ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 22.-24.05.2019. 1623 PRE-TREATMENT OF INDUSTRIAL WASTE WATER WITH HYDROCARBON SEPARATORS Stefan Vasilica 1 , Simion Maria Andra 2 , Lucretia Popa 1 , Ancuta Nedelcu 1 , Radu Ciuperca 1 1 National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry, Romania; 2 PURECO Environment SRL, Romania valle_vali@yahoo.com, andra.simion@pureco.ro, lucretia_popa@yahoo.com, nedelcuus@yahoo.com, ciupercaradu@yahoo.com Abstract. The aim of the article is to present a pre-treatment of industrial waste water with hydrocarbon separators. Three hydrocarbon separators with a coalescing filter were tested in three different situations (car wash, fuel station and parking lot). The quality of treated water that is leaving the separator must comply with the conditions of NTPA 001/2005 for wastewater discharge into natural receivers. The maximum amount of light liquid hydrocarbons in the effluent separator is 5 mg·l -1 . Petroleum products at concentrations of 0.1 to 10 mg·l -1 present in the surface area and wastewater are determined spectrophotometrically according to SR 7877-2/1995, petroleum products together with some substances present in water are extracted at pH < 5 in CCl4 (Carbon tetrachloride). Pre-treatment of polluted water discharged into the environment or into the sewage system is a necessity in order to protect the environment. Sizing the three light liquid separators is based on the nature and flow rate of the liquids to be treated and considering the following: the maximum flow of rainwater, the maximum flow of wastewater (e.g. industrial effluent), the density of the light liquid, presence of the substances that may impede separation (e.g. detergents). Oil separators nominal size is determined by the flow rate of 45 l·h·m - ² for areas not covered. A coefficient of 0.5 is applied to the surfaces provided with the cover. The novelty of the proposed separation system is that in a steal tank all components are introduced: the hydrocarbon separator with a coalescing filter, retention tank and the pumping station. Thus, by integrating all components into a single container divided into several independent compartments, savings in space and mounting time are achieved. Keywords: coalescing filter, hydrocarbon separator, waste water, pre-treatment, environmental protection. Introduction Contamination of the environment that surrounds us with certain materials that endanger human health, the quality of life or the natural functioning of ecosystems is called pollution. Pollution affects water, air and soil to the same extent. Air and water pollution is largely made by removing hydrocarbons from non-combustible fuels. The effects of hydrocarbon water pollution are: taste and unpleasant smell of water, prevention of surface oxygen absorption (self-cleaning), toxicity to aquatic flora and fauna, impossibility of using polluted water to supply irrigation facilities, recreation, etc. For these reasons it is necessary to pre-treat the water discharged into the environment by: • separating hydrocarbons from wastewater resulting from industrial processes, washing of vehicles, cleaning of lubricated oil components or other sources (fueling station yards, hydrocarbon storage area, etc.); • pre-treating meteoric water contaminated by oils coming from waterproof areas (car parks, airports, industrial platforms, vehicle fleets, roads, factory yards, markets, etc.). Hydrocarbon separators are based on the specific weight difference between water and hydrocarbons (gravitational separation) or solids in wastewater as follows: wastewater containing oil and hydrocarbon residues is collected from drainage platforms and channels and enters the separator by means of a calming and smoothing device [1-3]. As the wastewater flows slowly and evenly through the main body of the separator, coarse particles and suspended solids decant to the bottom (sludge hatch) forming a sludge layer, while the oil and hydrocarbons, lighter than water, rise to the surface. Due to the internal partition and the special construction of the outlet device, only the filtered water is evacuated, while the sludge, oil and hydrocarbons are kept inside. For these reasons hydrocarbon separators do not require external sources of energy or chemicals. Gravitational separation is the most used method for separating water suspensions. The gravitational separation phenomenon is based on the difference between the water and suspension densities and occurs in two forms, namely: DOI: 10.22616/ERDev2019.18.N362