научная статья по теме IMPACT OF DEBRIS FROM DEMOLITION OF BOUMERDES ON THE QUALITY OF GROUNDWATER Комплексное изучение отдельных стран и регионов

Текст научной статьи на тему «IMPACT OF DEBRIS FROM DEMOLITION OF BOUMERDES ON THE QUALITY OF GROUNDWATER»

Статья поступила в редакцию 05.01.10. Ред. рег. № 689

The article has entered in publishing office 05.01.10. Ed. reg. No. 689

УДК 556.15

ВЛИЯНИЕ СТРОИТЕЛЬНОГО МУСОРА ОТ РАЗРУШЕНИЯ ЗДАНИЙ В БУМЕРДЕСЕ НА КАЧЕСТВО ГРУНТОВЫХ ВОД

М. С. Бенменни, К. Бенрачеди

Лаборатория технологии продуктов питания, Факультет технических наук, Университет Бумердеса

35 000 Бумердес, Алжир E-mail: benrachedik@yahoo.fr

Заключение совета рецензентов: 10.01.10 Заключение совета экспертов: 15.01.10 Принято к публикации: 20.01.10

Муниципальная свалка города Бумердес расположена в 5 км от центра города в районе Тиджелабин на участке мер-гельно-известкового образования. Это образование характеризуется трещинной пористостью, что облегчает проникновение загрязняющих веществ в грунтовые воды. Характер рельефа этого участка также способствует миграции загрязняющих веществ. Просачивание воды со свалки в грунтовые воды приводит к ухудшению их качества. Химический анализ образцов, взятых из трех пьезометрических скважин, указывает на высокую концентрацию хрома, цинка и свинца, что подтверждает факт сильного ухудшения качества грунтовых вод. Для оценки степени загрязнения из-за близости свалки было проведено сравнение с другими аналогичными свалками, которое показало, что участок Тиджелабин находится в переходной фазе и стабилизация еще не наступила, поскольку кислотная фаза анаэробного разложения еще продолжается. Кроме того, бактериологический анализ грунтовых вод свидетельствует об их загрязнении микроорганизмами.

Ключевые слова: свалка; вода, просачивающаяся из свалки в грунт; тяжелые металлы; грунтовые воды; инфильтрация.

IMPACT OF DEBRIS FROM DEMOLITION OF BOUMERDES ON THE QUALITY OF GROUNDWATER

M.S. Benmenni, K. Benrachedi

Laboratory of Food Technology. Faculty of Engineer Sciences. University of Boumerdes.

35 000 Boumerdes Algeria E-mail: benrachedik@yahoo.fr

Referred: 10.01.10 Expertise: 15.01.10 Accepted: 20.01.10

The public discharge of the city Boumerdes is located at 5 km from downtown at Tidjelabine site which is constituted of marly-calcareous formation. This formation shows crack porosity that facilitates pollution of groundwater reserves. The slope character of the field also favours the movement of pollutants. Leachates penetrating from the discharge towards underground water result in water quality deterioration. Chemical analysis carried out on samples from three piezometers show large concentration of chromium, zinc and lead, thus confirming the high groundwater deterioration. To assess the degree of pollution caused by this discharge, a comparison with other similar discharges showed that the Tidjelabine site is in a transient phase and is not stabilized yet, as the acidic phase of anaerobic degradation is still going on. In addition, bacteriological analysis carried out on groundwater show a microbiological contamination.

Introduction

The solid waste management is governed by standards the user must respect otherwise they expose themselves to pollution that may follows. For instance, it is common sense that water pollution may be due to industrial effluents such as exhaust fumes and gases liquid or solid wastes that strongly contribute to water quality impoverishment. Same applies for extensive agriculture which requires fertilizers that induce increasing water pollution risks.

But, the pollution generated by solid waste from house demolition has long been underestimated as presenting no danger in the short term.

This work is a contribution for the assessment the impact on groundwater pollution by demolition debris generated by the may 23rd, 2003 earthquake of Boumerdes. To face the emergency and urgency, demolition debris were quickly buried in temporary sites (which still remain untreated) in places that posed no difficulty for approval (generally state owned agricultural lands) without any preliminary study of

impact. Indeed, this disaster has caused severe damage to facilities that generated tens of millions of tons of debris and rubble. Thus, there are more than 22 uncontrolled landfills totalizing some 30 million cubic meters and occupying a total area of 100 hectares.

Our study focuses on the landfill of the city of Boumerdes and surrounding communities (Boudouaou, Corso, Figuier and Tidjelabine), where more than debris from some 23 00 demolished homes have been stored.

This landfill may affect the quality of surface and underground water as rainfalls cause leaching of stored debris which, in turn, generate lixiviates, which infiltrate the soil and cause chemical pollution of water by the ETM. All of these inter-actions between the dump and the receiving environment exacerbate the risks of pollution.

