Anaerobic Wastewater Treatment

PurposeMicrobial pathogens can lead to health problems and disease transmission. Present study aimed to evaluate the microbial quality and quantity of vermicompost production and to compare to the current Iranian standards to protect public health and environmental concerns.MethodThis is a pilot-scale experimental study conducted in the Public Health laboratory of Shahid Sadoughi University of Medical Sciences. The samples included organic municipal solid waste, cow manure and wastewater treatment plant sludge which are used for vermicompost production. The samples are mixed as cow manure–organic waste and cow manure–sewage sludge in two reactors. Microbial tests such as fecal coliforms (FC) and parasite egg (Ascaris) were carried out during start, processing and curing time with duplication analysis in 56 days. Totally, a number of 128 samples was analyzed. Analyses were conducted according to standard methods. Data analysis was conducted through one-way ANOVA and Duncan tests.ResultsThe results showed a significant reduction in number of FCs in cow manure–organic waste so that the number of 350,000 MPN/g in the raw sample decreased to 800 MPN/g within 8-week period, also FC in the case of cow manure–sewage sludge was achieved to 2400 from 6,500,000 MPN/g. In two cocomposting cases, the parasite eggs were completely removed in the second week.ConclusionThe results showed vermicomposting as a feasible method to convert waste into fertilizer humus in agriculture which also enables to achieve Iranian class A compost standard.

Anaerobic digestion is an effective process for the treatment of organic solid waste and wastewater and the production of biogas, which is a clean energy source. The carbon dioxide in the biogas can be converted into methane using hydrogen generated from water electrolysis through an approach referred to as power-to-gas. Recently, hydrogen has been added to digesters as an in-situ or ex-situ biogas upgrade to reduce the levels of carbon dioxide. Biogas production systems consist of microbial complexes with highly organized microorganisms in different niches, which can either produce or consume hydrogen. However, the produced endogenous hydrogen should be constantly consumed to maintain a low hydrogen partial pressure. This review addresses the biochemical processes of anaerobic digestion and hydrogen-related microorganisms, including fermentative acid-producing bacteria, syntrophic organic acid degrading bacteria, syntrophic acetate-oxidizing bacteria, homoacetogens, hydrogenotrophic methanogens, and newly reported hydrogen-dependent methylotrophic methanogens. This study also investigates (1) the role of endogenous hydrogen as an intermediate metabolite and of interspecies electron transfer in anaerobic digestion, (2) effects of exogenous hydrogen addition on microbial community structure and metabolic processes, and (3) recent developments regarding in-situ and ex-situ biogas upgrading systems via hydrogen addition.

Anaerobic digestion (AD) is a technology that is gaining popularity because of the need for more renewable energy sources around the world. AD is a complex series of biochemical reactions that ultimately result in the formation of biogas, which is a mixture of methane and carbon dioxide with other trace elements. From large installations to small personal reactors, the underlying basic process is the same, but through research, pretreatments and substrate co-digestion are becoming more popular to enhance biogas production. Reactor design and substrate selection also vary depending on the installation’s location. Biogas cleaning and upgrading help to increase the usability of the gas for multiple applications. The economic viability depends on the location in the world and the available substrate quality and quantity. AD processes rely heavily on government subsidies to stay profitable. In developing countries, AD profitability is not a concern, as this technology provides a way to better human life in these areas. This review presents a detailed look at the AD technology, provides a discussion on the economics of AD, and suggests future studies to enhance the technology.

Historical data on organic waste and wastewater treatment during the period of 1970-2020 were used to assess the impact of treatment on energy and greenhouse gas (GHG) balances. The assessment included the waste fractions: Sewage sludge, food waste, yard waste and other organic waste (paper, plastic, etc.). Data were collected from Aalborg, a municipality located in Northern Denmark. During the period from 1970-2005, Aalborg Municipality has changed its waste treatment strategy from landfilling of all wastes toward composting of yard waste and incineration with combined heat and power production from the remaining organic municipal waste. Wastewater treatment has changed from direct discharge of untreated wastewater to full organic matter and nutrient (N, P) removal combined with anaerobic digestion of the sludge for biogas production with power and heat generation. These changes in treatment technology have resulted in the waste and wastewater treatment systems in Aalborg progressing from being net consumers of energy and net emitters of GHG, to becoming net producers of energy and net savers of GHG emissions (due to substitution of fossil fuels elsewhere). If it is assumed that the organic waste quantity and composition is the same in 1970 and 2005, the technology change over this time period has resulted in a progression from a net annual GHG emission of 200 kg CO( 2)-eq. capita(-1) in 1970 to a net saving of 170 kg CO(2)-eq. capita(-1) in 2005 for management of urban organic wastes.

