Artificial Aeration Research Articles

Assessment and Management of Ganga River Water Quality Using Multivariate Statistical Techniques in India

Multivariate statistical techniques, such as cluster analysis and principal component analysis (PCA), were applied for evaluation of spatial variations and interpretation of large complex water quality data set of the Ganga river basin, generated during one year (2013-2014) monitoring of eight water parameters at seven different sites. Hierarchical cluster analysis grouped seven sampling sites into three clusters, i.e., relatively low polluted (LP), medium polluted (MP) and highly polluted (HP) sites based on the similarity of water quality characteristics. Principal component analysis produced three significant main components and explaining more than 82.9% of the variance (anthropogenic and industrial effect) that present 57.1%, 13.8% and 12% respectively of the total variance of water quality in Ganga river. The result reveals that Turbidity, Dissolved oxygen and Biochemical oxygen demand are the parameters that are most important in assessing variations of water quality. Water quality index based on eight parameters (Turbidity, DO, BOD, COD, pH, TS, TSS and TDS) calculated for all the sites are found to be medium to bad. Thus, this study illustrates the usefulness of multivariate statistical techniques for analysis, interpretation of complex data sets and understanding spatial variations in water quality for effective river water quality management. The study reveals that untreated industrial and municipal discharges are the major source of the pollution to the Ganga river. Implementation of suitable management plan along with proper sewerage treatment network, maintaining sufficient dilution flow, artificial aeration and watershed management will control the pollution in the Ganga river.

Effects of aeration position on organics, nitrogen and phosphorus removal in combined oxidation pond–constructed wetland systems

Given that few studies investigated the effects of aeration position (AP) on the performance of aerated constructed wetlands, the aim of this study was to evaluate the effects of AP on organics, nitrogen and phosphorus removal in lab-scale combined oxidation pond–constructed wetland (OP–CW) systems. Results showed that middle aeration allowed the CW to possess more uniform oxygen distribution and to achieve greater removals of COD and NH3-N, while the CW under bottom aeration and surface aeration demonstrated more distinct stratification of oxygen distribution and surface aeration brought about better TN removal capacity for the OP–CW system. However, no significant influence of artificial aeration or AP on TP removal was observed. Overall, AP could significantly affect the spatial distribution of dissolved oxygen by influencing the oxygen diffusion paths in aerated CWs, thereby influencing the removal of pollutants, especially organics and nitrogen, which offers a reference for the design of aerated CWs.

Influence of intermittent aeration and organic loading rate on lab-scale constructed wetland systems treating synthetic wastewater

By coupling the intermittent characteristics of rural sewage discharge and solar energy density, the performance responses of lab-scale tidal flow constructed wetland (TF) and conventional vertical flow constructed wetland (VF) to different organic loading rates (OLRs) (166.3, 300.9, 451.2, 602.4, and 751.2 g/m2 d) in synthetic domestic sewage treatment were investigated to study its feasibility to replace conventional aeration and reduce the dependence of wastewater treatment plants on the grid in this study. Artificial aeration was conducted based on simulating photovoltaic aeration. The increase in OLR promoted the removal performances for the chemical oxygen demand (COD) and ammonia–nitrogen (NH4+-N) in TF, which could be up to 95.7 and 97.2%, respectively, under OLR of 751.2 g/m2 d. Excess organic carbons inhibited NH4+-N removal through competition for oxygen available in VF, where the COD removal efficiency could be 89.6% while low NH4+-N removal (40%) was obtained under OLR 751.2 g/m2 d. With the increase in OLR, the removal of total nitrogen (TN) was enhanced. A higher OLR can not only provide enough electron donors but also produce more anoxic regions for denitrification. The best TN removal was 77.5% in TF and 49.8% in VF, which occurred at OLR of 751.2 and 602.4 g/m2 d, respectively. A drop of TN removal in VF was attributed to the lack of nitrate–nitrogen (NO3--N) when reaching OLR of 751.2 g/m2 d. The removal efficiency for total phosphorus was increased gradually with the increase in OLR. This paper suggests that appropriate control of OLR can achieve the optimal effect of pollutants removal, especially the elimination of TN.

