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1.
Appl Opt ; 60(16): 4716-4722, 2021 Jun 01.
Article in English | MEDLINE | ID: mdl-34143029

ABSTRACT

White light-emitting diodes (LEDs) are widely used in various lighting fields as a part of energy-efficient technology. However, some shortcomings of luminescent materials for white LEDs, such as complexity of synthesis, high cost, and harmful impact on the environment, limit their practical applications to a large extent. In this respect, the present work aims to study the ability of using Berberine (BBR) chloride extracted from Rhizoma coptidis and Phellodendron Chinese herbs as yellow phosphor for white LEDs. For this, white LEDs were successfully fabricated by applying 0.006 g of BBR chloride onto the blue LED chips (450 nm). The produced LEDs exhibited good luminescence properties at a voltage of 2.4 V along with eco-friendly characteristics and low cost. The Commission International de l'Eclairage chromaticity, the correlated color temperature, and the color rendering index were determined to be (${x} = {0.32}$, ${y} = {0.33}$), 5934 K, and 74, respectively. Therefore, BBR chloride is a suitable environmentally friendly and easily accessible yellow phosphor for white LEDs.


Subject(s)
Berberine/isolation & purification , Coptis chinensis/chemistry , Drugs, Chinese Herbal/chemistry , Lighting/instrumentation , Luminescent Agents/chemistry , Phellodendron/chemistry , Phosphorus/isolation & purification
2.
Bioprocess Biosyst Eng ; 44(10): 2051-2059, 2021 Oct.
Article in English | MEDLINE | ID: mdl-33993384

ABSTRACT

The partial denitrification (PD) is a very promising process developed in the last decade, to study the comprehensive influence of influent carbon to nitrogen (C/N) on the activated sludge system under PD, six sequencing batch reactors (SBRs) were operated in parallel at C/N of 2.75, 3.30, 4.13, 5.50, 8.25 and 16.50, the nitrogen removal, phosphorus removal and sludge settleability of PD were investigated. The results showed that PD was observed treating synthetic wastewater in all the six SBRs, and the nitrite accumulation rate (NAR) was highest at C/N of 5.50 (NAR of 82.30%). However, due to the alternate inhibition of NO2--N and free nitrous acid (FNA) produced by a limited carbon source, both the sludge settleability and phosphorus removal deteriorated. The average SVI at C/N of 8.25 was 130% lower than C/N of 3.30, and the average amount of PO43--P released at C/N of 16.5 was 189% higher than C/N of 2.75. Kinetic analysis showed that the denitrification kinetics of PD and complete denitrification were similar, and the nitrite accumulation was caused by the difference between nitrate reduction rate and nitrite reduction rate. Variations of on-line parameters (pH and ORP) revealed that nitrite accumulation could be indicated by judging the nitrate turning point and nitrite turning point on pH and ORP curves, which provided guidance for the setup of PD.


Subject(s)
Denitrification , Nitrates/analysis , Nutrients/isolation & purification , Bioreactors , Hydrogen-Ion Concentration , Nitrogen/isolation & purification , Phosphorus/isolation & purification , Sewage , Wastewater/chemistry
3.
Bioprocess Biosyst Eng ; 44(8): 1741-1753, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33792778

ABSTRACT

This study aims to explore the feasibility of biochar as a carrier to improve the simultaneous removal of nitrogen and phosphorus in biological aerated filters (BAFs) for treating low C/N digested swine wastewater (DSW). Two similar BAFs (BAF-A with hydrophobic polypropylene resin as fillers and BAF-B with bamboo biochar as carrier) were developed for DSW treatment. Results showed that the NH4+-N, TN, and TP removal performances in BAF-B were higher than those in BAF-A. Carrier type had an obvious influence on the structures and diversity of the microbial population. The biochar carrier in BAF-B was conducive to the enrichment of the functional microorganisms and the increase of microbial diversity under high NH4+-N conditions. Microbial analysis showed that the genera Rhodanobacter (10.64%), JGI_0001001-h003 (14.24%), RBG-13-54-9 (8.87%), Chujaibacter (11.27%), and Ottowia were the predominant populations involved in nitrogen and phosphorus removal in the later stage of phase III in BAF-B. BAF with biochar as carrier was highly promising for TN and TP removal in low C/N and high NH4+-N DSW treatment.


