The Engineering Adjusting For Wastewater Of Scale Pig Farm Treated By Shortcut-simultaneous Nitrification And Denitrification

Mmarket economy is developing very fast in our country.The livestock and poultry industry has developed rapidly.Livestock and poultry industry is in the transition from scatter-feed to large-scale farming.Livestock and poultry industry brings high-yield livestock and poultry products,also produces a large number of livestock manure.According to the first national pollution census bulletin(2010): the ratio of agricultural water pollution accounted for 23.7%(COD),40.1%(TN),67.3%(TP)of total pollution.Livestock and poultry manure production was 2.43 million tons,and urine was 1.63 million tons.The ratio of COD,TN,TP accounted for 96%,38%,56% of agricultural pollution source.The pollution situation of livestock and poultry is very serious,but land resources are very scarce.Biogas irrigation needs large areas,unreasonable irrigation may lead to new non-point source pollution after the rain leaching.Traditional breeding industry focuses on production,but do not pay much attention to environmental protection.There are some obstacles of poor effluent quality and high cost of running for livestock and poultry breeding wastewater treatment.With the intensity of environmental protection,“Livestock and poultry pollution control regulations” and “Water pollution control action plan” was issued.To coordinate the development of livestock and poultry and environmental protection,and to solve the Non-point source pollution in where the land isn't enough for irrigating biogas liquid and in key river valleys,it is imperative to Find a treatment which is high pollutant removal efficiency,low investment,high efficiency,low consumption and suitable for livestock and poultry breeding wastewater.This study investigated the amount of wastewater generated and pollutant concentration in large-scale pig farm of different cleaning technology.The amount of wastewater was 1.5(winter)~2.5(summer)m3/(100 pigs·d)of dry collection,and 5.5(winter)~7.5(summer)m3/(100 pigs·d)of manure cleaning by water submerging or rinsing,and 3.5(winter)~4.5(summer)m3/(100 pigs·d)of dry collection combined manure cleaning by rinsing.Large-scale pig farm should pay attention to save water in production.Wastewater pollutant concentration of dry collection was lower then other cleaning technology.This study based on Huayan Pig Breeding Farm of Tongnan Wenshi Co.Ltd.in Tongnan Chongqing.The volume of wastewater treatment plant in the farm is 600 m3/d(now is 425 m3/d).To avoid affecting actual production,this research studied pilot first,then the suitable parameter would be used in practice.Pilot model was similar to the main structure——Multilevel A/O.The model was design by HRT similarity criterion,and the hole was design by Froude similarity criterion.Flow experiment investigated the hydraulic characteristics of model was 89.3% push flow.In this section we contrasted treatment efficiency between model and practical treatment after starting reactor.The similarity between model and practical treatment was less than 15%.The model could be used to simulation study.We contrasted 3 facultative-aerobic condition(DO 0.5mg/L,1.0mg/L,1.5mg/L),and the result investigated the best condition for SND was DO 0.5~1.0mg/L.For pretreatment,we improved the solid-liquid separation rate by equipping bar screen and adjusting the position of the intake in separator.For anaerobic treatment,we reduced the concentration of pollutants in biogas liquid by discharging anaerobic sludge.Then we chosen PAC(the equivalent is 68.24~84.71mg/L)and Hichlon(the equivalent is 28.24~47.06mg/L)as flocculant and disinfectant.The effluent reached "Standards for irrigation water quality"(GB5084-2005).But,in order to achieve depth denitrogenation,further studies needed regulate and control aerobic structure.For aerobic structure,we contrasted 4 facultative-aerobic condition(DO 0.25mg/L,0.5mg/L,1.0mg/L,1.5mg/L),and 3 gradient-aerobic condition.Under the positive gradient condition,DO increased from anoxia to 1.1mg/L(1.5mg/L in winter),the concentration of CODcr,NH3-N and TN in effluent reached 97.33mg/L,7.78mg/L and 39.56mg/L,and the total removal efficiency of CODcr and TN was 98.66% and 93.43%.And the effluent reached the goal of engineering adjusting: CODcr<100mg/L,NH3-N<15mg/L,TN<60mg/L.During realizing energy conservation by optimizing aeration rate,have no use to add to alkalinity and carbon source.The cost of treatment is 3.07 yuan/m3 in summer and 4.01 yuan/m3 in winter.There are large difference in wastewater quantity and quality for livestock and poultry industry.The precision management of livestock and poultry breeding wastewater treatment could achieve full potential for each processing unit.It can be applied to new construction and renovation projects,by adjusting the various operating parameters to achieve the best conditions,improving water quality,and reduces processing costs.