Manure Wastewater Research Articles

Microbial ecology, bacterial pathogens, and antibiotic resistant genes in swine manure wastewater as influenced by three swine management systems

The environmental influence of farm management in concentrated animal feeding operations (CAFO) can yield vast changes to the microbial biota and ecological structure of both the pig and waste manure lagoon wastewater. While some of these changes may not be negative, it is possible that CAFOs can enrich antibiotic resistant bacteria or pathogens based on farm type, thereby influencing the impact imparted by the land application of its respective wastewater. The purpose of this study was to measure the microbial constituents of swine-sow, -nursery, and -finisher farm manure lagoon wastewater and determine the changes induced by farm management. A total of 37 farms were visited in the Mid-South USA and analyzed for the genes 16S rRNA, spaQ (Salmonella spp.), Camp-16S (Campylobacter spp.), tetA, tetB, ermF, ermA, mecA, and intI using quantitative PCR. Additionally, 16S rRNA sequence libraries were created. Overall, it appeared that finisher farms were significantly different from nursery and sow farms in nearly all genes measured and in 16S rRNA clone libraries. Nearly all antibiotic resistance genes were detected in all farms. Interestingly, the mecA resistance gene (e.g. methicillin resistant Staphylococcus aureus) was below detection limits on most farms, and decreased as the pigs aged. Finisher farms generally had fewer antibiotic resistance genes, which corroborated previous phenotypic data; additionally, finisher farms produced a less diverse 16S rRNA sequence library. Comparisons of Camp-16S and spaQ GU (genomic unit) values to previous culture data demonstrated ratios from 10 to 10,000:1 depending on farm type, indicating viable but not cultivatable bacteria were dominant. The current study indicated that swine farm management schemes positively and negatively affect microbial and antibiotic resistant populations in CAFO wastewater which has future “downstream” implications from both an environmental and public health perspective.

Phosphate recovery from animal manure wastewater by struvite crystallization and CO2 degasification reactor

Abstract The problem of phosphorus discharge is related to environmental protection and food security. Struvite crystallization is a useful technology for phosphate recovery from wastewater. In the research, struvite crystallization process with CO2 degasification continuous U-shape reactor (CUSR) was application for phosphate recovery from animal manure wastewater. The result indicated PO4 3--P recovery ratio could achieve 47-53% without magnesium addition when CUSR hydraulic retention time controlled at 60 min. With extra magnesium addition, PO4 3--P recovery ratio could significant achieve 80-86% at magnesium addition amount 57.5 mg/dm3. PHREEQC modeling predictions trend of struvite crystallization was close to CUSR experimental results. The modeling calculation can provide a theoretical guide for operational parameters design. For seeding technology, high phosphate recovery efficiency was obtained and preformed struvite was the most effective seeding material. Surface characterization analysis demonstrated the dominant composition of chemical solids was struvite. Water extraction analysis indicated chemical solids recovery from animal manure wastewater could release PO4 3--P slowly and be available as slow-release fertilizer.

