Aerobic Waste Treatment Research Articles

Pengurangan Nilai COD pada Effluent Fermentor Biogas UASB-HCPB dengan Memanfaatkan Mikroalga Chlorella vulgaris

Palm oil mill effluent (POME) is the main waste generated from the palm oil industry. LCPKS has a COD level of 57,000-60,400 mg/L. High levels of COD can harm the environment. LCPKS treatment techniques generally use a combination of anaerobic and aerobic waste treatment methods. The anaerobic process has been conducted using a UASB-HCPB reactor. But, the COD levels of anaerobic results have not reached the quality standards so that further processing is needed. Microalgae have the potential to reduce contaminant levels in wastewater. Chlorella vulgaris microalgae is a microalgae that is widely used in wastewater treatment. This study utilized Chorella vulgaris in reducing the COD levels of the effluent of the UASB-HCPB biogas fermentor with variations in lighting intensity and variations in the ratio of effluent to microalgae. It was found that the lighting intensity of light:dark (24:0) hours provided optimal microalgae growth so as to provide the best COD reduction with a COD reduction efficiency of 87.5%. The ratio of microalgae to effluent of 1000 mL: 500 mL showed the best COD reduction with an efficiency of 93.75%.

Study on the degradability of plastics with prodegradant additives during anaerobic and aerobic biological waste treatment processes

The degradability of conventional plastic packaging specimens made from PP and PET, that were produced with novel prodegradant additives, was investigated during biological waste treatment processes. The additives were merchandised to foster the degradation of commodity plastics by enzymatic or by abiotic processes. Four different plastic packaging specimens and two different additives were evaluated for their biodegradability during anaerobic and aerobic waste treatment conditions. Aerobic treatment was investigated in laboratory rotting tests, simulating conditions during composting in a plant according to the Austrian state-of-the-art, while anaerobic treatment was investigated in laboratory digestion reactors. The study shows that only the PET specimens showed a loss of mass of ca. 6.5%, during 50 days of digestion at 52 °C. None of the specimens degraded during the aerobic rotting process. None of the materials fragmented into microplastic particles of sizes > 1 mm under the investigated conditions. However, FTIR analysis revealed the oxidation in the case of PP specimens, which indicated a mediated oxidation process during composting, independent of the merchandised mechanism of predegradation. Under anaerobic conditions, the plastic specimens containing reactors produced more biogas within the first 20 days of digestion, that did not originate from an observable degradation of the plastics.

Chemical Waste and Allied Products.

This review of literature published in 2016 focuses on waste related to chemical and allied products. The topics covered include waste management, aerobic waste treatment, anaerobic waste treatment, air emission, biological waste treatment, groundwater remediation, water recycle, water analysis, water reuse, soil remediation, sorption, physicochemical treatment, ozonation, and fertilizer waste. Future topics include the pollution effect on the environment, especially, to the ecosystem and human as well as improved treatment processes to alleviate the detrimental effects.

Chemical Waste and Allied Products

This review of literature published in 2015 focuses on waste related to chemical and allied products. The topics cover the waste management, physicochemical treatment, aerobic granular, aerobic waste treatment, anaerobic granular, anaerobic waste treatment, chemical waste, chemical wastewater, fertilizer waste, fertilizer wastewater, pesticide wastewater, pharmaceutical wastewater, ozonation. cosmetics waste, groundwater remediation, nutrient removal, nitrification denitrification, membrane biological reactor, and pesticide waste.

Enhancement of Aerobic Wastewater Treatment by the Application of Attached Growth Microorganisms and Microbubble Generator

This paper presents the efficiency improvement in aerobic wastewater treatment technology through the application of a microbubble generator (MBG) for aeration. Aeration using an MBG is accomplished through water circulation and does not need air compressors, making it more energy efficient than conventional aerators. The MBG aerobic system with the variations on liquid flow rate (Q1) and airflow rate (Qg) combination was tested using artificial wastewater with a typical composition of organic waste. Experimental data were evaluated by means of a simplified mathematical model to systematically compare different MBG schemes. The study confirmed that the soluble chemical oxygen demand (SCOD) removal efficiency was significantly affected by the Qg values. Lower Qg values were preferable because they tended to have higher soluble chemical oxygen demand (SCOD) removal efficiency. However, the microbubbles were less stable at lower Qg due to the high incidence of bubble collisions. The study concluded that for applications in an actual aerobic waste treatment pond, the positioning of the MBG in the pond had to be carefully designed to minimize the collision tendency.

