Mesquite wood chips (Prosopis) as filter media in a biofilter system for municipal wastewater treatment

2015 ◽  
Vol 73 (6) ◽  
pp. 1454-1462 ◽  
Author(s):  
D. B. Sosa-Hernández ◽  
J. M. Vigueras-Cortés ◽  
M. A. Garzón-Zúñiga

The biofiltration system over organic bed (BFOB) uses organic filter material (OFM) to treat municipal wastewater (MWW). This study evaluated the performance of a BFOB system employing mesquite wood chips (Prosopis) as OFM. It also evaluated the effect of hydraulic loading rates (HLRs) in order to achieve the operational parameters required to remove organic matter, suspended material, and pathogens, thus meeting Mexican and US regulations for reuse in irrigation. Two biofilters (BFs) connected in series were installed; the first one aerated (0.62 m3air m−2h−1) and the second one unaerated. The source of MWW was a treatment plant located in Durango, Mexico. For 200 days, three HLRs (0.54, 1.07, and 1.34 m3m−2d−1) were tested. The maximum HLR at which the system showed a high removal efficiency of pollutants and met regulatory standards for reuse in irrigation was 1.07 m3m−2d−1, achieving removal efficiencies of biochemical oxygen demand (BOD5) 92%, chemical oxygen demand (COD) 78%, total suspended solids (TSS) 95%, and four log units of fecal coliforms. Electrical conductivity in the effluent ensures that it would not cause soil salinity. Therefore, mesquite wood chips can be considered an innovative material suitable as OFM for BFs treating wastewaters.

2013 ◽  
Vol 68 (3) ◽  
pp. 599-607 ◽  
Author(s):  
Juan Manuel Vigueras-Cortés ◽  
Ignacio Villanueva-Fierro ◽  
Marco Antonio Garzón-Zúñiga ◽  
José de Jesús Návar-Cháidez ◽  
Isaías Chaires-Hernández ◽  
...  

Agave plants grow in semi-arid regions and are used for mescal production. However, agave fiber by-products are considered waste materials. Thus, we tested agave fiber as a filter media and biofilm material carrier for removing pollutants from municipal wastewater. Three laboratory-scale biofiltration reactors were used in two trials with five hydraulic loading rates (HLRs = 0.27, 0.54, 0.80, 1.07 and 1.34 m3 m−2 d−1). One series was conducted using mechanical aeration (0.62 m3 m−2 h−1). To prevent compaction, decreasing pressure and clogging of the filter media, 4, 8 and 12 internal divisions were evaluated in the biofilter column. After 17 months of continuous operation at an HLR of 0.80 m3 m−2 d−1, the removal efficiencies of the aerated biofilters were 92.0% biochemical oxygen demand, 79.7% chemical oxygen demand, 98.0% helminth eggs, 99.9% fecal coliforms and 91.9% total suspended solids. Statistical analysis showed that the chosen operational parameters significantly influenced the removal efficiencies of the biofilters. The effluent quality obtained under these conditions complied with the Mexican and US EPA standards for agricultural irrigation and green spaces, except for coliforms, which is why the effluents must be disinfected. Thus, agave fiber is a favorable choice for use as a packing material in biofiltration processes.


2019 ◽  
Vol 80 (9) ◽  
pp. 1654-1661
Author(s):  
J. Tauber ◽  
V. Parravicini ◽  
K. Svardal ◽  
J. Krampe

Abstract In this research, sources of methane emissions of an anaerobic digester (AD) system at a municipal wastewater treatment plant (WWTP) with 260,000 population equivalent (PE) capacity were detected by a non-dispersive infrared (NDIR) camera. The located emissions were evaluated qualitatively and were documented with photographs and video films. Subsequently, the emission sources were quantified individually using different methods like the Flux-Chamber method and sampling from the digester's circulation pipe. The dissolved methane in the sludge digester was measured via gas chromatography-mass spectrometry (GC-MS) and 6.8% oversaturation compared to the equilibrium after Henry's law was found. Additionally, the residual gas potential of the digestate was measured using batch tests with 10 days' additional stabilisation time. The PE-specific residual gas production of the full-scale AD was calculated to 12.4 g CH4/(PE · y). An extended chemical oxygen demand (COD) balance including methane emissions for the whole digester system was calculated. Also the measured methane loads were calculated and summed up. The total methane loss of the AD was calculated at 24.6 g CH4/(PE · y), which corresponds to 0.4% of the produced biogas (4,913 g CH4/(PE · y)). PE-specific methane emission factors are presented for each investigated (point) source like the sludge outlet at the digester's head, a leaking manhole sealing and cracks in the concrete structure.


