scholarly journals Impact assessment of water and nutrient reuse in hydroponic systems using Bayesian Belief Networks

2020 ◽  
Vol 10 (4) ◽  
pp. 431-442 ◽  
Author(s):  
Martin Zimmermann ◽  
Michaela Fischer

Abstract Water-saving agricultural practices can reduce negative environmental impacts in water-scarce regions all over the world. This study deals with an innovation that combines hydroponic crop production and municipal wastewater reuse for irrigation purposes. The research question was what impacts such hydroponic water reuse systems have on product confidence, economic viability, groundwater recharge, biodiversity and landscape quality. It should also be clarified under which conditions and with which measures these systems can be sustainable. To answer these questions, a number of generic hydroponic water reuse systems were modeled and assessed using a Bayesian Belief Network that included both numerical values and expert knowledge. The hydroponic water reuse systems with the most positive overall impacts are small-scale food production systems (tomatoes) equipped with lighting and heating whose products are marked with a quality label or with a label for regional products. The systems are located in a former industrial area. In addition, a wetland system and landscape integration are implemented as landscaping measures. Hydroponic systems can be operated economically viable, their products have a high level of product confidence and their ecological impacts can be positive. No tradeoffs have to be accepted between economic, social and ecological goals.

2020 ◽  
Author(s):  
Di Liu ◽  
Jean-Luc Legras ◽  
Pangzhen Zhang ◽  
Deli Chen ◽  
Kate Howell

AbstractMicrobial activity is an integral part of an agricultural ecosystem and influences the quality of agricultural commodities. Microbial ecology influences grapevine health and crop production, conversion of sugar to ethanol during fermentation, thus wine aroma and flavour. There are regionally differentiated microbial patterns in grapevines and must but how microbial patterns contribute to wine regional distinctiveness (terroir) at small scale (<100 km) is not well defined. Here we characterise fungal communities, yeast populations, and Saccharomyces cerevisiae populations during spontaneous fermentation using metagenomics and population genetics to investigate microbial distribution and fungal contributions to the resultant wine. We found differentiation of fungi, yeasts, and S. cerevisiae between geographic origins (estate/vineyard), with influences from the grape variety. Growth and dominance of S. cerevisiae during fermentation reshaped the fungal community and showed geographic structure at the strain level. Associations between fungal microbiota diversity and wine chemicals suggest that S. cerevisiae plays a primary role in determining wine aroma profiles at a sub-regional scale. The geographic distribution at scales of less than 12 km supports that differential microbial communities, including the dominant fermentative yeast S. cerevisiae can be distinct in a local setting. These findings provide further evidence for microbial contributions to wine terroir, and perspectives for sustainable agricultural practices to maintain microbial diversity and optimise fermentation function to craft beverage quality.


Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1822
Author(s):  
Ron Crites ◽  
Robert Beggs ◽  
Harold Leverenz

The practice of irrigation with municipal wastewater has evolved from avoidance of surface water pollution to beneficial reuse of water and nutrients for crop production. The ability of the soil to filter out pollutants and pathogens has been documented, such that groundwater quality is not degraded where recycled water to irrigate crops used for human consumption. The example of successful practice of the Castroville project in Monterey County, California illustrates safe reuse of recycled water for crop growth, marketing of crops grown into the fresh produce market, and groundwater protection. Impediments to the future more widespread reuse of recycled water for agricultural irrigation are also discussed. Many of the same technological advancements that have supported the development of modern agricultural water reuse projects have also improved the feasibility of various competing urban water reuse applications. The effects from increasing water scarcity has also had an impact on the quality and quantity of water available for agricultural water reuse projects. The historical practice of developing centralized and regional wastewater treatment facilities near a suitable surface water discharge location may need to be modified for better consideration of agricultural irrigation in integrated water resources planning.


2013 ◽  
Vol 67 (6) ◽  
pp. 1188-1193 ◽  
Author(s):  
V. Diamantis ◽  
W. Verstraete ◽  
A. Eftaxias ◽  
B. Bundervoet ◽  
V. Siegfried ◽  
...  

