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This study aims to use landfill leachate (LL) as an aqueous medium during hydrothermal carbonisation (HTC) of food waste to produce hydrochar (FWH-LL-C), which could be used as an electrode material in energy storage devices. The structural properties and electrochemical performance of the hydrochar were compared to that obtained using distilled water as a reaction medium (FWH-DW-C). The results showed that there is a difference in Brunauer–Emmett–Teller (BET) surface area of FWH-LL-C (220 m2 gm−1) and FWH-DW-C (319 m2 gm−1). The electrochemical properties were comparable, with FWH-LL-C having 227 F g−1 specific capacitance at 1 A g−1 current density and FWH-DW-C having 235 F g−1 specific capacitance at 1 A g−1 current density. Furthermore, at a power density of 634 W kg−1, FWH-DW-C achieved the highest energy density of 14.4 Wh kg−1. The energy retention capacity of the electrode was 98% which indicate that the material has an excellent energy storage capacity. The findings suggested that LL could be used as an alternative source of aqueous media during the HTC of food waste to produce hydrochar which could be used as an effective electrode material in supercapacitors.

Electrochemical pretreatment is considered a promising technique to reduce recalcitrance nature of lignocellulosic biomass. Yet, a comprehensive knowledge on the performance of alkaline reagents in electrochemical pretreatment and the associated environmental impacts are at an early stage. The present study investigated and compared the effect of electrochemical pretreatment by using NaOH reagent (EN) and electrochemical pretreatment by using Ca(OH)2 reagent (EC). The results showed that, both pretreatment techniques elicited the structural breakdown of the biomass, as evidenced by compositional changes, supernatant properties, SEM, FTIR, and XRD analyses. The batch anaerobic digestion results revealed that the improvement in methane production was highest for the EC pretreatment (434 mL/gVS) followed by the EN pretreatment (346 mL/gVS) and the untreated yard waste (245 mL/gVS). The Modified Gompertz model showed the best fit for untreated and pretreated yard waste. The results of economic analysis confirmed the highest net profit of 8922 rupees (US$ 119.29) for EC pretreatment. The findings of life cycle analysis revealed that the net environmental performance considering the inventory used and the limitations of the system boundary was highest for EC pretreatment followed by EN pretreatment and untreated condition.

Due to the ubiquitous nature of microplastic (MP), knowledge of its fate and migration in subsurface environments like soil becomes extremely important to understand underlying ecological risk. The fate and migration of MP in subterranean settings like sand are governed by the retention/transport properties influenced by the interaction of sand and MPs. In this study, sand column experiments under simulated rainfall conditions were conducted for 180 days to assess the vertical migration of mixed MPs consisting of polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). Sand column experiments were subjected to 60 wet-dry cycles over 180 days. The effects of polymer type, microplastic size, sand particle size, and surface roughness on the migration of MPs were evaluated. Results showed that the smallest-sized fragmented PE particles had the highest migration potential compared to PET and PE. The ratios of the diameters of MP particles and sand particles (d

Food waste constitutes a remarkable portion of municipal solid waste. About one-third of the global food waste produced is lost with the food supply chain. Food waste in many countries is still dumped of in landfill or incinerated simultaneously with other municipal wastes. Food waste requires proper management and recycling techniques in order to minimise its environmental burden and risk to human life. Despite considerable research on food waste conversion still, there is a shortage of comprehensive reviews of the published literature. In this review, we provide a mini global perspective of food waste with special emphasis on New Zealand and their conversion into the useful material through hydrothermal carbonisation (HTC). Other thermal technologies such as incineration and pyrolysis are also briefly discussed. The review discusses why HTC is more suitable thermal technology than others, which are currently available. Recognising the importance of techno-economic feasibility of HTC, we present a cost analysis on the production of value-added products via HTC with examples taken from the literature to gather information in the feasibility assessment process. Finally, key challenges and future directions for a better productive way of handling food waste are being suggested.

