2.1. When designing sewerage systems for settlements, the estimated specific average daily (per year) disposal of domestic wastewater from residential buildings should be taken equal to the calculated specific average daily (per year) water consumption according to SNiP 2.04.02-84 excluding water consumption for irrigation of territories and green spaces.
2.2. Specific wastewater disposal for determining the estimated wastewater flow rates from individual residential and public buildings, if necessary, taking into account concentrated costs should be taken in accordance with SNiP 2.04.01-85.
Table 1
|
Structures |
Sanitary protection zone, m, at the design capacity of structures, thousand m 3 / day |
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|
St. 0.2 to 5 |
St. 50 to 280 |
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|
Mechanical and biological treatment facilities with sludge pits for digested sludge, as well as separately located sludge pits | ||||
|
Structures for mechanical and biological treatment with thermomechanical treatment of sludge in enclosed spaces | ||||
|
Filter fields | ||||
|
Irrigated agricultural fields | ||||
|
biological ponds | ||||
|
Structures with circulating oxidation channels | ||||
|
Pumping stations | ||||
Notes: 1. Sanitary protection zones of sewer facilities with a capacity of more than 280 thousand m 3 /day, as well as in case of deviation from the accepted technology of wastewater treatment and sludge treatment, are established in agreement with the main sanitary and epidemiological departments of the ministries of health of the Union republics.
2. Sanitary protection zones specified in tab. one, it is allowed to increase, but not more than 2 times in the case of the location of residential buildings on the leeward side in relation to the treatment plant, or decrease by no more than 25 % with a favorable wind rose.
3. In the absence of sludge sites on the territory of treatment facilities with a capacity of more than 0.2 thousand m 3 / day, the size of the zone should be reduced by 30%.
4. The sanitary protection zone from filtration fields with an area of up to 0.5 hectares and from mechanical and biological treatment facilities on biofilters with a capacity of up to 50 m 3 / day should be taken as 100 m.
5. The sanitary protection zone from underground filtration fields with a capacity of less than 15 m 3 / day should be taken as 15 m.
6. The sanitary protection zone from filter trenches and sand and gravel filters should be 25 m, from septic tanks and filter wells - 5 and 8 m, respectively, from aeration plants for complete oxidation with aerobic stabilization of sludge at a capacity of up to 700 m 3 / day - 50 m
7. The sanitary protection zone from the drain stations should be 300 m.
8. The sanitary protection zone from surface water treatment facilities from residential areas should be taken 100 m, from pumping stations - 15 m, from treatment facilities industrial enterprises- in coordination with the bodies of the sanitary and epidemiological service.
9. Sanitary protection zones from sludge reservoirs should be taken depending on the composition and properties of the sludge in agreement with the bodies of the sanitary and epidemiological service.
table 2
|
General coefficient of non-uniformity of wastewater inflow |
Average waste water consumption, l/s |
||||||||
|
5000 and more |
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|
Maximum To gene . max | |||||||||
|
Minimum K gene . min | |||||||||
Notes: 1. General coefficients of non-uniformity of wastewater inflow given in tab. 2, it is allowed to accept when the amount of industrial wastewater does not exceed 45% of the total flow. When the amount of industrial wastewater is more than 45%, the general non-uniformity coefficients should be determined taking into account the uneven discharge of domestic and industrial wastewater by hours of the day according to the data of the actual inflow of wastewater and the operation of similar facilities.
2. With an average wastewater flow rate of less than 5 l / s, the estimated flow rates should be determined according to SNiP 2.04.01-85.
3. For intermediate values of the average wastewater flow rate, the total non-uniformity coefficients should be determined by interpolation.
2.3. Estimated average daily costs of industrial wastewater from industrial and agricultural enterprises and the coefficients of uneven inflow should be determined on the basis of technological data. At the same time, it is necessary to provide for the rational use of water through the use of low-water technological processes, water recycling, water reuse, etc.
2.4. Specific wastewater disposal in non-sewered areas should be taken as 25 l / day per inhabitant.
2.5. The estimated average daily wastewater consumption in a settlement should be determined as the sum of the costs established by pp. 2.1-2.4.
The amount of wastewater from local industry enterprises serving the population, as well as unaccounted expenses, may be taken additionally in the amount of 5% of the total average daily water discharge of the settlement.
2.6. Estimated daily wastewater flow rates should be determined as the sum of the products of the average daily (per year) wastewater flow rates determined by clause 2.5, on the coefficients of daily unevenness, taken according to SNiP 2.04.02-84.
2.7. Estimated maximum and minimum wastewater discharges should be determined as the product of the average daily (per year) wastewater discharges determined by clause 2.5, on the general non-uniformity coefficients given in tab. 2.
