The use of diatomaceous earth modified and applied to sewage treatment, as early as the early 80's at home and abroad are reported. This is a unit of technology, only under certain conditions conditional removal of pollutants in sewage. Therefore, this unit technology has certain advantages compared with other flocculation and adsorption technologies of the same kind. Therefore, in recent years, there are a lot of environmental protection companies and local governments expect to use diatom fine soil water treatment technology can be a one-time urban sewage treatment standards, and directly get the purpose of reuse. As a result, the goal has not been realized.
For example, the daily treatment of 10,000 tons in Inner Mongolia was implemented in 2001: when the concentration of water quality was low, the BOD and COD reached the standard, and the ammonia nitrogen and total phosphorus did not reach the standard.
Implemented in 2002, Qingyuan daily treatment of 10,000 tons: ammonia nitrogen, total phosphorus does not meet the standard.
Implemented in 2003, Haimen daily treatment of 10,000 tons: water quality concentration COD in 200mg / L can reach a standard, its ammonia nitrogen has reached the standard.
The above projects show that: only a single diatomaceous earth conventional technology is very difficult to make urban wastewater treatment to meet the full discharge standards, especially diatomaceous earth does not have the function of denitrogenation. Even with the combination of biochemical processes also speak of its scientific, rationality.
Comparison of several diatomaceous earth water treatment technology and biochemical technology composite process
(a) diatomaceous earth water treatment technology + contact oxidation technology
1, COD, BOD removal is more ideal; 2, ammonia nitrogen, total nitrogen removal is not ideal; 3, the investment is not provincial; 4, the amount of sludge is larger;
(b) diatomaceous earth water treatment technology + BAF technology. BAF technology
1, COD, BOD removal is ideal; 2, to remove ammonia nitrogen effect is more ideal, the total nitrogen removal effect is poor; 3, the investment is high; 4, the sludge is larger;
(c) diatom water treatment technology + other perfect biochemical technology, even if the effluent quality of the water can be more ideal but the investment cost is high, and can not reflect the investment advantage.
(d) if the biochemical technology in front of the diatom water treatment technology in the back of the depth of treatment, can play their respective advantages at the same time, and complementary advantages. The result is not only COD, BOD, N, P, SS water quality indicators are stable up to A standard (this water can meet the requirements of reuse) and investment, low operating costs, occupies an area of less. That is, it can truly reflect the characteristics of "high efficiency and low consumption". In recent years, Nanjing Jiaqing has successfully implemented six urban sewage treatment projects, fully proving the correctness of this view.