Study On Areca Wastewater Treatment By Using The Integrated UASB-Fenton/Enhanced Coagulation-Biological Contact Oxidation Process

In recent years, hunan areca industry developing rapidly, has become one of the country’s largest edible betelnut Production and sales of regional, its brand, product variety, has become an important pillar industry in hunan food industry. Because of the edible betelnut processing, cleaning, in Areca original fruit cooked in two link will produce large amounts of waste water, according to the calculation, edible betel nut per production processing1ton takes about12tons of water, water will be consumed in the form of waste water discharge.Betel nut wastewater contains a number of biological refractory organic matter. Of betel nut wastewater pollutants are:alkaloids, unsaturated hydrocarbon, phenolic compounds, heterocyclic material, etc., characterized by high organic matter content, including general biological inhibitory substances, biochemical treatment process difficult to achieve complete degradation of pollutants is more, is a kind of typical organic wastewater of high concentration, high pollution, difficult to degradation.This experiment in HuNan XiangTan area betelnut processing enterprises emissions a large comprehensive wastewater as the research object, Use the UASB-Fenton/improved coagulation-biological contact oxidation process, the running characteristics of the system are analyzed and summarized, for future in-depth research and engineering application for reference, test results show that:1、UASB reactor in the treatment of papermaking wastewater UASB reactor using mature particle sludge as inoculation sludge, in medium temperature (35±2℃) under the condition of circulating UASB reactor outside using betelnut processing wastewater treatment, and research shows that when the stable operation of reactor, the COD concentration of5000mg/L, the water volume load in5.05～5.20kgCOD/(m3·d), HRT as1d, COD removal rate over38%, effluent COD<3000mg/L; If HRT extended to4d, volume load in1.26～1.30kgCOD/(m3·d), COD removal rate can reach more than79%, effluent CODcr<1200mg/L.2、On the basis of system stable operation and the response matrix add right amount of nitrogen and phosphorus nutrients, improve the nutrient ratio of wastewater, the system of the COD removal rate increased by more than7%, the water pH is relatively increased, and has good resistance to impact load capacity.3、 Fenton reagent oxidation treatment, anaerobic effluent, start with H2O2dosing quantity, FeSO4·7H2O dosing quantity, initial pH, reaction time as the impact factor of orthogonal experiment design, Fenton oxidation initial operating conditions were determined, and single factor optimization experiment, Fenton oxidation optimal processing conditions were determined as:pH=4, H2O2dosing quantity is6mL/L, FeSO4·7H2O dosing quantity is1g/L, the reaction time of120min. Under the reaction conditions, the treatment effect is remarkable, COD removal rate over65%, waste water biochemical availability (BOD5/COD) from0.28to0.60, anaerobic effluent colority reduced significantly, changed from brown to light yellow.4、Through trial and error, use of supersaturated calcium hydroxide solution to adjust the pH to7.5of Fenton oxidation water around, PAM dosing quantity of4mg/L, are simultaneously strengthening coagulation, can greatly improve the processing effect of Fenton reagent, after strengthening coagulation, the effluent COD is246mg/L, of wastewater biochemical can be further increased to0.76, the effluent colority for33times.5、After strengthening coagulation treatment of water, by the contact oxidation pool eventually aerobic degradation. When the contact oxidation pool and stable operation, dissolved oxygen for3～4mg/L, under the condition of aeration time2h, the final effluent to "standard of sewage comprehensive discharge"(GB8978-1996) level of emissions standards.6、Combination during the actual operation process effluent COD<70mg/L, BOD5<15mg/L, SS<65mg/L, chromaticity<10, pH=7～8. Under impact load condition, the additive amount of H2O2is4ml/L, the effluent can meet emissions, for UASB-Fenton/combination strengthening coagulation, contact oxidation process in betel nut wastewater treatment engineering application provides experiment basis.7、 Through economic analysis, the application of UASB-Fenton/combination strengthening coagulation, contact oxidation process of betel nut wastewater treatment cost about8.13yuan/m3...