Extraction of medium chain fatty acids from organic municipal waste and subsequent production of bio-based fuels

This paper provides an overview on investigations for a new technology to generate bio-based fuel additives from bio-waste. The investigations are taking place at the composting plant in Darmstadt–Kranichstein (Germany). The aim is to explore the potential of bio-waste as feedstock in producing different bio-based products (or bio-based fuels). For this investigation, a facultative anaerobic process is to be integrated into the normal aerobic waste treatment process for composting. The bio-waste is to be treated in four steps to produce biofuels. The first step is the facultative anaerobic treatment of the waste in a rotting box namely percolate to generate a fatty-acid rich liquid fraction. The Hydrolysis takes place in the rotting box during the waste treatment. The organic compounds are then dissolved and transferred into the waste liquid phase. Browne et al. (2013) describes the hydrolysis as an enzymatically degradation of high solid substrates to soluble products which are further degraded to volatile fatty acids (VFA). This is confirmed by analytical tests done on the liquid fraction. After the percolation, volatile and medium chain fatty acids are found in the liquid phase. Concentrations of fatty acids between 8.0 and 31.5 were detected depending on the nature of the input material. In the second step, a fermentation process will be initiated to produce additional fatty acids. Existing microorganism mass is activated to degrade the organic components that are still remaining in the percolate. After fermentation the quantity of fatty acids in four investigated reactors increased 3–5 times. While fermentation mainly non-polar fatty acids (pentanoic to octanoic acid) are build. Next to the fermentation process, a chain-elongation step is arranged by adding ethanol to the fatty acid rich percolate. While these investigations a chain-elongation of mainly fatty acids with pair numbers of carbon atoms (acetate, butanoic and hexanoic acid) are demonstrated. After these three pre-treatments, the percolate is brought to a refinery to extract the non-polar fatty acids using bio-diesel, which was generated from used kitchen oil at the refinery. The extraction tests in the lab have proved that the efficiency of the liquid–liquid-extraction is directly linked with the chain length and polarity of the fatty acids. By using a non-polar bio-diesel mainly the non-polar fatty acids, like pentanoic to octanoic acid, are extracted. After extraction, the bio-diesel enriched with the fatty acids is esterified. As a result bio-diesel with a lower viscosity than usual is produced. The fatty acids remaining in the percolate after the extraction can be used in another fermentation process to generate biogas.

Analysis of aerobic biological waste treatment methods especially in the case of composting

In recent years the regulations of the EU unambiguously determine that the biodegradable wastes should be used in agriculture. The characteristics of the organic wastes in most cases make the direct utilization impossible, they need pre-treatment before use. One treatment solution of these wastes is composting. During composting the organic wastes lose their hazardous characteristics and we gain a final product, the compost, which can be used in agriculture as organic fertilizer. The main conditions of effective composting are the follow and understand of the degradation process. During our research we examined different measuring methods (gas concentration and reflectance measurements, temperature mapping) that makes a cost and time effective possibility to directly analyze the degradation.

Oxygen demand for the stabilization of the organic fraction of municipal solid waste in passively aerated bioreactors

Conventional aerobic waste treatment technologies require the use of aeration devices that actively transport air through the stabilized waste mass, which greatly increases operating costs. In addition, improperly operated active aeration systems, may have the adverse effect of cooling the stabilized biomass. Because active aeration can be a limiting factor for the stabilization process, passive aeration can be equally effective and less expensive. Unfortunately, there are few reports documenting the use of passive aeration systems in municipal waste stabilization. There have been doubts raised as to whether a passive aeration system provides enough oxygen to the organic matter mineralization processes. In this paper, the effectiveness of aeration during aerobic stabilization of four different organic fractions of municipal waste in a reactor with an integrated passive ventilation system and leachate recirculation was analyzed. For the study, four fractions separated by a rotary screen were chosen. Despite the high temperatures in the reactor, the air flow rate was below 0.016m3/h. Using Darcy’s equation, theoretical values of the air flow rate were estimated, depending on the intensity of microbial metabolism and the amount of oxygen required for the oxidation of organic compounds. Calculations showed that the volume of supplied air exceeded the microorganisms demand for oxidation and endogenous activity by 1.7–2.88-fold.

