Anaerobic reactor/high rate pond combined technology for sewage treatment in the Mediterranean area

2005 ◽  
Vol 51 (12) ◽  
pp. 125-132 ◽  
Author(s):  
F. El Hafiane ◽  
B. El Hamouri
Keyword(s):  
Retention Time ◽  
Biogas Production ◽  
Sewage Treatment ◽  
Mediterranean Area ◽  
High Rate ◽  
Anaerobic Reactor ◽  
Solids Retention ◽  
In Series ◽  
Pre Treatment ◽  
Final Effluent

Two high-rate, anaerobic/aerobic units were used to treat the sewage of the Institut Agronomique st Vétérinaire Hassan II (Morocco) campus in a 1,100 m2-plant designed for 1,500 e.p. and receiving 63 m3 per day. The anaerobic pre-treatment consisted of a two-step up-flow anaerobic reactor (TSUAR) comprising two reactors and one external settler all in series. The aerobic line, or post-treatment, consisted of a high-rate algal pond (HRAP) and one maturation pond in series. The system totalized a hydraulic retention time (HRT) of 9 days. A gravel filter (GF) was constructed behind the TSUAR to trap low-density particles. The TSUAR removed 80% of COD and 90% of SS within 48 h. Solids retention time in the reactors averaged 32 d with a specific sludge production of 0.28 g SS g−1 COD removed. Almost 93% of the sludge evacuated from the settler was stabilized. Specific biogas production from both reactors was 0.25 m3 kg−1 COD removed. Used in this configuration, the HRAP lost its BOD removal activity and increased its nutrients and pathogens removal capabilities (tertiary treatment). Results showed that 85% of total nitrogen and 48% of total phosphorus were removed by the HRAP. Land area requirement of this combination was less than 1 m2 per capita and filtered final effluent was of excellent quality (COD, 82 mg/l; TKN, 8.3 mg/l; total P, 2.7 mg/l, faecal coliforms, 2.4 103/100 ml and zero helminths eggs).

Anaerobic thermophilic digestion of sewage sludge with a thickened sludge recycle

2012 ◽  
Vol 65 (3) ◽  
pp. 403-409 ◽  
Author(s):  
A. Ya. Vanyushina ◽  
Yu. A. Nikolaev ◽  
A. M. Agarev ◽  
M. V. Kevbrina ◽  
M. N. Kozlov
Keyword(s):  
Retention Time ◽  
Municipal Wastewater ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Wastewater Sludge ◽  
Recycling Process ◽  
Digested Sludge ◽  
Volatile Solids ◽  
Solids Retention ◽  
Thermophilic Digestion

The process of anaerobic thermophilic digestion of municipal wastewater sludge with a recycled part of thickened digested sludge, was studied in semi-continuous laboratory digesters. This modified recycling process resulted in increased solids retention time (SRT) with the same hydraulic retention time (HRT) as compared with traditional digestion without recycling. Increased SRT without increasing of HRT resulted in the enhancement of volatile substance reduction by up to 68% in the reactor with the recycling process compared with 34% in a control conventional reactor. Biogas production was intensified from 0.3 L/g of influent volatile solids (VS) in the control reactor up to 0.35 L/g VS. In addition, the recycling process improved the dewatering properties of digested sludge.

scholarly journals Evaluation of acidogenic sludge from anaerobic reactors running at low solids retention times to reduce sludge generation and enhance biogas production

Water SA ◽  
2019 ◽  
Vol 45 (4 October) ◽  
Author(s):  
Wilza Da Silva Lopes ◽  
Ysa Helena Diniz Morais de Luna ◽  
Jose Tavares de Sousa ◽  
Wilton Silva Lopes ◽  
Valderi Duarte Leite
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Kinetic Constant ◽  
Oxygen Demand ◽  
Gas Production ◽  
Primary Sludge ◽  
Anaerobic Reactors ◽  
Solids Retention ◽  
Improved Performance ◽  
Pre Treatment

