Reducing Decomposition Time in Landfills by an Aerobic Process

This experiment was performed to determine if sludge produced by the paper industry could be composted faster by promoting the aerobic degradation process. To perform this experiment, I chose a sludge produced by a virgin pulp mill. Once I collected sludge, it was dewatered to a moisture content of sixty-five percent or less. As soon as the sludge was dewatered, I set up four separate composting systems, three of which were run under aerobic conditions and one that was run under anaerobic conditions. The anaerobic conditions only had sludge and plastic for its bulking agent. In the aerobic systems there were three different types of bulking agents used; pine bark, plastic and compost. In the aerobic systems air was introduced into the system. To determine how fast each of the processes was composting, I collected the gases that were produced by each of the systems. The gases that are produced by an anaerobic process was carbon dioxide and methane, whereas an aerobic process produces carbon dioxide and water. Therefore, by analyzing the gases produced by each of the systems periodically and determining the amount of carbon dioxide produced by each of the systems, one can determine the rate of decomposition of the sludge for each of the separate systems. Also the chemical oxygen demand (COD) was determined for each of the system, before and after the degradation occurred. COD was used to measure that content of organic matter in the sludge. This also helped in determining the degradation that has occurred in each of the systems

An anaerobic/aerobic process for solid waste composting

This research evaluated an innovative anaerobic/aerobic process for the treatment of the organic fraction of municipal solid waste (OFMSW). The complete experimental set-up includes a combination of an acidogenic batch reactor and a methanogenic filter. The effluent from the acidogenic reactor was fed into the methanogenic reactor through a holding/recycling tank. The experimental study was conducted by altering the operating conditions, including input total solids (TS), number of batch reactors in series, biomass seeding ratio (BSR), effluent recycle rate, solid waste retention time (SWRT), and pH in the holding/recycling tank. Operating conditions of the methanogenic filter were kept constant throughout the study. The substrate was introduced into the combined system by routinely alternating the batch feed to the acidogenic reactor. The optimum operating conditions, in terms of the highest TS and TVS destruction and the greatest methane production, were determined. The system was operated in a constant-temperature room at 35°C;At the end an operating period, or half SWRT, the digested wastes was removed from the acidogenic phase. In the meanwhile, free liquid was drained into the holding/recycling tank. Air at a temperature of 25°C was then pumped into the drained acidogenic reactor at a controlled rate to initiate aerobic composting, and, simultaneously, to dry the digested solid wastes;The system achieved a volatile solids destruction averaging 53% (90.4% of the biodegradable fraction of the solid wastes). The system produced a methane yield averaging 0.227 m[superscript]3/kg (3.64 ft[superscript]3/lb) of TS added to the system. Aerobic polishing reduced the moisture content of the composted residue to less than 5% and produced an odor-free product;These laboratory studies indicate that the anaerobic/aerobic approach has much to offer, as compared with aerobic composting. With the anaerobic/aerobic approach, solids destruction was equivalent to that normally achieved by aerobic composting. However, the anaerobic approach has the advantage of producing significant quantities of a valuable fuel (methane). Also, the process was operated in totally sealed reactors, avoiding release of the odors commonly associated with aerobic composting operations. The aerobic polishing step results in a product that is stable, low in moisture, and odor free

Model based study of autothermal thermophilic aerobic digestion (ATAD) processes : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Engineering and Automation of Massey University

An Autothermal Thermophilic Aerobic Digestion process, or ATAD process, is a relatively new sewage sludge treatment process. The ATAD process has been developed for the disinfection and stabilisation of sewage sludge, which is a by-product of wastewater treatment. The end product can be applied to the land as a soil additive or fertiliser with no restrictions, as the process dramatically reduces public health and environmental risks. The process is comparable to the composting process used for municipal solid waste and garden wastes. The process requires oxygen, usually in the form of air, to be applied to the sludge by an aeration system. The oxygen stimulates an exothermic biochemical reaction, which in turn heats the sludge up to thermophilic temperatures (between 50 and 65°C). At these temperatures the pathogenic bacteria, viruses and parasites in the sludge that are harmful to human health are effectively destroyed. The biochemical reaction also degrades a large portion of the organic sludge, which means that unstable, volatile odour generating substances are removed; this reduces the likelihood of smells and the attraction of flies and rodents (vector attraction) to the sludge.[FROM INTRODUCTION