Fig. 1. Map of the Wilaya of Boumerdes and its temporary uncontrolled landfills Рис. 1. Карта временных неконтролируемых свалок в районе города Бумердес

Our investigation concerns cross impact of possible pollution by the landfill on:

- health and environment caused by unpleasant smoke and odour, and/or toxic fume inhalation;

- water and soil contamination caused by lixiviates.

Location of landfill

There are five landfills for Boumerdes and its communities, one in Tidjelabine, two in Figuier another one in Corso and the last one in Boudouaou.

Fig. 1 below maps the different landfills across the territory of the Wilaya of Boumerdes, and Fig. 2 shows the location of the landfills of the city of Boumerdes and its communities.

All of these sites are in the form of low slope of about 5% to 10% and covers an area of 10 hectares, whereas their altitude varies between 850 m and 900 m.

The slope promotes water runoff (G. Castany in «Hydrogeology principles and methods», 1982). Indeed, lixiviate or rainwater entering the waste is the source of runoff processes favouring pollution by infiltration through limy soil cracks. The selection of any current site for land-filling obeyed only to criteria of accessibility and proximity.

Fig. 2. Air photographie of the Tidjelabine landfill Рис. 2. Аэроснимок свалки Тиджелабин

International Scientific Journal for Alternative Energy and Ecology № 12 (80) 2009

© Scientific Technical Centre «TATA», 2009

Hydrological and geological context

The geological formations at the outcrop in the studied area consist of marls with intercalations of fissured limestone and alluvium, respectively, of Cretaceous age and Mio-Plio-Quaternary.

These formations give the sites a variable permeability in the horizontal and vertical directions.

Indeed, frequent feature changes (transition from alluvial formation to cracked or compact limestone) are the reason for important variation in permeability.

As a matter of fact, we switch from a permeability of about 10-2 m/s to nearly 10-6 m/s.

Thus, the flow directions follow existing cracks.

However, the hydro-geological studies conducted in the area shows that there are two aquifer horizons. The first one has a relatively short depth (maximum 10 meters), the alluvial Mio-Plio-Quaternary being its bottom seat and which may be polluted by inputs from the landfill; on the other hand, the second for cons, the second is deeply located across the valangian-albian sandstone.

Precipitations for the area average 410.5 mm/year (2005/2006) and accentuate the movement of pollutants either through infiltration or by surface runoff.

Waste characterization

The town of Boumerdes covers an area of 1800 hectares occupied by 45000 inhabitants (2005). The estimated masses (tons) of various types of debris buried in the site (Table 1).

Table 1

Tonnage estimation of the most prevalent material types in disposed wastes. Tidjelabine landfill

Таблица 1

Оценка доли (в тоннах) преобладающих материалов на свалках. Свалка Тиджелабин

*Mainly beverage containers, grocery and trash bags, films and durable items.

** Includes food rests, stale fruits and vegetables leaves and grass, paper, textile, glass, plastic bags, domestic appliances and other small consumer electronics.

*** Includes used vehicle parts, batteries, used oil, ash, electronics, tires, asphalt, industrial sludges, glass.

Materiels and methods

In our study, a sampling campaign and analysis was performed on the leachate from the landfill and three control wells that serve as piezometers. The collection is made to the month of March 2005 and covered the major ions, heavy metals, nitrogen, chemical applications and biological oxygen demand (COD and BOD5), organic matter and minerals and some microbiological. Note that temperature, pH and conductivity were measured on site.

The three wells are selected near the discharge. Table 2 summarizes some information concerning the status of wells from the landfill. The proximity of the wells from the landfill because they become very vulnerable to all forms of pollution.

Table 2

Localisation and use of the selected piezomters close to the Tidjelabine discharge

Таблица 2

Расположение и назначение выбранных пьезометрических скважин поблизости от свалки Тиджелабин

Designation of taking point Situation vis-à-vis centre (0) of the landfill Distance (m) from (0)

S1 East. Well of 2 m depth domestic use. Piezometer 300

S2 North in residential. Well of 8 m depth domestic use 350

S3 South West in agricultural land. Well of 8 m depth irrigation use 420

Leachate

The composition of leachate from a landfill

The leachate contains may inorganic contaminants often very toxic. Thus, their composition varies depending on the nature of waste, age of discharge, the technical operating and climatic conditions. Farquhar (Faquhar G.J. "Leachate production and characterisation", 1989) thinks that the leachate may come from either waste water or rain water and also from the water of the aquifer. The colour is the first indicator of pollution. The analyzed leachate taken downstream of the discharge has a brownish colour and a faecal smell, thus influencing the quality of groundwater. The level of targeted pollution indicators proved to be high. Almost all of them a

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