THE IMPACT OF MUNICIPAL SOLID WASTE STORAGE FACILITY “ VIDRA ” ON GROUNDWATER

This case study is monitoring the impact of pH, nitrate, nitrogen in groundwater around Vidra landfill located in Ilfov; we used two monitoring wells, F19, and F10. For the obtained values, the following conclusions emerged: water from monitoring well F10 showed much higher loads compared to water from the monitoring well F19 on organic loading indicators (CCO-Cr, BOD5); although other values and indicators were higher in the monitoring well F10 to those obtained for the monitoring well F19.


INTRODUCTION
Waste disposal in landfills around the world threaten to pollute freshwater resources [1].In Europe, approximately 675,000 sites may have been contaminated by activities related to the handling of municipal and industrial waste [2], a significant part of these are landfill sites.
In Denmark alone more than 2000 old landfills without leachate collection or liners have been mapped [3].Older unlined landfills have preferably been located close to wetlands and streams, giving rise to impacts on both surface water and groundwater [4].A better understanding of this impact is critical for successful implementation of the EU Water Framework Directive (2000/60/EC).
The potential impacts of landfill leachate entering a surface water system are: (1) the toxicity and eutrophication potential of ammonia (NH) [5], (2) oxygen depletion in the surface water by addition of dissolved organic carbon (DOC) and nutrients [6,7], (3) accumulation of iron(III) on the fish gills [8], (4) the bioavailability and toxicity of iron(II), (5) the toxicity of inorganic trace elements [9] and (6) the toxicity of xenobiotic organic compounds (XOCs) [10].The main leachate related problems for groundwater as a drinking water source were identified by Christensen in 2000 as ammonium (NH) and XOCs.Ammonium may due to long-term leaching in high concentrations deteriorate groundwater quality, while the XOCs are problematic in lower concentrations due to their toxicity.Attenuation processes and the impact on groundwater in sandy aquifers have been studied intensively [11], while landfill studies in clay till geology and/or studies of discharge to surface water are few.
From previous studies of contaminant transport in clay till, we know that the flow field may be difficult to assess due to significant geological heterogeneity.
It is important to document how attenuation processes and heterogeneity affect the magnitude of the contaminant mass discharge and by that the impact on the receiving water body.Mass discharge estimates have been applied to quantify the impact of landfills on multiple water resources by Douglass and Borden in 1992.Douglass and Borden estimated the mass discharge to the Crabtree Creek by a four summations of the mass discharge from base flow, storm flow, and groundwater.This was done under the assumption that all groundwater eventually would discharge to the stream.Yusof, however, in 2009, compared the contaminant mass discharge in river systems up and downstream of landfills, with the contaminant mass discharges from these landfills through a drain discharging to the river.
They concluded that the effect of leachate on river water quality in their case could be estimated by monitoring the water chemistry in the river.
Urbanization is the current phenomenon with the most profound implications for the scale and patterns of consumption, leading to a growing demand for energy and natural resources.The town, taken as a whole, behaves as bodies that "absorbs much but turns and throw to the same degree".Metabolic processes that occur at the level of the urban organism generate a continuous and very diversified waste.
As a result of anthropogenic activity in the environment gets an enormous amount of polluting chemicals that accumulate in the soil and are included in the chemical reactions in the soil with the mandatory participation of living organisms.
Waste from human activity, such as industrialization and urbanization, are the main cause of environmental pollution, and may become the most important generator of waste, due to lack of interest, environmental education or human consciousness.
The concept has evolved from simple storage (downloading residues in pits, former construction careers or other land, without taking special measures for environmental protection) at controlled storage in planning downloads, respectively, subject to the special conditions of hygiene and environmental protection.Modern concepts of waste storage facilities available are considering compliance with the rules of hygiene and environmental protection, storage capacity as possible (at least 20 -25 years).Also involve the installation of an appropriate monitoring system.
If we consider the high degree of aggressiveness of some chemical waste or potential polluter of others, on the one hand, and the functional roles needed to be met by the components of organic deposits, on the other hand, it can be easily concluded that the materials and installations necessary for their construction must have specific characteristics and resistance, noticeably different from those for other types of construction.Elasticity, water tightness, resistance to differential subsidence at chemical and biological aggression, etc. are obvious features necessary for the proper behaviors in time of construction and at the same time to protect the environment.
Defects that may arise from the work of geomembrane are:  welding defects, which, according to experience gained in the field shows that when there is a strict control, the average frequency of defects is 1 m to 10 m of welding, with a diameter of the defect (d = 1...3) mm;  defective connecting areas of the geomembrane construction attachments;  defects due to grain (gravel) items or machinery movement, whose diameter can be contained within the boundaries of d = (1...10) mm.
These relatively common defects, accidental (unwelcome) obvious, appearing mainly in the execution phase of the operation or partial closing of an accompanying body.
They can be avoided only through rigorous control in the phase of implementation and performance monitoring.Rigorous control in the execution phase and monitoring of sealing effectiveness after closing can be achieved only if the liner is equipped with a network of sensors (cable) network, located on the bottom of it, and obviously inside other barriers sealing (clay, bentonite), to indicate (detect) possible effects.Joined this network, it is necessary to the existence of electronic devices to take signals from the network, to interpret the information received and to locate faults.
Between appliances known and already consecrated, LUMBRICUS type apparatus associated with TAUPE, calibration system is capable of detecting the humidity value sealing tested barriers, variable humidity influences and meteoric waters infiltrate maintained through areas with incidental flaws of geomembrane.
The link between the qualitative and quantitative aspect is possible by calling an analytical model of a relationship, which has been established by Giroud and associates in 1997.
Referencing the data offered by electronic monitoring equipment (Lumbricus-Taupe) with the analytical results of the relationship type Giroud, can make available specialist personnel in the maintenance of the repository information both quantitative as well as qualitative (location, intensity of seepage flow towards the body of the deposit, the extent of any malfunction of dimensional); such information is provided related to the degree of urgency and magnitude required remedial works related thereto.
Monitoring activities are aimed at securing or enabling the detection of changes to allow for the detection and measurement of the size and trend of its intensity.
This stage is considered as the easiest of the process of monitoring, is followed by a much more difficult phase: assessment of the significance of what occurred.
Monitoring plans, particularly those relating to environmental changes, are deprived of adequate criteria for appraisal of their significance.In the case of relatively well-established procedures, pollution is in reality based on the boundaries of acceptability of certain concentrations, which are often set arbitrarily.For the development of strategies for improved monitoring, it is necessary to adopt clearer and precise definitions.