Subject(s)
Charcoal/chemistry , Nitrogen/isolation & purification , Oxygen/chemistry , Phosphorus/isolation & purification , Waste Disposal, Fluid/methods , Water Purification/methods , Ammonia , Animals , Bioreactors , Cluster Analysis , Filtration , Hydrogen-Ion Concentration , Microbiota , Principal Component Analysis , Sewage , Swine , Temperature , Wastewater
4.
Bioprocess Biosyst Eng ; 43(11): 2039-2052, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32594316

ABSTRACT

In this study, a novel laboratory-scale synchronous enhanced biological phosphorus removal and semi-nitritation (termed as EBPR-SN) combined with anammox process was put forward for achieving nutrient elimination from municipal wastewater at 27 ℃. This process consisted of two 10 L sequencing batch reactors (SBRs), i.e. EBPR-SN SBR followed by Anammox SBR. The EBPR-SN SBR was operated for 400 days with five periods and the Anammox SBR was operated starting on period IV. Eventually, for treating municipal wastewater containing low chemical oxygen demand/nitrogen (COD/N) of 3.2 (mg/mg), the EBPR-SN plus Anammox system performed advanced total inorganic nitrogen (TIN) and P removal, with TIN and P removal efficiencies of 81.4% and 94.3%, respectively. Further analysis suggested that the contributions of simultaneous partial nitrification denitrification, denitrification, and anammox to TIN removal were 15.0%, 45.0%, and 40.0%, respectively. The enriched phosphorus-accumulating organisms (PAOs) in the EBPR-SN SBR facilitated P removal. Besides, the EBPR-SN SBR achieved P removal and provided stable anammox substrates, suggesting a short sludge retention time (SRT 12 d) could achieve synergy between ammonia-oxidizing bacteria and PAOs. These results provided an alternative process for treating municipal wastewater with limited organics.


Subject(s)
Bioreactors , Biotechnology/methods , Nitrogen/isolation & purification , Phosphorus/chemistry , Phosphorus/isolation & purification , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Ammonia/chemistry , Biological Oxygen Demand Analysis , Denitrification , Equipment Design , Hydrogen-Ion Concentration , Nitrification , Sewage/microbiology , Waste Disposal, Fluid/methods , Wastewater/chemistry
5.
Bull Environ Contam Toxicol ; 104(2): 273-281, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31938814

ABSTRACT

Adopting the concept of "using waste to treat waste", the waste bricks will be used for constructed wetland filling. Integrated vertical-flow constructed wetland (IVCW) studied on the purification effect in influent water under three hydraulic loads (0.15, 0.25, 0.35 m/day). The results show that the waste bricks can be used as the carrier for the growth of the system biofilm, and have positive effects on the removal of pollutants in the influent water. Under three different hydraulic load conditions, the vertical flow of CWs can significantly reduce the load of water intake. In the low hydraulic load condition of 0.15 m/day, the average removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP) can reach 66.52%, 72.10%, 56.53% and 91.55% in this system, respectively. The influent pool on removal efficiency of pollutants was obviously higher than that of the upper pool, especially in the inlet surface 0-30 cm ranges. This research has achieved the effect of using "waste" to treat wastewater, which has strong practical significance and popularization value.


Subject(s)
Waste Disposal, Fluid/methods , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Wetlands , Ammonia/isolation & purification , Biological Oxygen Demand Analysis , Hydrology , Nitrogen/isolation & purification , Phosphorus/isolation & purification
6.
Appl Microbiol Biotechnol ; 103(8): 3571-3580, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30809712