Pengaruh Penambahan Pupuk Organik Kotoran Sapi Terhadap Kualitas Kompos dari Sampah Daun Kering di TPST Undip

ABSTRAK Sebagian besar sampah organik di Universitas Diponegoro didominasi oleh sampah daun kering. Sampah daun kering merupakan salah satu bahan yang dapat untuk dijadikan kompos. Penambahan bahan organik lain diperlukan untuk meningkatkan kandungan unsur hara kompos. Tujuan dari penelitian ini adalah untuk menganalisis pengaruh dan menentukan variasi optimum penambahan pupuk organik kotoran sapi terhadap kualitas kompos dari sampah daun kering di TPST Undip. Pengomposan dilakukan secara aerobic dengan waktu pengomposan selama 28 hari. Pengomposan dilakukan dengan activator EM4. Variabel penelitian dengan menambahkan pupuk organik kotoran sapi (sampah daun : pupuk organik kotoran sapi) dengan variasi kontrol (1 : 0), P1 (4 : 1), P2 (7:3), P3 (3 : 2). Berdasakan penelitian menunjukkan bahwa penambahan pupuk organik kotoran sapi memberikan pengaruh pada hasil kualitas pengomposan, bahwa kualitas kompos yang dihasilkan lebih baik, dengan kompos yang paling optimum pada variasi P2 dengan rasio C/N 10,10%, C-organik 26,73%, N-total 2,64%, P-total 0,60%, K-total 0,44%. Kata kunci : Sampah organik, kompos, pengomposan, kotoran sapi ABSTRACT (The Effect of Cow Manure Organic Fertilizer Addition To The Quality Compost From Dried Leaf Litter at TPST Undip). Most of the organic waste at Diponegoro University is dominated by dry leaf litter. The dry leaf litter is one of the materials that can be composted. The addition of another organic materials need to increase the nutrient content in the compost. The purpose of this study is to analyze the effect and determining the optimum variation of addition organic fertilizer of cow manure to the quality of compost from dry leaf litter at TPST Undip. The composting is an aerobic process with composting time during 28 days. The composting was conducted by using EM4 activator. Variables of this study were the organic fertilizer of cow manure addition ( leaf litter : organic fertilizer of cow manure ) with variation of control ( 1:0), P1 (4:1), P2 (7:3), P3 (3:2). Based on the result of this study showed that the addition of organic fertilizer cow manure had an effect on the quality of composting, that the quality of the compost produced is better result, with the most optimal compost was P2 variation, with result C/N ratio 10.10%, C organic 26.73%, N-total 2. 64%, P-total 0.60%, K-total 0.44% . Keywords: Organic waste, compost, composting, cow manur

Bacterial community analysis in upflow multilayer anaerobic reactor (UMAR) treating high-solids organic wastes

A novel anaerobic digestion configuration, the upflow multi-layer anaerobic reactor (UMAR), was developed to treat high-solids organic wastes. The UMAR was hypothesized to form multi-layer along depth due to the upflow plug flow; use of a recirculation system and a rotating distributor and baffles aimed to assist treating high-solids influent. The chemical oxygen demand (COD) removal efficiency and methane (CH4) production rate were 89% and 2.10 L CH4/L/day, respectively, at the peak influent COD concentration (110.4 g/L) and organic loading rate (7.5 g COD/L/day). The 454 pyrosequencing results clearly indicated heterogeneous distribution of bacterial communities at different vertical locations (upper, middle, and bottom) of the UMAR. Firmicutes was the dominant (>70%) phylum at the middle and bottom parts, while Deltaproteobacteria and Chloroflexi were only found in the upper part. Potential functions of the bacteria were discussed to speculate on their roles in the anaerobic performance of the UMAR system

