https://doi.org/10.31871/IJNTR.6.8.12 International Journal of New Technology and Research (IJNTR) ISSN: 2454-4116, Volume-6, Issue-8, August 2020 Pages 41-46 41 www.ijntr.org Abstract— Oily sludge produced as by product from oil industry represent a potential source of environmental pollution. Land-farming is one of the least expensive and easiest methods to dispose of oily sludge. However, Run-off water of oily waste land farms may represent potential pollution source and require control concern. The purpose of this paper is to investigate surface run-off water pollution that is caused by land-farming an oily sludge produced by Daura Refinery in Iraq. A homogenous loamy sand soil was divided into 24 plots of one square meter and mixed with the sludge for the upper 15 cm layer according to different ratios and intervals. The ratios were three by weight as (1:3), (1:6), and (1:10) as sludge fresh weight: soil dry weight. The intervals were weekly, monthly, and seasonally. Some plots subjected to tillage for the upper 15 cm weekly. Raw water drawn from the Tigris River was used to irrigate the plots with (40 liters) by two-day intervals throughout the experiments of this study. Water samples were collected from plots surface run-off water and tested for Oil & Grease O&G, Chemical Oxygen Demand COD, pH and some heavy metals. The results showed that the monthly sludge application according to (1:10) (fresh sludge wt: dry soil wt.) was the best application rate among the others regarding run-off water quality. No considerable run-off water (drainage) pollution by oils (3-12ppm) and/or heavy metals contained in the applied sludge. No detectable adverse effect of soil tillage on run-off quality for the monthly (1:10) treatment. Index Terms—land-farming, run-off, oily sludge, Oil and Grease. I. INTRODUCTION Oily sludge produced as by product from oil industry represent a potential source of environmental pollution [1]. One of the important sources of the sludge produced by wastewater treatment plants of refineries. Ultimate disposal of oily sludge has been a problem for decades, and due to pressure imposed by environmental agencies, disposal alternatives has been reduced and optimized. The ultimate disposal may be done by many ways, such as deep-well injection, land-farming, ocean disposal, incineration [2]. Land-farming is one of the least expensive and easiest methods of disposal [3]. But, concern should be kept about sludge biodegradation through providing sufficient Oxygen to soil where micro-organism degreed the sludge. In addition, there is continued potential for leaching oil and soluble metals from the site [4]. Land-farming is also called as land treatment, land application, land spreading, sludge farming, and soil cultivation. Sometime, it has been referred to as land disposal [5], [6]. It has been practiced since the eighties of the last century in most of refineries of USA, United Kingdom, the Netherlands, Sweden, Denmark, France, New Zealand, Hasan Mahdi Mohammed Al-Khateeb, University of Kufa Civil Eng. Dept., Faculty of Engineering, Najaf, Iraq and Brazil [6], [7] and [8]. Some of Arab-oil producing countries adopted this method since the 1990s to dispose of oily sludge [9]. One of motivates to adopt this method is that improving soil fertility and structure [10]. Although microbial assimilation is the principal means of waste degradation in land-farming, the contribution of other non-biological processes (chemical and photochemical processes, evaporation, and volatilization) are also significant [7]. However, Run-off water of oily waste land farms may carry considerable amounts of pollutants, especially when higher rate of liquid oily waste application is followed in land-farming using a coarse-textured soil of high moisture content and low adsorption capacity. In practice, many refineries recycle the land farm run-off back to wastewater-treatment system for cleanup [11]. The purpose of this paper is to investigate surface run-off water pollution that is caused by land-farming the oily sludge. II. MATERIALS AND METHODS A. Materials A homogenous loamy sand soil was collected from top soil of a selected site inside Daura Refinery and leveled with a thickness of 50 cm over an area of (6.5m x 10m) inside the refinery. The land was divided into 24 plots of one square meter each distributed at one meter clear spacing, and each of them surrounded by 10 cm height bricks to be isolated from the others. Table (1) show some physical and chemical properties of the soil. Soil particle size distribution was determined by the hydrometer method after sieving [12], soil bulk density by Core method, electrical conductivity (EC) was measured in (1:2) water extract while pH was measured in (1:2.5), [13]. Fig. (1) shows a sketch for a typical plot. TABLE (1) DETERMINED CHARACTERISTICS OF THE SOIL USED. Characteristic Results Sand 84.6% Silt 4.5% Clay 10.8% Soil texture loamy sand Bulk density 1.35 g/cm3 pH 7.41 Electric conductivity (ECe) at 25 ºC 1.56, Total nitrogen mS/cm Raw water drawn from the Tigris River was used to irrigate the plots with (40 liters) by two-day intervals throughout the experiments of this study. This irrigation was found (by field trail runs) to keep soil moisture above 10%. Water used in irrigation had approximately constant physical and chemical characteristics. Table (2) lists raw water characteristics used. Effect of Land-farming Oily Sludge on Run-off Water Hasan Mahdi Mohammed Al-Khateeb