Surface wastewater impact on the environment from pig-breeding enterprise production territory

Abstract

An increase in suspended solids and BOD7 concentration in wastewater is related to a higher precipitation level: (r = 0.64) and (r = 0.62), respectively. It was estimated that pig-breeding enterprise production territory average surface wastewater contamination by organic compounds (BOD7) was low 5.6 mg O2I"1. Other chemical elements' average 5-year study concentrations were low as well: suspended solids - 12.1, total nitrogen - 3.1, total phosphorus - 0.6, oil products - 0.7 mg I"1. The chemical elements' concentrations in the surface wastewater run-off from pig-breeding enterprises production territory were lower than the maximum allowable concentration (MAC). In 2008, after the reconstruction of the enterprise and the installation of wastewater treatment facility, a declining trend in chemical substances from the surface water of pig-breeding complex was observed: BOD7 (r = 0.71), suspended solids (r = 0.58), total nitrogen (r = 0. 34), and total phosphorus (r = 0.34). Thus, it can be claimed that pig-breeding enterprises production areas surface wastewater impact on the environment is minimal, because the concentrations of tested chemical elements were lower than MAC. In order to reduce pollution in the Baltic Sea, surface wastewater management is given a special attention in Lithuania in recent years. It is a topical issue, given that wastewater from stationary pollution sources contains many harmful substances such as petroleum products, heavy metals and biogenic substances, stimulating water eutrophication. The biggest environmental problems in Lithuania are caused by 24 operating pig-breeding complexes with stock capacity higher than 5000, keeping 573 thousand pigs, 65 companys and pig farms with stock capacity higher than 200, keeping 77.0 thousand pigs, 2179 cow - cattle farms with stock capacity higher than 50, keeping 319.4 thousand cattle, and 21 poultry farms with stock capacity higher than 1000, keeping 9946.7 thousand fowls. The key reason is inadequate sewage treatment and poor technology. Not surprisingly, environmental pollution increases significantly as a large amount of livestock is kept in one place. However, the most exceptional attention should be paid to polluted livestock buildings and farms, where manure is collected and stored, areas trampled and slurred by cattle convenient for wastewater formation, as well as areas damaged by mechanisms. Farms are generally lacking or do not have any wastewater treatment facilities; therefore untreated wastewater is released into the environment, contaminating it. The 2007-2011 data is being analysed on the production territory surface wastewater quality of the pig-breeding enterprise. The aim of the analysis is to examine the impact of the surface wastewater run-off from pig- breeding enterprise territory on the environment. There is a positive relationship between surface wastewater contamination by organic compounds and suspended solids. Correlation analysis showed that a higher amount of suspended solids increased organic contamination in wastewater (r = 0.75).