2.8. The estimated costs of industrial wastewater from industrial enterprises should be taken:
for external collectors of the enterprise that receive wastewater from workshops - according to the maximum hourly costs;
for plant-wide and off-site collectors of the enterprise - according to a combined hourly schedule;
for an off-site collector of a group of enterprises - according to a combined hourly schedule, taking into account the time of wastewater flow through the collector.
2.9. When developing the schemes listed in clause 1.1. specific average daily (per year) water disposal is allowed to be taken according to tab. 3.
The volume of wastewater from industrial and agricultural enterprises should be determined on the basis of consolidated standards or existing analog projects.
Table 3
Notes: 1. Specific average daily water disposal may be changed by 10-20% depending on climatic and other local conditions and the degree of improvement.
2. In the absence of data on the development of industry beyond 1990, it is allowed to accept additional wastewater consumption from enterprises in the amount of 25% of the consumption determined by tab. 3.
2.10. Gravity lines, collectors and channels, as well as pressure pipelines for domestic and industrial wastewater, should be checked for skipping the total calculated maximum flow rate according to pp. 2.7 and 2.8 and additional inflow of surface and ground waters during periods of rains and snowmelt, unorganized entering the sewerage networks through leaks in manholes of wells and due to infiltration of ground waters. The amount of additional inflow q ad, l / s, should be determined on the basis of special surveys or data from the operation of similar objects, and in their absence - according to the formula
where L- total length of pipelines to the calculated structure [pipeline alignment), km;
t d- the value of the maximum daily precipitation, mm, determined according to SNiP 2.01.01-82.
Verification calculation of gravity pipelines and channels with a cross section of any shape for the passage of increased flow should be carried out when filling 0.95 height.
6.1.3 Calculation of coefficients for hourly, daily and general unevenness
Due to the duration of the processing of fur sheepskin, fluctuations in wastewater consumption are observed daily. The initial data on the flow of wastewater to treatment facilities are presented in Table 6.
Table 6 - Initial data on the flow of wastewater to treatment facilities
This table describes the uneven flow of wastewater to the treatment plant at different hours of the day. The discharged volume also differs in different hours and days. This is due to the peculiarity of technological processes in the production of fur sheepskin. Those. drainage is explained by the ability of the leather tissue to absorb the solution, determined by the moisture content of the raw material.
Therefore, for each day of the week, the coefficient of hourly unevenness is calculated using the formula (6):
K hour = Q max day / Q cf hour, (6)
where: K hour - the coefficient of hourly unevenness; Q max - the maximum volume of wastewater inflow during the day, m 3; Q cf - average hourly inflow of wastewater, m 3.
The average hourly inflow of wastewater is determined by the formula (7):
Q cf = ∑Q i / 24, (7)
where: Q i – wastewater inflow to the treatment plant at i – hour; 24 is the number of hours in a day.
The coefficient of daily unevenness is determined by the ratio of the maximum daily flow to the average daily flow according to the formula (8):
K day \u003d Q max weeks / Q avg weeks, (8)
The overall coefficient of non-uniformity of water disposal at enterprises is calculated by the formula (9):
K total \u003d K hour × K day, (9)
Calculation example:
Day of the week-Tuesday
a) Calculation of the average daily wastewater inflow:
Qav = (2.863+0.026+2.753+2.863+0.032+2.753+2.753+2.753+2.753+ 2.753+0.031+ +0.02)/24=0.93
b) Calculation of the coefficient of hourly unevenness:
K hour \u003d 2.863 / 0.93 \u003d 3.1
c) Calculation of the coefficient of daily unevenness:
K day = 2.863/((2.863+0.026+2.753+ 2.863+0.032+2.753+2.753+2.753+2.753 +2.753+ + 0.031+0.012)/7) = 0.23
d) General coefficient of unevenness:
K total \u003d 3.1 × 0.23 \u003d 0.713
A similar calculation is carried out for each day of the week, the data obtained are entered in table 7.
Table 7 - Coefficients of non-uniformity of wastewater inflow to treatment facilities during the week
| Irregularity coefficient | Days of the week | |||||
| Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | |
| 3,1 | 3,1 | 3,1 | 3,1 | 3,1 | 3,1 | |
| 0,23 | ||||||
| 0,713 | 0,713 | 0,713 | 0,713 | 0,713 | 0,713 | |
6.1.4 Calculation of specific water consumption and wastewater disposal per unit of output
One of the indicators characterizing the level of the enterprise's impact on the environment is the assessment of specific water consumption and wastewater disposal per unit of output.