Release and Reduction of Organosilicon Compounds in MBT-Plants

About seven million tons of residual waste are treated in mechanical–biological and mechanical–physical waste treatment plants (MBT) in Germany every year. Organosilicon compounds are getting released during the process of aerobic waste treatment and lead to cost intensive clogging problems in the exhaust gas treatment systems. Release of volatile methyl siloxanes (VMSs) in MBT plants as well as biological filtering as a gas treatment option were investigated in order to develop a strategy to reduce VMSs in the exhaust gas of the rotting process. This paper presents the results of a comprehensive measurement series at Germany’s largest MBT plant in terms of VMSs release during the intensive rotting process as well as investigations on the reduction of these compounds when using biological filters. Regarding the intensive rotting process we found the main release of VMSs during the first days of the process as well as a dependency between VMSs release on oxygen supply. Investigations at the biological filter of an Austrian MBT plant revealed VMSs reduction rates up to 80 %. Similar effects were also observed by investigations at a biofilter test facility over a testing period of 7 months. First results of experiments with bacteria indicate an unspecific contribution of microbial biomass to the VMSs reduction effects in biofilters.

Forced modulation of biological processes: A review

Cell culture or biochemical processes utilizing free or immobilized cells or enzymes are candidates for periodic operation. Even though these processes are isothermal, inhibition frequently arises giving their kinetics a push–pull character of the Turing type so that excited states or multiplicity are observed. Modulation of an input such as a substrate or a nutrient concentration or the cell environment such as the pH can enhance the rates of biochemical reactions that are occurring. This possibility was realized by explorers of reactor periodic operation in the 1980s. However, the use of rotating disc biological filters for aerobic waste treatment precedes these activities by at least a decade. The biologically active slime on the disc surface is exposed alternately to air and to an aqueous media containing dissolved and/or suspended waste matter. Indeed, periodic variation of reactor volume in a CSTR, which is equivalent to periodic variation of space velocity, was explored in the early 1970s. The application of this was to activated sludge waste treatment. Periodic operation has been used to address the problem of plasmid loss in continuous fermenters to produce genetically altered microorganisms. A twofold increase in the concentration of plasmid bearing cells using square wave modulation of the dilution rate has been found in a simulation using a model validated by experimental data. These results are in agreement with other studies attempting to control species populations in chemostats. Improvement in the rate of fermentation of a substrate to form a metabolite has been addressed by modulation. It has been shown that the rate of xylose utilization by a yeast is affected by a periodic variation of pH. These were lowered, but the metabolite yield, ethanol, remained the same. With secondary metabolites associated with the non-growth period in fermentation, modulation of the growth-limiting substrate concentration fed to immobilized live cells resulted in significantly higher yields. Differences in the effect of cycling on primary and secondary metabolites has been observed in several biochemical systems, such as those used for penicillin and monoclonal antibody production or in citric acid fermentation.

Greenhouse gas emission reduction and environmental quality improvement from implementation of aerobic waste treatment systems in swine farms

Trading of greenhouse gas (GHG) emission reductions is an attractive approach to help producers implement cleaner treatment technologies to replace current anaerobic lagoons. Our objectives were to estimate greenhouse gas (GHG) emission reductions from implementation of aerobic technology in USA swine farms. Emission reductions were calculated using the approved United Nations framework convention on climate change (UNFCCC) methodology in conjunction with monitoring information collected during full-scale demonstration of the new treatment system in a 4360-head swine operation in North Carolina (USA). Emission sources for the project and baseline manure management system were methane (CH4) emissions from the decomposition of manure under anaerobic conditions and nitrous oxide (N2O) emissions during storage and handling of manure in the manure management system. Emission reductions resulted from the difference between total project and baseline emissions. The project activity included an on-farm wastewater treatment system consisting of liquid-solid separation, treatment of the separated liquid using aerobic biological N removal, chemical disinfection and soluble P removal using lime. The project activity was completed with a centralized facility that used aerobic composting to process the separated solids. Replacement of the lagoon technology with the cleaner aerobic technology reduced GHG emissions 96.9%, from 4972 tonnes of carbon dioxide equivalents (CO2-eq) to 153 tonnes CO2-eq/year. Total net emission reductions by the project activity in the 4360-head finishing operation were 4776.6 tonnes CO2-eq per year or 1.10 tonnes CO2-eq/head per year. The dollar value from implementation of this project in this swine farm was US$19,106/year using current Chicago Climate Exchange trading values of US$4/t CO2. This translates into a direct economic benefit to the producer of US$1.75 per finished pig. Thus, GHG emission reductions and credits can help compensate for the higher installation cost of cleaner aerobic technologies and facilitate producer adoption of environmentally superior technologies to replace current anaerobic lagoons in the USA.