Nutrient balance of a two-phase solid manure biogas plant

So called "dry fermentation" prototype plants for anaerobic digestion of organic material containing 15-50 % total solids show added advantages compared to slurry digestion plants (Hoffman 2001): Less reactor volume, less process energy, less transport capacity, less odour emissions. However on-farm dry fermentation plants are not common and rarely commercially available. Recent on-farm research (Kusch & Oechsner 2004) and prototype research (Linke 2004) show promising technical solutions for dry fermentation batch reactors on-farm. The Biodynamic Research Institute in Järna developed a two-phase on-farm biogas plant. The plant digests manure of dairy cattle and organic residues originating from the farm and the surrounding food processing units containing 17.7-19.6 % total solids. A new technology for continuously filling and discharging the hydrolysis reactor was developed and implemented. The output of the hydrolysis reactor is separated into a solid and liquid fraction. The solid fraction is composted. The liquid fraction is further digested in a methane reactor and the effluent used as liquid fertiliser. Initial results show that anaerobic digestion followed by aerobic composting of the solid fraction improves the nutrient balance of the farm compared to mere aerobic composting. Composted solid fraction and effluent together contain about 70 % of total input nitrogen and 94 % of input NH4. The manure that was merely aerobic digested contained about 51 % of total input nitrogen and 3.9 % of input NH4. Additionally anaerobic digestion improves the energy balance of the farm producing up to 269 l biogas kg-1 volatile solids or 1,7 kWh heat kg-1 volatile solids

Derivation of the formyl-group oxygen of chlorophyll b from molecular oxygen in greening leaves of a higher plant (Zea mays)

Using mass spectroscopy, we demonstrate as much as 93% enrichment of the 7-formyl group oxygen of chlorophyll b when dark-grown, etiolated maize leaves are greened under white light in the presence of 18O2. This suggests that a mono-oxygenase is involved in the oxidation of its methyl group precursor. The concomitant enrichment of about 75% of the 131-oxygen confirms the well-documented finding that this oxo group, in both chlorophyll a and b, also arises from O2. High 18O enrichment into the 7-formyl oxygen relative to the substrate 18O2 was achieved by optimization of the greening conditions in combination with a reductive extraction procedure. It indicates not only a single pathway for Chl b formyl group formation, but also unequivocally demonstrates that molecular oxygen is the sole precursor of the 7-formyl oxygen

Characterisation of microorganisms responsible for EBPR in a sequencing batch reactor by using the 16S rDNA-DGGE method

Analysis of the bacterial community in the biological phosphorus removal system is propitious to study the phosphorus-removal mechanism. The activated sludge was acclimated through a repeated anaerobic-aerobic process with glucose as carbon source for 2 months and a stable EBPR was established in an SBR. Total phosphate of the wastewater decreased by 12.43 mgE.-1 after 4 h aerobic treatment while total P uptake in the raw sludge was 0.57 mgE.-1 under the same conditions, and the phosphate content of the sludge increased from 1.83% to 6.79%. The protozoa and dominant bacteria of the two sludges were observed by optical and electron microscope. The genomic DNA of samples was extracted as the template and the 16S rDNA genes (V3 region) were amplified; denaturing gradient gel electrophoresis (DGGE) separated these amplified DNA fragments with the denaturant from 35% to 70%. The DGGE profiles showed that the raw sludge, acclimated sludge and dominant bacteria in the acclimated sludge had different band patterns. The results indicated that micro-organisms were selected by the repeated anaerobic-aerobic process and some non-phosphorus accumulating organisms were eliminated. The cultured strains obtained from acclimated sludges were purified and their DNA was amplified using F27 and R1522 to 1.5 kb; the gene sequences were located on the GenBank and they were identified as Acidovorax sp.BSB421 and Sphingomonas sp.SA-3

Effect of oxygen transfer rate on cellulases production in stirred tank and internal-loop airlift bioreactors

In an aerobic process, such as enzymes production by fungi, the oxygen supply into fermentation medium is an important factor in order to achieve good productivities. Oxygen has an important role in metabolism and microorganism growth, being of extreme importance the control of both the dissolved oxygen transfer rate into the bioreactor and the oxygen consumption by the microorganism [1,2]. Dissolved oxygen transfer rate can be analyzed and described by means of the mass transfer coefficient, KLa, being one of the most important parameters for the design and operation of mixing/sparging of aerobic bioreactors. (…