FOLIAR CONTENTS IN BABYCORN AND CHEMICAL ATTRIBUTES OF AN OXISOL UNDER APPLICATION OF SWINE WASTEWATER

This objective of this study was to evaluate the influence of swine wastewater (ARS), applied alone and in combination with nitrogen fertilizer (AD), on foliar concentrations of macronutrients (Ntotal, P, K, Ca, Mg and S ) and micronutrients (Cu, Zn, Mn and Fe), as well as chemical attributes of an Oxisol (pH, potential acidity (H+Al +3), organic matter (OM), cation exchange capacity (CEC), base saturation (V), Ca, Mg, K, P, Na, sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) on the cultivation of baby corn. For this purpose an experiment was conducted at the State University of Western Parana in a completely randomized design with eight treatments and three replications, consisting of a 4 x 2 factorial arrangement with the application of four swine manure wastewater doses (0, 40, 80 and 120 kg ha-1 of N) prior to sowing and two levels of AD (0 and 40 kg ha-1 ) as urea at sowing and in coverage. Soil samples were collected at a depth of 0-60 cm during three periods: before sowing and application of the ARS, at the middle and at the end of the cycle. The results were subjected to analysis of variance at 5% probability, and they indicated that the application of ARS combined with AD resulted in increases to the soil chemical properties: H+Al +3, CTC, V, P, K, Ca and Mg, decreases in pH, organic matter and PST, and consistent values for RAS. For the foliar nutrient concentrations there was an increase in fertilization using
 wastewater from swine manure which resulted in significant differences for foliar concentrations of N and P in babycorn; it also promoted lower levels than adequate for N and K, and appropriate levels of Cu, Zn, Mn and Fe. Concentrations of ARS should be less than 345 m3 ha-1 when applied alone, or when combined with AD should be less than 120 kg ha-1 of N, since systematic use elevated levels of plant nutrients (P, Ca, Mg and S), suggesting their accumulation.

The treatment of animal manure wastewater by coupled simultaneous methanogenesis and denitrification (SMD) and shortcut nitrification–denitrification (SND)

AbstractBACKGROUNDThe anaerobic–aerobic system is considered an efficient process for simultaneous removal of organic matter and nitrogen from animal manure wastewater. In this work, coupled simultaneous methanogenesis and denitrification (SMD) and shortcut nitrification–denitrification (SND) was investigated to treat animal manure wastewater having high concentrations of nitrogen and organic matter.RESULTSThe best COD and NO2−‐N removal efficiency was achieved when the influent COD loading rate in the anaerobic reactor was 3 kg m‐3 d−1 and the COD/NO2−‐N ratio was above 30. It was advantageous to the treatment of high‐strength ammonia animal manure wastewater to adopt SND when the pH and free ammonia were about 8.0 and 18 mg L−1, respectively. The average efficiency of of removal COD, NH4+‐N, and total nitrogen when adopting the coupling technology was 96.7%, 94.9% and 86.5%, respectively, and the nitrite accumulation rate reached 94.55%.CONCLUSIONThis study suggested that it was technically feasible to adopt SMD–SND coupling technology of to treat animal manure wastewater with high concentrations of nitrogen and organic matter. © 2013 Society of Chemical Industry © 2013 Society of Chemical Industry

Swine Manure-Based Pilot-Scale Algal Biomass Production System for Fuel Production and Wastewater Treatment—a Case Study

Integration of wastewater treatment with algae cultivation is one of the promising ways to achieve an economically viable and environmentally sustainable algal biofuel production on a commercial scale. This study focused on pilot-scale algal biomass production system development, cultivation process optimization, and integration with swine manure wastewater treatment. The areal algal biomass productivity for the cultivation system that we developed ranged from 8.08 to 14.59 and 19.15-23.19 g/m(2) × day, based on ash-free dry weight and total suspended solid (TSS), respectively, which were higher than or comparable with those in literature. The harvested algal biomass had lipid content about 1.77-3.55%, which was relatively low, but could be converted to bio-oil via fast microwave-assisted pyrolysis system developed in our lab. The lipids in the harvested algal biomass had a significantly higher percentage of total unsaturated fatty acids than those grown in lab conditions, which may be attributed to the observed temperature and light fluctuations. The nutrient removal rate was highly correlated to the biomass productivity. The NH₃-N, TN, COD, and PO₄-P reduction rates for the north-located photo-bioreactor (PBR-N) in July were 2.65, 3.19, 7.21, and 0.067 g/m(2) × day, respectively, which were higher than those in other studies. The cultivation system had advantages of high mixotrophic growth rate, low operating cost, as well as reduced land footprint due to the stacked-tray bioreactor design used in the study.