ABSTRACT

Graesiella emersonii was cultivated in an osmotic membrane photobioreactor (OMPBR) for nutrients removal from synthetic wastewater in continuous mode. At 1.5 days of hydraulic retention time and under continuous illumination, the microalgae removed nitrogen (N) completely at influent NH4+-N concentrations of 4-16 mg/L, with removal rates of 3.03-12.1 mg/L-day. Phosphorus (P) removal in the OMPBR was through biological assimilation as well as membrane rejection, but PO43--P assimilation by microalgae could be improved at higher NH4+-N concentrations. Microalgae biomass composition was affected by N/P ratio in wastewater, and a higher N/P ratio resulted in higher P accumulation in the biomass. The OMPBR accumulated about 0.35 g/L biomass after 12 days of operation under continuous illumination. However, OMPBR operation under 12 h light/12 h dark cycle lowered biomass productivity by 60%, which resulted in 20% decrease in NH4+-N removal and nearly threefold increase in PO43--P accumulation in the OMPBR. Prolonged dark phase also affected carbohydrate accumulation in biomass, although its effects on lipid and protein accumulation were negligible. The microalgae also exhibited high tendency to aggregate and settle, which could be attributed to reduction in cell surface charge and enrichment of soluble algal products in the OMPBR. Due to a relatively shorter operating period, membrane biofouling and salt accumulation did not influence the permeate flux significantly. These results improve the understanding of the effects of N/P ratio and light/dark cycle on biomass accumulation and nutrients removal in the OMPBR.


Subject(s)
Microalgae/growth & development , Nutrients/isolation & purification , Photobioreactors/microbiology , Photoperiod , Wastewater/chemistry , Water Pollutants, Chemical/isolation & purification , Water Purification/instrumentation , Biofouling , Biomass , Carbohydrate Metabolism , Chlorophyta/growth & development , Chlorophyta/metabolism , Membranes, Artificial , Microalgae/metabolism , Nitrogen/chemistry , Nitrogen/isolation & purification , Nitrogen/metabolism , Nutrients/chemistry , Nutrients/metabolism , Osmosis , Phosphorus/chemistry , Phosphorus/isolation & purification , Phosphorus/metabolism , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/metabolism
7.
Water Environ Res ; 91(2): 144-156, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30735298

ABSTRACT

This paper analyzes six case studies of new water technology innovations in the last three decades and investigates the differences in timelines for moving through the various stages of water technology commercialization. The concept of two different types of innovation was explored: Crisis/Needs Driven and Value Driven. It was found that the case studies that mapped to the Crisis/Needs Driven innovation moved relatively quickly compared to Value Driven innovations and in most cases involved new entrants. New entrants refer to new companies or start-ups that have recently entered the water technology market. The case studies, which could be mapped to Value Driven innovation, had a slower rate of technology diffusion, and they involved a combination of existing companies as well as new entrants. PRACTITIONER POINTS: The paper identifies two key types of innovation: Crisis/Needs Driven and Value Driven. Legislation was observed to be a key driver for the adoption of new technology innovation in the water sector. The Crisis/Needs driven innovations studied were observed to diffuse through the Water Technology Diffusion model at up to twice the pace of Value driven innovation. Crisis/Needs driven innovation typically involves disruptive innovation offered by new entrants, whereas with Value driven innovation, the solutions are provided by both existing companies as well as new entrants. It is also observed that in most cases a technology that is adopted in order to meet a crisis or need in the market is more expensive at the outset compared with incumbent solutions. While value driven adoption has a slower cycle for adoption, it presents a lower risk as it is less dependent on external factors and timing of implementation of regulations or the occurrence of some public health related or environmental crisis.


Subject(s)
Inventions , Water Purification , Disinfection , Drinking Water/chemistry , Drinking Water/microbiology , Hydrolysis , Phosphorus/isolation & purification , Sewage , Temperature , Ultraviolet Rays
8.
Water Environ Res ; 91(3): 250-258, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30624834

