Responding to the water reuse policy advocated by Chinese National Development and Reform Commission, SafBon has actively promoted its automated lime dosing technology. There are many tough problems in conventional lime dosing processes:
Lime powder flying;
Bad waste discharging condition;
Arching and bridging;
Bad transportation condition;
Difficulty in metering.
SafBon automated lime dosing technology, including automated powdered lime storage, metering and preparation system, solves all the problems mentioned above.
As a result, this conventional technology became a leading one. This evolved and developed lime treatment technology by SafBon is a reflection of the Chinese sustainable development strategy, in which waste is minimized and neither contaminates the environment. The lime material can be available easily and economically locally. Considering the lower cost and excellent treatment results, the technology outperforms other chemical methods.
Powdered Chemical Feeding System
has been leading the China chemical industry, is an editor of
“Automated dosing set with regards to hydrated lime milk preparation”
part in China chemical industry standards. The system combines the bin
activator, volumetric feeder screw and cylindrical silo, which is
extensively used in the applications such as reclaimed water lime
treatment, the municipal industry, the chemical industry, the food
industry, the medicine industry, the coal to oil conversion industry,
the metallurgy industry and the power industry.
Volumetric Feeder Screw
has delivered more than 30 systems of reclaimed water treatment, using
the automated lime dosing system for power plants, as well as more than
10 reclaimed water treatments EPC (Engineering-Procurement-Construction)
projects. In addition, SafBon continues to provide wastewater
desulfurized treatment systems for engineering companies.
Membrane bio-reactor (MBR) is a technology which combines biological aeration and membrane separation. Through biochemical process, nitrification bacteria can convert the nitrogen into nitrite and nitrate and thus remove the ammonia nitrogen.
The hollow fiber membrane module immersed into the reactor, usually adopts ultrafiltration (UF) membrane with pore size of 40 nm, which will mainly hold suspended solid and organic matter. Thus, the concentration of microorganisms in the reactor can be kept high and MBR can further treat secondary effluent of municipal sewage.
Membrane Bio-Reactor Process Princile
SafBon adopts the advanced immersed outside-in MBR technology, which has the following advantages:
Removal of ammonia and refractory organic matter (ammonia removal rate approx. 92%; COD and BOD5 removal rate >67%; effluent turbidity <0.5 NTU);
Retaining rate of bacteria is as high as 99.999%;
High recycle rate (recycle rate can reach 99% or higher);
Small footprint is required, unlimited by the setting occasion;
Easy operation and management; High level of automatic control;
Good and stable effluent quality;
Less excess sludge production;
It is easy to transform from the traditional process, and it can be used as the deep treatment for the traditional process.
The SafBon MBR technology has wide application prospects in the city’s secondary sewage treatment plants and the other areas.
Track Record & Achievements
a unique and innovative scheme, SafBon utilizes the municipal sewage as
the source of water in the Guodian Shanxi Datong second power plant,
specifically in its 2×600 MW super critical unit third phase engineering
phase, using the SafBon MBR + two-stage RO (reverse osmosis) system +
EDI (electrode ionization) membrane technology. It is the first
successful commercial scale application of this technology (16,800m3/d)
in large power plant in China since 2009, satisfying all the clients
Generally, the flue gas desulfurization (FGD) wastewater refers to the discharged water from the gypsum dewatering system and cleaning system, and the overflow water of wastewater cyclone. The wastewater quality is influenced by various factors in the power generation process. For instance, the purity of coal used, the operating conditions of the power plant, the quality of desulfurization process, and the purity of limestone. The FGD wastewater characterized as high turbidity, high hardness and high COD coupled with large variations in water quality and quantity. Thus, the FGD wastewater treatment is quite complicated but nonetheless important.
Typical Processes of FGD Wastewater Treatment
In order to overcome the FGD treatment dilemma, which mainly caused by the FGD wastewater complex features, SafBon cooperated with institute of power plant chemistry at Wuhan University established an associated lab focusing on the development of FGD wastewater zero discharge technology development for industry. The cooperation resulted in the development of an innovative system which integrates and consists of a new technology developing phase, a pilot-scale testing phase, a pilot exercise phase and a talent cultivating phase. Not only can this new lab facilitate the research and development of strategic frontier technologies, it can also contribute to the testing and development of feasible technical solutions for the clients in wastewater management.
FGD Wastewater Treatment
As shown in the flow diagram (Fig. Typical processes of FGD wastewater treatment), there are generally three steps in an FGD wastewater treatment process: pre-treatment, evaporation and crystallization. There are a number of treatment approach options that SafBon provides, such as physicochemical methods, electrochemical methods, biological methods and spray drying methods.
In order to respond the low environmental impact requirements, the FGD wastewater treatment process has been improved. When a certain degree of pre-concentration is achieved, the wastewater is evaporated and crystallized in the forced circulation system. With additional reverse osmosis, evaporation and crystallization processes, the FGD wastewater treatment by SafBon is able to achieve the zero liquid discharge (ZLD) requirement.
Zero liquid discharge (ZLD) refers to a process which minimizes the pollutant emission and discharge until no liquid is released back into the environment. It follows the concepts of cleaner production, 3Rs (reduction, reuse and recycling) and eco-industry to maximum the use of natural resources without discharging any waste to environment. The promotion of ZLD process is not only beneficial to the ecosystem, but also good for industries and the government.
Multi Effect Distillation (MED) for evaporation Crystallizer
For different types of industrial wastewaters, the appropriate technologies will be employed to achieve ZLD requirements. In general, there are membrane separation, thermal evaporation and crystallization process.
Some sample ZLD processes are shown below:
Multi-effect evaporation and crystallization
The condensate is recycled to the circulating cooling water system, and the crystallized salt is dried as industrial raw material;
Reverse osmosis - evaporation crystallization
Recycling clean water by reverse osmosis desalination , and the concentrated wastewater is crystallized in evaporation crystallizer;
Reverse osmosis - forward osmosis - evaporation crystallization
Flue gas desulfurization (FGD) wastewater is concentrated by reverse osmosis and forward osmosis methods, and the condensate and salt are respectively collected by evaporation crystallization treatment.
With SafBon ZLD processes that best suits our customers’ needs, most of the water can be recycled as cooling water, boiler make-up water and for other industrial uses. The solid salts can be landfilled or used as the raw material in chemical industry.
Typical Processes of Mechanical Vapor Compression (MVR) Evaporation Crystallization
In the oily water treatment process, oil-water separators and floating oil collectors are the most commonly used equipment. SafBon oil-water separator design adheres to guidelines mentioned below:
The separator inlet water-distribution installation should allow the water flow to stay in the laminar flow state (Renold’s number < 500). Under this condition, the oil droplets can steadily float upwards.
The inlet and outlet water-distribution installations should distribute the water evenly. When water flow through the aggregating filter, its surface area should be fully used to prevent short flow from occurring.
According to the American API-421 standard, the designed water flow horizontal velocity should either be below 55 m/h, or lower than 15 times the velocity of an oil droplet rising velocity (the smallest is chosen).
Cross-Fluid Corrugated Plate
Additionally, in order to meet the requirements from different customers, SafBon provides dissolved air floatation (DAF) technology, biological purification and ultrafiltration membrane (UF) technology, for further or enhanced treatment.
The Structure Diagram of Oil-Water Separator
SafBon oil-water separators have been widely applied in various industries throughout China like Hunan Valin LY steel (1500 t/h) project, Wuhan Wisco (1260 t/h) project and Gujiao power plant (500 t/h x 2) project. The total processing capacity in China s up to 50,000 t/h.