Visiting the beautiful West Lake with ease and happiness is a very happy thing for both tourists and local citizens. But if you walk around and suddenly a cloud of mosquitoes hovers over your head, I'm afraid everyone will fly away.
Recently, such a miracle occurred near the West Lake near the Huizhou Central People's Hospital: mosquitoes were rampant, and each group had a sense of overwhelmingness, which once caused the surrounding masses and patients to seek medical treatment, and even the street passers-by did not dare to pass through when it was serious.
After learning about it, the health department of Huizhou City attached great importance to it and quickly convened relevant units and personnel to carry out drag-net disinfection of sewers and green belts inside and outside the hospital and around the hospital, and has achieved phased results.
What is the difference between a shaking mosquito and an ordinary mosquito?
I have lived in Lipu Fengqing by the West Lake for several years, of course, there are mosquitoes, but it seems that I have never encountered such a serious mosquito infestation.
Upon investigation, it turned out to be an aquatic mosquito, Diptera. Distributed worldwide, throughout the major regions. More than 5,000 species are known in the world. It is a very common and highly tolerant aquatic insect, which is widely distributed in various types of water bodies, accounting for more than half of the total number of benthic invertebrates and 70% to 80% of the biomass of aquatic benthic animals. Numerous insects of great importance in the ecological balance of freshwater waters and the cause of fish farming. Tiny to medium sized. The body is generally similar to that of mosquitoes (Mosquitoes), which are slender and fragile, but the large-shaped species are similar to mosquitoes and are more stout. The body color is diverse, white, yellow, light green, black and can have distinct color spots.
This mosquito is different from ordinary mosquitoes in that its mouthparts degenerate. That is, will not stare at people?
In the warm season, the water is rich in food, the eggs laid by female mosquitoes do not need to be fertilized, and several to dozens of eggs are laid at a time, and they directly develop into small rocking mosquitoes in the incubator of the mother, and these small "rocking mosquitoes" are usually female.
That is to say, the mosquito is completely self-propagating, and the development speed is far beyond that of ordinary mosquitoes. No wonder that some time ago, there were so many mosquitoes by the West Lake that passers-by were afraid.
We all know that killing mosquitoes is definitely a palliative rather than a cure.
The relevant departments launched an investigation and found that the root cause was originally caused by the direct discharge of sewage into the lake.
There are 6 sewage outlets in a corner of the lake
Such a serious breeding of mosquitoes was originally one of the West Lakes in nanfeng Lake, the Huangtang embankment of Nanfeng Lake, and there were 6 obvious sewage discharged directly into the lake.
There is a history of direct sewage discharge by Huangtang Lake, and many years ago I have read the investigation and design plan of the sewage pipe network in this area, and I have always thought that it has been clearly handled here.
Now found 6 of them, including 1 in front of the Manyue Garden Hotel, 10 meters on the left side of the lower lake staircase on the right side of the Huangtang Community Cultural and Sports Square, 20 meters on the left, 25 meters on the left, and 100 meters on the left side, plus 1 rainwater pipe on the lake side of the Huangtang intersection opposite the central hospital, these 6 sewage hydrants are black and smelly.
It is precisely because the eutrophication of these 6 expels is more serious and the oxygen content is low, which is particularly suitable for the growth and development of the mosquito.
According to the West Lake management department, these sewage direct discharge to the West Lake has been for a long time, not only to the West Lake water environment management has brought great trouble, and every year in the summer and autumn rainy season or when the temperature is high, a large amount of sewage is directly discharged into the West Lake, resulting in rapid deterioration of water quality in the area, serious damage to the ecosystem, a large number of water and grass deaths, and turbid water bodies.
According to the project implementers who are carrying out construction on both sides of the road, the goal of this year's implementation of the demonstration project of rainwater and sewage diversion transformation in the old residential area around the West Lake is to build a complete sewage collection system of "user-branch pipe-sub-main pipe-sewage plant" through the implementation of the rainwater and sewage diversion transformation project in The Huangtang area, reduce the direct discharge of pollutants, and thus improve the pollution situation of the West Lake. However, the current implementation of the project is located in the old city, the buildings are dense, the flow of people and traffic is large, the inner streets and alleys are narrow, and the underground pipelines are intricate, and the construction space of rain and sewage pipes is limited, which affects the normal progress of construction and is full of difficulties.
What is even more strange is that the sewage interception project should have improved the sewage discharge situation, but so far, the number of sewage outlets around the Seventh Elementary School that is directly discharged into the West Lake has increased from the original 3 to the current 6.
Why is it difficult to cure sewage directly into the lake?
The problem of direct sewage discharge around the West Lake and the interception of old residential areas has always been a big problem plaguing the management department of the West Lake, and over the years, including the main leaders of Huizhou City, the planning and planning of various departments, and the implementation of many projects for the interception of pollution in the West Lake have not been completely solved, or the efficiency of pollution interception is very low.
Since 2015, Huizhou has continued to carry out water restoration and rectification in Nanfeng Lake after successful water restoration in two lake areas, including Nannan Lake in West Lake, and also intercepted the embankment in the Huangtang area. In 2107, the restoration of the water body of Nanfeng Lake was declared successful, but in recent years, the phenomenon of sewage entering the lake has still emerged from time to time.
