Heavy metal pollution from Russian landfill leachates and its elimination together with other contaminants

2004 ◽  
Vol 50 (5) ◽  
pp. 51-58 ◽  
Author(s):  
S. Kalyuzhnyi ◽  
M. Gladchenko

Systematic monitoring of raw leachates (RL) from the operating landfill “Khmet'yevo7rdquo; during December, 2001-June, 2002 with regard to heavy metals (HM) revealed that these RL were moderately contaminated with Fe, Zn, Pb and Cd (Cu is present in non-dangerous concentrations). This contamination depends on season - the winter leachates are less polluted compared to the summer ones. For removal of HM together with removal of bulk COD, the UASB reactors were applied where, besides elimination of the major part of organic matter, concomitant precipitation of HM in the form of insoluble sulphides inside the sludge bed occurred due to development of the process of biological sulphate reduction. Both removal processes were quite efficient even during operation under submesophilic and psychrophilic conditions (20-10°C). The subsequent submesophilic aerobic-anoxic treatment of submesophilic anaerobic effluents led to only 75% of total inorganic N removal due to COD deficiency for denitrification created by a too efficient anaerobic step. On the contrary, psychrophilic anaerobic effluents (richer in COD compared to the submesophilic ones) were more suitable for subsequent aerobic-anoxic treatment giving the total N removal of 95 and 92% at 20 and 10°C, respectively. The final effluent is approaching the current national standards for direct discharge of treated wastewater.

2004 ◽  
Vol 49 (5-6) ◽  
pp. 301-312 ◽  
Author(s):  
S.V. Kalyuzhnyi ◽  
M.A. Gladchenko

As a first step in treatment of high strength, strong nitrogenous landfill leachates (total COD - 9.66-20.56 g/l, total nitrogen 780-1,080 mg/l), the performance of laboratory UASB reactors has been investigated under sub-mesophilic (19±3°C) and psychrophilic (10±2°C) conditions. Under hydraulic retention time (HRT) of around 1.2 days, when the average organic loading rate (OLR) was around 8.5 g COD/l/day, the total COD removal accounted for 71% (on average) for sub-mesophilic regime. The psychrophilic treatment conducted under the average HRT of 2.44 days and the average OLR of 4.2 g COD/l/day showed an average total COD removal of 58% giving effluents more suitable for subsequent biological nitrogen removal. Both anaerobic regimes were quite efficient for elimination of heavy metals by concomitant precipitation in the form of insoluble sulphides inside the sludge. The subsequent submesophilic aerobic-anoxic treatment of submesophilic anaerobic effluents led to only 75% of total inorganic N removal due to COD deficiency for denitrification created by too efficient anaerobic step. On the contrary, psychrophilic anaerobic effluents (richer in COD compared to the submesophilic ones) were more suitable for subsequent aerobic-anoxic treatment giving the total N removal of 95 and 92% at 19 and 10°C, respectively.


2003 ◽  
Vol 48 (6) ◽  
pp. 311-318 ◽  
Author(s):  
S. Kalyuzhnyi ◽  
M. Gladchenko ◽  
A. Epov

As a first step of treatment of landfill leachates (total COD - 1,430-3,810 mg/l, total nitrogen 90-162 mg/l), a performance of laboratory UASB reactors has been investigated under mesophilic (30°C), sub-mesophilic (20°C) and psychrophilic (10°C) conditions. Under hydraulic retention times (HRT) of around 7 h, when the average organic loading rates (OLR) were around 5 g COD/l/day, the total COD removal accounted for 81% (on the average) with the effluent concentrations close to anaerobic biodegradability limit (0.25 g COD/l) for mesophilic and sub-mesophilic regimes. The psychrophilic treatment conducted under the average HRT of 8 h and the average OLR of 4.22 g COD/l/day showed a total COD removal of 47% producing the effluents (0.75 g COD/l) more suitable for subsequent biological nitrogen removal. All three anaerobic regimes used for leachate treatment were quite efficient for elimination of heavy metals (Fe, Zn, Cu, Pb, Cd) by concomitant precipitation in the form of insoluble sulphides inside the sludge bed. The application of aerobic/anoxic biofilter as a sole polishing step for psychrophilic anaerobic effluents was acceptable for elimination of biodegradable COD and nitrogen approaching the current standards for direct discharge of treated wastewater.