ABSTRACT

The impact of solids residence time (SRT) on the dynamics of phosphorus (P) removal by hydrous ferric oxide (HFO) floc was characterized through experimental and modeling studies. Three abiotic process conditions were considered in systems operated over a range of SRTs (~3 to 27 days): uptake in sequencing batch reactors (SBRs) under (a) constant and (b) dynamic P loading conditions, and (c) uptake in batch sorption tests with preformed HFO solids. P removal under all conditions was characterized by an initial period of fast removal followed by a period of slower removal until pseudo-equilibrium was reached. The initial removal rate increased with increasing P concentrations and was attributed to a larger concentration gradient between soluble- and adsorbed-phase concentrations. A kinetic model was developed and found to describe the dynamic behavior of P adsorption onto HFO floc under all conditions tested. A consistent mass transfer rate coefficient (k) was found to describe mass transfer over a range of SRTs for low initial P concentrations. At elevated SRTs (23-27 days) and elevated influent P concentrations, k values were found to deviate from those estimated at reduced SRTs. Differences in process mixing conditions were reflected in the estimated rate coefficients (k). Integration of the kinetic model with existing equilibrium models in wastewater process simulators will improve the ability to predict P uptake onto HFO floc under dynamic loading conditions in water resource recovery facilities. Models that consider the kinetics of P uptake will be particularly relevant for facilities that are required to achieve ultralow P concentrations. PRACTITIONER POINTS: This work provides a kinetic model that can be integrated with existing equilibrium models in wastewater process simulators to improve the ability to predict P uptake onto HFO floc under dynamic loading conditions. This research can be used to assist WRRFs to achieve ultralow effluent P requirements.


Subject(s)
Ferric Compounds/chemistry , Phosphorus/chemistry , Phosphorus/isolation & purification , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/isolation & purification , Adsorption , Kinetics , Wastewater/chemistry
9.
Molecules ; 24(15)2019 Jul 31.
Article in English | MEDLINE | ID: mdl-31370233

ABSTRACT

The chemical composition and daily mineral intake (DMI) of six macro (calcium, magnesium, sodium, potassium, phosphorous, and chloride) and four microminerals (copper, iron, manganese, and zinc) were determined in four types of Portuguese breads (white wheat, maize, wheat/maize, and maize/rye breads). Samples were processed with microwave assisted digestion and mineral composition was determined with a high-resolution continuum-source atomic absorption spectrometer with flame and graphite furnace. Bread contributes to an equilibrated diet since it is rich in several minerals (0.21 mg/100 g of copper in wheat bread to 537 mg/100 g of sodium in maize/rye bread). Maize/rye bread presented the highest content of all minerals (except phosphorous and chloride), while the lowest levels were mainly found in wheat bread. Median sodium concentrations (422-537 mg/100 g) represented more than 28% of the recommended daily allowance, being in close range of the maximum Portuguese limit (550 mg/100 g). Maize/rye bread exhibited the highest DMI of manganese (181%), sodium (36%), magnesium (32%), copper (32%), zinc (24%), iron (22%), potassium (20%), and calcium (3.0%). A Principal Component Analysis (PCA) model based on the mineral content allowed the differentiation among white wheat, maize, and maize/rye bread. Zinc, magnesium, manganese, iron, phosphorus, potassium, copper, and calcium proved to be good chemical markers to differentiate bread compositions.


Subject(s)
Bread/analysis , Flour/analysis , Minerals/chemistry , Triticum/chemistry , Bread/standards , Copper/chemistry , Copper/isolation & purification , Dietary Fiber/analysis , Humans , Iron/isolation & purification , Magnesium/chemistry , Magnesium/isolation & purification , Minerals/isolation & purification , Phosphorus/chemistry , Phosphorus/isolation & purification , Portugal , Spectrophotometry, Atomic , Zinc/chemistry , Zinc/isolation & purification
10.
Article in English | MEDLINE | ID: mdl-30929568

ABSTRACT

Conventional activated-sludge (AS) technologies are deficient for nutrient removal because they require specific floc characteristics. Therefore, the encapsulated AS with polyvinyl alcohol (PVA) will favor floc's formation that removes nutrients. The applied method was based on monitoring the removal of organic matter and nutrients (NH4+, NO3-, NO2-, PO43-) from synthetic domestic wastewater using laboratory-scale AS. The experimental reactors were operated at 8 h as optimized Hydraulic Retention Time (HRT). The sludge characteristics evaluation was carried out through the Sludge Volumetric Index (SVI), Food/Microorganism ratio (F/M), and Mixed Liquor Volatile Suspended Solids (MLVSS). Other specific floc characteristics, such as zeta potential and effective diameter were also evaluated. The results showed that the encapsulated AS with PVA favors nitrogen and phosphorous removal up to 35% but it did not improve organic matter removal. In addition, encapsulated AS with PVA has the characteristics of filamentous sludge (F/M: 0.7 g COD g-1 MLVSS d-1) with good settleability conditions (SVI: 43 mL g-1 MLSVS h-1) and low zeta potential (ZP: -0.9 mV), which favors its separation from the liquid phase. In conclusion, the encapsulation of AS with PVA improves nutrient removal by improving floc characteristics.


