"Bacteria Eating Sludge" Becomes A Decontamination Weapon For Shaoxing Printing And Dyeing Enterprises

At present, biochemical treatment of sewage is regarded as the most effective way to reduce sludge production. Examples and data show that this way brings much less sludge than physicochemical treatment. The environmental protection department also believes that the standard of printing and dyeing enterprises should meet the new standard 200mg/L stipulated by the state, and biochemical technology must be used to treat sewage.

However, the reality is that there are still 30% of the city. Printing and dyeing enterprise No biochemical technology was used to treat sewage. Behind this reality, what kind of confusion is it that makes these enterprises hesitate?

　 The two emission reduction example: "bacteria eat sludge" sludge output has dropped significantly.

What is biochemical treatment? For this reason, Yang Ying, deputy director of Jinghu Environmental Protection Bureau, has made a popular explanation to reporters. The so-called biochemical treatment is biological chemical treatment, the core content is to let bacteria "eat" sludge.

Reporters noted that since 2009, many printing and dyeing enterprises in Shaoxing have exposed many classic examples of using biochemical methods to treat sewage to reduce sludge production.

In the case of repeated attempts to treat sewage in other ways, Shengzhou YOUNGOR, 2008 Yarn dyed weaving technology Limited company introduced the Bacillus subtilis intervention pollution control link from Taiwan. The sewage treatment process is that all the sewage enters the neutralization tank, and the system automatically neutralizes the sewage according to the pH value of the Bacillus subtilis. Under the supporting conditions such as blowing oxygen, Bacillus subtilis repeatedly decomposes sewage.

According to Liu Xuefeng, head of the equipment department of Shengzhou YOUNGOR yarn dyeing technology Co., Ltd., the daily sewage generated by the company is about 3500 tons. After using the Bacillus subtilis to treat the sewage, the output of the sludge is almost zero, and the COD index also falls below 250mg/L. From the cost point of view, the initial purchase of about 500 kg of Bacillus subtilis and PU membrane (Bacillus natto growth) cost more than 20 yuan, and after running for a year and a half, "YOUNGOR yarn dyed fabric" almost no big input.

Here, Bacillus subtilis introduced from YOUNGOR yarn dyed fabric is fermented from soybean raw materials, and can be used as feed accelerant, soil amendment, bio organic fertilizer and so on. At the same time, it can be applied to sewage treatment industry because of its fast propagation and strong adaptability to environment. This is a typical biochemical treatment technology.

Jin Xianghui of Shaoxing County Spin The technology adopted by printing and dyeing company is similar to the technology adopted by YOUNGOR yarn dyed fabric.

The way of "Jin Xiang Hui" is to put a lot of fungi in the sewage pond. The bacteria quickly eat the chemicals in the sewage under the action of oxygen. The concentration of COD (chemical oxygen demand) of the sewage is greatly reduced, and it can basically drop to 10mg/L. According to the person in charge of the company, the amount of sewage produced by the enterprise is 10 thousand tons per day. According to the traditional way of processing, they produce fifty or sixty tons of sludge a day, and now only two or three tons, with a difference of more than 20 times.

Comparison between the two methods: several times to dozens of times.

In the end, in terms of reducing the production of printing and dyeing sludge, how much is the biochemical way of "eating bacteria to eat sludge" than traditional physical and chemical methods? Different people have different opinions.

According to the person in charge of the environmental protection technology company of Shaoxing, which is responsible for the "Jin Xiang Hui" sewage treatment, the amount of sludge produced by the traditional way is 6%, while the amount produced by biotechnology is only 0.2%.

According to the person in charge of dyeing and printing enterprises who did not want to disclose their names, even the same biochemical treatment method, the amount of printing and dyeing sludge produced by different printing and dyeing wastewater is also very different.

The person in charge said that according to the data he possessed, Printing and dyeing wastewater The amount of sludge treated by physicochemical treatment can reach up to 3%, and about 1% of sludge can be produced by biochemical and physicochemical treatment. If combined with two methods, 1000 tons of dyeing and finishing wastewater will produce 10 tons of wet sludge and 1.5 cubic meters of dry sludge after dewatering. Taking a daily processing plant of 10 thousand tons of dyeing and finishing wastewater as an example, there are about 15 cubic meters of dry sludge produced every day.

How effective is it to treat sludge with biochemical technology? Zhao Sihai, director of the Environmental Protection Bureau of the Pearl River, made a comparison with reporters.

"Generally speaking, the amount of sludge produced by physicochemical treatment of sewage is about 3% to 7%. If the sewage is treated in a biochemical way, the amount of sludge generated will be below 3%." Zhao Sihai said that no matter how it was used, the amount of sludge produced by biochemical treatment of sewage would be much less than that of sewage treated by physicochemical treatment.