Analytical pyrolysis of re-circulated leachates: Towards an improved municipal waste treatment

The harmless removal of municipal solid waste (MSW) requires the biodegradation of organic matter to decrease the risk of gaseous emissions and leaching of contaminants. We studied the re-circulation of leachates from an aerobic treated MSW in a lysimeter and compared these results with a similar laboratory study using small-scale reactors. The reduction of total organic C and biological and chemical oxygen demands provided clear evidence for the biodegradation of organic matter in MSW after 12 months of leachate re-circulation. Curie-point pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and pyrolysis-field ionization mass spectrometry (Py-FIMS) revealed that the biodegradation was more efficient in the large-scale lysimeter than in the laboratory reactors. Different from the laboratory experiments, carbohydrates and N-containing compounds were decomposed almost completely after 2 months. Furthermore, temperature-resolved Py-FIMS showed that leachate re-circulation led to a higher thermal stability of the residual, non-decomposed organic matter. In summary, the two analytical pyrolysis methods proved that the re-circulation of leachates through MSW promoted organic matter biodegradation and offers an improved aerobic waste treatment technology.

Treatability of a simulated disperse dye-bath by ferrous iron coagulation, ozonation, and ferrous iron-catalyzed ozonation

Dyeing and finishing of textile yarns and fabrics are extremely important processes in terms of both quality and environmental concerns. Among the commercial textile dyes, particularly disperse dyestuffs are of environmental interest because of their widespread use, their potential for formation of toxic aromatic amines and their low removal rate during aerobic waste treatment as well as advanced chemical oxidation. Thus, in the present paper ferrous iron coagulation, ozonation and ferrous iron-catalyzed ozonation were employed at varying pH (3–13) and Fe(II)-ion doses (0.09–18 mM) for the treatment of a simulated disperse dye-bath (average initial apparent color as absorbance at 566 nm=815.4 m −1; COD 0=3784 mg l −1; TOC 0=670 mg l −1; BOD 5,0=58 mg l −1) that more closely resembled an actual dyehouse effluent than an aqueous disperse dye solution. Coagulation with 5000 mg l −1 FeSO 4·7H 2O (18 mM Fe 2+) at pH 11 removed up to 97% color and 54% COD, whereas oxidation via ozonation alone (applied ozone dose=2300 mg l −1) was only effective at pH 3, resulting in 77% color and 11% COD removal. Fe(II)-ion-catalyzed ozonation (3.6 mM Fe 2+ at pH 3; Fe 2+:O 3 molar ratio 1:14) eliminated 95% color and 48% COD and appeared to be the most attractive option among the investigated chemical treatment methods as for its applicability at the natural acidic pH of the disperse dye-bath effluent and at relatively low Fe 2+-ion doses as compared to ferrous sulfate coagulation. However, no TOC reduction was observable for ozonation and catalytic ozonation at the investigated reaction conditions (14 g l −1 O 3 at pH 3). An average six-fold enhancement in the biodegradability parameter of the synthetic dye wastewater expressed in terms of the BOD 5/COD ratio could be achieved by the investigated chemical treatment methods.

Microbial Degradation of Organic Wastes at Low Temperatures.

Microbial degradation of organic wastes mainly comprising animal and human wastes, is drastically reduced at extreme low temperatures. For the biodegradation of these wastes, technological inputs are required from disciplines like microbiology, biochemistry, molecular biology, digester modelling and heat transfer at extreme low temperature climates. Various steps in the process of biodegradation have to be studied to formulate an effective organic waste disposal method. Anaerobic digestion of organic wastes is preferred over aerobic waste treatment method, since it yields biogas as a by-product, which in turn can be utilised for heating the digester contents to increase its efficiency. Furthermore, one of the possibilities that can be explored is the utilisation of high rate anaerobic digesters which maintain temperature by means of artificial heating. It is either met by non-conventional energy sources, such as solar and wind energy, or by expending liquid fuels. In addition, insulation of the digester with polymeric materials and immobilisation of slow growing bacterial population may enhance the digester performance to a great extent. In spite of several developments, inoculum adaptation is considered to be one of the essential steps for low temperature anaerobic digestion to obtain methane as a by-product. With advancements in recombinant DNA technology, it may be possible to increase the efficiency of various microbial population that take part in the anaerobic digestion. However, till date, the options available for low temperature biodegradation are digester insulation, inoculum adaptation, and use of high rate/second-generation digesters.