ABSTRACTThe proper treatment of organic or inorganic solid wastes is necessary for economic and environmental interests. Added-value by-products of market interest can be obtained through the recovery, reuse, and treatment of solid wastes, which are otherwise discarded inappropriately in large quantities into the environment. In this review, the drying process is presented as an alternative environmental technology for the thermal treatment of residues of different natures from different origins. The main techniques applied to solid waste drying are described and, in parallel, the most relevant studies found in the literature for this theme are analyzed. Moreover, the main dryers currently used are presented, as well as their most important characteristics. Some general aspects of the thermal and energetic performance of these dryers fundamental for process feasibility analysis are also discussed in this review. Essential aspects of the solid waste drying process are primarily presented with the purpose of showing the particularities that this approach offers when it comes to putting the theory into practice.

Energy from food waste

A diverse world of microorganisms inhabits anaerobic environments on Earth, and these obtain their energy by fermentation or by anaerobic respiration, in which electron acceptors other than molecular oxygen drive the oxidation of organic compounds. We also know phototrophic and chemoautotrophic processes that function in the absence of oxygen. Collaboration of different groups of microorganisms can lead to degradation of complex organic matter also under anaerobic conditions, with carbon dioxide or a mixture of carbon dioxide and methane as the main products, depending on the availability of electron acceptors other than molecular oxygen, such as nitrate or sulfate. The different groups of anaerobes are essential for the functioning of the biogeochemical cycles of carbon, nitrogen, sulfur and other elements, and also play important roles in the production of fermented food products, treatment of organic wastes and other biotechnological processes. Key Concepts: Life developed on planet Earth in the absence of molecular oxygen (O 2 ). The anaerobic way of life is widespread in the prokaryotic world – in Bacteria as well as Archaea. Permanently anaerobic environments include marine and freshwater lake bottom sediments, digestive systems, the deep subsurface and others. Some protozoa can live anaerobically. Recently a community of multicellular meiozoa that lives in permanently anoxic conditions was discovered in L'Atalante basin, 3.5 km below the surface of the Mediterranean Sea. In the absence of molecular oxygen, many prokaryotes can use alternative electron acceptors, such as nitrate, sulfate, Fe(III) and others, for respiration (‘anaerobic respiration’). When no suitable electron acceptor is available, energy can be gained by fermentation processes, in which ATP is gained by substrate‐level phosphorylation. Complete anaerobic breakdown of organic matter is a cooperative process in which fermentative microorganisms, bacteria performing anaerobic respiration and methanogenic Archaea cooperate. Hydrogen and acetate are key intermediates in many anaerobic degradation processes.

Insight into FeOOH-mediated advanced oxidation processes for the treatment of organic polluted wastewater

Anaerobic digestion is an established technology for the treatment of wastewater and its sludge and has been used by humans for centuries. Anaerobic digestion is considered to be a useful tool that can generate renewable energy, and significant research interest has arisen recently. The final product of the anaerobic digestion is biogas: a mixture of methane (55–75 vol%) and carbon dioxide (25–45 vol%) that can be used for heating, upgrading to natural gas quality or cogeneration of electricity and heat. Digestion installations are technologically simple with low energy and space requirements. Anaerobic treatment systems are divided into ‘high-rate’ systems involving biomass retention and ‘low-rate’ systems without biomass retention. High-rate systems are characterized by a relatively short hydraulic retention time but long sludge retention time and can be used to treat many types of wastewater and the sludge. Low-rate systems are generally used to digest slurries and are characterized by a long hydraulic retention time, equal to the sludge retention time. The biogas yield varies with the type and concentration of the feedstock and process conditions. The aim of the chapter is to discuss the basic principles of the anaerobic process, the affecting factors, advantages and disadvantages, various treatment methods and energy recovery in the form of biogas. The energy recovery from the anaerobic digestion would open the doors in the conservation of energy resources and also a sustainable method for management of wastewater and its sludge.

