Tham khảo tài liệu 'wiley wastewater quality monitoring and treatment_18', khoa học tự nhiên, công nghệ môi trường phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Mass Loading Calculation 317 The error of load estimates for monthly sampling compared with weekly sampling is 20-30 for the Danube while for the Zola it is higher due to the faster dynamic in the smaller water shed. The error in the estimates with Monte Carlo simulation does not differ substantially from the analytical statistical results. Calculation for Long-term Periods Because sampling frequency is generally reduced the load of a specific sampling day is extrapolated to the entire period of days up to the following sampling day. A theoretical interpolation could moreover be made from the measured single day loads. Table summarizes the main characteristics of different procedures that can be used for calculating mass loadings over long-term periods from months to one year . The unit loading factor mass of specific pollutant discharged per person per day is the least accurate but may be a rapid easy and no or low cost method of estimation that could be used as a guide . in calculating annual loads of nutrients . The uncertainties of estimation lie in the use of standard national and fixed factors regarding pro capita daily discharges into the sewer system and removal efficiencies of influent loads during treatment. A more precise estimation could be obtained utilizing local or site specific factors including a better definition of the contributing population inhabitants equivalent and transient population if such data were available at low cost. Another procedure involves the utilization of dependent or independent data as regards sampling time . To calculate the annual average of mass loading the daily average load is required. The frequency of measurement of each daily load depends on the technique of sampling concentration and measuring flow rate which is used Considering the level and nature of fluctuation of both variables the accuracy of the annual load depends on the number of daily data available their distribution throughout the period