Subject(s)
Nutrients/isolation & purification , Polyvinyl Alcohol/pharmacokinetics , Sewage/chemistry , Waste Disposal, Fluid/methods , Wastewater/chemistry , Bioreactors/microbiology , Cities , Drug Compounding/methods , Humans , Nitrogen/isolation & purification , Nitrogen/pharmacokinetics , Phosphorus/isolation & purification , Phosphorus/pharmacokinetics , Polyvinyl Alcohol/chemistry , Residence Characteristics , Water Purification/methods
11.
J Environ Sci (China) ; 76: 121-132, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30528004

ABSTRACT

It was focused on the effect of different sludge concentrations on the performances of an algal-activated sludge symbiotic system in terms of wastewater treatment, algal-activated sludge characteristics and community structure. The results showed that the highest nutrient removal efficiencies were obtained in the reactor R2 with soluble chemical oxygen demand (sCOD), ammonia nitrogen (NH4+-N) and phosphate (PO43- -P) removal efficiencies of (90.6±2.3)%, (97.69±2.6)% and (83.81±2.3)%, respectively. Further investigation exhibited that sludge concentration has a great effect on the dissolved oxygen (DO) concentration, the pH, the growth of algae and the extracellular polymeric substance (EPS) production, which resulted in influencing the settleability and the performance of symbiotic system. The denaturing gradient gel electrophoresis (DGGE) analysis demonstrated that the sludge concentration had a selective power for particular members of algae. Meantime, the stimulated algal population would selectively excite the members of bacteria benefited for the formation of algal-bacterial consortia. The variation of microbial compositions, which was influenced by the different sludge concentrations, might be ultimately responsible for the different treatment performances.


Subject(s)
Bacteria/metabolism , Bioreactors/microbiology , Microbiota , Sewage/microbiology , Symbiosis , Bacteria/cytology , Extracellular Polymeric Substance Matrix/metabolism , Nitrogen/isolation & purification , Nitrogen/metabolism , Phosphorus/isolation & purification , Phosphorus/metabolism , Sewage/chemistry
12.
Crit Rev Biotechnol ; 38(7): 1077-1088, 2018 Nov.
Article in English | MEDLINE | ID: mdl-29631450

ABSTRACT

Aerobic granules are the potential tools to develop modern wastewater treatment technologies with improved nutrient removal efficiency. These granules have several promising advantages over conventional activated sludge-based wastewater treatment processes. This technology has the potential of reducing the infrastructure and operation costs of wastewater treatment by 25%, energy requirement by 30%, and space requirement by 75%. The nutrient removal mechanisms of aerobic granules are slightly different from that of the activated sludge. For instance, unlike activated sludge process, according to some reports, as high as 70% of the total phosphorus removed by aerobic granules were attributed to precipitation within the granules. Similarly, aerobic granule-based technology reduces the total amount of sludge produced during wastewater treatment. However, the reason behind this observation is unknown and it needs further explanations based on carbon and nitrogen removal mechanisms. Thus, as a part of the present review, a set of new hypotheses have been proposed to explain the peculiar nutrient removal mechanisms of the aerobic granules.