Enhancement of surface water quality using trading discharge permits and artificial aeration

Water quality trading (WQT) is a strategy for surface water quality management. This study focused on finding the optimal waste load allocation by WQT framework based on the concentrations of BOD and dissolved oxygen (DO) in Sefidrud River. It also assessed the consequences of using artificial aeration on trading discharge permits. For these purposes, river was simulated by Qual2kw. Two checkpoints were considered for monitoring the upstream (Sangar) and downstream (Caspian). Sensitivity analysis was carried out to find the impact factors of each emission sources. The required total maximum daily loads (TMDLs) were determined through simulation results. It predicted that the concentrations of ultimate BOD in both Sangar and Caspian stations may decrease from 3.6 and 8.1 mg/L, respectively, to 2.1 mg/L. Conversely, DO may increase from 5.8 and 0.9 mg/L to 7 and 3.7 mg/L, respectively. This could solely save 7 % of total treatment costs in comparison with the conventional command and control (C&C) policy. WQT may increase the revenues to 21 %. However, this could not provide enough flexibility and robustness in regard to the permit pricing and profits attained by stakeholders. Artificial aeration was considered as an improvement solution in the second scenario. The experimental results of hydroponic systems and hydraulic river simulation by CCHE2D showed that 0.25 day−1 can be added to the aeration coefficients. This modified TMDLs and impact factors thoroughly. Results verified that this approach may increase the revenues of TMDLs and discharge permit market, respectively, to 17 and 30 %. Permits can also be sold with higher prices and stakeholders may attain considerable profits. Consequently, the integration of artificial aeration with WQT was recommended for surface water quality enhancement.

Evaluation of the performance and space requirement by three different hybrid constructed wetlands in a stack arrangement

Lack of space for a wastewater treatment plant is a common problem in many areas, especially in dense cities. Constructed wetlands (CWs) are efficient natural systems; however, they require large areas. The aim of this study is the development of a compact CW design for the treatment of domestic wastewater, the Duplex-CW: a hybrid system with a stacked design (vertical flow CW (VFCW) on top of a horizontal flow filter (HFF)). The performance of three different configurations of Duplex-CW, called fill and drain, stagnant batch and free drain, was compared. The VFCWs operated differently with the intention of creating different oxygen conditions, whereas the HFFs were operated identically. The Duplex-CWs were subjected to three different wastewater strengths, corresponding to designs of 7.9, 3.4 and 2.6m2PE−1. The highest strength was treated with and without artificial aeration of the VFCW of each configuration. The contribution to the total removal of each compartment (VFCW and HFF), the effects of the use of artificial aeration, the solids accumulation, above- and below-ground biomass and the footprint requirements of the three configurations tested were determined. The fill and drain configuration performed better than the other two, the VFCW compartment being more active in the treatment than the HFF. It achieved an area of 2.6–3.4m2PE−1 and it needed 2–3 times lower area than what a single VFCW would have needed to reach similar total nitrogen effluent concentrations. The Duplex-CW did not contribute to the footprint reduction, for other parameters (e.g. COD, TSS and total phosphorus).

Kudoa spp. (Myxozoa) infection in musculature of Plagioscion squamosissimus (Sciaenidae) in the Amazon region, Brazil.

Ninety specimens of Plagioscion squamosissimus captured using fishing tackle in the Outeiro district, state of Pará, were examined. Fish were placed in plastic bags containing water, under conditions of artificial aeration, and transported live to the Carlos Azevedo Research Laboratory (LPCA), in Belém, Pará. They were anesthetized, euthanized and necropsied; small fragments of the epaxial and hypaxial muscles were removed for examination of fresh histological sections by means of optical microscopy. In 100% of the specimens analyzed, parasitic pseudocysts were seen to be interspersed within and between the skeletal muscle. These contained pseudoquadrate and/or star-shaped spores that presented four valves and four polar capsules, which were identified from their morphology as belonging to the genus Kudoa. This is the first report of Kudoa in P. squamosissimus in the Amazon region, Pará, Brazil.