Simultaneous carbon and nitrogen removal using a litre-scale upflow microbial fuel cell

A 10 L upflow microbial fuel cell (UMFC) was constructed for simultaneous carbon and nitrogen removal. During the 6-month operation, the UMFC constantly removed carbon and nitrogen, and then generated electricity with synthetic wastewater as substrate. At 5.0 mg L(-1) dissolved oxygen, 100 Ω external resistance, and pH 6.5, the maximum power density (Pmax) and nitrification rate for the UMFC was 19.5 mW m(-2) and 17.9 mg·(L d)(-1), respectively. In addition, Pmax in the UMFC with chicken manure wastewater as substrate was 16 mW m(-2), and a high chemical oxygen demand (COD) removal efficiency of 94.1% in the UMFC was achieved at 50 mM phosphate-buffered saline. Almost all ammonia in the cathode effluent was effectively degraded after biological denitrification in the UMFC cathode. The results can help to further develop pilot-scale microbial fuel cells for simultaneous carbon and nitrogen removal.

Establishment of Methanogenesis Dynamics Model in the Process of Methane Fermentation with Manure Wastewater<sup></sup>

Anaerobic fermentation experiment was carried out with manure wastewater to produce biogas by using six parallel glass digesters system. Basic process conditions were chosen reference to previous studies. Based on the theory of methane fermentation, a prediction model was deduced, which can be used to forecast methane production according to a few of process parameters. In the experiment, two pivotal parameters involved in model were calculated, the sludge yield coefficient (YH) is 2.829×10-2 and the sludge digestion coefficient (Kd) is 0.0215. The certain parameters, such as the oxygen equivalent (λ), the difference of COD between influent and effluent (D), the volume of fermentation broth (V), YH and Kd were substituted into prediction model, and then got the methanogenesis dynamics model in the process of methane fermentation by manure wastewater.

Influence of algae species, substrata and culture conditions on attached microalgal culture

The objective of this study was to understand and optimize the formation of microalgae biofilms in specific culture conditions. Firstly, the adhesion of six freshwater algae species was compared. Chlorococcum sp. was selected because of the high adhesion biomass productivity (ABP) and adhesion rate achieved. Secondly, the adhesion of Chlorococcum sp. was compared with nine commonly used supporting materials, and glass fiber-reinforced plastic proved to be the optimal substrata. Thirdly, based on response surface methodology experiments, a second-order polynomial model was developed to examine the effect of culture period, initial total nitrogen concentration (ITNC) in manure wastewater, pH and culture volume of the growth chamber on the adhesion of Chlorococcum sp. using glass fiber-reinforced plastic. The experimental and modeling results showed that ITNC, pH and culture volume as well as the interactions between culture period and ITNC, culture period and culture volume were significant on ABP. Optimum culture conditions were predicted at a culture period of 11days, ITNC of 70mgL(-1), pH of 8 and culture volume of 340mL, under which the predicted maximum ABP was 4.26gm(-2)day(-1). The prediction was close to validation experimental results, indicating that the model could be used to guide and optimize the attached culture of Chlorococcum sp. using glass fiber-reinforced plastic.

Purification of UF-treated anaerobically digested manure wastewater by two-pass reverse osmosis

Membrane technology provides a potential promise towards manure treatment as well as nutrients concentration and recovery in the livestock industry. A two-pass reverse osmosis (RO) system was described in this study for the purification of UF-treated anaerobically digested manure wastewater (ADMW) with respect to permeate flux, ionic rejection, permeate quality, and membrane cleaning. The permeate flux fluctuated at 26.6–33.4 and 73.7–91.2 L m−2 h−1 for the first- and second-pass RO processing, respectively, at operating pressure of 1,500 kPa in the temperature range of 24–34°C. The overall rejections of both Na+ and K+ by the two-pass RO were greater than 99%, whereas in case of ammonia, it was approximately 88%. The significant presence of molecular NH3 at relatively high pH in ADMW solution probably induced a lower rejection of total ammonium, which also largely led to the low rejection of alkalinity and further pH increase in the RO permeate. The two-pass RO treatment afforded a complete rejection of Cl−. The overall rejections of dissolved solids (DS) were estimated to be 94% with the first-pass RO and 98.8% after the two-pass RO resulting in product water containing only 45 mg/L of DS. Chemical cleaning of used membrane was successfully performed by successive flush of specific acid and base cleaning agents.