Pre-concentration of municipal wastewater by chemically enhanced primary treatment (CEPT) was studied under controlled laboratory conditions. Both iron and aluminium-based coagulants were examined at gradually increasing concentrations (0.23, 0.35, 0.70 and 1.05 mmol/L). The CEPT sludge generated from different coagulation experiments was digested in batch anaerobic reactors, while the supernatant was tested in a dead-end microfiltration setup. The results of the study show that biogas yield was dramatically decreased (from 0.40 to 0.10 m3/kg chemical oxygen demand of influent) with increasing coagulant dose. In contrast, supernatant filterability was improved. Based on the laboratory results, a conceptual design was produced for a community of 2000 inhabitant equivalents (IE), using CEPT technology (at low coagulant dose) with anaerobic digestion of the concentrates. According to this, the capital and operational costs were 0.11 and 0.09 €/m3, respectively. The biogas generated is used for digester heating and the overall process is energy self-sufficient. At a small-scale and in private applications, CEPT technology is preferably operated at higher coagulant dose, followed by membrane filtration for water reuse. Accordingly, sewage purification and reuse is possible without implementing aerobic biological processes.


Author(s):  
Hasrat Arjjumend ◽  
Konstantia Koutouki ◽  
Olga Donets

The use of unsustainable levels of chemical fertilizers and plant protection chemicals has resulted in a steady decline in soil and crop productivity the world over. Soil biology has undergone irreversible damage, coupled with a high concentration of toxic chemical residues in plant tissues and human bodies. Agricultural practices must evolve to sustainably meet the growing global demand for food without irreversibly damaging soil. Microbial biocontrol agents have tremendous potential to bring sustainability to agriculture in a way that is safe for the environment. Biopesticides do not kill non-target insects, and biosafety is ensured because biopesticides act as antidotes and do not lead to chemical contamination in the soil. This article is part of a larger study conducted in Ukraine by researchers at the Université de Montréal with the support of Mitacs and Earth Alive Clean Technologies. The responses of farmers who use biofertilizers (“user farmers”) and those who do not (“non-user farmers”), along with the responses of manufacturers or suppliers of biofertilizers, and research and development (R&D) scientists are captured to demonstrate the advantages of applying microbial biopesticides to field crops. Participants reported a 15-30% increase in yields and crop production after the application of biopesticides. With the use of biopesticides, farmers cultivated better quality fruits, grains, and tubers with a longer shelf life. Moreover, while the risk of crop loss remains high (60-70%) with chemically grown crops, this risk is reduced to 33% on average if crops are grown using biopesticides. The findings indicate that a large proportion of farmers would prefer to use biopesticides if they are effective and high quality products. In this context, the quality and effectiveness of products is therefore very important. Despite their benefits to soil, human health, and ecosystems, biopesticides face significant challenges and competition vis-à-vis synthetic pesticides for a variety of reasons. Therefore, the development of biopesticides must overcome the problems of poor quality products, short shelf life, delayed action, high market costs, and legal/registration issues.


1997 ◽  
Vol 35 (6) ◽  
pp. 37-44 ◽  
Author(s):  
Boran Zhang ◽  
Kazuo Yamamoto ◽  
Shinichiro Ohgaki ◽  
Naoyuki Kamiko

Activated sludges taken from full-scale membrane separation processes, building wastewater reuse system (400m3/d), and two nightsoil treatment plants (50m3/d) as well as laboratory scale membrane separation bioreactor (0.062m3/d) were analyzed to characterize membrane separation activated sludge processes (MSAS). They were also compared with conventional activated sludges(CAS) taken from municipal wastewater treatment plants. Specific nitrification activity in MSAS processes averaged at 2.28gNH4-N/kgMLSS.h were higher than that in CAS processes averaged at 0.96gNH4-N/kgMLSS.h. The denitrification activity in both processes were in the range of 0.62-3.2gNO3-N/kgMLSS.h without organic addition and in the range of 4.25-6.4gNO3-N/kgMLSS.h with organic addition. The organic removal activity in nightsoil treatment process averaged at 123gCOD/kgMLSS.h which was significantly higher than others. Floc size distributions were measured by particle sedimentation technique and image analysis technique. Flocs in MSAS processes changed their sizes with MLSS concentration changes and were concentrated at small sizes at low MLSS concentration, mostly less than 60 μm. On the contrary, floc sizes in CAS processes have not much changed with MLSS concentration changes and they were distributed in large range. In addition, the effects of floc size on specific nitrification rate, denitrification rate with and without organic carbon addition were investigated. Specific nitrification rate was decreased as floc size increased. However, little effect of floc size on denitrification activity was observed.