Remediation of Urban River Water by Pontederia Cordata Combined with Artificial Aeration: Organic Matter and Nutrients Removal and Root-Adhered Bacterial Communities

Macrophyte combined with artificial aeration is a promising in situ remediation approach for urban rivers polluted with nutrients and organic matter. However, seasonal variations and aeration effects on phytoremediation performance and root-adhered microbial communities are still unclear. In this study, Pontederia cordata was used to treat polluted urban river water under various aeration intensities. Results showed that the highest removal efficiencies of chemical oxygen demand (CODCr) and total nitrogen (TN) were attained under aeration of 30 L min−1 in spring and summer and 15 L min−1 in autumn, while total phosphorus (TP) removal reached maximum with aeration of 15 L min−1 in all seasons. Moderate aeration was beneficial for increasing the diversity of root-adhered bacteria communities, and the shift of bacterial community structure was more pronounced in spring and autumn with varying aeration intensity. The dual effect, i.e. turbulence and dissolved oxygen (DO), of aeration on the removal of CODCr and TN prevailed over the individual effect of DO, while DO was the most influential factor for TP removal and the root-adhered bacterial community diversity. P. cordata combined with 15 L min−1 aeration was deemed to be the best condition tested in this study.

Influence of different recultivation methods on durability of nitrogen compounds changes in the waters of an urban lake

The study was conducted on Długie Lake, which was fed with raw domestic sewage for 20 years. After preliminary conservation operations, the lake was restored by the artificial circulation and phosphorus inactivation methods. Before the restoration of lake, average amount of ammonia in the bottom water layer achieved a value of 20.71 mg/L, and Total nitrogen (TN) 22.89 mg/L. Start up of artificial aeration caused a distinct change in the concentration of nitrogen compounds in the lake. The intensive nitrification processes occurred due to improving oxygenation of the lower layer and increasing the temperature. It resulted in an increase of nitrate nitrogen concentration to about 1.30 mg/L. A tenfold decrease in ammonia and TN concentration has been achieved as a result of the artificial aeration. Concentrations of nitrogen compounds which were noted 8 years after termination of the lake recultivation were typical for reservoirs with moderate trophic status.

Four stage hybrid constructed wetlands treating low-strength aquaculture wastewater with and without artificial aeration

Four stage hybrid constructed wetlands treating low-strength aquaculture wastewater with and without artificial aeration

Four stage hybrid constructed wetlands treating low strength aquaculture wastewater with and without artificial aeration

Four stage hybrid constructed wetlands treating low strength aquaculture wastewater with and without artificial aeration

Scenedesmus dimorphus와 질산화 박테리아의 공배양이 하수고도처리능에 미치는 영향

This study investigated the effect of a co-culture of Scenedesmus dimorphus and nitrifiers using artificial wastewater on the removal of ammonium, nitrate and phosphate in the advanced treatment. To test the synergistic effect of the co-culture, we compared the co-culture treatment with the cultures using S. dimorphus-only and nitrifiers-only treatment as controls. After 6 days of incubation, nitrate was removed only in the co-culture treatment and total amount of N removal was 1.3 times and 1.6 times higher in the co-culture treatment compared to those in the S. dimorphus- and nitrifiers-only treatments, respectively. In case of total amount of P, co-culture treatment removed 1.2 times and 12 times more P than the S. dimorphus -and nitrifiers-only conditions, respectively. This indicates that the co-culture improved removal rates for ammonium, nitrate, and phosphate. This further implies that there was no need for denitrification of nitrate and luxury uptake of P processes because nitrate and phosphate can be removed from the uptake by S. dimorphus. In addition, co-culture condition maintained high DO above 7 mg/L without artificial aeration, which is enough for nitrification, implying that co-culture has a potential to decrease or remove aeration cost in the wastewater treatment plants.