Subject(s)
Bioreactors , Carbon , Nitrogen , Phosphorus , Water Purification/methods , Aerobiosis , Carbon/analysis , Carbon/isolation & purification , Carbon/metabolism , Nitrogen/analysis , Nitrogen/isolation & purification , Nitrogen/metabolism , Phosphorus/analysis , Phosphorus/isolation & purification , Phosphorus/metabolism , Sewage
13.
Biodegradation ; 29(1): 11-22, 2018 02.
Article in English | MEDLINE | ID: mdl-29080942

ABSTRACT

For municipal wastewater treatment, main stream biological nutrient removal (BNR) process is becoming more and more important. This lab-scale study, novel MBR_based BNR processes (named A2N-MBR and A2NO-MBR) were built. Comparison of the COD removal, results obtained demonstrated that COD removal efficiencies were almost the same in three processes, with effluent concentration all bellowed 30 mg L-1. However, the two-sludge systems (A2N-MBR and A2NO-MBR) had an obvious advantage over the A2/O for denitrification and phosphorus removal, with the average TP removal rates of 91.20, 98.05% and TN removal rates of 73.00, 79.49%, respectively, higher than that of 86.45 and 61.60% in A2/O process. Illumina Miseq sequencing revealed that Candidatus_Accumulibacter, which is capable of using nitrate as an electron acceptor for phosphorus and nitrogen removal simultaneously, was the dominant phylum in both A2N-MBR and A2NO-MBR process, accounting for 28.74 and 23.98%, respectively. Distinguishingly, major organism groups related to nitrogen and phosphorus removal in A2/O system were Anaerolineaceae_uncultured, Saprospiraceae_uncultured and Thauera, with proportions of 11.31, 8.56 and 5.00%, respectively. Hence, the diversity of dominant PAOs group was likely responsible for the difference in nitrogen and phosphorus removal in the three processes.


Subject(s)
Bacteria/metabolism , Bioreactors/microbiology , Membranes, Artificial , Nitrogen/isolation & purification , Phosphorus/isolation & purification , Aerobiosis , Ammonia/metabolism , Anaerobiosis , Biodegradation, Environmental , Biological Oxygen Demand Analysis , Denitrification , Nitrates/metabolism , Nitrification , Phylogeny , Sewage/microbiology , Wastewater/microbiology
14.
J Dairy Res ; 85(3): 379-383, 2018 Aug.
Article in English | MEDLINE | ID: mdl-30088457

ABSTRACT

This Research Communication describes an investigation into the viability of an Intermittently Aerated Sequencing Batch Reactor (IASBR) for the treatment of dairy processing wastewater at laboratory-scale. A number of operational parameters have been varied and the effect has been monitored in order to determine optimal conditions for maximising removal efficiencies. These operational parameters include Hydraulic Retention Time (HRT), Solids Retention Time (SRT), aeration rate and cycle length. Real dairy processing wastewater and synthetic wastewater have been treated using three laboratory-scale IASBR units in a temperature controlled room. When the operational conditions were established, the units were seeded using sludge from a municipal wastewater treatment plant for the first experiment, and sludge from a dairy processing factory for the second and third experiment. In experiment three, the reactors were fed on real wastewater from the wastewater treatment plant at this dairy processing factory. These laboratory-scale systems will be used to demonstrate over time that the IASBR system is a consistent, viable option for treatment of dairy processing wastewater in this sector. In this study, the capacity of a biological system to remove both nitrogen and phosphorus within one reactor will be demonstrated. The initial operational parameters for a pilot-scale IASBR system will be derived from the results of the study.


Subject(s)
Dairy Products , Food-Processing Industry/methods , Wastewater , Water Purification/instrumentation , Water Purification/methods , Dairying , Nitrogen/isolation & purification , Oxygen/administration & dosage , Phosphorus/isolation & purification , Sewage/chemistry , Wastewater/chemistry
15.
J Dairy Res ; 85(3): 384-387, 2018 Aug.
Article in English | MEDLINE | ID: mdl-30088469