1987 ◽  
Vol 19 (1-2) ◽  
pp. 107-118 ◽  
Author(s):  
Hans Brix

The present paper describes the theoretical basis of wastewater treatment in the rhizosphere of wetland plants, the so-called “root-zone method”, along with the first working experiences from eight treatment plants in Denmark. Mechanically treated wastewater is led horizontally through the rhizosphere of wetland plants. During the passage of the wastewater through the rhizosphere, the wastewater is cleaned by microbiological degradation and by physical/chemical processes. The wetland plants supply oxygen to the heterotrophic microorganisms in the rhizosphere and stabilize the hydraulic conductivity of the soil. Nitrogen is removed by denitrification and phosphorus and heavy metals are bound in the soil. The first working experiences from Denmark show, that as far as BOD is concerned root-zone treatment plants are very nearly up to conventional secondary treatment standards already from the first growing season (removal efficiency: 51-95%). For the nutrients nitrogen and phosphorus the results vary (total-N removal: 10-88%; total-P removal: 11-94%). The removal efficiencies depended mainly on the composition of the soils and the degree of surface runoff in each treatment plant. It is concluded that root-zone treatment plants seem to be a viable alternative to conventional wastewater treatment technology, especially suitable for single households and small to medium sized communities. There is, however, still very little information on the removal processes for nitrogen (denitrification), on the effect of soil type and on the required surface area to load ratio,


1999 ◽  
Vol 39 (5) ◽  
pp. 89-96 ◽  
Author(s):  
P. G. Hien ◽  
L. T. K. Oanh ◽  
N. T. Viet ◽  
G. Lettinga

Wastewater from tapioca processing factory containing high COD (11,077-19,083 mg/l), SS (4,180-7,600 mg/l) and low pH (4.33-5.60) still causes heavy pollution to receiving water in South Vietnam. Closing the water circuit in the tapioca industries represents a very attractive option for eliminating pollution problems and the reuse of treated wastewater and solid wastes. The investigated and presently occasionally already implemented system consists of primary sedimentation tank, anaerobic treatment using UASB-reactors, aeration tanks using attached growth reactor and oxidation ponds system. Under laboratory conditions, organic loading rates applied in UASB-reactors are up to 40,35 kg COD/m3.d with treatment efficiency of 90-95%, reducing the COD concentration from up to 13,449 mg/l to 624-780 mg/l. The final effluent COD (sol.) after treatment in the pond system operated at hydraulic retention time of 12-20 days is lower than 10 mg/l. This effluent is suited very well either for use in agriculture or in the factory.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498e-498
Author(s):  
S. Paramasivam ◽  
A.K. Alva

For perennial crop production conditions, major portion of nutrient removal from the soil-tree system is that in harvested fruits. Nitrogen in the fruits was calculated for 22-year-old `Hamlin' orange (Citrus sinensis) trees on Cleopatra mandarin (Citrus reticulata) rootstock, grown in a Tavares fine sand (hyperthermic, uncoated, Typic Quartzipsamments) that received various N rates (112, 168, 224, and 280 kg N/ha per year) as either i) broadcast of dry granular form (DGF; four applications/year), or ii) fertigation (FRT; 15 applications/year). Total N in the fruits (mean across 4 years) varied from 82 to 110 and 89 to 111 kg N/ha per year for the DGF and FRT sources, respectively. Proportion of N in the fruits in relation to N applied decreased from 74% to 39% for the DGF and from 80% to 40% for the FRT treatments. High percentage of N removal in the fruits in relation to total N applied at low N rates indicate that trees may be depleting the tree reserve for maintaining fruit production. This was evident, to some extent, by the low leaf N concentration at the low N treatments. Furthermore, canopy density was also lower in the low N trees compared to those that received higher N rates.