Case study-non-hazardous waste Landfill Vidra
Presentation of the area and land area: nearby the landfill is part of the outskirts of Vidra town.On this site, there was no construction or other previous landfill facilities.The land on which it was achieved the objective review had agricultural destination belonging to CAP Vidra.Prior to the construction of the landfill, the ground was not conducive to intensive agricultural exploitation because there were too many hollows.
Elements of hydrogeology the landfill: Site is located on interfluves Sabar -Dâmbovița, on the underside of the Argeş River, in an area covered by loess deposits with micro outlines of hollows with diameters of 50 -100 m.
Hydrographic network is represented by the Sabar River, tributary of the Argeş River, which is a tributary of the river Cocioc.All of these valleys have permanent flows.In this unit, aquifers are developed on sand and gravel deposits of Pleistocene Age superior deposits known as the Colentina (upper horizon) and the layer of Mostiştea (lower horizon).Water depth varies between 3 to 5 m underground.General course of the aquifer in the site is N-S with focus on Sabar River that provides care drainage aquifer in the area.
Hydraulic gradient groundwater flow is about I=0.17 to 0.20 %.Regarding the groundwater flow we can appreciate that it presents a moderate growth, the overall orientation of the swift lines of landfill is to Vidra community.Gravel of Colentina and sands of Mostiştea having the thickness of 20 -25 m in analyzed site are situated between 5 -6 m, and 25 -30 m depth are the main source of water for local people.Because of the high vulnerability of the aquifer to be polluted, for potable uses is used the deep aquifer (Frățești deposit) at depths of 30-35 m and it is protected on top of loam complex about 6 -10 m thick.
Hydrological data: groundwater depth varies between 3 -5 m.Hydraulic gradient of the ground water flow is about I = 0.17 -0.20 %.Because of the high vulnerability to pollution of the aquifer for drinking mixed use deep aquifer (Strate de Fratesti) located at depths greater than 30 -35 m and at the top of a clayey complex 6 -10 m thick.
Surface water: in the area of the site, at a distance of 20 -30 m (eastern boundary) is linked to the river Cocioc.The flow rate near the deposit is 25.5 m 3 /sec, respectively 45 cm/sec.
Climate and natural phenomena investigated perimeter area: climate is temperate-continental, continental climate transition subtype characterized by contrasts between winter and summer, with scorching heat during the summer and strong snowstorms in winter, with the following parameters the average yearly temperature 10.7 °C minimum absolute temperature -30.2 °C, maximum temperature absolute 42.2 °C.Annual average rainfall is between 500 and 600 mm, as shown in Figure 1.Activities: urban solid waste deposit Vidra, belonging to industrial S.C. ECO SUD SRL Bucharest is a modern landfill in accordance with the legal provisions of the construction and operation of the deposit of non-hazardous waste, the urban solid waste are stored, as well as other similar industrial waste.The emplacement plan of the objective may be found in Figure 2. The objective includes both basic facilities for the storage of waste, which constitutes the main activity carried out on site, as well as facilities, installations and storage facilities for materials related activities of proper storage, as well as plant protection and monitoring of the quality of the environment.The site image is shown in Figure 3.   Waste storage system will be composed of 8 compartments (cells) independent constructive.These compartments are fitted with all the facilities necessary for the proper functioning, namely perimeter dams, dikes, subdivision of the waterproofing system and slope, drainage system, and evacuation of leachate.The bins, which features a grilling surface horizontal average around 4.2 ha, are delineated on the outside by perimeter barrier dykes of two types:-dams of hydraulic separation (leachate collection) and administration; these dams have heights of around 2.0; leachate treatment plant which consists of a metal container in which it is attached a cleaning facility based on the principle of reverse osmosis in two stages, which is equipped with all the equipment needed for measurement and control, as presented in Figure 4.
Figure 4 -cleaning station leachate -pool for the first rain (volume 330 m 3 ) and sedimentary basin rainwater (volume 60 m 3 for rainwater, which is used for temporary storage of leachate purged (permeate).
SEWAGE: for treatment of leachate from the landfill Vidra has opted for a new installation, greater capacity, which works on reverse osmosis procedure P, the process by which pollutants are removed from all leachate in more than 90 %.The facility is semi-automatic (optimal flow leachate supply of 8 m 3 /h, operating pressure 30 -65 bar), being composed of modular parts of the leaching phase (reverse osmosis) connected in series, in a standard container.
Technological flow within the treatment of leachate is as follows: leachate is collected in a concrete pool, with volume V = 330 m 3 , where through a submersible pumps FEKA 1800 T type is carried in the storage tank, the step to correct the pH to a value between 6 -6.5 by adding sulfuric acid and also takes place at this stage, reducing the amount of hydro carbonate and avoiding a possible uncontrolled precipitation.The study is based on 18 measurements from two monitoring drills, F10 and F19.The placement of the monitoring wells around the landfill is shown in Figure 5, and also how they look like in site.

