| In recent years,the proportion of large-scale dairy farming in my country has been increasing year by year,and the large-scale and intensive development of manure has brought new problems to the dairy farming industry.In addition to manure and urine,the source of dairy farm manure is also related to the large amount of manure discharged from the large amount of clean water in the dairy farm to the manure treatment system.Therefore,reducing cleaning water consumption is particularly important in reducing total manure production.In this study,through literature retrieval,investigation of the cleaning water situation of milking parlors in large-scale dairy farms,laboratory simulation experiments as theoretical basis and dairy farm verification experiments in Dali Experimental Station,the circulating cleaning process of acid-base cleaning solution for dairy farms was obtained..Through investigation,the methods of in-situ cleaning of milking equipment,water consumption for cleaning,milking equipment cleaning wastewater and post-processing methods were obtained.The dairy farm(Shenchi Ranch),which uses the cleaning method of "two alkalis and one acid",analyzes the water quality of different wastewater generated during the cleaning process of milking equipment,and designs a set of milking parlors according to the characteristics of different water quality.Equipment wastewater classification and collection process.Finally,according to the test dairy farm milking equipment wastewater classification collection process,laboratory simulations were carried out to explore the cycle cleaning threshold of acid-base cleaning solution in in-situ cleaning(CIP),and after the acid-base cleaning solution reached the threshold value How to restore the function of the acid-base cleaning solution,and the number of times of recycling the acid-base cleaning solution,combined with the actual investigation,the test data of the dairy farm,the laboratory simulation test and the verification test of the dairy farm of the Dali Experiment Station,the following conclusions are drawn: Research result:(1)Based on the actual investigation of 16 large-scale dairy farms.The results show that: Tianjin,as a typical area of ??urban dairy farming,mainly concentrates 500 to 3,000 large-scale dairy farms,accounting for 68.75% of the total surveyed large-scale dairy farms;the large-scale dairy farms in the survey have milking equipment abroad The brand utilization rate reached 93.75%.The milking equipment is mainly divided into three categories: turntable type,side-by-side type and fishbone type.Among them,the side-by-side type accounts for the highest proportion,reaching 43.75%.Between 8.5 t-70 t,the average daily water consumption is 27.16 t.There are 7 companies with an average daily water consumption that exceeds the average,accounting for 43.75% of the total survey;the large-scale dairy farm milking equipment in-situ cleaning(CIP)mainly adopts the cleaning method of "two alkalis andone acid";the large-scale dairy cows are surveyed The wastewater generated during the cleaning-inplace(CIP)process of milking equipment on the farm is directly discharged into the sewage collection tank without any treatment,accounting for 62.5% of the total number of large-scale dairy farms investigated.(2)Based on quantitative monitoring and composition analysis of wastewater generated by the sorting and collection process of wastewater from milking equipment in Shenchi Ranch.The results show that: Shenchi ranch milks milk three times a day and adopts the cleaning method of "two alkalis and one acid".The average daily production of wastewater from milking equipment cleaning is 5.29 m3,and the pre-wash and post-wash wastewater accounts for 50% of the average daily wastewater.Above,taking effective recovery measures can save water resources;among them,the daily production of acidbase cleaning liquid wastewater that is difficult to treat is 1.29 m3,accounting for 24.39% of the total amount of milking equipment cleaning wastewater.The p H and conductivity values ??of acid-base cleaning wastewater also vary greatly compared with other types of pipeline cleaning wastewater.The p H value of acid-base cleaning wastewater is 2.55±0.03,and the conductivity is 7236.00±136.00 us·cm-1;The p H value is 11.64±0.09,and the conductivity is 4455±185.63 us·cm-1.The p H value of the acidbase cleaning wastewater varies greatly,which requires high post-processing treatment and has a high risk of environmental pollution.The high conductivity of acid-base cleaning wastewater,It is proved that the ion concentration in wastewater is high and the composition is complex.The discharge of wastewater into the manure treatment system increases the total amount of manure produced and the difficulty of treatment.The research on the classification,collection and recycling process of acid-base cleaning wastewater is a new research focus for high-efficiency utilization,water-saving and optimization of acidbase cleaning wastewater from milking equipment cleaning wastewater in dairy farms.(3)Based on the laboratory simulation of the classification and collection process of the acid-base cleaning solution of Shenchi Ranch and the simulated equipment for circulating and flushing the acidbase cleaning solution collected by classification,the visual inspection method and the laboratory analysis method are used to analyze the cycle flushing threshold of the acid-base cleaning solution and the After the cycle cleaning of the acid-base cleaning solution fails,add different proportions of acidbase stock solution to restore the efficacy of the acid-base cleaning solution and increase the number of cycle cleanings.Finally,the optimal cleaning process in the laboratory is verified in the dairy farm of the Dali experimental station.The results show that the optimal cycle cleaning process of the acid-base cleaning solution should be as follows: the alkaline cleaning agent is circulated twice,adding 30% of the original solution,and continuing to circulate and rinse for 2 times before discharging;,continue to circulate and rinse for 2 times and then discharge.Taking 4 days as a process,the alkaline cleaning agent is replaced once,and the acidic cleaning agent is not replaced,which can realize the reduction of waste water source under the condition of ensuring the cleaning effect.Taking the milking parlour of Shenchi Ranch as an example,the daily fixed waste water generated by cleaning-in-place(CIP)is 5.29 m3,and the annual shared water is 1930.85 m3.Under certain conditions,the annual collection volume of prerinsing water and post-rinsing water is 989.15 m3,which can be used for other cleaning,reducingcleaning water consumption.The annual water consumption of acid-base cleaning solution mixture is reduced from 470.85 m3 to 117.71 m3,and the water saving rate reaches 75%.At the same time,the total consumption of acid-base stock solution was reduced from 4.71 t·y-1 to 2.24 t·y-1,with a reduction ratio of 52.33%.In the whole year,the water consumption for cleaning in place(CIP)was reduced by1342.29 t,and the water saving ratio reached 69.52%.%.The laboratory simulated in-situ cleaning(CIP)process was also applied to the dairy farm of Dali Experimental Station.The acid-base mixed cleaning wastewater was reduced from 14.24 m3 to 5.93 m3 throughout the year,and the water saving rate was as high as 58.33%.At the same time,the total annual consumption of acid-base stock solution was reduced from 0.142 t to 0.08 t,and the reduction ratio was as high as 44.17%.The water-saving and waterreducing effect of dairy farms in Dali Experimental Station is lower than that of Shenchi Ranch by 75%and 52.33%.It also proves that "daily water consumption of milking parlor is related to breeding volume to a certain extent but not positively correlated.The cleaning process of milking parlor is The level of management of dairy farms also affects daily water consumption.”... |
PDF Full Text Request