The commercial success of hydrothermal carbonization (HTC) is contingent on seeking solutions for the downstream wastewater (process water) generated during the process which is still regarded largely as a nuisance. In the present study, the reusability and valorization strategy of process wastewater generated during co-HTC of organic fraction of municipal solid waste (food and yard waste) at 220 °C for 1 h was established. The process wastewater was anaerobically digested in the first part to determine its methane-generating capacity; and in the second part, it was recirculated up to five times to understand the evolution of physicochemical and fuel characteristics of hydrochar. The process water was characterized by the presence of high total organic carbon (up to 40 g/L) and chemical oxygen demand (up to 96 g/L). The decreasing trend of heavy metals with increasing recirculation suggested possible adsorption/immobilization mechanism taking place to the hydrochar surface. The process water generated from co-HTC condition has anaerobic biodegradability of 72% while experimental and theoretical methane yield observed were 224 mL/g COD and 308 mL/g COD, respectively. The presence of high organic and ionic species in recirculated process water promoted the overall carbonization process which was evident from the increased energy yield (86 to 92%), carbon content (68 to 71%) and calorific value (20 to 27 MJ/kg). The recirculation also enhanced overall combustion characteristics of hydrochar as analyzed by thermogravimetric analysis. The recirculation strategy enhanced fuel properties of hydrochar while making sure upstream and downstream water related burden is reduced (as illustrated by life cycle analysis) to create a cleaner production system for renewable solid biofuels production.

Yard waste is either dumped or is being openly burned to get rid of it, instead of using it as a valuable renewable energy source. In this study, hydrothermal carbonization of yard waste was conducted to valorize it as a solid bio fuel, using a batch reactor. The effect of process parameter on yield, energy and physicochemical properties of the valorized solid bio fuel (hydrochar) was examined in this study by varying reaction temperature (160–200 °C for 2 h) and reaction time (2–24 h at 200 °C). The calorific value of hydrochar was within a range of 17.72–24.59 MJ/kg as compared to 15.37 MJ/kg for untreated yard waste. Hydrochar mass yield decreased from 78.6% at operating temperature – time of 160 °C –2 h to 45.6% at 200 °C –24 h. The plot of atomic ratios (H/C and O/C) demonstrates improvement in the coalification process which was mainly governed by decarboxylation and dehydration reactions. The grindability of the prepared hydrochar was comparable to that of coal. Hydrochar produced at lower reaction condition (160–200 °C at 2 h) have better flowability as compared to that produced at higher reaction condition (4–24 h at 200 °C). The reaction time longer than 12 h has a minimal effect on the yield, energy and physicochemical properties of hydrochar. Increasing reaction time and temperature improved the ignition and burnt temperature of hydrochar. All reaction condition has an energy ratio (energy output to energy input) of more than one making HTC process a net energy producer.

With the steady growth in the worldwide solar installed capacity, there is an immediate concern about the fate of the solar panels at the end of their life. Solar panel waste is often disposed of indiscriminately, exposing the environment to chemical hazards. The major objective of the current study was to evaluate the leaching potential of the polycrystalline solar panel waste under different simulated disposal conditions through toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP) and pH static leaching procedure tests. Moreover, the study evaluates the effects of ageing and the breakage of the Glass Laminate Encapsulation (GLE) of solar panels on their leaching potential. Among the metals studied (silver (Ag), aluminium (Al), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), lead (Pb), and zinc (Zn)), the concentrations of Pb were as high as 9.3 mg/L, 1.4 mg/L, 6.7 mg/L in the TCLP, SPLP, and pH static test respectively. This indicated the hazardous nature of the waste with leaching potential of Pb above the permissible limits stipulated by various regulatory bodies. The presence of GLE reduced the mobility of Pb by a factor of 4.1–8.8 in the TCLP test, thereby rendering the waste as non-hazardous for its disposal in a landfill. However, the indiscriminate disposal of solar panel waste in the natural environment as simulated by the SPLP test indicated its harmful nature irrespective of the physical condition. Ageing of the solar panels before disposal and acidic pH conditions also positively influenced the leaching potential of the selected metals subjected to their reactivity and the accessibility of internal layers of waste to the leaching solution. Strategies such as extended producer responsibilty, advance-recycling fee, and incentivizing the recycling industry will lead to both economic benefit creation and effective waste management of this waste stream.