2014 ◽  
Vol 1030-1032 ◽  
pp. 387-390
Author(s):  
Chun Di Gao ◽  
Shi Xin Fan ◽  
Er Long Jiao ◽  
Hao Li ◽  
Wei Xiao Wang

A novel alternating oxic-anoxic operation mode of shortcut nitrification-denitrification was developed in a sequencing batch reactor at ambient temperature. Operational parameters favorable for maintaining the shortcut nitrification-denitrification were investigated and optimized. The experiments showed that alternating oxic-anoxic shortcut nitrification-denitrification system was able to be an independent treatment process in domestic wastewater treatment. And the optimization approach was so efficient that the main pollutant discharge targets achieved Standard A of the first class in "Discharge standard of pollutants for municipal wastewater treatment plant". Moreover, the reliability of the operation strategy in this experimentation was proved, which indicated the excellent nitrogen removal performances.


2013 ◽  
Vol 20 (1) ◽  
pp. 199-208 ◽  
Author(s):  
Marketa Julinova ◽  
Jan Kupec ◽  
Roman Slavik ◽  
Maria Vaskova

Abstract A synthetic polymer, polyvinylpyrrolidone (PVP - E 1201) primarily finds applications in the pharmaceutical and food industries due to its resistance and zero toxicity to organisms. After ingestion, the substance passes through the organism unchanged. Consequently, it enters the systems of municipal wastewater treatment plants (WWTP) without decomposing biologically during the waste treatment process, nor does it attach (through sorption) to particles of activated sludge to any significant extent, therefore, it passes through the system of a WWTP, which may cause the substance to accumulate in the natural environment. For this reason the paper investigates the potential to initiate aerobic biodegradation of PVP in the presence of activated sludge from a municipal wastewater treatment plant. The following agents were selected as the initiators of the biodegradation process - co-substrates: acrylamide, N-acethylphenylalanine and 1-methyl-2-pyrrolidone, a substance with a similar structure to PVP monomer. The biodegradability of PVP in the presence of co-substrates was evaluated on the basis of biological oxygen demand (BOD) as determined via a MicroOxymax O2/CO2/CH4 respirometer. The total substrate concentration in the suspension equaled 400 mg·dm-3, with the ratio between PVP and the cosubstrate being 1:1, while the concentration of the dry activated sludge was 500 mg·dm-3. Even though there was no occurrence of a significant increase in the biodegradation of PVP alone in the presence of a co-substrate, acrylamide appeared to be the most effective type of co-substrate. Nevertheless, a recorded decrease in the slope of biodegradation curves over time may indicate that a process of primary decomposition was underway, which involves the production of metabolites that inhibit activated sludge microorganisms. The resulting products are not identified at this stage of experimentation.


2018 ◽  
Vol 77 (11) ◽  
pp. 2723-2732 ◽  
Author(s):  
Xiaowei Zheng ◽  
Shenyao Zhang ◽  
Jibiao Zhang ◽  
Deying Huang ◽  
Zheng Zheng

Abstract With the improvement of wastewater discharge standards, wastewater treatment plants (WWTPs) are continually undergoing technological improvements to meet the evolving standards. In this study, a quartz sand deep bed denitrification filter (DBDF) was used to purify WWTP secondary effluent, utilizing high nitrate nitrogen concentrations and a low C/N ratio. Results show that more than 90% of nitrate nitrogen (NO3-N) and 75% of chemical oxygen demand (COD) could be removed by the 20th day of filtration. When the filter layer depth was set to 1,600 mm and the additional carbon source CH3OH was maintained at 30 mg L−1 COD (20 mg L−1 methanol), the total nitrogen (TN) and COD concentrations of DBDF effluent were stabilized below 5 and 30 mg L−1, respectively. Analysis of fluorescence revealed that DBDF had a stronger effect on the removal of dissolved organic matter (DOM), especially of aromatic protein-like substances. High throughput sequencing and qPCR results indicate a distinctly stratified microbial distribution for the main functional species in DBDF, with quartz sand providing a good environment for microbes. The phyla Proteobacteria, Bacteroidetes, and Chloroflexi were found to be the dominant species in DBDF.


2017 ◽  
Vol 75 (8) ◽  
pp. 1784-1793 ◽  
Author(s):  
Ben Said Ines ◽  
Mezghani Imed ◽  
Donyez Frikha ◽  
Chaieb Mohamed ◽  
Muscolo Adele

This study aims to evaluate the possibility of using reclaimed municipal wastewater for agricultural purpose. We assessed the validity of municipal wastewater treatment, analyzing its chemical characteristics before and after the biological stabilization by pond treatment (WSP). The reclaimed municipal treated wastewater (TWW) was used to irrigate Cenchrus ciliaris. Experiments were carried out in greenhouse, from July 2013 to July 2014, comparing the effects of TWW with the water normally used for irrigation (tap water, TW) on the growth and flowering parameters of C. ciliaris. During this study, total coliforms, fecal coliforms, Escherichia coli, and Salmonella spp. were detected in TW, TWW, soils and plants under irrigation. Our results evidenced that TWW increased plant growth, producing taller plants with respect to TW. Total coliforms and fecal coliforms in TWW, TW, soils and plants were under the threshold recommended by the World Health Organization (WHO). Salmonella was never found in TW, TWW, or soil and plants irrigated with TWW. The absence of pathogens suggests that the pond treatment is an effective method to reclaim wastewater, lowering biochemical oxygen demand (BOD), chemical oxygen demand (COD) and pathogens. In this respect, TWW can be used as a valid alternative to freshwater for irrigation of fodder species.


