Physical composition, nutrients and contaminants of typical waste dumping sites.

Author:Meuser, H.
 
FREE EXCERPT

INTRODUCTION

With increasing regulatory pressure prohibiting ocean-based disposal of wastes and effluents, there is an increasing tendency to dispose wastes in landfill sites. Such disposals are the preferred option in India as well as in many other countries of the world. In India the waste disposal can be assessed as problematical. The possible reasons are low collection capacity, lack of landfill management, reduced recycling activities, waste dispersion through livestock, a low awareness with respect to waste problems and absence of garbage incineration or only restricted to private companies, hotels and hospitals and a low level of composting technology.

The raw waste in India is generally a mixture of domestic, commercial and industrial activities. The composition of these wastes (solid as well as effluents or leachates from them) is quite variable depending upon the generating source, mode of collection and treatment provided. Most of the material which comes from the domestic activities (e.g., plant residues, weeds, household garbage, sewage sludge) will be organic in nature and contains essential plant nutrients. The dumping material of commercial and industrial wastes (like plastic bags, tires of automobiles, lead batteries, parts of electronic equipments), however, contain appreciable amounts of heavy and potentially toxic metals such as As, Cd, Cr, Hg, Ni and Pb and organic pollutants. Their continuous dumping on surface land may result in an accumulation in the soil in the vicinity of the dumping site. The leachate runoff from these sites during rainy seasons further aggravates this problem to the surrounding areas.

Apart from the environmental pollution, there is a possibility that pollutants from city dumping sites may contaminate the underground water or may be absorbed by plants growing in the nearby agricultural fields and may thus create human and animal health problems. It has also been observed that the leachate of these dumping sites sometimes accumulates in the low-lying areas (Williams, 2005; Meuser, 2010).

Management of city solid waste in the State of Haryana, India, was found deplorable and the people's perceptions about solid waste varied, depending on their life style, food habits, region, religion, seasons. The wastes generated were dumped in a variety of places mainly in open areas of the localities. It is collected on each day or alternate day and then transported to the dumping sites by means of various modes managed by municipal committees and/or through contractual basis. Overall, the dumping sites are not properly guarded and well maintained, resulting into an easy accessibility by stray animals. Municipal solid wastes generally comprise of rotten food and household articles, tree branches, papers, paints, sewage sludge, plastic and bricks/rubbles. Though composition of solid wastes generated in the cities needs to be studied, plastic is a great nuisance amongst the various components of municipal waste and is growing at an alarming rate.

The exact data of the waste being generated in each city/town of concern was not available because of different reasons, such as:

* The waste collection is largely done on annual contract basis by the contractors and for the sake of ease their workers dump the collected wastes at nearby open fields or areas in and around the cities and the entire waste does not reach the dumping sites

* The waste collected is estimated in terms of vehicle carrying capacity/tractor trolleys coming to the dumping sites

* Data available on municipal solid waste management with municipalities is scarce

* information is not publicly available on websites of the municipalities

* Most of the officials and staff are reluctant to provide any information on the present practices of solid waste management

The literature is very meager with respect to the possible effects and composition of the solid waste in and around the city dumping sites. The present collaborative study was therefore planned with the objectives of the physicochemical characterization of the waste material and the distribution and extent of toxic pollutants in selected dumping sites.

MATERIALS AND METHODS

Investigation sites: An extensive field survey was done at various waste disposal sites in Haryana to evaluate the general solid waste management procedure, present situation and nature and amount of waste being collected and deposited in and around the cities. For the present study various dumping sites were assessed by onsite observations and finally three waste dumping sites i.e., Rohtak, Jind and Karnal (Fig. 1) were selected on the basis of variability of the nature of dump being received. The waste deposits varied ranging from relatively fresh (3-4 years) deposits at Karnal (Fig. 2) to very old deposits (35-40 years) at Rohtak (Fig. 3). The Jind site (8-10 years) consisted largely of construction debris and household waste and presently is situated in the centre of the town (Fig. 4).

Collection of samples: For sampling, the sites were divided into three blocks of > 1,000 [m.sup.2] each and then samples were taken from surface (0-1 m) and subsurface (1-2 m) depths from approximately15 randomly selected places in each block using hand operated window augers. A composite sample (1.0 kg) of each block for each sampling depth was then made by quartering method. This way six waste samples were collected from each site. Bulk duplicate samples (around 20 kg each) were also taken from these sites for segregation purpose. The samples were immediately transported to the laboratory on the day of sampling.

Laboratory methods: The bulk samples were air-dried for several days and segregated manually for different composition fractions. The rest of the solid waste samples were also air-dried and separated into 2 mm fractions. Both fractions were ground with the help of wooden pestle and mortar and finally stored in cloth bags for laboratory analysis. To analyze heavy metals the material was additionally ground by a ball mill. For laboratory analysis, internationally accepted and standardized analytical techniques were used. They are summarized in Table 1.

Table 1: Analytical methods Parameter Method Water content Gravimetric method (ISO 11465:1993-12) Texture Piper (1966) (ISO 11277: 2002-03) Total Organic Walkley and Black (1934) Carbon (TOC) (ISO 10694: 1995-03) pH value Glass electrode method in CaCl2 (1:5) (ISO 10390: 2005-02) Electrical Conductivity bridge method in H2O (1:5) Conductivity (EC) (ISO 11265: 1996-10) Total nitrogen ISO 13878: 1998-03 Total phosphorus Koenig and Johnson (1942) Available phosphorus Olsen (1954) Total potassium Page...

To continue reading

FREE SIGN UP