ABSTRACT   Sludges generated in the biological processing of sewage are complex mixtures, the constituents of which pose risks to public health and the environment. Anaerobic digestion is considered the most sustainable option for treating sludge because it offers the possibility of generating biogas. The aim of this study was to compare the quantities, properties, biodegradabilities and biochemical methane potentials (BMP) of primary sludge (PS) generated by a primary decanter with acidogenic sludges produced by upflow anaerobic (UA) reactors operating at solids retention times (SRTs) of 2, 4, 6 and 8 days (Samples S2, S4, S6 and S8, respectively). Sludges from both pre-treatments were submitted to alkaline solubilization in order to determine the efficiency of the process in disrupting extracellular complexes. Based on the levels of total solids (TS) present, the primary decanter was found to generate higher quantities of excess sludge (yield of 3.1 gTS∙d-1) than UA reactors operating at low SRTs (yields in the range 1.69 to 0.64 gTS∙d-1). The concentrations of dissolved materials in PS and Samples S2 and S8 were considerably higher after alkaline solubilization, with respective increases of 8, 14 and 28-fold in dissolved organic carbon, 12, 20 and 40-fold in chemical oxygen demand, 25, 31 and 59-fold in proteins, and 17, 21 and 63-fold in carbohydrates. In addition, the BMP value for S8 was some 13% higher than that recorded for PS while the kinetic constant for gas production by S8 was 1.8-fold greater than that of PS. It is concluded that a pre-treatment combining anaerobic digestion at low SRT and alkaline solubilisation would lead to improved performance in subsequent stages of anaerobic digestion and, consequently, increased efficiency in biogas production.

scholarly journals Pre-treatment of wastes containing keratin in industrial conditions

2008 ◽  
pp. 59-64
Author(s):  
Lili Mézes ◽  
Tibor Bíró ◽  
János Petis ◽  
János Tamás
Keyword(s):  
Retention Time ◽  
Biogas Production ◽  
Degradation Process ◽  
Element Ratio ◽  
Industrial Experiments ◽  
Aeration System ◽  
Heat Treated ◽  
Pre Treatment

The aim of the research was a development of a featherdegradation technology in industrial circumstances. During the experiments we determined the parameters of the critical environmental and technological limitation factors. Because of the high keratin-content the degradation (and composting) of the feather is difficult. With the developed technology huge mass of feather can be used fast and easily in biogas production and in the adjustment of the optimal element ratio of biomass. The industrial experiments were implemented in a 6m3 heatable double-walledtank with stirring-shovels and aeration-system. The degradation process was followed with extinction measurements.According to the experiments that were done the best results were given at the case which was heat-treated at 70°C, was injected with 1% bacteria concentration, and where 1:3 feather:water ratio was set if we consider the effectiveness of degradation and the hydraulical retention time.

scholarly journals ADM1 approach to the performance optimisation and biogas H2S prediction of a large-scale anaerobic reactor fed on sugarcane vinasse

2019 ◽  
Vol 80 (9) ◽  
pp. 1774-1786
Author(s):  
Jorge Vinicius da Silva Neto ◽  
Marcelo Leite Conde Elaiuy ◽  
Edson Aparecido Abdul Nour
Keyword(s):  
Retention Time ◽  
Large Scale ◽  
Settling Tank ◽  
Extended Model ◽  
Retention Efficiency ◽  
Anaerobic Reactor ◽  
Solids Retention ◽  
Sugarcane Vinasse ◽  
Practical Demonstration