Treatment of Anaerobically Digested Cattle Manure Wastewater by Tubular Ultrafiltration Membrane

A resurgent interest in anaerobic treatment of organic wastes intrigues the subsequent wastewater purification and nutrient recovery. This study investigated the feasibility of tubular ultrafiltration to treat anaerobically digested wastewater (AnDW) in the pilot-scale. Due to the gel-layer filtration mechanism, which primarily governed the AnDW wastewater passing through the membrane module, the change of operating pressure in the experimental conditions showed a minor effect on the permeate flux, while the cross-flow tangential velocity showed a significant effect on the permeate flux. A permeate flux on average of 22 l m−2 h−1 was obtained when the feed superficial-velocity was up to 2 m s−1. The permeate flux decreased with increasing suspended solid concentration, implying a potential advantage of preliminary solid-liquid separation such as mechanical centrifugation. Irrespective of the arranged order of the sequential cleaning, the fouled membrane can be successfully cleaned using specific cleaning agents, which included a weak acid, a detergent, and an oxidant, respectively. A commercial detergent, namely KLD II, exhibited the greatest contribution to the flux recovery during the sequential cleaning.

Enrichment of anaerobic ammonium oxidizing (Anammox) bacteria from OLAND and conventional sludge: Features and limitations

The discharge of nitrogen is increasingly restricted. The autotrophic nitrogen removal process, which combines partial nitritation and anaerobic ammonium oxidation (Anammox), is recommended for high ammonium loaded streams with no or low organic carbon content because of the lower operational costs. However, the cultivation and start-up period can be long and time-consuming due to the slow growth rate of Anammox bacteria.The aim of this research was to evaluate the feasibility of Anammox cultivation in an anaerobic continuous stirred tank reactor (CSTR). Monitoring of nitrogen conversion showed Anammox activity with an increasing nitrogen removal rate up to 700mgNL−1day−1 in a reactor inoculated with OLAND (Oxygen-Limited Autotrophic Nitrification/Denitrification) seed sludge. A second lab scale reactor, a modified CSTR which was operated as an anaerobic upflow fixed bed reactor (UFBR), was inoculated with nitrifying and denitrifying sludge from a manure treatment plant. The fixed bed consisted of polyurethane sponge which served as a carrier material for the slowly growing biomass. The UFBR showed removal according to the Anammox metabolism within 3months and a nitrogen removal rate up to 250mgNL−1day−1 was achieved. Primary research on the treatment on pig manure wastewater indicates that organic load had an inhibitory effect on the Anammox activity. The results also indicate that Anammox bacteria can stay dormant or hidden for longer periods, but will reactivate under the suitable conditions.

Mass Cultivation of Microalgae on Animal Wastewater: a Sequential Two-Stage Cultivation Process for Energy Crop and Omega-3-Rich Animal Feed Production

In this study, 97 microalgal strains purchased from algae bank and 50 microalgal strains isolated from local waters in Minnesota were screened for their adaptability growing on a 20-fold diluted digested swine manure wastewater (DSMW). A pool of candidate strains well adapted to the DSMW was established through a high-throughput screening process. Two top-performing facultative heterotrophic strains with high growth rate (0.536 day(-1) for UMN 271 and 0.433 day(-1) for UMN 231) and one strain with high omega-3 unsaturated fatty acid (EPA, 3.75 % of total fatty acids for UMN 231) were selected. Subsequently, a sequential two-stage mixo-photoautotrophic culture strategy was developed for biofuel and animal feed production as well as simultaneous swine wastewater treatment using above two strains. The maximal biomass concentration and lipid content at the first and second stages reached 2.03 g/L and 23.0 %, and 0.83 g/L and 19.0 % for UMN 271 and UMN 231, respectively. The maximal nutrient removals for total phosphorus and ammonia after second-stage cultivation were 100 and 89.46 %, respectively. The experiments showed that this sequential two-stage cultivation process has great potential for economically viable and environmentally friendly production of both renewable biofuel and high-value animal feed and at the same time for animal wastewater treatment.