In recent times, the mutation of complex municipal solid waste (MSW) biodegradable portion to an energy recovery resource became an extraordinary innovation as it conserves our precious natural resources and maintains the ecological balance. The various thermo-chemical and biological treatment approaches also succeeded in synthesizing efficient energy recovery resources like solid biofuel (char) and biogas. Despite, the process instability due to precursor heterogeneity, environmentally non-benign, and non-viable processes have shown their inefficiency in on-site executions (Liu and Balasubramanian 2012). Nevertheless, on the other side intercontinental MSW generation is almost 1.3 × 103 million tons and reaches 2.2 × 103 million tons by 2025 (Xu 2013). Therefore, a promising futuristic viable and sustainable treatment technology for producing active energy recovery resource is the need of the hour. Likewise, hydrothermal carbonization (HTC) has recently gained well-built recognition as key enabling mechanization for converting the MSW biodegradable portion to desirable commodities (Wang et al. 2018; Zhao et al. 2014). The HTC process operates under lower temperatures, making use of distilled/de-ionized water as a catalyst or medium within a residence time of minutes to several hours (Ramke et al. 2009). The process finally yields into an energy-dense product named “hydrochar”, can be the replacement by lignite/bituminous coal. The usage of HTC as a waste conversion technology can notably minimize the greenhouse gas emissions (GHG’s) via compost centres and municipal solid waste (MSW) landfill sites (Berge et al. 2013). Also, the synthesized energy-dense hydrochar can be practiced as an economical replacement to different environmental applications to deal with the imminent universal energy shortage and environmental challenges (Wang et al. 2020). However, HTC is manifesting as a robust technology, along with the process advantages and hydrochars wide variety applications in environmental and energy sectors, the process disadvantages are also discussed in this chapter for its better practical scale execution.

Some of the inferior properties, including high heterogeneity and high moisture content, limit the resource recovery option from the organic fraction of municipal solid waste (MSW). Most of the thermochemical processes are only able to process dry waste and therefore are seldom successful in treating organic-rich wet MSW, which is pertinent to most of the developing nations. Hydrothermal carbonization (HTC), which treats waste in the presence of subcritical water, can easily handle organic-rich wet MSW. Hydrochar, due to its wide potential application in agriculture, water treatment, and as an energy carrier, has a possible market value. It can be integrated with other treatment processes either upstream or downstream to minimize waste generation; it is due to this flexibility that HTC is been seen as a futuristic treatment technology that greatly advocates the concept of circular economy in the waste management sector. Successful implementation of HTC for recovering value-added product from organic waste provides an opportunity to handle high moisture content waste while assuring entrepreneurial and socioeconomic benefits. Available literature suggests that before any large industrial-scale deployment of HTC more vigorous study on technoeconomic and life cycle should be conducted.

Hydrothermal carbonization (HTC) of yard waste (YW) and food waste (FW) was performed in landfill leachate (LL) to overcome the unnecessary exploitation of our limited natural resources. The physicochemical properties and combustion behavior of the resulting hydrochars were compared with those obtained using distilled water (DW) as reaction medium. Although performing HTC in LL led to lower hydrochar mass yields (43% YWH and 36% FWH) than DW (47.1% YWH and 41.5% FWH), it had minimal impact on the fuel characteristics of the hydrochars. Notably, the higher heating value of the hydrochars prepared in LL (22.8 MJ kg−1 for YWH and 30.2 MJ kg−1 for FWH) is comparable to that of conventional solid fuels, and may, therefore, be considered as inexpensive alternatives to fossil fuels. Overall, the results of this study conclusively suggest that the use of LL as an alternative moisture source can significantly improve the sustainability of HTC technology.

