Based on the amount of sewage to determine whether it is necessary to access the municipal large pipe network, we know that decentralized point source sewage access to the pipeline network is very costly, sewage network you can certainly follow the method of municipal sewage network calculations, but it is important to know that the pipeline network construction troublesome investment in the large may not be cost-effective, and now some studies have shown that doing rural sewage is generally within 5 kilometers to be collected in the countryside to more than 100 households to be worthwhile! To do the network will be connected to the sewage trunk sewers, if not up to should be used to decentralize the treatment of the way more cost-effective. --This reference data is the 2011 Beijing International Conference Center held in small and medium-sized towns and rural sewage conference on a U.S. scholar did research and came to a conclusion.
I am doing water treatment, rural projects in the 100 tons / day below the project to do about a dozen, you this scale does not seem to be very large. If you do sewage treatment station in rural Beijing, according to the 2012 market price investment should be between 30 ~ 500,000 yuan; tons of water treatment costs including labor without depreciation should be in the 2 ~ 4 yuan / ton, without labor is in the 1 yuan / ton or so.
So it is recommended that you first compare, is not decentralized treatment more cost-effective. Because I've done a lot of projects in Beijing because it's really not cost-effective to do the network using decentralized sewage treatment stations for decentralized treatment. For example, I did a village in 2009, I would rather spend 680,000 to do a 50-ton / day sewage treatment station, do not want to do a lifting pumping station will be elevated to 5 kilometers outside the pipeline network, because of the buried depth of the large, expensive, must be on the lifting pumping station management trouble, and land acquisition is not good to get a number of constraints on the problem.
Rural sewage characteristics:
1, water during the day, morning and evening concentration, almost no water flow out at night, the coefficient of variation is very large to take 10 are not excessive.
2, the amount of rural sewage in the north in winter is actually very large, but the water quality is very clear and easy to deal with, mainly a lot of water does not cost a lot of rural villagers are worried about the winter pipeline is clogged so all day to open the pipe, at least in Beijing so the villagers are still there, so do the design of the village before the verification of the village's winter living habits. --Why? For example, a village in Fangshan District, Beijing, do not pay for water, summer daily only 30 tons / day sewage, to the winter surprisingly high 120 tons / day. So the theory of the so-called pipeline calculation is completely invalid. --This is the real version of China's rural sewage. So if you dare to build the official website of the village, we suggest that it is best to investigate whether the water in this village costs money.
3, rural pipeline network facilities and sewage treatment facilities management level is very weak, many are illiterate old people in the management, so you have to consider the level of your future maintenance and management workers. It is not that people are very lazy, it is true that no one can get these jobs, the strong labor force in rural areas is becoming less and less, more to work. Especially the sewage treatment station management technology is even weaker, now sewage treatment stations do very fancy, not applicable to rural areas, so many are set up not open. So you have to pay attention to, your pipe network design time if you need to do sewage treatment station please you put beyond the pipe are to sewage treatment station to stay well, must pay attention to this. To say a few words, I hope to see this answer to the other network peers can pay attention to do rural decentralized wastewater treatment station, it is best not to choose the activated sludge process class, especially like AO, MBR and such complex technology. Water quality changes in water quantity, management quality is low, plus the village is very poor depreciation is high really can not afford to use. Really can not run. We also have to face the situation that every village has to face the monthly blackout, and the sludge of activated sludge method can't be fed normally. Must use the land treatment process (artificial fast seepage, artificial wetlands, biological sand filter) because the rural areas do not lack of land, and lack of money, lack of people and lack of technical support, Beijing in the past five years to do three or four hundred rural sewage treatment station small-scale basic traditional technology is finished the vast majority of the lie down, a profound lesson ah.
Back to business, you are going to do the network, the rural area to do the network of some personal experience:
I have not done municipal large-scale network design, but I do not do less rural sewage treatment facilities, the amount of water network is still more of a right to speak, to give you some of the network calculations, it is worth your while to consider:
1) rural sewage is generally not to do septic tanks, unless it is the newly relocated immigrant villages (the government paid to build houses), generally not do the same, but to do the same thing. The government paid to build houses), the general rural areas are their own houses, no one built septic tanks, not to mention that even the official network is not, rural sewage is actually directly along the yard to the road. Beijing has the habit of splashing the yard with wash water, especially in summer.
2) There is a lot of sewage and garbage in the countryside, more than you can imagine. Because there is no septic tank and good garbage collection habits, many new new rural sewage facilities to water found very much garbage, large and small. So your pipeline at least according to not less than d300 concrete pipe design.
3) rural rainwater problem is very troublesome and troublesome, 04 years when I did a certain several villages in Shenzhen river rainfall calculations. Feeling rural villages in general are very large and extensive. So collect rainwater is actually very unrealistic, in fact, it is really better not to collect, people's villages are basically land, good permeability, good nullah drains actually really enough. I don't think you need to make too much trouble over this. Rural rainwater are directly into the fields and rivers, especially in agriculture-based rural villages, the villagers hope that the rainwater are flowing into the fields to be good, and a lot of years of long villages, its drainage are using open ditches, because the flux of large management is simple, it is best not to get with the city like to do the rainwater pipeline. Because of the rural garbage littered everywhere is very inevitable, do not expect your rain grate can stop how much (because in China as long as the metal is facing the risk of theft), once the rain are washed into the storm water pipe network, the village will be very troublesome, it is recommended to do the open ditch, in the countryside is really very practical. If you have to do the pipe network drainage stormwater, not to talk about investment and management, you must watershed catchment areas are outlined with topographic lines, and then select a N-year standard, such as the first 1 ~ 2 hours of rainfall statistics (preferably from the meteorological data to find a "typical rain" - this expert review meeting will certainly be asked! -This expert review will certainly ask you), and then determine a precipitation and the maximum amount of water, and then in accordance with the specification to check a runoff coefficient multiplied by the calculation of your rainfall should take how much accounting. But in principle, even if the smallest should not be less than 500mm, otherwise the rural unorganized garbage a rain down will be blocked you heartbreak.
You are still asking about the length of the network, the length of this thing can not tell you, you can only measure yourself against the drawings, if the sewage can be lifted to the main network of the most trouble-free, but I understand the information is that the area near the town of rural areas are basically done almost the rest are remote.
Lastly remind you, don't do the same with the city of rural sewage, or you're in big trouble, rural characteristics are very prominent, the water quality of the water pipeline design concepts are completely different from the city, if you copy the norms, then wait to lose, of course, if you run into the real rural network sewage class of this area of the experts, will not agree to copy the norms. Rural "norms" is completely blank, because the personality of the rural areas are too distinct, the village is different from the village can not come up with a specification. I can only give you some experience here, so that you can think about it after their own investigation and decision-making.