Integration of kinetic modeling and desirability function approach for multi-objective optimization of UASB reactor treating poultry manure wastewater

An integrated multi-objective optimization approach within the framework of nonlinear regression-based kinetic modeling and desirability function was proposed to optimize an up-flow anaerobic sludge blanket (UASB) reactor treating poultry manure wastewater (PMW). Chen–Hashimoto and modified Stover–Kincannon models were applied to the UASB reactor for determination of bio-kinetic coefficients. A new empirical formulation of volumetric organic loading rate was derived for the first time for PMW to estimate the dimensionless kinetic parameter (K) in the Chen–Hashimoto model. Maximum substrate utilization rate constant and saturation constant were predicted as 11.83gCOD/L/day and 13.02gCOD/L/day, respectively, for the modified Stover–Kincannon model. Based on four process-related variables, three objective functions including a detailed bio-economic model were derived and optimized by using a LOQO/AMPL algorithm, with a maximum overall desirability of 0.896. The proposed optimization scheme demonstrated a useful tool for the UASB reactor to optimize several responses simultaneously.

Novel Fungal Pelletization-Assisted Technology for Algae Harvesting and Wastewater Treatment

A novel fungi pelletization-assisted bioflocculation technology was developed for efficient algae harvesting and wastewater treatment. Microalga Chlorella vulgaris UMN235 and two locally isolated fungal species Aspergillus sp. UMN F01 and UMN F02 were used to study the effect of various cultural conditions on pelletization process for fungi-algae complex. The results showed that pH was the key factor affecting formation of fungi-algae pellet, and pH could be controlled by adjusting glucose concentration and fungal spore number added. The best pelletization happened when adding 20 g/L glucose and approximately 1.2E8/L spores in BG-11 medium, under which almost 100% of algal cells were captured onto the pellets with shorter retention time. The fungi-algae pellets can be easily harvested by simple filtration due to its large size (2-5 mm). The filtered fungi-algae pellets were reused as immobilized cells for treatment wastewaters and the nutrient removal rates of 100, 58.85, 89.83, and 62.53 % (for centrate) and 23.23, 44.68, 84.70, and 70.34% (for diluted swine manure wastewater) for ammonium, total nitrogen, total phosphorus, and chemical oxygen demand, respectively, under both 1- and 2-day cultivations. The novel technology developed is highly promising compared with current algae harvesting and biological wastewater treatment technologies in the literature.

A hetero-photoautotrophic two-stage cultivation process to improve wastewater nutrient removal and enhance algal lipid accumulation

A hetero-photoautotrophic algal growth model was studied for improved wastewater treatment and low cost algal biofuel feedstock production. The microalga, Auxenochlorella protothecoides UMN280, was grown heterotrophically on concentrated municipal wastewater and then autotrophically with CO2 supplementation (air, 1% and 5%, respectively). Strain UMN280 was harvested by self-sedimentation after the heterotrophic stage and the supernatant was aerated with different levels of CO2 to facilitate autotrophic growth in the second stage. The maximal biomass concentration and lipid content at the first and second stages reached 1.12g/L and 28.90%, and 1.16g/L and 33.22%, respectively. The nutrient removal efficiencies for total phosphorus, ammonia, nitrogen and chemical oxygen demand at the end of the two-stage cultivation were 98.48%, 100%, 90.60% and 79.10%, respectively. The above process can be used to treat organic-rich wastewaters (e.g. industrial and animal manure wastewaters) to achieve the dual purpose of low-cost wastewater treatment and biofuel feedstock production.