In this study, Co-HTC of food waste with yard waste was conducted for biofuel pellets production, and also to understand any possible synergy between two feedstock types. The calorific value of blended raw feedstock was 13.5 MJ/kg which increased to 27.6 MJ/kg after Co-HTC at 220 °C for 1 h. Energy yield and fuel ratio calculated was 45% and 0.65 respectively. Hydrochar produced demonstrated a stable combustion profile as compared to reactive combustion profile for raw samples. The blend of food and yard waste hydrochar was easily pelletized, and its pellets showed improvement in mechanical properties as compared to pellets made from mono-substrate((food waste) hydrochar. Pellets produced from the blend of food and yard waste hydrochar showed higher energy (46.4 MJ/m3) and mass density (1679 kg/m3) as compare to the pellet produced from food waste hydrochar alone. Tensile strength obtained for the blended hydrochar pellet was 2.64 MPa while same for the pellets produced from food waste hydrochar alone was 1.30 MPa. In addition to improving hydrophobicity, soften lignin from yard waste also helped in binding the food waste hydrochar particles together within the pellets matrix during heated pelletization. The results presented in the study indicated that in the presence of all favorable conditions, there is a potential that approximately 11% of the global coal consumption could be replaced by the combustion of hydrochar produced from food and yard waste globally.

The major challenges associated with the anaerobic digestion of urban lignocellulosic biomass are its recalcitrance nature and the disposal of resulted digestate. In this study yard waste was thermally pretreated to overcome inherent recalcitrant nature during anaerobic digestion. The resulted digestate after anaerobic digestion, which poses a serious land disposal problem was hydrothermally treated to produce energy-rich solid biofuel knows as hydrochar. After pretreatment the biogas production was improved from 328 to 364 mL/g VS. Then hydrochar prepared from the digestate at a temperature of 180 and 200 °C for a treatment duration of 6 h. The produced hydrochar had a calorific value in the range of 20–23.5 MJ/kg as compared to 15 MJ/kg for raw digestate. The present research on integration of anaerobic digestion and hydrothermal carbonization not only improved the bioenergy production but also minimized the waste production.

The possible sustainable technologies for waste-to-energy production are anaerobic digestion and hydrothermal carbonization. In this paper, aforementioned technologies were explored on yard waste. Yard waste was thermally pretreated to overcome inherent recalcitrant nature during anaerobic digestion to enhance biogas production. In addition, hydrothermal carbonization (HTC) of yard waste was also conducted for bio-solid fuel production. After pretreatment, the biogas production was improved from 311 ± 5 to 361 ± 11 mL/g VS. HTC of yard waste at different treatment conditions yields a higher calorific value up to 24.59 MJ/kg as compared to 15.37 MJ/kg for raw. In addition, the structural and chemical changes in biomass after pretreatment and hydrothermal carbonization were also studied. The HCT of yard waste at 200 °C for 24 h converted it into the dark lignite like coal with enhanced energy.

Food waste (FW) is difficult to manage during thermal treatment. In this study hydrothermal carbonization (HTC) of FW was carried out at increasing temperatures and retention times using the approach of reaction severities (logR0 = 5.31–7.09). The hydrochar sample with the best-obtained energy yield was further pelletized using molasses as a binder at different ratios (5%, 10%, 20% and 30%). A conceptual framework was proposed using the circular economy concept. As severity increases, hydrochar yield declines while its fuel properties improve. Decarboxylation and dehydration allow functional groups to become impaired, including C-O and –OH. Carbon microspheres were observed on the hydrochar surface due to extensive FW carbonization. The pellets with 30% molasses as binder showed the highest mass density (1683.24 kg/m3), while the energy density for it was 37.54 GJ/m3. Food waste management will generate local employment and new business prospects by integrating HTC and pelletization.