Content of phosphorus and selected metals in bottom sediments of Starzyc Lake under conditions of pulverizing water aeration

Artificial aeration of benthic water is a method promoting more intensive phosphorus bonding in bottom sediments. The purpose of this paper was to evaluate changes in the content of phosphorus and some selected metals in the bottom sediments of Starzyc Lake in relation to changes occurring in some quality parameters for the benthic water. During the research, conducted in 2005, 2006 and 2009, the lake water was aerated with a pulverizing aerator. Water and the bottom sediment were sampled in seven sites distributed uniformly throughout the water surface, the inflow area and the area of the lake water outflow to the Krąpiel River. The bottom sediments were analyzed for the total content of P, Ca, Mg and K, while the water samples were tested for pH and the levels of phosphate phosphorus (P-PO4) In the period covered by the research, the TP content in the bottom sediments of Starzyc Lake decreased only in the inflow area (by a mean of 43%). Additionally, a gradual decrease of the P-PO4 concentration (on average by 42%) in the benthic water was recorded in that period as well as a decrease in the content of Ca, Mg and K in the bottom sediments. The results from the analysed metal content show that the Ca content was most stable, decreasing by an average 21%, whereas the difference for the Mg and K content was 64% and 56%, respectively. The horizontal variability in the content of the analysed elements was found in the bottom sediments collected from various zones of the lake. The lowest content was found in the sediment material collected from the outflow zone of water to the Krąpiel River, and the highest one was recorded in the watercourse inflow zone. The highest variability was observed for the content of Ca and K, which on average was six times higher in the water inflow zone from drainage ditches than in the outflow zone. Throughout the research period, the bottom sediments comprised an indigenous source of phosphorus for the Starzyc Lake waters. key words: lake eutrophication, bottom sediment, benthic water, phosphorus, artificial aeration. dr hab. inz. Hanna Siwek, Department of General and Ecological Chemistry, West Pomeranian University of Technology in Szczecin, J. Slowackiego 17, 71-434 Szczecin, Poland, e-mail: hanna.siwek@zut.edu.pl

Description of microsporidia in simulids: molecular and morphological characterization of microsporidia in the larvae of Simulium pertinax Kollar (Diptera: Simuliidae).

Microsporidia constitute the most common black fly pathogens, although the species' diversity, seasonal occurrence and transmission mechanisms remain poorly understood. Infections by this agent are often chronic and non-lethal, but they can cause reduced fecundity and decreased longevity. The objective of this study was to identify microsporidia infecting Simulium (Chirostilbia) pertinax (Kollar, 1832) larvae from Caraguatatuba, State of São Paulo, Brazil, by molecular and morphological characterization. Larvae were collected at a single point in a stream in a rural area of the city and were kept under artificial aeration until analysis. Polydispyrenia spp. infection was characterized by the presence of at least 32 mononuclear spores measuring 6.9 ± 1.0 × 5.0 ± 0.7 µm in persistent sporophorous vesicles. Similarly, Amblyospora spp. were characterized by the presence of eight uninucleate spores measuring 4.5 × 3.5 µm in sporophorous vesicles. The molecular analysis confirmed the presence of microsporidian DNA in the 8 samples (prevalence of 0.51%). Six samples (Brazilian larvae) were related to Polydispyrenia simulii and Caudospora palustris reference sequences but in separate clusters. One sample was clustered with Amblyospora spp. Edhazardia aedis was the positive control taxon. Samples identified as Polydispyrenia spp. and Amblyospora spp. were grouped with P. simulii and Amblyospora spp., respectively, corroborating previous results. However, the 16S gene tree showed a considerable distance between the black fly-infecting Amblyospora spp. and the mosquito-infecting spp. This distance suggests that these two groups are not congeneric. Additional genomic region evaluation is necessary to obtain a coherent phylogeny for this group.

Nitrogen dynamics at the sediment–water interface in a tropical reservoir

Nitrogen dynamics at the sediment–water interface were examined in a tropical reservoir, Upper Peirce Reservoir, Singapore to provide information on the relative importance of each process and evaluated the spatial differences of nitrogen dynamics. The intact sediment cores were collected from three locations with different depths and distances to the artificial aeration system. The flow-through system combined with the isotope pairing technique was applied to estimate the nitrogen fluxes, potential denitrification rates and anammox rates. A mass balance model was developed and calibrated with the experimental results, and calculated mineralization, nitrification and dissimilatory nitrate reduction process rates. The sediment had a strong mineralization rate (13.39 mmol m−2 d−1) at shallow section, thus, had obvious NH4-N fluxes (17.61 mmol m−2 d−1). The total N2 removal rates through denitrification and anammox processes ranged from 0.08 to 0.28 mmol m−2 d−1, relatively lower than that in estuaries and coastal systems. Denitrification was performed as the main loss pathway, dominating up to 98% of total N2 removal rates. The coupled nitrification–denitrification (Dn) was dominant as compared to denitrification that happened from water column nitrate (Dw). Nitrification and N2 removal rates increased with water column depth. The artificial aeration around the deeper section might have contributed to the bacteria activities, and thus might stimulate high microbial processes converting NH4-N to NO3-N and bioactive nitrogen to N2 gas. The discovery of nitrogen transformation pathways in tropical freshwater systems are proposed to be incorporated into future conceptual models of global nitrogen cycles.

