand/g volatile solids (VS). The 1.42 ratio had the highest CH-COD recovery: 90% of the initial total chemical oxygen demand (TCOD) was from food waste, followed by ratios 0.42 and 3.0 at 69% and 57%, respectively. Addition of food waste above 0.42 caused a lag time for CH production that increased with higher ratios, which highlighted the negative impacts of overloading with food waste. The Gompertz equation was able to represent the results well, and it gave lag times of 0, 3.6 and 30days and maximum methane productions of 370, 910, and 1950mL for ratios 0.42, 1.42 and 3.0, respectively. While ratio 3.0 endured a long lag phase and low VSS destruction, ratio 1.42 achieved satisfactory results for all performance criteria. These results provide practical guidance on food-waste-to-inoculum ratios that can lead to optimizing methanogenic yield.

Background While petroleum-based plastics are extensively used in health care, recent developments in biopolymer manufacturing have created new opportunities for increased integration of biopolymers into medical products, devices and services. This study compared the environmental impacts of single-use disposable devices with increased biopolymer content versus typically manufactured devices in hysterectomy. Methods A comparative life cycle assessment of single-use disposable medical products containing plastic(s) versus the same single-use medical devices with biopolymers substituted for plastic(s) at Magee-Women's Hospital (Magee) in Pittsburgh, PA and the products used in four types of hysterectomies that contained plastics potentially suitable for biopolymer substitution. Magee is a 360-bed teaching hospital, which performs approximately 1400 hysterectomies annually. Results There are life cycle environmental impact tradeoffs when substituting biopolymers for petroplastics in procedures such as hysterectomies. The substitution of biopolymers for petroleum-based plastics increased smog-related impacts by approximately 900% for laparoscopic and robotic hysterectomies, and increased ozone depletion-related impacts by approximately 125% for laparoscopic and robotic hysterectomies. Conversely, biopolymers reduced life cycle human health impacts, acidification and cumulative energy demand for the four hysterectomy procedures. The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects. However, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts of products and devices made using biopolymers. Conclusions The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects; however, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts.

Food waste and biopolymers, plastics derived from plants, are unexploited sources of energy when discarded in landfills without energy recovery. In addition, polylactic acid (PLA) and food waste have complimentary characteristics for anaerobic digestion; both are organic and degrade under anaerobic conditions. Lab-scale reactors were set up to quantify the solubilization of pretreated amorphous and crystalline PLA. Biochemical methane potential (BMP) assays were performed to quantify CH4 production from both treated and untreated PLA in the presence of food waste and anaerobic digested sludge. Amorphous and crystalline PLA reached near-complete solubilization at 97% and 99%, respectively, when alkaline pretreatment was applied. The PLA that received alkaline treatment produced the most of CH4 throughout the run time of 70 days. The PLA without treatment resulted in 54% weight reduction after anaerobic digestion. Results from this study show that alkaline pretreatment has the greatest solid reduction of PLA and maximum production of CH4 when combined with food waste and anaerobic digested sludge.

Analytical limitations make it challenging to develop effective methodologies for understanding glyphosate-based herbicide levels in drinking water and groundwater. Due to their lack of chromophores and zwitterionic nature, glyphosate-based herbicides are difficult to detect using traditional methods. This paper offers a straightforward method for quantifying glyphosate, glufosinate, and aminomethylphosphonic acid (AMPA) via 9-fluorenylmethylchloroformate (FMOC-Cl) pre-column derivatization and analysis by liquid chromatography with tandem mass spectrometry (LC–MS/MS). Method development was focused on optimizing the critical variables for optimal derivatization using a 24-factorial design. We found that complete derivatization significantly depends on the inclusion of borate buffer to create the alkaline conditions necessary for aminolysis. Ethylenediaminetetraacetic acid (EDTA) addition was critical to minimize metallic chelation and ensure reproducible retention times and peaks. However, EDTA concentrations ≥5% decreased peak intensity due to ion suppression. The FMOC-Cl concentration and derivatization time exhibited a direct proportional relationship, with the complete reaction achieved with 2.5 mM FMOC-Cl after 4 h. Concentrations of FMOC-Cl greater than 2.5 mM led to the formation of oxides, which interfere with the detection sensitivity and selectivity. Desirable results were achieved with 1% EDTA, 5% borate, and 2.5 mM FMOC-Cl, which led to complete derivatization after 4 h.

Residual biosolids from wastewater treatment facilities and the organic fraction of municipal solid waste (OFMSW), such as food and yard wastes (FW and YW), are difficult to manage due to increased waste generation and recent stringent regulations. This study investigated the effect of substrate to inoculum ratio (S/I) on biochemical transformation mechanisms and biomethane production during high solids anaerobic digestion of FW, YW, and biosolids. Biochemical methane potential (BMP) assays were set up under mesophilic conditions at S/I of 1.0, 2.0, and 3.0 g OFMSW total solids (TS)/g inoculum TS. BMP with the lowest S/I (1.0) produced the highest cumulative CH 4 yield of 126 mL CH 4 /(g VS added ), with 90% of its maximum yield by day 37, and a hydrolysis rate constant (K hyd ) of (0.06 day -1 ). S/Is 2.0 and 3.0 resulted in higher volatile fatty acid release than S/I 1.0. This led to pH-induced inhibition of methanogenesis, longer lag phases (S/I 2.0 = 12 days and S/I 3.0 = 26 days)], and lower cumulative CH 4 yields [S/I = 2.0 at 45.6-mL CH4/(g VS added ); S/I = 3.0 at 6.75-mL CH 4 /(g VS added ). The results show that accumulation of inhibitory intermediates can cause system failure due to mass transfer limitation under low moisture conditions when S/I > 1.0 based on TS. Results from this work assist in developing best solid waste management practices for OFMSW and resource recovery.