| Objectives:1.Understand the construction,use and treatment effects of AAO household latrines;2.Construct an evaluation model to evaluate AAO household latrines;3.Analyze the effects of AAO household latrines and their influencing factors.Methods:Through field investigation,sampling and laboratory testing,this study investigated the construction,use and treatment effects of 85 randomly selected household in Village A in Shandong Province and Village B in Beijing.At the same time,the AHP and Delphi method were used to construct the evaluation model of AAO household latrines,and the weight values of each index were determined.The comprehensive evaluation of AAO household latrines were explored by multiple linear regression.Results:1.The evaluation model includes 4 major first-level indicators,including the construction of latrines on the ground,usage,sanitation effect,and household evaluation,and 11 second-level indicators.In the criterion level,B3 sanitation effect has the largest weight,which is 0.3674,and B1 has the smallest weight on the ground building.In the scheme layer,C11 management and maintenance evaluation has the largest weight,which is 0.1391,followed by C10 service evaluation,C8 smell,C6 domestic sewage treatment and C7 sanitation condition,and C2 latrine house size has the least weight.2.In terms of construction,the occupancy rate was only 14.1%,of which 98.3%of the households in Village A built their latrines in the courtyard,and the household latrines in Village B were located indoors,accounting for 48.0%and 44.0%of the households respectively;the completeness rate of latrines was 91.8%,and the construction of latrines in 8.2%of households was incomplete.Among them,Village A and Village B accounted for 8.3%(without door)and 8.0%(without window)respectively.82.3%of bathing water and 80.0%of dishwashing and vegetable washing water are discharged into the feces of household latrines.3.In terms of use:94.1%of the latrines can be used normally,and the main reason for the rest is that the water pipes are frozen in winter and cannot be flushed normally;problems encountered during use(multiple choice),58.8%of households think there is no problem,27.1%of households think that the biggest problem in household latrines is the smell,11.8%of households encountered the problem of not being able to flush water,5.9%of households believed that fecal water was frozen in winter in household latrines,and 3.5%chose other households.3.3%of households in Village A believed that maintenance costs are high,and 4.0%of the residents in Village B believe that it is difficult to buy replaceable accessories when the latrines are damaged.4.Hygiene:74.1%of the households thought it was odorless,24.7%thought it had a slight odor,1.2%thought it had an obvious odor,the main cause of the odor is the off-flavor from the septic tank;in summer,there were no adult flies in the latrines.65.9%.Fewer adult flies(less than 5)in latrine houses accounted for 24.7%,and more(greater than 5)adult flies accounted for 9.4%;cognitive aspect:according to the survey on the understanding of the use of AAO household latrines(multiple choices),87.1%of the households thought it was clean and hygienic,50.6%of the households thought it was safe and convenient,1.2%of the households thought it was preventable,and 1.2%of the households did not understand.5.The satisfaction rate of the households with respect to the latrine construction was 90.6%,among which Village A was 98.3%,and Village B was 72.0%.The difference between the two villages was statistically significant(x2=14.728,P<0.05);the satisfaction rate of handling household latrine management,maintenance and use is 96.5%,which is higher than the satisfaction rate of the building.6.The average removal rates of chroma,TN,COD,TP and NH3-N were 67.8%,64.5%,58.0%,48.0%and 46.2%,respectively.The compliance rate of TP in the effluent water quality is the lowest at 7.3%.The compliance rate of COD,NH3-N and TN is low,ranging from 10%to 20%;the total compliance rate of fecal coliform value is 48.8%,and there is a positive correlation between the fecal coliform value and the compliance of NH3-N.7.Comparing the comprehensive scores of each household in the two village,the score range of Village A is more concentrated than that of Village B,and the average score is one level higher than that Village B.The total scores of household latrines in the two villages are between average and excellent.In terms of B1 above-ground buildings,the two villages scored close to 5 points;in terms of B2 usage,C5 maintenance cost scores were both low;in terms of B3 sanitation effect,Village A had the lowest score in C6 domestic sewage treatment,which was close to poor,but both Village scores are not high;in terms of household evaluation of B4,Village A’s three indicators are all excellent,Village B is worse than Village A,and the worst is C9 construction evaluation.8.Among the independent variables included in the multiple linear regression model,the knowledge of the area and users on the use of AAO latrines was P<0.05,which was statistically significant.Conclusion:1.In terms of construction:the entry rate of the latrines in the two villages is low;the integrity is relatively high,but a small number of toilets lack doors or windows.In terms of usage:the normal use rate of household latrines is relatively high,but there are problems such as bad smell and the freezing of water pipes in winter,and the water cannot be flushed normally;some household latrines do not treat all household sewage.Hygiene:the sanitary condition of the latrines is normal,and some latrines have the problem of odor and adult flies.2.Cognitive aspect:residents have certain knowledge about the use of AAO latrines,but they lack awareness of disease prevention.Residents in the two villages are satisfied with the construction,management,maintenance and use of AAO latrines.3.On the whole,the construction of latrine houses is better,but the sewage treatment effect is poor.The compliance rate of nitrogen,phosphorus,and fecal coliform in the effluent is lower,and TP and NH3-N are lower.Household latrines have a certain effect on COD treatment.4.The comprehensive evaluation results of the AAO household latrine effect evaluation model constructed by the analytic hierarchy process:the overall use effect of the AAO household latrines in the two villages is better,and Village A is better than Village B.5.The understanding of the use of AAO household latrines in different regions and users is the main factor that affects the evaluation of AAO household latrines. |
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