The aim of this study was to investigate the anaerobic granular sludge (AGS) as feedstock for hydrochar production using the hydrothermal carbonization (HTC) process. HTC experiments were conducted at 250 °C for 2 h. The hydrochar produced was then co-pelletized with yard waste to produce densified biofuel pellets. The hydrochar yield was around 80%, while the hydrochar energy yield was around 93%. The calorific value of hydrochar increased to approximately 19 MJ/kg as compared to 16 MJ/kg for the raw AGS. HTC improved the combustion behavior of hydrochar by improving ignition and burnout temperatures. Hydrochar pellets were able to withstand the compressive force of 3.10 MPa as compared to 2.44 MPa by raw AGS pellets thus proving its enhanced robustness. This study demonstrated that combined HTC and pelletization could be integrated with the wastewater treatment plant for solid biofuel production from AGS, providing a valuable renewable energy source.

Developing a treatment technology which minimizes the production of by-product (waste) is need of an hour. In this study, municipal yard waste (primary raw material) was microwave-pretreated before anaerobic digestion (AD) to improve biogas production. The anaerobically digested, Pretreated Yard Waste (PTY) and the Untreated Yard Waste (UTY) (waste/secondary raw material) was Hydrothermally Carbonized as a downstream treatment technique to produce energy rich hydrochar. The Hydrothermal carbonization (HTC) was conducted at a temperature of 180 °C and 200 °C for 6 h to produce carbon-rich hydrochar. Physicochemical, structural and combustion properties of PTY and UTY hydrochar were characterized and compared using a range of techniques to gain detailed insight into individual hydrochar samples. Microwave pretreatment of yard waste enhanced the biogas production from 264 ± 11 mL/g VS to 370 ± 14 mL/g VS. The carbon content and higher heating value of digestate increased considerably from 44 and 44.35% to 53–56% and15–16 MJ/kg to 21–23 MJ/kg, respectively after HTC. Thermal gravimetric analysis of the prepared hydrochar showed that the high-temperature carbonization increased the combustion properties of hydrochar. The hydrochar prepared from PTY showed enhanced physicochemical, structural and combustion properties as compared to hydrochar prepared from UTY. The finding asserted that the pretreatment of yard waste before AD not only improved biogas production but also improved yield with better quality hydrochar when its resulting digestate was hydrothermally carbonized. AD of yard waste yields biogas and HTC of the resulting digestate yields hydrochar; both are biofuel, hence, augmenting HTC as a downstream treatment process along with AD would result in the creation of near-zero loss process.

The advent of the COVID-19 pandemic has enhanced the complexities of plastic waste management. Our improved, hyper-hygienic way of life in the fear of transmission has conveniently shifted our behavioral patterns like the use of PPE (Personal protective equipment), increased demand for plastic-packaged food and groceries, and the use of disposable utensils. The inadequacies and inefficiencies of our current waste management system to deal with our increased dependence on plastic could aggravate its mismanagement and leakage into the environment, thus triggering an environmental crisis. Mandating scientific sterilization and the use of sealed bags for safe disposal of contaminated plastic wastes should be an immediate priority to reduce the risk of transmission to sanitation workers. Investments in circular technologies like feedstock recycling along with improving the infrastructure and environmental viability of existing techniques could be the key to dealing with the plastic waste fluxes during a crisis. Transition towards environmentally friendly materials like bioplastics and harboring new sustainable technologies would be crucial to fighting future pandemics. Although the rollbacks and relaxation of single-use plastic bans may be temporary, their likely implications on the consumer perception could hinder our long-term goals of transitioning towards a circular economy. Likewise, any delay in building international willingness and participation to curb any form of pollution through summits and agendas may also delay its implementation. Reduction in plastic pollution and inclusive, sustainable plastic waste management can be achieved by restructuring our policies to instill individual behavioral as well as social, institutional changes. Incentivizing measures that encourage circularity and sustainable practices, public-private investments in research and infrastructure would help in bringing the aforementioned changes. Individual responsibility, corporate action, and government policy are all necessary to keep us from transiting from one disaster to another., Graphical abstract Unlabelled Image, Highlights • COVID-19 has increased our reliance on plastics for safety and hygienic purposes. • Increase in plastic waste generation adds up to the woes of our management system. • Temporary relaxation on use of single-use plastic could alter consumer's behavior. • Innovation in existing products and technologies could help achieve sustainability. • Social responsibility, corporate action, and government policy are vital for change.