Abstract In this paper, we present extensions to the Anaerobic Digestion Model No. 1 (ADM1) to simulate hydrogen sulphide in biogas and solids retention efficiency. The extended model was calibrated and validated against data from a large-scale covered in-ground anaerobic reactor (CIGAR), processing sugarcane vinasse. Comparative scenarios and set-ups of a CIGAR with and without a settling tank unit (settler) were simulated to investigate the reactor's performance. Biogas flow, methane content, and yield with settler were 15,983 Nm3/d, 57%, and 0.198 Nm3CH4/kgCOD, respectively, which were 9.4%, 1.8%, and 11.64%, higher than without the settler. Improvements are combination of influent flow rate 116% higher and increased solids retention time by using a settler. The optimised modelled reactor, the volume of which was reduced by 50%, was able to produce 83% more methane per volume of reactor with half the retention time. After model calibration and validation, we assessed the quality of predictions and its utility. The overall quality of predictions was assessed as high accuracy quantitative for CH4 and medium for H2S and biogas flow. A practical demonstration of ADM1 to industrial application is presented here to identify the potential optimisation and behaviour of a large-scale anaerobic reactor, reducing, consequently, expenditure, risk, and time.

Control of algal production in a high rate algal pond: investigation through batch and continuous experiments

2014 ◽  
Vol 69 (12) ◽  
pp. 2519-2525 ◽  
Author(s):  
H. Derabe Maobe ◽  
M. Onodera ◽  
M. Takahashi ◽  
H. Satoh ◽  
T. Fukazawa
Keyword(s):  
Retention Time ◽  
Algal Growth ◽  
High Rate ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Flow Reactors ◽  
Solids Concentration ◽  
Solids Retention ◽  
Continuous Flow Reactors ◽  
Algal Productivity

For decades, arid and semi-arid regions in Africa have faced issues related to water availability for drinking, irrigation and livestock purposes. To tackle these issues, a laboratory scale greywater treatment system based on high rate algal pond (HRAP) technology was investigated in order to guide the operation of the pilot plant implemented in the 2iE campus in Ouagadougou (Burkina Faso). Because of the high suspended solids concentration generally found in effluents of this system, the aim of this study is to improve the performance of HRAPs in term of algal productivity and removal. To determine the selection mechanism of self-flocculated algae, three sets of sequencing batch reactors (SBRs) and three sets of continuous flow reactors (CFRs) were operated. Despite operation with the same solids retention time and the similarity of the algal growth rate found in these reactors, the algal productivity was higher in the SBRs owing to the short hydraulic retention time of 10 days in these reactors. By using a volume of CFR with twice the volume of our experimental CFRs, the algal concentration can be controlled during operation under similar physical conditions in both reactors.

scholarly journals Pushing the limits of solids retention time for enhanced biological phosphorus removal: process characteristics and Accumulibacter population structure

2020 ◽  
Vol 82 (8) ◽  
pp. 1614-1627
Author(s):  
Paul Roots ◽  
Alex Rosenthal ◽  
Yubo Wang ◽  
Fabrizio Sabba ◽  
Zhen Jia ◽  
...  
Keyword(s):  
Retention Time ◽  
Phosphorus Removal ◽  
Energy Recovery ◽  
High Rate ◽  
Stable Operation ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Biological Phosphorus

Abstract Reducing the solids retention time (SRT) of the enhanced biological phosphorus removal (EBPR) process can increase organic carbon diversion to the sidestream for energy recovery, thereby realizing some of the benefits of the high rate activated sludge (HRAS) process. Determining the washout (i.e. minimum) SRT of polyphosphate accumulating organisms (PAOs), therefore, allows for simultaneous phosphorus and carbon diversion for energy recovery from EBPR systems. However, few studies have investigated the washout SRT of PAOs in real wastewater, and little is known of the diversity of PAOs in high rate EBPR systems. Here we demonstrate efficient phosphorus removal (83% orthophosphate removal) in a high rate EBPR sequencing batch reactor fed real primary effluent and operated at 20 °C. Stable operation was achieved at a total SRT of 1.8 ± 0.2 days and hydraulic retention time of 3.7–4.8 hours. 16S rRNA gene sequencing data demonstrated that Accumulibacter were the dominant PAO throughout the study, with a washout aerobic SRT between 0.8 and 1.4 days. qPCR targeting the polyphosphate kinase gene revealed that Accumulibacter clades IIA, IIB and IID dominated the PAO community at low SRT operation, while clade IA was washed out at the lowest SRT values.