The actual water consumption in the dressing of fur sheepskin is determined by the following indicators:
For production needs 75-85%
For household needs 5-6%
Water formed after precipitation or storm water 2-3%
Conditionally clear waters used for equipment cooling or in refrigerators, fans, compressor units 6-18%
Initial data:
The capacity of the enterprise is 10,000 pieces of sheepskin per year
Number of working days 250
The volume of waste water is:
Production 75%
Household 6%
Conditionally net 16%
Stormwater 3%
The volume of water disposal, taking into account industrial and household needs in the processing of sheepskin, is: 23.84 m 3 / day or 5960 m 3 / year, of which:
Production 17.88 m 3 /day or 4470 m 3 /year
Household 1.43 m 3 / day or 357.5 m 3 / year
Conditionally clean 3.81 m 3 / day or 952.5 m 3 / year
Stormwater 0.72 m 3 / day or 180 m 3 / year
It is known that in the process of performing technological operations, on average, water losses for production needs do not exceed 6%, then the total volume of water consumption will be:
23.84 + (23.84 × 0.06) \u003d 25.27 m 3 / day or 6317.5 m 3 / year
Let us determine the specific volume of water consumption and wastewater disposal per unit of output:
a) specific volume of water consumption per unit of output
The actual volume of water consumption will be 6317.5 m 3 / year
The capacity of the enterprise per year is 10000 pieces of sheepskin
Then, 6317.5 m 3 / year - 10000 pieces
X m 3 / year - 1 unit of output, X \u003d 0.63 m 3 / year
b) specific volume of water disposal per unit of output
The actual volume of wastewater is 5960 m 3 / day
5960 m 3 / year - 10000 sheepskins
X m 3 / year -1 unit, X \u003d 0.6 m 3 / year
Information about the work "Study of the properties of a bacterial suspension and its application in the preparatory processes for the processing of fur raw materials"
From the calculated data in Table. 7.2 it is established that the coefficient of irregularity in the receipt of material and raw materials is 3.29 (irregularities \u003d 236 108/21 800 - \u003d Y10.83 - \u003d\u003d + 3.29). The coefficient of unevenness shows that the supply of raw materials and materials was carried out in violation of the plan and monthly deviated from the planned conditions by 3.3%.
On gas pipelines, fluctuations in the mode of operation of the main are taken into account using the coefficient of non-uniformity of gas supply
gas consumption Ku (in RUB/1000 m) with UGS capacity, mln. m1 EU IB RUB/1000 m") with UGS capacity, mln. m
Gas consumption fluctuation coefficient Storage capacity, mln m3 Storage capacity, mln m1
To assess the rhythm of supplies, the following indicators are used: coefficient of rhythm, number of arrhythmia, standard deviation, coefficient of irregularity in supplies, coefficient of variation.
The coefficient of uneven supply of materials is calculated by the formula
In addition, the determination of the required volume of capacities of transshipment points using existing methods can be made only on the basis of average or maximum transshipment volumes per month, taking into account the coefficient of unevenness.
Consequently, the main disadvantage of the non-uniformity coefficients used in the calculations is that they do not take into account the non-uniformity of oil products transshipment (in time and quantity).
Since the calculations of the required volume of the tank farm of transshipment points, obtained taking into account the coefficient of non-uniformity, do not provide a reliable and even more optimal solution, it becomes obvious that a different fundamental basis must be chosen.
The algorithm for calculating the coefficient of uneven oil supply is presented in the form of a block diagram (Fig. 14). To clarify the block diagram, we introduce the designations t - years of the retrospective period th month t-th year of the retrospective period Kr - coefficient of unequal
Block 13 - issuing for printing the calculated values of the unevenness coefficients for each oil depot for the years of the retrospective period. The form of presentation of the output information is similar to the form shown in Table. 24.
When determining the reduced costs for the processing of petroleum products at the facilities of the oil storage facilities, it is necessary to take into account the movement of fixed assets, their write-off and restoration. Moreover, capital investments in the development of these facilities for reconstruction and expansion for each control year of the planning period should be accounted for separately. All capital investments for the first planning period refer to the first control year, and capital investments of the second period - to the second control year on an accrual basis. When determining the reduced costs, the minimum cost of processing corresponding to the maximum possible throughput should also be taken into account. The minimum cost should be determined on the basis of studying for each tank farm the dependence of the level of current costs on the main factors of production, i.e., demand for petroleum products in the service area (sales volume), the cost of existing fixed assets, the coefficient of uneven supply of the tank farm and the time factor. When determining the reduced costs, taking into account the expansion of existing oil depot facilities provided for by the projects, one should take into account the share of costs that depend on the volume of sales of petroleum products. It can vary over a wide range depending on the "category of tank farms, the volume of sales of petroleum products and the characteristics of transport services. In this regard, the share of dependent costs should be determined separately for each tank farm based on a study of the behavior of this indicator over a long retrospective period.