At present, the West Lake Scenic Area has won the honor of the national 5A scenic spot, and Huizhou has also legislated the "Huizhou West Lake Scenic Area Protection Regulations" for the West Lake, making it clear that the municipal government should establish a long-term management mechanism for the water environment protection of the Huizhou West Lake Scenic Area, and take measures such as pollution interception, drainage, dredging, ecological restoration, and barge treatment to improve the water quality of the scenic spot and improve the self-purification ability of the water ecosystem. The municipal government shall make overall plans and construction of centralized sewage treatment facilities and supporting pipe networks in the Huizhou West Lake Scenic Area, and implement rain and sewage diversion. It is forbidden to use seepage wells, seepage pits, and fissures to privately set up hidden pipes or take other methods to evade supervision to discharge water pollutants into water bodies in scenic spots. At the same time, it is clear that no new sewage outlets shall be built in the Huizhou West Lake Scenic Area. Sewage outlets that are not set up in accordance with regulations shall be ordered by the competent departments of ecology and environment to be dismantled within a time limit; the sewage outlets of those who are not responsible (claimed) shall be blocked by the management agency of scenic spots. The management agency of Huizhou West Lake Scenic Area shall establish a water quality monitoring and early warning system for Huizhou West Lake Scenic Area, conduct water quality monitoring, assess the eutrophication status of water bodies, and disclose relevant information to the public.
That is to say, if a sewage discharge lake is found, the West Lake management department can immediately take measures to completely block these outlets in accordance with the "Regulations", but in the interview, the reply of the relevant departments is full of concerns and helplessness, after all, forcibly blocking these sewage outlets will definitely cause some sewage recharge in the area, which will cause greater social contradictions.
Obviously, it is still necessary to increase efforts to improve the pipe network, and completely intercepting pollution is the top priority.
There are plans and goals, but progress is too slow
The West Lake is completely intercepted according to the reason, there is no problem, is not to build a circle of sewage pipes along the lake, after the rainwater is separated, it is directed to different pipelines, the sewage is sent to treatment, and the rainwater flows into the East River! The pipe is buried under the water by the lake, and you can bury as much pipe as you want.
On the basis of the many sewage interception projects carried out in previous years, the "Huizhou West Lake Sewage Interception Project Planning" released at the end of 2017 can be regarded as the largest scale, such as the planning requirements to be based on the principles of environmental priority, sustainable development, implementability, economic rationality and other principles, and to prepare a practical sewage interception project plan to effectively improve the water quality of the West Lake. At the same time, a planning plan was formulated for the main pollution sources, in which the Huangtang, Shangpai and Longfeng areas should be transformed into rainwater and sewage diversion. After the transformation, the sewage in the area is collected by the municipal sewage pipe and lifted by the pump station, and then discharged into the sewage pipe, and finally discharged to the Meihu sewage treatment plant after being lifted through the Meihu Phase III sewage pumping station; the rainwater in the area is discharged to the West Lake after the sedimentation pond.
In 2018, the preparation and completion of the "Detailed Planning of Huizhou West Lake Scenic Area" is very attractive: the implementation of the "Clear Water Renewal City" plan, the implementation of the lake interception, dredging and barge repair, drainage, ecological restoration and other projects.
The sewage interception project around the lake, that is, the municipal drainage pipe network around the West Lake in Huizhou, the current drainage outlet discharged into the West Lake, etc. are comprehensively and systematically investigated, and the sewage interception project plan of the West Lake is prepared in combination with the current situation, and on the basis of the existing interception system, the interception standard is improved and the amount of pollutants entering the lake is reduced.
However, there is one thing worth telling you: in the second half of 2018, Huizhou City implemented the integrated reform of supply and discharge, the Municipal Water Affairs Group was responsible for the construction and management of sewage treatment facilities in the central area of Huicheng, the sewage interception project along the Lake organized and implemented by the former Public Utilities Administration, the rainwater and sewage diversion renovation project in the Huangtang area has been handed over as a whole, and the Municipal Drainage Management Center, as the maintenance and management department of the municipal pipe network, has also been handed over to the Water Affairs Group since March this year.
That is to say, the original Garden Administration (West Lake Administration) merged with the Public Utilities Bureau and became the Municipal Garden Affairs Center, which is only responsible for management and maintenance, but does not undertake construction projects, and the drainage and sewage projects are responsible for by the water affairs group.
In 2019, the rainwater and sewage diversion transformation project and the design review of the rainwater and sewage diversion transformation of the old residential area around the West Lake were completed, and the underground pipeline survey and relocation plan preparation and bidding were organized, of which the focus was on the Huangtang area. The demonstration project of rainwater and sewage diversion transformation in Huangtang Area includes the construction of a new rainwater main with a length of about 4.64 kilometers, a sewage main with a length of about 6.34 kilometers, a building riser with a length of about 13 kilometers, a new integrated sewage lifting pumping station, and the improvement of the community environment within the construction area.