5587081 Thermophilic aerobic waste treatment process : Norcross Kenneth L; Li Yanlong Edwardsville, KS, United States assigned to Jet-Tech Inc

5587081 Thermophilic aerobic waste treatment process : Norcross Kenneth L; Li Yanlong Edwardsville, KS, United States assigned to Jet-Tech Inc

Bacteria and Viruses in Aerobically Digested Sludge: Influence of Physical and Chemical Treatments on Survival and Association with Flocs under Laboratory Conditions

The effect of chemical (NaF, NaN3) and physical (heating, autoclaving) treatments of sludge flocs on bacteria and viruses in sludge undergoing aerobic digestion was studied as part of studies on the mechanisms of removal of these agents by aerobic waste treatment. Following either chemical or physical treatments, aerobically digested sludge flocs adsorbed only a small portion of added or indigenous bacteria. These treatments also reduced inactivation of bacteria as compared with untreated sludge flocs. In contrast, these treatments had relatively little effect on either adsorption of enteroviruses to sludge flocs or on inactivation of viruses. The treatments that decreased bacterial association with sludge flocs and decreased the inactivation rate of bacteria also reduced the number of active protozoans and other predators. It is concluded that enteric viruses and bacteria have different affinities for sludge flocs and are inactivated by different mechanisms during aerobic digestion of sludge.

The effects of temperature, inlet pollutant concentration, and microorganism concentration on the rate of aerobic biological treatment

Systematic errors obtained in using traditional models of aerobic waste treatment processes are discussed. These errors are observed to arise due to the lack of matching of traditional models to experimental data in the case of broad variations of process parameters, for instance, organic loading. It is shown that the generalized models of waste treatment proposed earlier by the author permit these errors to be eliminated.

The effect on aerobic waste treatment of supplementing pig diets with penicillin, chlortetracycline or copper

Penicillin, chlortetracycline and copper are widely used as growth promotants in the pig industry. The aim of this study was to investigate the effect of these excreted antibacterials on aerobic waste treatment. The work reported was carried out in aerated, laboratory scale fermentors operating at ambient temperatures and a retention time of 12·5 days. The wastes treated were from pigs of 30–50 kg. A penicillin-sensitive test microorganism (Micrococcus luteus) was not inhibited by wastes from pigs given penicillin (100 mg kg −1 DM of the feed). The level of chlortetracycline in wastes from pigs given this supplement (250 mg kg −1 DM) was approximately 2·5 mg litre −1. However, the oxygen uptake rates and the levels of COD and volatile solids in fermentors treating supplemented and unsupplemented wastes were not significantly different. Copper added to the diet at 250 mg kg −1 DM did not significantly affect waste treatment. It was concluded that penicillin, chlortetracycline or copper in pig diets were unlikely to adversely affect aerobic waste treatment processes operating at conventional retention times.

A first-order kinetic model for designing anaerobic ponds in the treatment of palm oil mill effluent

Anaerobic ponds have been used as an initial step in the treatment of palm oil mill effluent (POME). Data on BOD loading rate and subsequent reduction exist but no systematic attempts have been made to synthesise these data into a theoretical framework for proper engineering design. This paper discusses alternative kinetic models for the design of ponding systems. First-order kinetic rate coefficients, k, are derived from the analysis of existing data from several sources. The average k value was found to be 0·36 day −1. With this theoretical model, derived from practical data, a simple approach can be used to arrive at an effective design. A case for further aerobic waste treatment following the anaerobic ponds is proposed.

The microbial associations developing on experimental trickling filters irrigated with domestic sewage.

Summary. The bacterial flora of the film which developed on experimental trickling filters irrigated with domestic sewage was dominated by Acinetobacter and yellow‐pigmented Gram negative rod‐shaped organisms and it was deduced that purification in certain aerobic waste treatment processes may depend upon an association of these 2 organisms. Further evaluation of the operational procedures likely to have a selective influence on the microbial association which becomes dominant was made in studies using synthetic sewage.