Given in table. 7.1, the data indicate that in the analyzed period the logistics plan was not fulfilled, the supply of material and raw materials was carried out unevenly. To measure the degree of non-uniformity of supplies, we use the indicator of the standard deviation (coefficient of non-uniformity) as an indicator of the average size of the fluctuation in the value or other feature of the object under study compared to its average level. The procedure for calculating this indicator will be considered using the example of the iosta-
M201. Calculation of the coefficient of non-uniformity of oil supply by oil depots
Oil depot Year Observation number Capital productivity Cost price 2, rub/t Labor productivity X, Tank capacity X4, t Coefficient of oil supply unevenness Sales volume of oil products X t
Block 2 - formation of a working array of the oil supply unevenness coefficient using the M201 module.
MODULE M201. CALCULATION OF THE COEFFICIENT OF IRREGULARITY OF OIL SUPPLY BY OIL DEPOSITS
Block /0 - calculation of the coefficient of non-uniformity of oil supply at the p-th oil depot by years of the retrospective period. Creating array B2111.
The array of the coefficient of uneven supply of oil depots for the retrospective period is the array B2111.
Block 11 - construction of predictive models for the dependence of economic indicators (cost, capital productivity and labor productivity) on the p-th oil depot on objective factors of production (freight turnover, replacement cost of fixed assets, coefficient of unevenness) and the time factor t. The predictive model is built on the basis of the dependence of economic indicators on objective factors of production for the retrospective period using the M108 module
When determining the reserves for increasing throughput in the second way, an attempt is made using the methods of multivariate classification and correlation-regression analysis to establish the influence of the main objective factors of oil supply on the economic performance of tank farms and develop economic and statistical models of indicators that could be used for the purposes of oil supply planning. At the same time, the dependence of capital productivity (x) on such factors as the volume of sales of petroleum products (xv), the coefficient of uneven oil supply (x5), and the volume of the reservoir capacity (x4) is studied. Initially, a multidimensional classification of tank farms is carried out according to objective factors of production. Then in each class is built
The calculation of drainage networks consists in determining the diameters and slopes of pipelines, which, under the most favorable hydraulic conditions, ensure the passage of wastewater flows at any time. Since the gravity flow of wastewater in terms of energy is the most advantageous, the main task in the design is to build a longitudinal profile of the collectors, which determines the volumes earthworks and the position of the drainage pipelines in the underground part relative to others engineering communications. The basis for determining the diameters of pipelines is the estimated flow rate, which depends on the specific rate of wastewater disposal from the city - the average daily (per year) water consumption, l / day, discharged from one person.
The specific rate of wastewater disposal depends on the level of sanitary equipment of buildings and, to a certain extent, on climatic conditions.
In table. 2.1 shows the influence of the degree of improvement of buildings on the amount of specific water disposal.
Table 2.1
Specific discharge of domestic wastewater from the city
In some microdistricts in buildings with increased comfort, specific norms can reach 500-1000 l / (person day). Russian experience shows that usually the specific water disposal is equal to the specific water consumption. The effect of market relations in public utilities will affect the specific water disposal, so it should be constantly studied and refined.
The specific wastewater disposal of domestic water from industrial enterprises is given in Table. 2.2.
Table 2.2
Specific wastewater disposal of domestic water from industrial enterprises
Water consumption from showers and foot baths is determined by hourly water consumption, equal to: for one shower net - 500 l/h; for one foot bath with a mixer - 250 l/h. The duration of the water procedure is 8 minutes for a shower, 16 minutes for a bath. The duration of using the shower and bath is 45 minutes with uniform water consumption and drainage. Specific wastewater disposal of industrial wastewater is the amount of water, m 3, discharged per unit of output. The value of specific water disposal depends on the type of production and the degree of perfection of water technology. The most advanced - continuous production processes with the re-circulation of water have the lowest values of specific water removal. During the period of rains and snowmelt, a significant flow of rain and melt water into the drainage network is observed. In this regard, a requirement arose to carry out test calculations of drainage networks for the passage of the maximum flow rate, taking into account the additional inflow of rain and melt water. Additional expense
where? - total length of the drainage network, km; t s1 - maximum daily precipitation, mm, determined according to SNiP 2.01.01-82.
Reliable reception and disposal of wastewater in the above period can be ensured by a decrease in the calculated filling of collectors, not exceeding h/d= 0.7, which, of course, increases the cost of building drainage networks. The experience of operation of drainage networks in Moscow has revealed another, more efficient way of increased drainage during flood periods and days of intense rain.
A new technology for regulating the inflow of wastewater is implemented using emergency control tanks, which can significantly reduce the peak hydraulic load on the main sewage facilities, reduce the coefficient of uneven flow of wastewater to pumping stations and treatment facilities, which significantly increases the stability of their work.
Irregularity coefficients. The inflow of sewage fluctuates daily within the year and by hours of the day.
Coefficient of daily non-uniformity of wastewater inflow
where (?, (? 2 - maximum and average daily expenses for the year.
The coefficient of daily non-uniformity is used in the analysis of fluctuations in domestic wastewater from the city. Depending on local conditions, it is equal to 1.1 -1.3.