ABSTRACT

This Research Communication describes the initial operation of a pilot-scale intermittently aerated sequencing batch reactor system, which is located at an Irish dairy processing factory. Laboratory-scale research has facilitated the design specifications and operational parameters necessary for the construction and running of a pilot-scale. Laboratory scale research was necessary prior to the pilot scale system to ensure high quality treatment and nutrient removal efficiencies. The pilot system operates with a hydraulic retention time of 4 d, a solids retention time of 16 d and a cycle length of 12 hours. There are 4 non-aeration and aeration phases within the system's react phase. This system has a 3000 l working volume, treating 375 l of wastewater per cycle, 750 l daily. The system was seeded from an aeration tank at the dairy processing factory where the unit is located. The system is operating with the goal to remove both nitrogen and phosphorus from the wastewater biologically, reducing the need for chemical treatment. Currently, the system is performing with high efficiency, treating the wastewater to an acceptable level according to the Irish Environmental Protection Agency for discharge into surrounding water bodies. Therefore, the initial removal results demonstrate this technology's suitability for the treatment of high strength dairy wastewaters.


Subject(s)
Dairy Products , Food-Processing Industry/methods , Wastewater/chemistry , Water Purification/instrumentation , Water Purification/methods , Nitrogen/isolation & purification , Oxygen/administration & dosage , Phosphorus/isolation & purification , Sewage/chemistry
16.
J Environ Manage ; 209: 57-64, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-29275285

ABSTRACT

A new process was proposed by integrating a three-dimensional biofilm electrode reactor with sulfur autotrophic denitrification and electrocoagulation within the same reactor. The results indicated that under the wastewater influent condition of NO3--N = 30 mg/L, COD = 45 mg/L, total phosphorus (TP) = 1.5 mg/L, hydraulic retention time (HRT) = 8 h, and I = 400 mA, the NO3--N and TP removal of the proposed process reached 89.8% and 83.0%, respectively. It was observed that the electrocoagulation process improved phosphorus removal, while the simultaneous existence of heterotrophic, hydrogen, sulfur and iron autotrophic denitrifying bacteria led to enhanced and stabilized nitrogen removal. The Sulfuritalea hydrogenivorans sk43H and Sulfuricella denitrificans skB26 were found as the dominant denitrifying bacteria in the electrocoagulation section and the section of biofilm electrode with sulfur filler, respectively. As compared to conventional technologies, the proposed new process can achieve simultaneous, stable and deep nitrogen and phosphorus removal from wastewater treatment plant effluent with low organic carbon content.


Subject(s)
Denitrification , Nitrogen , Phosphorus/isolation & purification , Wastewater , Bioreactors , Carbon
17.
J Environ Manage ; 216: 305-314, 2018 Jun 15.
Article in English | MEDLINE | ID: mdl-28648547

ABSTRACT

The ability of biochars, derived from the pyrolysis at 400 °C; 500 °C and 600 °C of pretreated cypress sawdust with 20 wt% magnesium chloride (MgCl2) solutions, in recovering phosphorus from aqueous solutions was investigated under various experimental conditions in batch mode. The experimental results indicated that cypress sawdust pretreatment with MgCl2 induced important modifications of the physical and chemical biochars' properties favoring phosphorus recovery from the used synthetic solutions. Moreover, phosphorus recovery efficiency increased with the increase of the used pyrolysis temperature. Indeed, for an aqueous pH of 5.2 and a phosphorus concentration of 75 mg L-1, the recovered amounts increased from 19.2 mg g-1 to 33.8 mg g-1 when the used pyrolysis temperature was raised from 400 °C to 600 °C. For all the tested biochars, the phosphorus recovery kinetics data were well fitted by the pseudo-second-order model, and the equilibrium state was obtained after 180 min of contact time. Furthermore, the phosphorus recovery data at equilibrium were well described by the Langmuir model with a maximal recovery capacity of 66.7 mg g-1 for the magnesium pretreated biochar at 600 °C. Phosphorus recovery by the used biochars occurred probably through adsorption onto biochars' active sites as well as precipitation with magnesium ions as magnesium phosphates components. All these results suggested that biochars derived from MgCl2 pretreated cypress sawdust could be considered as promising materials for phosphorus recovery from wastewaters for a possible further subsequent use in agriculture as amendments.


