Not the same process. Both are not suitable for treating rural water, but if you want to compare, CASS process is more in line with the operational requirements of rural sewage treatment.
1, CASS (Cyclic Activated Sludge System) process
CASS process is in the sequential batch activated sludge method (SBR) based on the length of the reaction tank will be divided into two parts of the pre-reaction area and the main reaction area, and in the rear of the main reaction area installed in the lifting decanting device, to achieve the continuous water intake intermittent drainage cycle cycle operation, the collection of aeration and drainage. Drainage cycle cycle operation, aeration and sedimentation, drainage in one of the sewage wastewater treatment process.
CASS process operation process includes water filling - aeration, sedimentation, decanting, idle four stages, is an anaerobic / anoxic / aerobic alternating process, with a certain effect of nitrogen and phosphorus removal, the wastewater to push the flow of the way to run, while the reaction area is completely mixed form of operation in order to achieve synchronized nitrification and denitrification and biological phosphorus removal.
It has the advantages of simple process flow, small footprint, low investment, large driving force of biochemical reaction, good sedimentation effect, flexible operation, strong shock resistance, not easy to sludge expansion, wide range of application, suitable for phased construction, small amount of residual sludge, stable nature, and so on.
2, CAST (Cyclic Activated Sludge Technology) process
CAST process is a kind of SBR process on the basis of increasing the selector and sludge reflux facilities, and some adjustments to the timing, thus greatly improving the reliability of the SBR process and the efficiency of the domestic sewage treatment process.
The SBR treatment tank is divided into three parts: biological selector, aerobic area and main aeration area, and the operation stage can be divided into four stages: inlet mixing or aeration stage, aeration stage, static sedimentation stage and exhaust (idle) stage, which can be operated intermittently and cyclically.
CAST process compared to the CASS process, based on the SBR process to make further improvements. Water intake from the precipitation stage can be into the precipitation stage can not be into the water, in the selection area and the main aeration area between the addition of partially oxygenated area, the system is more complex, but improves the CASS process of nitrogen and phosphorus removal efficiency.
Rural sewage treatment needs sewage treatment process has the advantages of low cost, small scale and better treatment effect. Therefore, the CASS process is relatively more in line with the operational requirements of rural sewage treatment, and CAST process because of the complexity of the system, although the treatment effect is better, but not as good as the CASS process for rural sewage treatment.
Nevertheless, the existing sewage treatment methods are not suitable for rural sewage treatment, really suitable for rural sewage treatment process has to be studied and developed.
Expanded Information
Several methods suitable for treating rural domestic sewage
1, artificial wetland treatment
Artificial wetland treatment system in general, that is, the domestic sewage will be controlled allocation of the soil is often in a saturated state, the growth of swampy plant land, the use of plant root system and microbial absorption, and through the use of plant roots. The plant root system is used to absorb and microorganisms, and through multi-layer filtration, to achieve the purpose of degradation of pollution and purification of water quality.
The domestic sewage wetland treatment system is divided into natural and artificial wetland treatment system, the natural wetland is the natural swamp, artificial wetland sewage treatment technology is a new technology based on natural ecological principles, so that the sewage treatment to achieve engineering, practical. It is a composite process that combines natural and artificial treatment of sewage purification.
2, underground soil filtration purification
Soil filtration treatment system is an artificially strengthened sewage ecological engineering treatment technology, which makes full use of the soil below the surface of the soil inhabited by soil animals, soil microorganisms, plant roots, and the soil has the physical and chemical characteristics of the sewage purification, belonging to the small-scale sewage land treatment system. Suitable for small-scale sewage treatment projects in villages and towns.
3, aerobic biological treatment
Aerobic biological treatment system is a new rural sewage treatment more commonly used in a treatment technology. The method is through the fan and other equipment to sewage oxygen, cultivate biological strains and microorganisms, the use of strains and microorganisms in the sewage most of the organic decomposition of non-polluting substances, so that sewage can be purified and discharged. Sewage treatment works, aerobic biological treatment method has two categories of activated sludge method and biofilm method.
Biological treatment method and natural treatment system comparison, covers an area of small, resistant to climate and other external influences of the ability to build a large range of choice of locations, processing stability, high processing efficiency, but the infrastructure investment, operating costs and other relatively high.
4, anaerobic biological treatment
China's domestic sewage from the 1980s began to carry out the development of anaerobic biological method of development and research work, many forms of non-powered or micro-powered low-energy integrated wastewater treatment device has been applied. Micro-power buried domestic sewage treatment device using anaerobic biofilm technology, such technology is generally lower energy consumption, in the decentralized sewage treatment projects have significant advantages.
Baidu Encyclopedia-CASS Process
Baidu Encyclopedia-CAST Process