Coefficient of hourly unevenness
K 2 \u003d i ( / c 2, (2.3)
Overall maximum ripple factor
K \u003d K ( to g (2.4)
Taking into account dependences (2.2) and (2.3), the total maximum coefficient has the form
K = (24^/24^)^,/^),
K \u003d i x / i, (2.5)
where I - average hourly consumption per day with an average inflow of wastewater.
The general non-uniformity coefficient is the ratio of the maximum hourly flow per day with the maximum inflow of wastewater to the average hourly flow per day with an average wastewater discharge.
Numerous studies have established that the overall non-uniformity coefficient depends on the average wastewater flow rate.
For the reliability of the operation of some sewage facilities, it is necessary to know the minimum costs, i.e. values of the overall minimum coefficient of unevenness
where I - minimum hourly consumption per day with minimum drainage.
In table. 2.3 shows the values of the coefficients of non-uniformity from the average second flow, with the help of which the values of the calculated maximum and minimum expenses Wastewater.
The inflow of domestic water from industrial enterprises is characterized by a maximum hourly coefficient to 7sh
General coefficients of non-uniformity of domestic wastewater inflow from the city
Notes:
^bp^max /
where qmax and q mid - maximum and average costs per hour per shift. Numerous observations have established that the coefficient of hourly irregularity in the inflow of domestic wastewater is practically the same for various industries.
The mode of disposal of domestic water of an industrial enterprise
|
Cold shop, 25 l/(cm-person) |
G Hot shop, 45 l/(cm-person) |
|||
|
Shift hours |
The value of K^ n at ^dep.max ° |
Expenses, % |
Meaning/C^ |T at To _ p s; ^dep.max,and |
Expenses, % |
|
Total per shift |
||||
Under the design flow is meant the flow, which is limiting in the calculation of sewage facilities.
For the calculation of drainage structures, the average and maximum daily, hourly and second flow rates are used.
The estimated costs of domestic water from the city are determined by the following formulas:
where N is the estimated population by the end of the estimated period of operation of the drainage network - 25 years.
The maximum second consumption is conveniently determined by the formula
where R - residential area of quarters, ha; q() - runoff module, l / (s ha) - a generalized indicator of consumption per unit area of residential quarters, determined by the formula
Р/24 3600, (2.15)
where R - population density, person/ha.
The norms for the disposal of domestic water from the city do not take into account the flow of water from rest homes, sanatoriums, dispensaries, etc. These water flows are determined and accounted for separately.
Estimated costs of domestic water from industrial enterprises
are determined by the formulas:
C tM \u003d (25UU, + 45LU / 1000, m 3 / sug; (2.16)
(2 tach. s „ \u003d (25 / U 3 + 45Lu / 1000, m 3 / day; (2.17)
Yat ax, = K 6 d) / r? 3600, l/s, (2.18)
where / V, and YU 2 - the number of workers per day with a specific water discharge, respectively, in cold and hot shops of 25 and 45 l / cm per worker (see table. 2.4); UU 3 and /U 4 - the same per shift with the maximum number of workers at a specific water discharge of 25 and 45 l / cm3 per worker, respectively; 0 m[th - average daily consumption; (2 max cm - consumption per shift with the maximum number of employees; K bh= 3 and K 6 r \u003d 2.5 - coefficients of hourly unevenness at specific water disposal, respectively, 25 and 45 l / cm per worker; t- shift duration, hours
Estimated costs of shower water, taking into account their uniform formation within 45 minutes of the last hour of the shift, can be determined by the formulas:
Stax,™ = “d L? 45/1000? 60, m 3 /cm; (2.19)
60) ^ si ^ tt), m 3 / cm; (2.20)
tahd \u003d? d.s t d / 3600 - L / S >
where m) x - the number of shower screens; /U cm and Nmax- the number of workers using the shower, respectively, in the calculated and maximum shifts; 45 - the duration of the shower in the last hour of the shift, min.
Number of shower screens
t d \u003d L "max" L-PC -
where t n = 9 - the duration of the water procedure with one shower, min; / = 45 - the duration of the shower, min.
The flow rate of shower water can be determined by the formulas:
where CU 5 and N1 - number of shower users in cold and hot shops with a specific rate of 40 l/person; L ^ 6 and UU 8 - the same in hot shops with a specific rate of 60 l / person.
The estimated costs of industrial wastewater are determined by the formulas:
0, w \u003d H „m, m 3 / day; (2.26)
btahhm = ", Ash> m>/cm'
"max.x \u003d" Aah * "L" 3.6), l / s, (2.2V)
where M and M max - the number of products produced per day and shift with the highest productivity, respectively; K p - coefficient of hourly unevenness of the inflow of industrial wastewater; Г - the duration of the shift (technological process), h.
