Views:4 Author:Site Editor Publish Time: 2018-10-30 Origin:Site
The harm of livestock and poultry breeding wastewater to the environment
With the development of society, livestock and poultry breeding technology has become more and more extensive and professional. Compared with the traditional scattered farming, large-scale farming can greatly improve production efficiency and feed conversion rate, reduce production cost and increase economic benefits. However, large-scale farming of livestock and poultry also causes excessive concentration of fecal and urine and large increase of irrigation water, which brings great pressure to the ecological environment.
Characteristics of wastewater
The aquaculture wastewater has typical "three high" characteristics------high CODcr, high ammonia nitrogen and high SS. Taking pig farm as an example, the investigation of wastewater quantity and quality of three kinds for dung cleaning processes is shown in Table 1 as below.
The harm to water bodies
Aquaculture wastewater is a kind of high concentration organic wastewater containing a large number of pathogens. When a large number of organic substances enter the water body, the decomposition of organic substances will consume a large amount of dissolved oxygen in the water, making the water odor and resulting in a large number of deaths of aquatic organisms, while nitrogen and phosphorus can make the water eutrophication.
The harm to atmospheric environment
Under anaerobic conditions, livestock and poultry breeding wastewater will produce a large number of NH3, H2S and other odorous gases. These odorous gases will affect and endanger the health of feeders and the surrounding residents.
The harm to farmland and crops
Livestock and poultry breeding wastewater contains much more nitrogen, phosphorus, potassium and other nutrients. If it is used directly, continuously, excessively without any treatment, it will cause adverse effects on the growth of soil and crops, such as crop yield reduction, delayed maturity and affecting the production of follow-up crops.
No matter what comprehensive measures are adopted to treat livestock and poultry farms wastewater, solid-liquid separation must be carried out firstly. At present, many countries have mature solid-liquid separation technology and corresponding equipment, the main types of equipment are screw sludge dewatering machine, horizontal centrifuge, filter press and so on.
BOEEP has optimized the design of screw sludge dewatering machine. Besides, through the selection of flocculants, the machine is fully suitable for the solid-liquid separation of livestock and poultry breeding biogas residue. The application in many cases of sludge dewatering treatment of livestock and poultry breeding wastewater shows that the separation effect of the screw sludge dewatering is very ideal, and has been unanimously recognized by the users, and is highly praised.
Livestock and poultry breeding industry as a key pollution prevention and control industry in many countries, whether the treatment of wastewater is up to the standard has attracted more and more attention. Livestock and poultry breeding wastewater has a typical "three high" characteristics, high CODcr, high ammonia nitrogen and high SS. At present, a single treatment method can not meet the requirements of wastewater discharging standard. Therefore, it is necessary to adopt the combined treatment method according to the different types of aquaculture, different ways of excrement removal along with the water quantity and quality. On the other hand, we must consider the investment, daily operation cost and operation convenience of this treatment method.
In order to do a good job in pollution prevention and control of livestock and poultry breeding, reduce the discharge of wastewater and the input of chemical substances to the environment, so as to minimize the pollution, we should not only realize the harmlessness of the treatment process, but also realize the recycling of the treatment process. In this situation, we can effectively protect and improve the rural ecological environment, and promote the sustainable and coordinated development of livestock and poultry breeding environment and economy.