Fuzzy-logic modeling of Fenton's oxidation of anaerobically pretreated poultry manure wastewater

A multiple inputs and multiple outputs (MIMO) fuzzy-logic-based model was proposed to estimate color and chemical oxygen demand (COD) removal efficiencies in the post-treatment of anaerobically pretreated poultry manure wastewater effluent using Fenton's oxidation process. Three main input variables including initial pH, Fe+2, and H2O2 dosages were fuzzified in a new numerical modeling scheme by the use of an artificial intelligence-based approach. Trapezoidal membership functions with eight levels were conducted for the fuzzy subsets, and a Mamdani-type fuzzy inference system was used to implement a total of 70 rules in the IF-THEN format. The product (prod) and the center of gravity (centroid) methods were applied as the inference operator and defuzzification methods, respectively. Fuzzy-logic predicted results were compared with the outputs of two first-order polynomial regression models derived in the scope of this study. Estimated results were also compared to the multiple regression approach by means of various descriptive statistical indicators, such as root mean-squared error, index of agreement, fractional variance, proportion of systematic error, etc. Results of the statistical analysis clearly revealed that, compared to conventional regression models, the proposed MIMO fuzzy-logic model produced very smaller deviations and demonstrated a superior predictive performance on forecasting of color and COD removal efficiencies with satisfactory determination coefficients over 0.98. Due to high capability of the fuzzy-logic methodology in capturing the non-linear interactions, it was demonstrated that a complex dynamic system, such as Fenton's oxidation, could be easily modeled.

Cocomposting of Olive Mill Wastewater with Manure and Agro-industrial Wastes

The use of olive mill wastewater (OMW) for composting was studied by the addition of this liquid waste to a mixture of olive husks, poultry manure and confectionery wastewater. The composting process was compared with that of another pile of similar composition, but without olive mill wastewater. In order to study the effects of both composts on plant yield and soil properties, a field experiment was carried out with potato. Three amendments were applied: manure and two composts with same rate 30 tonnes/ha. The olive mill wastewater addition produced compost with higher organic matter concentrations and higher electrical conductivity, and a stabilized and humified organic matter lower than the compost produced without olive mill wastewater. The olive mill wastewater compost application to soil did not injure plants, producing a similar plant yield to both compost without olive mill wastewater and manure. The olive mill wastewater compost application to soil also improved the chemical and physicochemical properties of the soil mainly fertilizing elements such as calcium, magnesium, nitrogen, potassium and phosphorus. With respect to potato yield, both composts showed higher plant production in comparison to manure, reaching a potato yield of 46 and 47 t/ha in amended soil with compost with and without OMW, respectively.

Subtilase Genes Diversity in the Biogas Digester Microbiota

Biogas digesters contain microbial assemblages that process a mass of extracellular polymeric substances from animal manure and domestic wastewater; however, due to the limitation of available technology in cultivation of majority of the micro-organisms in biogas digesters, the enzymatic potential of these microbial communities remains largely unexplored. In this study, to evaluate subtilase gene diversity in a biogas digester, the partial sequences of the gene were directly amplified from the metagenomic DNA by using consensus-degenerate primers. The desired PCR products were cloned into pGEM-T Easy vector, and thirty positive clones were chose for Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, from which thirteen distinguished patterns were obtained and then sequenced. Phylogenetic analysis showed that ten out of the thirteen sequences were related to the subtilase genes in GenBank and were grouped into three families of the subtilases superfamily. The nucleotide sequences analysis through BLAST search revealed that none of the partial genes the authors isolated showed significant similarity against the non-redundant Nucleotide database of NCBI. Meanwhile, the deduced amino acid sequences of ten partial subtilase genes showed moderate identities to the previously identified sequences in GenBank, with a range from 39 to 61%. Collectively, the data indicate that there is a great diversity of subtilase genes in the biogas digester; and may be a rich reservoir for novel subtilase genes.