Coefficient K p depends on the industry, the type of products produced and the degree of perfection of the technological process.
When designing the coefficient K p should be taken based on the experience of similar industrial enterprises or on the recommendations of technologists.
The calculation made according to the above formulas allows you to set the extreme hourly wastewater flow rates and costs for other times.
For the convenience of calculating drainage facilities, it is advisable to summarize the results of determining costs in a statement. The form of the summary sheet is given in table. 2.5.
List of total wastewater costs
|
Serviced object |
Waste water costs |
|||||
|
average daily, mR/day |
maximum hourly, m 3 / h |
maximum seconds, l/s |
||||
|
household and shower |
production essential |
household and shower |
production essential |
household and shower |
production essential |
|
|
Industrial company |
||||||
The mode of wastewater disposal by hours of the day. It is convenient to represent the distribution of wastewater consumption by hours of the day in the form of a step graph (Fig. 2.1). The time of day is plotted along the abscissa axis, and the hourly costs in m 3 or in% of the daily consumption are plotted along the ordinate axis.
8 10 12 14 16 18 20 22 24
Hours of the day
Rice. 2.1. Stepped schedule of wastewater inflow:
The deviation from the value of the average hourly flow rate, equal to 100/24 = 4.17%, depends on the average second flow rate and the corresponding coefficient of uneven drainage.
Such graphs are visual and more accurate if they are built when filling out a summary table of wastewater inflow from the city and industrial enterprises, taking into account the distribution of domestic and industrial wastewater from an industrial enterprise by shift hours.
Estimated sections of pipelines and collectors are separate calculated sections, within which the flow rate is considered conditionally
permanent. It is difficult to determine the total (maximum) estimated discharges of wastewater of various origins, taking into account the schedules of their inflow for all sites, since these peak discharges do not coincide in time, which contributes to the creation of a certain reserve. This reserve is most noticeable only in a few initial sections, when the so-called concentrated flow of domestic, shower and industrial wastewater from industrial enterprises is commensurate with the flow of domestic water from the city, discharged through the collectors of the largest section.
The experience of designing drainage networks confirms the possibility of the above method for determining the estimated (total) costs.
When calculating pumping stations, emergency control tanks and treatment facilities, it is necessary to have a distribution of daily and shift costs by hours of the day and shifts.
The total wastewater flow rates at certain hours of the day are obtained by compiling a summary table of wastewater inflow, the form of which is presented in Table. 2.6.
Table 2.6
Statement of the total hourly inflow of wastewater from the city and industrial enterprises
|
Watch days |
Domestic water from the city |
Water from industrial enterprise No. 1 |
Total expenses |
||||||
|
household |
soul |
production |
|||||||
|
|||||||||
The maximum hourly consumption according to the table. 2.6 will be less than the sum of the maximum costs of certain types of wastewater, obtained using table. 2.5, since peak costs do not coincide in time.
Calculation using the table. 2.6 excludes the stock, and this consumption is closer to the actual one.
The values of specific wastewater disposal of domestic water take into account the costs not only from residential buildings, but also from administrative buildings and public utilities. Formulas (2.14) and (2.15) assume uniform discharge of wastewater from the area of blocks. When placing administrative and communal facilities on this area, this principle is violated.
In areas diverting water from such facilities, pipelines should be checked for the passage of concentrated costs from them. These costs are set in accordance with the relevant applicable regulations.
At the same time, water discharges in other sections of the network may be less than those calculated using formulas (2.14) and (2.15). In this case, for the area where administrative buildings and public utilities are located, the runoff module should be determined without taking into account the water flow from the above facilities using the formula
“These-10:)-”000 ?/’ 86400
L/(s ha),
where 0 you - average daily wastewater consumption from the considered sewerage area, m 3 / day, with the total area of quarters? / g, ha; Ha - the amount of concentrated costs from non-residential facilities, m 3 / day.
Specific wastewater disposal without taking into account costs from non-residential facilities d" 6 can be determined by the formula
P » l / (person C U T) -
Determination of the estimated wastewater costs for individual sections of the network. The estimated flow rate for the calculated section of the network can be determined by the gravitating areas and the specific flow rate per unit length of the pipeline. The first method of "area" is widely used in engineering practice, the second - the method of "lengths" - is used less frequently, mainly when calculating a network using a computer.
When determining the estimated flow rate for gravitating areas, the concepts of transit, lateral, associated and concentrated costs are used.
On fig. 2.2 presents models illustrating the methodology for determining the flow
Transit expense d s - concentrated expense from a non-residential facility.
I - network tracing along the lowered edge; II - the same according to the enclosing scheme; a-d - parts of quarters gravitating to adjacent branches
When determining the design flow rate, the total non-uniformity coefficient can only be entered for the total average flow rate q i ^.
q i = q 0 ? F j , l/s, (2.31)
where q 0 - sink modulus calculated by formula (2.15); - general
the area of blocks gravitating to this settlement area.