The influence of different recultivation techniques on primary production processes in a degraded urban lake

Abstract The study was conducted in Lake Długie located in Olsztyn, the Masurian Lake District. In the 1950s and in the 1960s, Lake Długie was used for 20 years as a collector of raw domestic and storm sewage. This has led to complete degradation of the lake. After preliminary protection measures implemented in the catchment, the lake was restored by artificial aeration and phosphorus inactivation methods. Long-term recultivation of the reservoir resulted in a significant and long-lasting improvement of the water quality. Before restoration, the average concentration of organic phosphorus in the surface water layer amounted to 0.166 mg Porg l−1 and of organic nitrogen — to 3.0 mg Norg l−1. After restoration, these values decreased to 0.058 mg Porg l−1 and 2.0 mg Norg l−1. The results obtained eight years after the recultivation of Lake Długie are extremely interesting. The amounts of chlorophyll a did not exceed 7 μg l−1, water transparency remained at a depth of 2.9 m, and BOD5 did not exceed 2 mg O2 l−1. These observations show that during implementation of recultivation treatments, only chemical parameters of the water significantly changed, while biological elements reacted to the treatments with some delay.

Comparative Study of Nirmalya Solid Waste Treatment by Vermicomposting and Artificial Aeration Composting

Temple waste normally contains floral offering, leaves and milk product i.e. “Abishek waste water”, and this solid waste management is one of the important issues in the world, because of shortage ofdumping sites and strict environmental legislation. Now days ‘Nirmalyasolid waste’ is generated in large quantity due toincreased in population are commonly treated using different types of bins by the method of composting or vermicomposting. Vermicomposting of solid waste can be done by using different types of earthworms providing natural and artificial aeration along with mixture of cow dung and soil, artificial aeration is carried out by providing diffused aerators or perforated pipes. The parameters like C/N ratio, temperature, moisture contain are carried out. The main objective of this study is to minimize the problem of solid waste management by treating nirmalya solid waste by vermicomposting and suggesting that which method gives good quality of compost at short interval of time comparing artificial and natural aeration composting.

Mineral cycling and pH gradient related with biological activity under transient anoxic-oxic conditions: effect on P mobility in volcanic lake sediments.

Phosphorus (P) mobility from the sediments to the water column is a complex phenomenon that is generally assumed to be mainly redox sensitive and promoted by anoxic conditions. Thus, artificial aeration of the hypolimnium has been used as a remediation technique in eutrophic water bodies but several times with unexpected disappointing results. To optimize lake restoration strategies, the aim of the present study is to assess the P flux from the sediments under transient anoxic-conditions and to identify the relevant drivers. P sequential extraction, microprofiling (of pH, O2 and H2S), and bacterial community identification were performed on a sediment microcosm approach. The results demonstrated that the overall P release from sediments to the water column during transient phase was higher during the oxic phase, mainly from pH sensitive matrixes. The microprofiles signature suggests that the observed pH gradient during the oxic phase can be a result of H2S oxidation in suboxic layers spatially separated and pared to O2 reduction in top layers, through an electroactive bacterial network. These findings point to an additional driver to be considered when assessing P mobility under transient anoxic-oxic conditions, which would derive from pH gradients, built on the microbial electrical activity in sediments from freshwaters volcanic lakes.