Highlights 11• Changes in the composition of waste generated during COVID-19 presents considerable new challenges. 11• Ensuring safe waste management practices should be a part of emergency response services during COVID-19 crisis. 11• Temporary relaxation on use of single-use plastic during COVID-19 crises could impact consumer's behavior. 11• Shift to automated waste treatment systems will reduce the risk of transmission. 11• Building localized robust supply chains could help fight possible future pandemics., The crisis brought upon by the COVID-19 pandemic has altered global waste generation dynamics and therefore has necessitated special attention. The unexpected fluctuations in waste composition and quantity also require a dynamic response from policymakers. This study highlights the challenges faced by the solid waste management sector during the pandemic and the underlying opportunities to fill existing loopholes in the system. The study presents specific cases for biomedical waste, plastic waste, and food waste management - all of which have been a major cause of concern during this crisis. Further, without active citizen participation and cooperation, commingled virus-laden biomedical waste with the regular solid waste stream pose significant negative health and safety issues to sanitation workers. Single-use plastic usage is set to bounce back due to growing concerns of hygiene, particularly from products used for personal protection and healthcare purposes. It is expected that household food waste generation may reduce due to increased conscious buying of more non-perishable items during lockdown and due to concerns of food shortage. However, there is a chance of increase in food waste from the broken supply chains such as food items getting stuck on road due to restriction in vehicle movements, lack of workers in the warehouse for handling the food products, etc. The study also stresses the need for building localized resilient supply chains to counter such situations during future pandemics. While offering innovative solutions to existing waste management challenges, the study also suggests some key recommendations to the policymakers to help handle probable future pandemics if any holistically.

The energy demand of the world is expected to reach 739 quadrillions BTU in 2040, which therefore demand for exploring more alternative source of renewable energy. Waste biomass though vast in reserve for generating renewable energy has its own downside. High moisture, fibrous nature, high bulk volume, hydrophilic nature and low calorific value are some of the inferior quality of waste biomass which creates bottleneck for easy renewable energy generation. Pre-treatment of biomass to overcome these challenges has created a new research interest. Among the treatment options available, the hydrothermal carbonization (HTC) method, which can process wet waste has become the most preferred choice among researchers recently. The HTC eliminates energy-intensive pre-drying process needed for other treatment methods such as pyrolysis, dry torrefaction and incineration. Through this article, we attempt to provide a detailed review of how renewable biomass can be effectively used to produce renewable energy by improving their inherent inferior characteristics. The review also highlights bottlenecks that constrain the deployment of renewable energy using HTC methods. The scope of further research direction is well identified in this review. The paper also present recent advancements which are filling the knowledge gap of HTC technology that were there earlier. Critical analysis of microwave assisted HTC and conventional heated HTC is also presented in this review. The analysis in this paper reveals that biomass is a valuable resource, and should be explored to take advantage of its renewable energy generation potential. The HTC method of biomass upgradation improves transport, storage and fuel characteristics by improving grindability, pellets durability, hydrophobicity, energy density, combustion behaviour and calorific value, and also helps in improving the environmental performance of solid fuel produced. Despite the fact that the technology is in the early stage of development and there still exist knowledge gap and shortcomings, the vast literature reviewed suggests that it has a potential of being future technology. Therefore, it needs further investigation which should fill existing shortcoming of the technology.

Solid state anaerobic digestion of food waste (FW) with yard waste (YW) appears to be an efficient technique for bioenergy production. However, the reluctant nature of YW and nutrient imbalance due to high C/N ratio are the two major obstacles for maximum methane production. In this study to improve the methane production potential, YW was thermally pretreated to reduce its recalcitrance nature and then the pretreated YW was co-digested with FW to balance nutrient for anaerobic co-digestion. Moreover, optimization of F/M (Food/Microorganism) ratios (1.0, 1.5, 2.0 and 2.5) for solid state anaerobic co-digestion was also considered. The highest methane production of 431 mL/gVSadded was observed for co-digestion of FW with microwave pretreated YW at the F/M ratio of 1.5. Energy balance of the pretreatment technique was conducted and the highest net energy gain 3.98 kJ/gVS (= output energy of 14.04 kJ/gVS - input energy of 10.05 kJ/g VS) obtained at the F/M ratio of 1.0.