According to the diagrams in Fig. 2.2 shows that the associated consumption
Concentrated consumption qc from a non-residential facility is determined as the sum of the estimated costs of wastewater of various origins (for example, domestic, shower and industrial), each of which is calculated, respectively, by formulas (2.18), (2.21) and (2.28). There are local and transit concentrated costs.
I. Local concentrated consumption - consumption from an industrial enterprise located in an adjacent quarter or part of it (when tracing the network along the lower side of the quarter), is shown in fig. 2.2, city
II. Transit concentrated flow - flow from an industrial enterprise entering the network above calculated point 21 (Fig. 2.2, b).
Thus, the estimated flow in a separate section of the network ^21-22 0P
“21-22 \u003d ““ pop + “6ok> + “tr]? To+ “S’ L / S -
In order to simplify the calculations are carried out in a certain form.
3. BASICS OF DESIGN AND CALCULATION OF WATER DRAINAGE SYSTEMS
Drainage systems are divided into off-site, street, intra-quarter and internal (inside the building).
The off-site drainage system consists of collectors with structures on them, pumping stations, treatment facilities and wastewater outlets into reservoirs.
When designing pipelines, it is necessary to reduce their metal consumption by minimizing the use of steel and cast iron pipes, replacing them with pressure reinforced concrete, polyethylene, asbestos-cement pipes and applying protection of internal and external surfaces steel pipes from corrosion. Treatment facilities and pumping stations are designed, if possible, from unified products. It is necessary to apply the dimensions of structures in multiples of 3 m, and in height 0.6 m. In practice, the design of capacitive structures is provided for as precast-monolithic: the bottom is monolithic; walls, columns - prefabricated. There are "Unified prefabricated reinforced concrete structures for water supply and sewerage facilities".
Before starting the design of drainage systems, it is necessary to carry out engineering surveys, which are divided into topographic, hydrological, geological and hydrogeological. Topographic- survey of the site, site of structures, collector. Geological and hydrogeological surveys determine the geological structure of the routes of water conduits and collectors, construction sites; physical and mechanical properties of soils; the position of the groundwater level; give information about the aggressiveness of soils and groundwater in relation to metal and concrete; determine the seismicity of the area, landslide phenomena. The quality and completeness of the research depends on the quality design work and further operation of the facilities.
That's why engineering surveys is given special attention.
Researches consist of field, laboratory and cameral works. For their implementation, expeditions and parties are created.
When designing drainage networks, it is required to perform calculations a large number individual sections of pipelines with different operating conditions. Therefore, various tables are used to calculate gravity pipelines: tables for the hydraulic calculation of sewer networks and siphons according to the formula of Academician N.N. Pavlovsky, Lukinykh A.A. and Lukinykh N.A. and tables of Fedorov N.F. and Volkova L.E. – Hydraulic calculation of sewer networks. The Lukin tables were compiled using the Chezy and Pavlovsky formulas, and the Fedorov tables - according to the Darcy formulas and the constancy of the flow rate. These tables show the flow rates of wastewater, speeds for various fillings of pipelines for all diameters and slopes of pipes possible in engineering practice.
Therefore, when designing drainage networks, it is first necessary to determine the wastewater costs. The slopes of pipelines are taken taking into account the slope of the earth's surface, and the calculation of pipelines according to the tables is reduced to the selection of pipeline diameters that ensure the passage of the estimated flow rate during filling and speed that meet the requirements of Table. 16 .
Thus, for the design of drainage systems, the following initial data are required:
^ 3.1. Waste water costs
The calculation of the drainage network and structures is carried out for the estimated costs.
Under estimated expense wastewater means the most possible flow rate that can enter the facilities and it depends on the specific water disposal, the coefficient of unevenness, building density and the area of \u200b\u200bthe settlement.
^ Specific water disposal of domestic wastewater from the city is the average daily wastewater consumption in l / day, diverted from one person using the sewerage system. The specific water disposal depends on the degree of improvement of buildings, i.e. the degree of equipment of buildings with sanitary devices (cold and hot water supply, bathtubs, etc.).
The higher the degree of improvement, the higher the specific water disposal. In addition, the specific water disposal also depends on climatic conditions: in the southern regions with a warmer climate, it is higher than in the northern ones.
Usually, the specific water disposal is practically equal to the specific water consumption in accordance with Table. one . Specific water disposal is given in table. 3.1.
Table 3.1 - Specific discharge of domestic wastewater from the city
The specific water disposal per person takes into account not only the amount of wastewater coming from residential buildings, but also the amount of domestic wastewater coming from public facilities (baths, laundries, hospitals, schools, etc.).