Evaluation of Yeast <i>Saccharomyces cerevisiae</i> and Algae <i>Chlorella vulgaris</i> as Diet for Rotifer <i>Brachionus calyciflorus</i>

A study was conducted to evaluate the effect of yeast Saccharomyces cerevisiae and algae Chlorella vulgaris on the production of rotifer Brachionus calyciflorus. The Brachionus calyciflorus were cultured using four different types of diets: fresh Chlorella vulgaris (T1), yeast with fresh Chlorella vulgaris (T2), powder Chlorella vulgaris with fresh Chlorella vulgaris (T3) and yeast with powder Chlorella vulgaris (T4). We compared these diets to find out their potentiality on the population growth of Brachionus calyciflorus. The rotifers were cultured under natural environmental condition with continuous artificial aeration. Initial density of Brachionus calyciflorus were 8 individuals ml-1 (ind. ml-1). Water temperature and pH were measured during the culture period. Among the four different diets the fresh Chlorella vulgaris (T1) and it’s yeast combination (T2) gave satisfactory production of rotifer 73±9 and 67±8 ind. ml-1, respectively. However, processing of fresh Chlorella vulgaris to produce powder form declined the production ability of rotifer. The diet sample T3 and T4 containing powdered Chlorella vulgaris produced 48±9 and 25±6 ind. ml-1, respectively. So, the diet in combination of yeast and fresh Chlorella is suggested for the sustainable production of the rotifer Brachionus calyciflorus. DOI: http://dx.doi.org/10.3329/agric.v12i1.19484 The Agriculturists 2014; 12(1) 1-9

Enhanced nitrogen removal in constructed wetlands: Effects of dissolved oxygen and step-feeding

Four horizontal subsurface flow constructed wetlands (HSFCWs), named HSFCW1 (three-stage, without step-feeding), HSFCW2 (three-stage, with step-feeding), HSFCW3 (five-stage, without step-feeding) and HSFCW4 (five-stage, with step-feeding) were designed to investigate the effects of dissolved oxygen (DO) and step-feeding on nitrogen removal. High removal of 90.9% COD, 99.1% ammonium nitrogen and 88.1% total nitrogen (TN) were obtained simultaneously in HSFCW4 compared with HSFCW1–3. The excellent TN removal of HSFCW4 was due to artificial aeration provided sufficient DO for nitrification and the favorable anoxic environment created for denitrification. Step-feeding was a crucial factor because it provided sufficient carbon source (high COD: nitrate ratio of 14.3) for the denitrification process. Microbial activities and microbial abundance in HSFCW4 was found to be influenced by DO distribution and step-feeding, and thus improve TN removal. These results suggest that artificial aeration combined with step-feeding could achieve high nitrogen removal in HSFCWs.

Three-stage horizontal subsurface flow constructed wetlands for organics and nitrogen removal: Effect of aeration

Improving nitrogen removal in wastewater treatment is necessary for the extensive and effective use of constructed wetlands (CWs) in rural areas. Six different three-stage horizontal subsurface flow (HSSF) CWs were designed to examine the effects of artificial aeration and aeration location on the treatment of organics and nitrogen. In a typical configuration (unaerated surface and subsurface flow), single-stage CWs fail to support aerobic and anoxic environments simultaneously. To adjust the distribution of dissolved oxygen (DO) in CWs and to improve the efficiency of sewage water purification, typical HSSF CWs were divided into different sections with enhanced functions. The treatment efficiency of the proposed HSSF CWs was compared with that of typical HSSF CW. Results show that the removal efficiencies of chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), and total nitrogen (TN) in typical HSSF CW were 70.3%, 18.4%, and 24.6%, respectively, whereas the removal efficiencies of CW1 with front and rear aeration and anoxic treatment were 90.1%, 99.7%, and 51.3%, respectively, at average influent COD and NH4+-N concentrations of 184.6 and 21.7mgL−1, respectively. Furthermore, front aeration greatly improved organics and nitrogen removal compared with middle aeration and rear aeration. The oxidized conditions in the HSSF CWs could facilitate efficient biological and biochemical reactions, thus resulting in efficient organics and NH4+-N removal. However, high DO level and lack of carbon resources might restrain denitrification even though NH4+-N removal was enhanced due to aeration. Therefore, TN removal has potential for improvement.