Questions about the separation of rainwater and sewage
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Our factory is an old coal chemical enterprise with a history of over 50 years. The plant’s sewage and water circulation systems are quite complex; after several years of restructuring and improvement, separation of clean water from wastewater as well as internal separation of sewage streams has been partially achieved. The environmental protection measures in place now basically meet the requirements set by the higher-level environmental authorities. However, the local environmental protection agency has required us this year to separate rainwater from wastewater in order to ensure compliant discharge during heavy rainfall seasons. The staff in our department find it difficult to meet this requirement. While separating and upgrading the pipeline systems is relatively straightforward and only requires investment in labor and resources, there are two challenges that seem insurmountable: 1. How to collect water that leaks or drips; if it isn’t collected and ends up in open channels, it will surely mix with rainwater. 2. How to recycle water used for cleaning floors. Our old-style coal chemical plants have a lot of dust on the floors, so the wastewater from floor cleaning must be sent to thermal horizontal flow tanks for sedimentation before the coal ash can be recovered and reused in boilers. I think it’s difficult to achieve true separation of rainwater and wastewater unless we build a very large enclosure to cover the entire factory. Sigh. . . . . . Therefore, I have come to consult the experts at HaiChuan for any good suggestions you might have; I earnestly hope you will share your insights with me.
It’s definitely difficult to change the situation at the moment: (the company required the two to be separated from the start of the design process)； Valve switching is installed on all the drainage pipelines in our company’s various areas ； (The switch between rainwater and sewage can be made at will; in principle, the water used for cleaning floors within the company is treated as sewage. A control valve can be installed between the main rainwater outlet and the sewage outlet to enable switching between the two.) ；
For the first issue of leaks, can it be resolved by using materials for on-site repair? Can’t that solve it? I don’t know how to separate the second issue either; I’m not very clear about the actual situation
It’s a very good topic; we are also working on similar things, but it’s not as challenging as what you’re dealing with.
Separation of rainwater and wastewater is essential; new factories must accomplish this during the three simultaneities phase, otherwise they cannot pass the inspection. In our area, it is not allowed to discharge rainwater when it is not raining; rainwater inlets are equipped with online COD monitoring systems and cameras. It is recommended to complete the separation of rainwater and sewage as soon as possible; otherwise, strict regulations will affect the company’s production.
This post was last edited by liu7710 on 2016-3-1 14:21. What does it mean by \"It is not allowed to discharge rainwater when it is not raining\"? Isn’t the rainwater collected in the rainwater pond the rainwater from 15 minutes later? Can’t it be discharged? What parameters are monitored by the surveillance system installed at the rainwater inlets? Does it need to be the same as the surveillance for our main sewage outlet?
Does the original poster’s wastewater treatment system have two circuits? If so, install separate valves and use sequential switching to control initial rainwater and initial flushing water. It’s difficult if it’s a single system
May I ask what you mean by the two sewage treatment systems? Our current wastewater treatment system works as follows: it features a closed-loop system for circulating clean water (which is actually wastewater as well, but with relatively low turbidity and suspended solids). This water is not treated nor discharged; it is replenished with river water, and any excess flows over into another wastewater treatment system ； Another wastewater treatment system is fed both by river water and by overflow water from the previous system; it also operates in a closed-loop manner, with a biological treatment unit at its end to treat the wastewater in fixed quantities before discharge.
I would also like to ask, which indicators need to be monitored for compliant rainwater discharge?
The chemical plant operates continuously 24 hours a day