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Two kinds of cost annoyance: tens of millions of expenses, enterprises say great pressure.

Since there is such a good effect, why do 30% of the printing and dyeing enterprises do not use biochemical methods to treat sludge? What makes them reluctant to use it?

Reporters learned in many interviews that the primary factor restricting the wider use of biochemical methods for sewage treatment is the cost. This cost is not only the cost of capital, but also the cost of time.

In terms of the cost of capital, the cost of equipment such as tens of millions of dollars and acquisition of bacteria often make enterprises overburdened. Take "Jin Xiang Hui" and "YOUNGOR yarn dyed fabric" as an example. "Jin Xiang Hui" spent about 20000000 yuan on purchasing this set of processing equipment, and the strain introduced from YOUNGOR in Taiwan is now about 300 thousand yuan per ton, and when the strain is used up, the strain will need to be bought and the processing cost will not be low.

Zhao Sihai, director of the Environmental Protection Bureau of the ROC River, told reporters that in general, the investment of sewage disposal equipment by biochemical method can be calculated by 1000 yuan per ton of daily sewage treatment. Based on this data, if a printing and dyeing enterprise produces tens of thousands of tons of sewage, then the cost of the biochemical technology and equipment will be more than ten million yuan. Obviously, many printing and dyeing enterprises have reached the sewage discharge volume in reality.

Chen Guohe, a postdoctoral fellow in Environmental Science at Xiamen University and a teacher from the Shaoxing University School of health, told reporters that it is for this reason that some small businesses that produce little sludge are reluctant to use biochemical methods to treat sewage. Printing and dyeing sludge The total amount can not be effectively reduced.

Bacteria need time to eat sludge?

The other cost is time cost.

Chen Guohe, who has been studying the printing and dyeing sludge, said Printing and dyeing enterprise They all have their own sewage treatment ponds, which usually store the sewage discharged every day. But biochemical treatment of sewage, bacteria often take at least 48 hours or even 72 hours. "That is to say, bacteria often eat sludge for two or three days, and the effluent of printing and dyeing enterprises is discharged every day. For ordinary enterprises, the sewage pool can not be expanded on a large scale."

"The most important thing is that many of the strains introduced in biochemical technology should also be adapted to experiments, that is to say, the environment is not suitable for using this bacterium. Chen Guohe said that enterprises are highly efficient and can not afford to wait for this time. "Enterprises generally only use mature technology to do experiments on immature things, they think this is a laboratory matter."

In fact, the effect of biochemical technology is not perfect.

Chen Guohe told reporters that bacteria and microbes have their own lifespan, usually about three days. After the death of these bacteria and microbes, organic sludge will also be produced. "That is to say, biochemical methods can only reduce and not completely avoid sludge generation." In addition, bacteria and microorganisms can only eat organic sludge instead of heavy metals in sludge. According to Yang Jian, director of the municipal solid waste management center of the Environmental Protection Bureau, there are also exhaust gas generation in the process of biochemical treatment, which affects the treatment effect.

It is precisely because of these factors. Many enterprises still use the combination of physicochemical and biochemical methods to treat printing and dyeing wastewater.

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　 Two proposals for pollution control: are technical innovations and appropriate subsidies feasible?

How to reduce the printing and dyeing sludge from the root causes? Chen Guohe believes that in addition to comprehensively promoting the biochemical treatment of printing and dyeing wastewater in printing and dyeing enterprises, the most important thing is to increase the capacity of biochemical methods to reduce sludge and reduce the cost of biochemical treatment of sewage, which requires technological innovation.

"As an enterprise, its biggest goal is to maximize profits. Enterprises are not interested in technological innovation until it is too late. Chen Guohe believes that in addition to encouraging technological innovation in all aspects, government departments should also subsidize enterprises that actively deal with sewage and reduce pollution and sludge.

Reporters learned from the environmental protection department, for printing and dyeing wastewater treatment, the city has not yet issued a corresponding policy to subsidize enterprises. And the Xiaoshan District of Hangzhou, which is adjacent to us, seems to have this policy.

Some people think that Xiaoshan District Printing and dyeing enterprise There are many, but there is no large-scale printing and dyeing sludge to steal down phenomenon, the reason is that the local government has a "bonus substitute" environmental subsidy special fund for printing and dyeing sludge disposal, and the number of various types of sewage treatment companies is also more.

However, environmentalists believe that subsidies can not be the reason for enterprises to steal and Print sewage sludge. "If enterprises want to make money, they should also assume corresponding social responsibilities and take the initiative to reduce the occurrence of pollutants."