In areas not equipped with rafting systems, the specific water discharge is taken to be 25 l / day. per inhabitant. During the period of rains and snowmelt, an unorganized flow of rain and melt water into the drainage network is observed. Therefore, it is necessary to determine the additional flow of wastewater entering the drainage network, according to the formula
(3.1)
Where L is the length of the drainage network, km;
-
the maximum daily amount of sediment in mm, which is determined according to SNiP 2.01.01-82.
Check calculation of gravity pipelines for the passage of increased flow should be carried out when filling 0.95 height.
^ 3.2. Irregularity coefficients
Since the inflow of wastewater into the drainage network fluctuates by the day and by the hour per day, an important characteristic of this fluctuation is the non-uniformity coefficient, which determines the largest possible costs, i.e. settlement.
1) ^ For populated areas
Daily irregularity coefficient
:
 , | (3.2) |
, 
- maximum and average daily consumption for the year, m 3 / day. The coefficient of daily non-uniformity is used to assess fluctuations in the inflow of only domestic wastewater from the city. Depending on local conditions, it is 1.1-1.3.
Coefficient of hourly unevenness
:
Taking into account the dependencies (3.1) and (3.2), the overall non-uniformity coefficient will be:
  , | (3.5) |
- average hourly consumption per day with an average wastewater disposal. Therefore, the overall non-uniformity coefficient is the ratio of the maximum hourly inflow per day with maximum drainage to the average hourly inflow per day with average drainage. Moreover, with an increase in the average flow rate, the maximum non-uniformity coefficient decreases, and the minimum increases.
Overall minimum unevenness factor:
 , | (3.6) |
- the minimum hourly consumption per day with a minimum drainage, m 3 / h. Table 4.2 - General coefficients of non-uniformity of the inflow of domestic wastewater in the city
| General coefficient of unevenness | Average waste water consumption, l/s |
||||||||
| 5 | 10 | 20 | 50 | 100 | 300 | 500 | 1000 | > 5000 |
|
 | 2,5 | 2,1 | 1,9 | 1,7 | 1,6 | 1,55 | 1,5 | 1,47 | 1,44 |
 | 0,38 | 0,45 | 0,5 | 0,55 | 0,59 | 0,62 | 0,66 | 0,69 | 0,71 |
The irregularity of wastewater inflow from the territory of industrial enterprises during the day is taken into account using the coefficient of hourly unevenness - 
; in this case, there is no concept of the daily coefficient of unevenness (it is believed that the enterprise should work evenly throughout the year).
The value of the coefficient of hourly non-uniformity of industrial wastewater inflow should be obtained from production technologists.
The value of the coefficient of hourly unevenness of the receipt of domestic wastewater from the territory of industrial enterprises depends on the specific water disposal n(l / cm per 1 person), type of workshop and is:
At n= 45 l/cm per person (hot shop) – = 2.5;
At n= 25 l/cm per person (cold shop) – = 3.0.
^ 3.3. Determining the costs of domestic and industrial wastewater
3.3.1. Wastewater consumption from the population
Average daily consumption
, m 3 / day
Estimated consumption
, l/s
| , | (3.9) |
, human; R– population density, persons/ha;
F– area of residential quarters, ha;
– specific water disposal, l/day. per inhabitant;
- the total maximum coefficient of non-uniformity of wastewater inflow.
To simplify the calculation of wastewater inflows in the sewerage network, engineering practice uses the concept of "flow rate module" or drain module.
The runoff module is determined for residential areas (for each district or quarter with different population densities and specific water disposal rates). Drain module
- wastewater consumption per unit area of residential quarters, is determined by the formula
If the runoff module is multiplied by the corresponding area of the quarter, then the average wastewater inflow from this quarter will be obtained, l / s:
where N 1 , N 2 - the number of employees per day, respectively, in cold and hot shops;
25 and 45 - specific wastewater disposal in l/cm. per 1 worker, respectively, in cold and hot shops.
Estimated consumption
, l/s
 , | (3.13) |
To 1 , To 2 - coefficients of hourly non-uniformity of water disposal, equal to 3 and 2.5 with specific water disposal, respectively, 25 and 45 l / shift per worker;
T is the duration of the shift in hours.
^ 3.3.3. Shower wastewater consumption
The shower must run for 45 minutes.
Maximum cost per shift
m 3 / cm
where 
- water consumption through one shower net, equal to 500 liters per hour;
- the number of shower nets, depends on the number of workers using showers in the maximum shift. The number of people served by one shower net is taken from Table. 6 depending on the sanitary characteristics of production processes.
Table 4.3 - Number of people served by one shower screen
^ 3.3.4. Consumption of industrial waste water
Average daily wastewater consumption from technological processes
, m 3 / day
where M and M 1 - the number of units of output, respectively, per day and in the maximum shift;
- specific water disposal, m 3, per unit of production;
To 1 – coefficient of hourly uneven discharge of industrial wastewater.