F10
Monitoring wells: Fig. 5.The placement of the monitoring wells; images from site.

RESULTS AND DISCUSSION
Monitoring program included monitoring well F10 and F19.The location of the two wells was monitored for compliance with General Practice to monitor the impact on groundwater of some problems with potential contamination, F19 monitoring well is located upstream and one down to the location of the landfill, F10.On samples with a frequency of every month from these two wells were identified specific indicators of physical and chemical.The results are presented in    Comparing the obtained values with the M.A.C. in the drinking water standard is not justifiable because the groundwater in the area is not used for the purpose of drinking.

CONCLUSIONS
Based on the average values of the quality indicators identified in samples of groundwater of two drillings can set alert thresholds for evaluation of local water quality in the area located upstream and downstream of the site review direction of groundwater flow.
Based on the values shown in Table 2. the following conclusions emerged: water from monitoring well F10 showed much higher loads compared to water from the monitoring well at an organic loading indicators F19 (CCO-Cr.BOD 5 ).Although other values and indicators (nitrates.total nitrogen.nitrates) were higher in the monitoring well F10 to those obtained for the monitoring well F19.
waste Depot and Vidra, similar belonging to industrial S.C. ECO SUD SRL.Bucharest is a modern landfill in accordance with the legal provisions of the construction and operation of the deposit of nonhazardous waste, the urban solid waste are stored, as well as other similar industrial waste.The objective includes both basic facilities for the storage of waste, which constitutes the main activity carried out on site, as well as facilities, installations and storage facilities for materials related activities of proper storage, as well as plant protection and monitoring of the quality of the environment.

Fig. 6 .
Fig. 6. pH values in for the two monitoring drills.

Fig. 7 .
Fig. 7. Nitrate and Nitrogen values in for the two monitoring drills.

Table 1 .
Technical characteristics the River Cocioc.
Characteristic elements of the river Cocioc are: length: 38 km, area: 156 km 3 basin, longitudinal average slope: 1 %.A table with technical characteristics of the River Cocioc may be found below in Table 1.

Table 2 .
Assessment of groundwater quality was done by comparison with the values and allowed values allowed in the standard for drinking water quality -STAS 1342/91.In Figures 6, 7 and 8 is pictured the variation of the values of indicators that have been important to our study, and the comparison between monitoring well F10 and F19.Materials and methods: Analysis Program was the same throughout the period of monitoring being carried out by the same laboratory, which confers a high degree of credibility of results, and the values achieved are shown in Table2.: pH value was employed within acceptable limits, with the exception of one sample that had a weak acid; organic loading expressed by CCO-Cr has been identified in all samples, in concentrations in field 6.16 -192.0 mgO 2 /L, with an average value of 33.16 mg O 2 /L, exceeding the exceptionally M.A.C.; organic loading BOD5 expressed through also has been identified in all samples, in concentrations in the 2.40 -86.00 mgO 2 /L, with an average value of 13.51 mgO 2 /L, exceeding the exceptionally M.A.C.; the nitrate was determined in concentrations ranging between 2.23 -24.36 mg/L, with an average value 13.19 mg/L, under M.A.C.; the nitrogen was determined in 10 of the 15 samples obtained values hovering in field 0 -0.48 mg/L, with an average of 0.09 mg/L, located over M.A.C., but under exceptional M.A.C.; total nitrogen concentrations had 17.00 mg/L, with a mean value 6.10 mg/L that are not standardized.

Table 2 .
Data achieved for 16 and 18 measurements.Monitoring well F10: pH value was framed within the limits permitted in all the samples; organic loading expressed by CCO-Cr has been identified in all samples, in the field of concentrations 18.09 -452 mgO 2 /L, with an average value of 99.25 mgO 2 /L that goes far beyond exceptional M.A.C.; organic loading expressed by CB0 5