2014 ◽  
Vol 955-959 ◽  
pp. 3393-3399 ◽  
Author(s):  
Wei Zheng ◽  
Yan Ming Yang ◽  
Yun Long Li ◽  
Jian Qiu Zheng

The process technique and design parameters of project of Solar Ozonic Ecological Sewage Treatment Plant (short for SOESTP) which consists of anaerobic reactor, horizontal subsurface flow (HSSF) constructed wetlands(CWs) and the combination of solar power and ozone disinfection are described, the paper further examines the removal efficiency for treating rural domestic sewage, running expense and recycling ability of product water. The results show that the average percentage removal values of CODcr,BOD5,SS,TN,NH3-N,TP range from 95.6% to 98.0%, 96.0% to 98.7%, 93.1% to 96.1%, 97.0% to 98.9%, 96.9% to 99.5%, 98.2% to 99.6%, respectively, the reduction of fecal coliform (FC) reaches 99.9%, the effluent quality meets the first level A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB18918-2002). The running cost of SOESTP is 0.063yuan/ m3, saves much more than traditional sewage treatment, and the ozone water obtained from the reservoir will be an ideal choice for disinfection .The system has characteristics of easy manipulation, low operating cost, achieving advanced water, energy conservation and environment protection, is thought to be very suitable for use as the promotion of rural small - scale sewage treatment.


Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 60
Author(s):  
Vincenzo Michele Sellitto ◽  
Severino Zara ◽  
Fabio Fracchetti ◽  
Vittorio Capozzi ◽  
Tiziana Nardi

From a ‘farm to fork’ perspective, there are several phases in the production chain of fruits and vegetables in which undesired microbial contaminations can attack foodstuff. In managing these diseases, harvest is a crucial point for shifting the intervention criteria. While in preharvest, pest management consists of tailored agricultural practices, in postharvest, the contaminations are treated using specific (bio)technological approaches (physical, chemical, biological). Some issues connect the ‘pre’ and ‘post’, aligning some problems and possible solution. The colonisation of undesired microorganisms in preharvest can affect the postharvest quality, influencing crop production, yield and storage. Postharvest practices can ‘amplify’ the contamination, favouring microbial spread and provoking injures of the product, which can sustain microbial growth. In this context, microbial biocontrol is a biological strategy receiving increasing interest as sustainable innovation. Microbial-based biotools can find application both to control plant diseases and to reduce contaminations on the product, and therefore, can be considered biocontrol solutions in preharvest or in postharvest. Numerous microbial antagonists (fungi, yeasts and bacteria) can be used in the field and during storage, as reported by laboratory and industrial-scale studies. This review aims to examine the main microbial-based tools potentially representing sustainable bioprotective biotechnologies, focusing on the biotools that overtake the boundaries between pre- and postharvest applications protecting quality against microbial decay.


2021 ◽  
Vol 11 ◽  
pp. 100094
Author(s):  
Eva Reynaert ◽  
Angelika Hess ◽  
Eberhard Morgenroth
Keyword(s):  

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1862
Author(s):  
Alexandros-Georgios Chronis ◽  
Foivos Palaiogiannis ◽  
Iasonas Kouveliotis-Lysikatos ◽  
Panos Kotsampopoulos ◽  
Nikos Hatziargyriou

In this paper, we investigate the economic benefits of an energy community investing in small-scale photovoltaics (PVs) when local energy trading is operated amongst the community members. The motivation stems from the open research question on whether a community-operated local energy market can enhance the investment feasibility of behind-the-meter small-scale PVs installed by energy community members. Firstly, a review of the models, mechanisms and concepts required for framing the relevant concepts is conducted, while a clarification of nuances at important terms is attempted. Next, a tool for the investigation of the economic benefits of operating a local energy market in the context of an energy community is developed. We design the local energy market using state-of-the-art formulations, modified according to the requirements of the case study. The model is applied to an energy community that is currently under formation in a Greek municipality. From the various simulations that were conducted, a series of generalizable conclusions are extracted.


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