scholarly journals Efecto de la aplicación de pre-tratamientos físicos y químicos en la digestión anaerobia de pulpa de café

2019 ◽  
pp. 14-22
Author(s):  
Noemi Nava-Valente ◽  
Luis Antonio López-Escobar ◽  
Oscar Andrés Del Ángel-Coronel ◽  
Jesús Atenodoro-Alonso
Keyword(s):  
Anaerobic Digestion ◽  
Retention Time ◽  
Biogas Production ◽  
Hydrolysis Rate ◽  
Coffee Pulp ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Three Stages ◽  
Pre Treatment

The present study aims to evaluate the effect of thermal pre-treatment (50, 70 Y 90 °C during 1 h) and acid pre-treatment (2.5%, 5% y 10% v/v during 1 h) in anaerobic digestion process of coffee pulp. The methodology consisted of three stages where the waste was obtained and characterized, applied pre-treatments to evaluate the solubilization degree and biogas production. The residue presented a %VS of 91.80, pH of 5.04, total COD 24.26 g/L and soluble COD 14.88 g/L. The solubilization values obtained by applying thermal pre-treatment increased to 0.92-4.98%, while applying acids pre-treatments of 2.6-18.86%. Subsequently, in the anaerobic digestion process, retention time decreased from 23 up to 14 days. The results obtained in this study demonstrate that, pretreatment is significant to increase the percentage of hydrolysis rate, however, the hydrolysis rate percentage cannot be directly related to biogas production in anaerobic digestion.

scholarly journals BIOGAS POTENTIAL OF DIGESTATE AFTER FERMENTATION OF SIDA HERMAPHRODITA SILAGE

2018 ◽  
Author(s):  
Paulina RUSANOWSKA ◽  
Magda DUDEK ◽  
Marcin ZIELIŃSKI ◽  
Marcin DĘBOWSKI
Keyword(s):  
Organic Compounds ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Complex Structure ◽  
Yield Potential ◽  
High Yield ◽  
Two Samples ◽  
Pre Treatment ◽  
High Yield Potential

Lignocellulosic biomass is one of the most widely used substrate in methane digestion. Among plants with a high yield potential, Sida hermaphrodita is particularly noteworthy, due to Sida can be grown on low quality soils and its utilization for energy purposes is not competitive with food crops. Methane fermentation of biomass with such a complex structure usually requires application of pre-treatment methods for efficient utilization of its cellulose and hemicellulose. It is economically justified to control of digestate if substrate was efficiently used. The study aimed to measure biogas potential of digestate after fermentation of Sida hermaphrodita silage. The post-fermentation of two samples of digestate from the reactors operated at organic compounds loading 2 kg/(m3∙d) – S1 and 3 kg/(m3∙d) – S2 was performed. Hydraulic retention time in these reactors was 50 d and 33 d, respectively. Biogas potential of fermented sludge was measured with the use of AMPTS II (Bioprocess control). Biogas production was 0.012 L/g TS and 0.031 L/g TS from digestate’s S1 and S2, respectively. The methane content in biogas was 15% from digestate S1 and 50% from digestate S2. The obtained results suggest that digestate from reactor with organic compounds loading of 3 kg/(m3∙d) still has high biogas potential, and hydraulic retention time in this reactor should be prolonged.

scholarly journals Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

2014 ◽  
Vol 40 (2) ◽  
pp. 123-136 ◽  
Author(s):  
Jan Suschka ◽  
Klaudiusz Grübel
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Biogas Production ◽  
Sewage Treatment ◽  
Anaerobic Treatment ◽  
Waste Activated Sludge ◽  
Sludge Digestion ◽  
Sludge Pretreatment ◽  
Negative Side Effects ◽  
Pre Treatment

Abstract Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

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