Harmless and resourceful utilization of solid waste: Multi physical field regulation in the microbiological treatment process of solid waste treatment

The escalating global population and subsequent rise in consumerism underscore the critical need for proper solid waste management, with a specific focus on the daily disposal of organic waste. Inadequate waste management poses direct threats to public health, as uncontrolled fermentation provides a fertile ground for bacterial growth. This study explores the efficacy of employing Microorganisms, specifically comparing Trichoderma to a Microbial Biocatalyst, for the treatment of daily solid organic waste (D.S.O.W.). Following Falconi's (2013a) methodology for the capture, multiplication, and conidial count of microorganisms, a pilot study utilizing a Bioreactor was conducted. The statistical analysis of parameters such as Humidity, Weight, pH leachates, Temperature, Time, and Volume, with corresponding ANOVA significance levels, resulted in the rejection of null hypotheses for most parameters, except pH m.o. The capture and multiplication of Trichoderma spp. microorganisms reached a count 7.6×109 /ml. Treatment 6 (T6) emerged as more effective and efficient in decomposing organic matter (OM), exhibiting distinct stages of psychrophilic, mesophilic (3 days), thermophilic (6 days), psychrophilic (3 days), and cooling (3 days), culminating in the decomposition of OM in 15 days within the bioreactor. The results validate the working hypothesis, affirming the potential of Microorganisms, especially Trichoderma, in enhancing the treatment of daily solid organic waste.

Nizam Zachman is a modern fishery port located in Muara Baru, Jakarta, Indonesia. Some of its facilities include a temporary collection of solid waste and wastewater treatment plants, emitting greenhouse gases that lead us to climate change by warming up the global temperature. In this study, greenhouse gas emissions are estimated from these two facilities by using the IPCC Tier 1 method and emission factor calculation. By estimating greenhouse gas in this area, it will give knowledge and convicing to make greenport as a consideration of the strategy to reduce greenhouse gas emission, starting from waste and wastewater management. Solid waste treatment comprises open dumping, recycling, and transportation of wastes to the temporary landfill in this area. With a total waste of 5, 411.4 tons/year, greenhouse gas emissions from open dumping and transportation are estimated to be 14, 340.2 and 22.3 tons CO2eq/year, respectively. Meanwhile, recycling activities contribute to 143 tons CO2 eq/year of greenhouse gas emissions. In addition, the estimated greenhouse gas emissions include emissions from wastewater treatment, discharge of industrial wastewater to waterways via the drainage system, and domestic wastewater treatment by using a septic tank. In addition, greenhouse gas emissions from wastewater treatment, drainage system, and septic tanks are estimated to be 2, 830; 108.7; and 3.2 tons CO2 eq/year, respectively. Based on the estimation, solid waste treatment generates 83% of the total greenhouse gas emissions, while wastewater treatment generates only 17% of the total emissions. Herein, composting, increase of recycling, and utilization of methane are recommended to reduce the greenhouse gas emissions from waste management.

Treatment of organic wastewater containing nitrogen and chlorine by combinatorial electrochemical system: Taking biologically treated landfill leachate treatment as an example

Polytetrafluoroethylene (PTFE) hollow fiber AnMBR performance in the treatment of organic wastewater with varying salinity and membrane cleaning behavior

Treatment of solid waste that can be applied to reduce solid waste into the landfill is the treatment of organic solid waste into a biogas. The largest component of biogas is CH4 and CO2 Alternative organic solid waste treatment is anaerobic digestion, besides reducing waste, this process can also produce renewable fuels. This research processed the leachate organic solid waste from Itenas cafetaria using fixed bed reactor. Volume reactor 180 liters with sponge filter media. An increase the concentration gas CH4 conducted using pressure swing absorption technology with pressure 1 bar on the reactor metanogen and -0,01 bar on stripper. Variation circulation a substrate for 0,30, 0,32, and 0,33 circulation per hour. Parameter measured are COD, TVA, pH, temperature, alkalinitas, and CO2, CH4. The result of this research obtained gas CH4 highest concentration of 90 % in a gas holder metanogen, and the highest CO2 24,36 % in a gas holder stripper on volumetric 0,33 circulation/hours.