Subject(s)
Charcoal , Phosphorus/isolation & purification , Adsorption , Cupressus , Magnesium , Solutions
18.
J Environ Manage ; 211: 1-8, 2018 Apr 01.
Article in English | MEDLINE | ID: mdl-29408058

ABSTRACT

Nitrogen and phosphorus are among the potential pollutants of receptive water sources entering into these water sources via sewage, which are not sufficiently treated. The purpose of this study is to investigate the efficiency of a new two-stage aerobic-anoxic continuous-flow baffled cycling reactor (CFBCR) to reduce nitrogen and phosphorus load from wastewater. Therefore, a double-stage baffled reactor was used in which the second part was integrated with the settling part causing the sludge to be spontaneously returned to the second reservoir. Additionally, the effect of different concentrations of chemical oxygen demand (COD) of 400-800 mg/L, ammonia of 40-60 mg/L, phosphate of 12-20 mg/L, internal rate of return of 100-200% and the retention time of 18-30 h was investigated. Furthermore, to investigate the performance of this reactor, four phases with different aeration and mixing conditions were designed. The percentage of ammonia removal with influent concentration of 40 mg/L in phase 2 with intermittent mixing and one-hour aeration time was 98.7%; effluent nitrate average concentration was 8.4 mg/L NO3-N, and phosphate removal percent was 83%. The best nutrient removal efficiency was with the retention time of 24 h and internal return rate of 150%. In conclusion, CFBCR reactor with continuous influent and effluent and reduction of the need for sludge return, has the potential to be applied to remove nutrients from wastewater.


Subject(s)
Bioreactors , Wastewater , Denitrification , Nitrogen/isolation & purification , Phosphorus/isolation & purification , Sewage , Waste Disposal, Fluid
19.
J Environ Manage ; 226: 70-75, 2018 Nov 15.
Article in English | MEDLINE | ID: mdl-30114574

ABSTRACT

The leaching procedure of post-precipitated aluminium phosphate sludge with dilute phosphoric acid was developed. The leaching offers a route to recover both critical phosphorous from sewage sludge and the metal used in precipitation. Using phosphoric acid as leaching solution makes it possible to continue the recovery process without the need to remove chloride or sulfate anions. The optimization of the leaching was based on experimental three-level-four-variable central composite face-centered design. The four variables included were acid concentration, volume of acid, temperature and time of leaching. The leaching was conducted for dewatered and water-containing sludge (total solid content 3-4%) and for both second-order regression models were obtained. For water-containing sludge optimal conditions for leaching are solid to liquid ratio (S/L) 400 gL-1, a temperature of 60 °C and a leaching time of 6 h. For the dewatered sludge, optimal leaching is attained when S/L ratio 119 gL-1 with 2 M acid is used at a temperature of 20 °C. The obtained results enable the developing of full-scale process where phosphate in the sludge is refined to phosphorous acid and metal used in sludge production recycled back to precipitation.


Subject(s)
Phosphorus/chemistry , Sewage , Chemical Precipitation , Metals , Phosphorus/isolation & purification , Temperature , Water , Water Purification
20.
J Environ Manage ; 213: 297-308, 2018 May 01.
Article in English | MEDLINE | ID: mdl-29502015

ABSTRACT

This study evaluated the unique features of a filamentous algae matrix (FAM) that can be applied to high rate algal ponds (HRAPs) as a promising way to remove nutrient from polluted rural streams. The results show that the HRAPs, coupled with the FAM, effectively removed nitrogen and phosphorus (79.8% and 81.2%, respectively), and achieved high production of DO, with a maximum of 11.0 g O2 g FAM-1 d-1. The FAM functioned wells as a screen to prevent excessive algae loss from the system and obtained relatively high biomass growth rate (0.032 mg L-1 d-1 for nitrogen and 0.344 mg L-1 d-1 for phosphorus). The harvested FAM was a useful fertilizer and the rate of addition of FAM were 1.52 kg d-1 ha-1 of nitrogen and 0.44 kg d-1 ha-1 of phosphorus. Thus, combining the HRAP with the FAM was an effective nutrient removal and resource utilization system for rural streams.


Subject(s)
Denitrification , Phosphorus/isolation & purification , Spirogyra , Waste Disposal, Fluid , Agriculture , Biomass , Nitrogen , Phosphorus/chemistry , Ponds , Rivers
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