For the improvement in underwater acoustic sensor networks, vector based technique is used to increase the efficiency of network and reduce the chances of link failure. It is also improve robustness and scalability of the network. Underwater acoustic are used sensor nodes and autonomous vehicles to communicate from one place to another under the ocean and also used a surface station. They create a link to on-shore control center. UANs are different from terrestrial networks. These are used in different fields like military and commercial fields. Underwater networks are connected with number of vehicles and sensors which are used to monitor the underwater activities. This paper evaluates the research problems of underwater acoustic networks like energy consumption and different layers are used to solve the issues which occur in UANs.

Objectives: Investigation for low cost, small scale, decentralized waste water treatment system for small communities and suburbs was done in this study. Total passive system, artificially engineered to treat domestic wastewater by mimicking the natural water purifying processes of river, swamp and wetlands, gives us what is known as constructed wetland. Methods: In this paper, we carried out the design and installation of two laboratory scale vertical flow constructed wetland within the premises of Lovely Professional University sewage treatment Plant. Two separate systems of height 45 cm and average diameter 15 cm was created, one with gravel and sand as a media and other with gravel, sand and soil as a media. Both the wetland was planted with Canna sp as an excellent phytoremediating plant and was available easily in locality. This plant shows very high growth rate and has a large rhizome. The waste water was fed through the 1.5cm diameter pipe. Eight liter of pretreated wastewater from the university Sewage treatment plant was fed with a retention period of 2 days, feeding was done in such a way that the gravitation does all the work, as the feeding tank was placed higher above both the wetland. Feeding was control by the valve. Findings: Initial analysis of wastewater subjected to wetland shows dramatic reduction in the visible suspended solids and color. Dissolve oxygen was improved from 3.6±0.4mg/L to 5±.2mg/L in both the wetland system. pH in effluent from both the CW was in between 6.5-8.5, pH of influent was in between 9±0.4. BOD5 at 20oC of both the effluent form vertical flow CW was found to be below 30mg/L as against the 180-190mg/L of influent given to wetland, which was well within the range as per as Environment (protection) rules, 1986 of GOI for inland surface water discharge. Application/Improvement: Potable water is already a scare resource; even the water for irrigation is becoming scarce and not to forget the depleting ground water table. The findings of this study shows us a potential cheap method to treat wastewater generated, which can be used to met our agricultural water demand and can even be used to recharge ground water.

Liquid hot water (LHW) pretreatment is considered as a key step in reducing biomass recalcitrance and improving its accessibility to microorganisms during anaerobic digestion. In the present study, a comprehensive comparison among hot air oven, hot water bath, autoclave and microwave (MW) pretreated yard waste (YW) was conducted. The effect of treatment temperature and duration for all the four LHW pretreatment techniques were optimized with respect to the organic matter solubilisation. The results showed that all four LHW pretreatment techniques have a positive effect on organic matter solubilisation. The highest organic matter solubilisation was found in case of MW pretreatment for a treatment duration of 100 s at a temperature of 140 °C. Therefore, batch biochemical methane potential (BMP) of untreated and MW pre-treated YW was carried out for this treatment condition. The BMP of MW pretreated YW resulted in an improvement in methane yield to 364.5 ± 11 mL/g VS on 26th day of anaerobic digestion, which was 1.1 times higher than that of untreated (328.9 ± 15 mL/g VS on 45th day of anaerobic digestion). The FTIR and XRD analysis confirmed that LHW pretreatment technique removed amorphous constituents due to the polymerization of polysaccharides present in YW. In addition, SEM analysis confirmed that the LHW pretreatment led irregular and distorted structure of biomass which improved cellulose accessibility to anaerobic bacteria. A positive energy balance confirmed the possible applicability of MW pretreatment in real life projects.