1995 ◽  
Vol 31 (5-6) ◽  
pp. 243-246 ◽  
Author(s):  
Ernst M. Davis ◽  
M. Truett Garrett ◽  
Terri D. Skinner

An urban coastal stream, above tidal reach, and three municipal wastewater treatment plant effluents were analyzed for fecal coliforms, fecal streptococci and enterococci to determine the effect of dechlorination on those bacterial populations. Analyses were conducted during low and high flow periods from stormwater inflow. Improvement in bacterial water quality was found, principally due to municipality efforts to correct illicit connections and other sewerage system problems. Fecal coliform genera were identified and quantified. Regrowth of dechlorinated effluent bacteria was minimal.


Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 253
Author(s):  
Carlos Carbonell-Alcaina ◽  
Jose Luis Soler-Cabezas ◽  
Amparo Bes-Piá ◽  
María Cinta Vincent-Vela ◽  
Jose Antonio Mendoza-Roca ◽  
...  

Management of wastewater is a major challenge nowadays, due to increasing water demand, growing population and more stringent regulations on water quality. Wastewaters from food conservation are especially difficult to treat, since they have high salinity and high organic matter concentration. The aim of this work is the treatment of the effluent from a table olive fermentation process (FTOP) with the aim of reusing it once the organic matter is separated. The process proposed in this work consists of the following membrane-based technologies: Ultrafiltration (UF) (UP005, Microdyn Nadir), Forward Osmosis (FO) (Osmen2521, Hydration Technology Innovation) and Nanofiltration (NF) (NF245, Dow). The FO process was implemented to reduce the salinity entering the NF process, using the FTOP as draw solution and, at the same time, to concentrate the centrate produced in the sludge treatment of a municipal wastewater treatment plant with the aim of obtaining a stream enriched in nutrients. The UF step achieved the elimination of 50% of the chemical oxygen demand of the FTOP. The UF permeate was pumped to the FO system reducing the volume of the anaerobically digested sludge centrate (ADSC) by a factor of 3 in 6.5 h. Finally, the ultrafiltrated FTOP diluted by FO was subjected to NF. The transmembrane pressure needed in the NF stage was 40% lower than that required if the ultrafiltration permeate was directly nanofiltered. By means of the integrated process, the concentration of organic matter and phenolic compounds in the FTOP decreased by 97%. Therefore, the proposed process was able to obtain a treated brine that could be reused in other processes and simultaneously to concentrate a stream, such as the ADSC.


2010 ◽  
Vol 62 (4) ◽  
pp. 956-962 ◽  
Author(s):  
Agostina Chiavola ◽  
Piero Sirini ◽  
Sandro Cecili

The present paper shows the results obtained through an experimental activity carried out on a pilot-scale plant using an innovative technology which couples the granular aerobic sludge with the sequencing batch process. Treatment efficiency and operation costs were evaluated in order to assess feasibility of this new technology for the upgrading of the existing continuous flow activated sludge treatment plant located in Casal Monastero, a decentralized area of the City of Rome. During start-up (about 3 months), the granular aerobic sludge was developed by controlling the dissolved oxygen concentration, the value of pH and the up-flow velocity. Besides, the influent organic loading was progressively increased starting from 0.1 kg/m3 d up to 0.9 kg/m3 d. In order to improve nitrogen removal, an anoxic phase was temporary added to the operative cycle. Complete development of the granular sludge determined an appreciable improvement of the denitrification process which allowed to eliminate the anoxic phase. At regime conditions, the plant was operated with 3 daily cycles, each one of 8 h. The new system showed a reduced sludge production (of about 20–35%) as compared to the existing plant, along with high removal efficiency of both Chemical Oxygen Demand (COD) and nitrogen. However, the operation was discontinuous and strictly related to the strength of the granular sludge. Therefore, a careful monitoring is recommended in order to control operation and performance of this new system.


2017 ◽  
Vol 19 (3) ◽  
pp. 130-135
Author(s):  
Anna Ciaciuch ◽  
Jerzy Gaca ◽  
Karolina Lelewer

Abstract The research presents the changes in chemical oxygen demand (COD) fractions during the two-stage thermal disintegration and anaerobic digestion (AD) of sewage sludge in municipal wastewater treatment plant (WWTP). Four COD fractions have been separated taking into account the solubility of substrates and their susceptibility to biodegradation: inert soluble organic matter SI, readily biodegradable substrate SS, slowly biodegradable substrates XS and inert particulate organic material XI. The results showed that readily biodegradable substrates SS (46.8% of total COD) and slowly biodegradable substrates XS (36.1% of total COD) were dominant in the raw sludge effluents. In sewage effluents after two-stage thermal disintegration, the percentage of SS fraction increased to 90% of total COD and percentage of XS fraction decreased to 8% of total COD. After AD, percentage of SS fraction in total COD decreased to 64%, whereas the percentage of other fractions in effluents increased.


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