Development of an attached microalgal growth system for biofuel production

Algal biofuel production has gained a renewed interest in recent years but is still not economically feasible due to several limitations related to algal culture. The objective of this study is to explore a novel attached culture system for growing the alga Chlorella sp. as biodiesel feedstock, with dairy manure wastewater being used as growth medium. Among supporting materials tested for algal attachment, polystyrene foam led to a firm attachment, high biomass yield (25.65 g/m(2), dry basis), and high fatty acid yield (2.31 g/m(2)). The biomass attached on the supporting material surface was harvested by scraping; the residual colonies left on the surface served as inoculum for regrowth. The algae regrowth on the colony-established surface resulted in a higher biomass yield than that from the initial growth on fresh surface due to the downtime saved for initial algal attachment. The 10-day regrowth culture resulted in a high biodiesel production potential with a fatty acid methyl esters yield of 2.59 g/m(2) and a productivity of 0.26 g/m(-2) day(-1). The attached algal culture also removed 61-79% total nitrogen and 62-93% total phosphorus from dairy manure wastewater, depending on different culture conditions. The biomass harvested from the attached growth system (through scraping) had a water content of 93.75%, similar to that harvested from suspended culture system (through centrifugation). Collectively, the attached algal culture system with polystyrene foam as a supporting material demonstrated a good performance in terms of biomass yield, biodiesel production potential, ease to harvest biomass, and physical robustness for reuse.

Anaerobic digestion technology in poultry and livestock waste treatment — a literature review

A literature review has been undertaken to investigate the performance of the different anaerobic process configurations and operational conditions used in poultry and livestock waste treatment. The results of the extensive literature review showed that a wide range of different reactor volumes varying from 100 mL to 95 m3 were utilized in the investigation of anaerobic processing of poultry manure. Retention times studied were between 13.2 h and 91 days. Most of studies were carried out under mesophilic conditions maintained between 25 and 35 degrees C. Chemical oxygen demand (COD) removals and organic loading rate (OLR) ranged from 32 to 78%, and from 1.1 to 2.9 kg COD m(-3) day(-1), respectively. Biogas yields were achieved between 180 mL g(-1) COD added and 74 m3 day(-1) for a wide range of different reactor configurations. Up-flow anaerobic sludge blanket (UASB) seems to be a suitable process for the treatment of poultry manure wastewater and the liquid fraction of hen manure, due to its ability to maintain a sufficient amount of active biomass. The literature review showed that various reactor configurations such as fixed-film reactor, attached-film bioreactor, anaerobic rotating biological reactor, batch reactors, downflow anaerobic filter, fixed dome plant, UASB, continuously stirred tank reactor (CSTR), up-flow anaerobic filter (UAF), temperature-phased anaerobic digestion (TPAD), anaerobic hybrid reactor (AHR), and two-stage anaerobic systems are well suited to anaerobic processing of cattle manure. At both mesophilic and thermophilic conditions, high COD removals (87-95%) were achieved for treatment of cattle manure wastewaters. The COD and volatile solids (VS) reductions obtained were 37.9 to 94% and 9.6 to 92%, respectively. During the studies, OLR and retention times ranged between 0.117 and 7.3 g VS L(-1) day(-1) and between 0.5 and 140 days, respectively. In anaerobic processing of cattle manure, methane yields between 48 mmol CH4 L(-1) and 4681.3 m3 CH4 month(- 1) were found for the corresponding reactor volumes of 120 mL and 1300 m3, respectively. In anaerobic processing of swine manure, OLR ranged from 0.9 to 15.42 g VS L(-1) day(- 1) at mesophilic conditions (25-35 degrees C). The reactor volumes varied between 125 mL and 380 L. Temperature and retention times ranged from 25 to 60 degrees C, and 0.9 to 113 days, respectively. COD and VS reductions achieved were between 57 and 78% and between 34.5 and 61%, respectively. Moreover, methane yields were obtained between 22 and 360 mL CH4 g(-1) VS added. The results showed that UASB, anaerobic baffled reactors, CSTR, and anaerobic sequencing batch reactor (ASBR) were successfully utilized in anaerobic processing of swine manure at both mesophilic and thermophilic conditions.