In order to speed up the completion of the shortcomings of sewage collection and treatment in the main urban area, achieve full coverage of the sewage pipe network as soon as possible, and fully collect and treat sewage, the Huizhou Municipal Housing and Urban-Rural Development Bureau has formulated the "Huizhou Urban Sewage Treatment Quality improvement and efficiency three-year action plan (2019-2021)", requiring that through three years of efforts, the city's sewage collection rate will increase from 56% in 2018 to 66%.
According to the actual situation, the recent drainage of the old city uses a combined flow system to set up a sewage interception pipe along the drainage trunk canal, intercepts the dry flow sewage and the initial rainwater, discharges it into the sewage system, and then implements the sewage and rainwater diversion discharge when the road or the old urban area is unified. Newly built and reconstructed roads and communities are all subject to a diversion system, and two sets of drainage systems for sewage and rainwater are constructed.
Judging from the current situation, the progress of the West Lake sewage interception project is too slow, the old one has not been intercepted, and the new sewage outlet is still emerging.
How to deal with the 6 sewage outlets?
The relevant departments also responded to the report on the leakage of the sewage pipe network in the Huangtang community section of the West Lake, and formulated measures for the detection of 6 sewage leakages to the West Lake:
1. The sewage in front of The Manyue Garden Hotel is discharged into the rainwater pipe mouth of the West Lake (1 place). Analysis of the main reasons: the sewage pipe near the parking lot of Manyue Garden has fallen into disrepair and some of it has leaked; there is sewage flowing out under the fountain of Manyue Garden Hotel, which is not connected to the sewage pipe and is directly discharged into the rainwater pipe.
Figure 1 The staircase of the lower lake on the right side of the Huangtang Community Cultural and Sports Square
Reply: After the construction according to the design drawings, after the original sewage pipeline flowing into the West Lake through the parking lot of the Moonflower Hotel is connected to the new sewage pipeline on the main road of Huangtang, there is no sewage inflow within the design range.
Second, some of the sewage leakage from the old sewage interception pipeline is discharged into the West Lake (3 places). Analysis of the main reasons: the rain and sewage diversion project was generated after the excavation of the lakeside greenway, and the preliminary understanding was that after the new rainwater and sewage diversion pipeline was made, the old pipeline was directly abandoned, and the old pipe network was not connected in time, resulting in the original sewage flowing out from the side of the sewage interception. However, for the unexplored section of the road, the old sewage pipe still has the problem of water seeping out, the cause of which has not yet been identified.
Figure 2 25 meters to the left of the lower lake staircase on the right side of the Huangtang Community Cultural and Sports Square
Reply: The original seventh primary school sewage pipeline is complex, after the construction unit, design unit, supervision unit, construction unit inspection, the original seventh primary school gate stall and building sewage pipes in many places directly discharged into the seventh primary school, temporarily found out of one, is negotiating to formulate a plan to solve.
Figure 3 20 meters to the left of the lower lake staircase on the right side of the Huangtang Community Cultural and Sports Square
Reply: In the case that the old sewage pipeline of the original lakeside greenway and the new sewage pipeline of the lakeside greenway are not fully connected, there is leakage in the original old sewage pipeline. When the new sewage pipe is completed, no sewage flows in Figure 3.
Figure 4 10 meters to the left of the lower lake staircase on the right side of the Huangtang Community Cultural and Sports Square
Reply: After the investigation of the design unit, the supervision unit and the construction unit, it was found that the original sewage pipe in Huangtang Market was directly discharged into the rainwater inlet and directly flowed into the West Lake. After waiting for the construction of the main road in Huangtang, the original sewage pipeline of The Huangtang Market will be connected to the new sewage pipeline of the main road of Huangtang. Figure 4 No sewage inflow.
Third, part of the sewage leakage of the sewage interception project is discharged into the West Lake (1 place). Analysis of the main reasons: the original sewage interception project is not thorough, the sealing is not good enough, and there is a problem of leakage and aging.
Figure 5 100 meters to the left of the lower lake staircase on the right side of the Huangtang Community Cultural and Sports Square
Re: The discharge port design has been modified, the rainwater is filtered by the particle separator and discharged into the new rainwater discharge outlet, and the sewage is discharged from the lifting pumping station to the downstream sewage pipe. After the completion of the construction of the Huangtang project, there will be no sewage inflow in Figure 5.
Fourth, the rainwater pipe at the intersection of Huangtang Road on Eling North Road has traces of slight water leakage (1). After on-site investigation, it has not rained recently, but there is still a problem of water leakage in the rainwater pipes, and the cause has not yet been identified.
Figure 6 Rainwater pipe at the lake at the intersection of Huangtang Road opposite the central hospital
Reply: Due to the leakage of car wash water and sewage pipes in the parking lot of the original Fenghu Hotel directly into the West Lake, the original car wash water and sewage pipes were connected to the new sewage pipe according to the design requirements.
The above measures certainly cannot completely solve the problem of direct sewage discharge in the West Lake, but pushing and moving, in the end, it still needs to wait for a comprehensive interception of pollution around the lake to be cured.