1999 ◽  
Vol 39 (12) ◽  
pp. 257-264 ◽  
Author(s):  
Hans E. Andersen ◽  
Brian Kronvang ◽  
Søren E. Larsen

An empirical leaching model was applied to data on agricultural practices at the field level within 6 small Danish agricultural catchments in order to document any changes in nitrogen (N) leaching from the root zone during the period 1989-96. The model calculations performed at normal climate revealed an average reduction in N-leaching that amounted to 30% in the loamy catchments and 9% in the sandy catchments. The reductions in N leaching could be ascribed to several improvements in agricultural practices during the study period: (i) regulations on livestock density; (ii) regulations on the utilisation of animal manure; (iii) regulations concerning application practices for manure. The average annual total N-loss from agricultural areas to surface water constituted only 54% of the annual average N leached from the root zone in the three loamy catchments and 17% in the three sandy catchments. Thus, subsurface N-removal processes are capable of removing large amounts of N leached from agricultural land. An empirical model for the annual diffuse N-loss to streams from small catchments is presented. The model predicts annual N-loss as a function of the average annual use of mineral fertiliser and manure in the catchment and the total annual runoff from the unsaturated zone.


Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.


2021 ◽  
Vol 83 (2) ◽  
Author(s):  
Beat Müller ◽  
Raoul Thoma ◽  
Kathrin B. L. Baumann ◽  
Cameron M. Callbeck ◽  
Carsten J. Schubert

AbstractFreshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, however, it is unclear what the main controlling factors are. Here, we investigated the factors that moderate the rates of N removal under contrasting trophic states in two lakes located in central Switzerland. In the eutrophic Lake Baldegg and the oligotrophic Lake Sarnen, we specifically examined seasonal sediment porewater chemistry, organic matter sedimentation rates, as well as 33-year of historic water column data. We find that the eutrophic Lake Baldegg, which contributed to the removal of 20 ± 6.6 gN m−2 year−1, effectively removed two-thirds of the total areal N load. In stark contrast, the more oligotrophic Lake Sarnen contributed to 3.2 ± 4.2 gN m−2 year−1, and had removed only one-third of the areal N load. The historic dataset of the eutrophic lake revealed a close linkage between annual loads of dissolved N (DN) and removal rates (NRR = 0.63 × DN load) and a significant correlation of the concentration of bottom water nitrate and removal rates. We further show that the seasonal increase in N removal rates of the eutrophic lake correlated significantly with seasonal oxygen fluxes measured across the water–sediment interface (R2 = 0.75). We suggest that increasing oxygen enhances sediment mineralization and stimulates nitrification, indirectly enhancing denitrification activity.


2019 ◽  

<p>In order to study the chemical parameters of the soil after sub-irrigation with wastewater, a system was installed in one of the greenhouses of the Agricultural University of Athens. Wastewater was applied subsurface into the soil mass of the pots were used. Three treatments were used: Untreated wastewater (U), Treated wastewater (T) and tap water (W) as control. Two different types were used: Soil (a) characterized as Sandy loam and soil (b) characterized as Loamy sand. Moreover, in order to investigate the change of total Nitrogen and organic matter concentrations at the point where the emitter was placed, the soil mass was divided into two zones. The upper (zone I) and the lower one (zone II). The total nitrogen content, ammonia nitrogen (NH4-N), nitrogen nitrate (NO3-N) and the percentage of organic matter, were determined in the soil samples. Statistically significant differences (p &lt;0, 05) were observed in the organic matter and the total N%, only for soil (b). For soil (a), organic matter percentage was increased in zone (I) (irrigation with treated wastewater at 20 cm depth). For soil (b), total N% was increased in zone (I), while nitrate and ammonium were increased in zone (II) (irrigation with untreated wastewater at 20 cm depth).</p>


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