The basic principle of biomass gasification power generation technology is to convert biomass into combustible gas, and then use the combustible gas to push gas power generation equipment to generate electricity. It can solve the shortcomings of biomass that is difficult to burn and distributed, and can fully take advantage of the compactness and low pollution of gas power technology equipment, so it is one of the most effective and cleanest utilization methods of biomass energy.

The gasification power generation process includes three aspects. One is the gasification of biomass, which converts solid biomass into gaseous fuel. The other is gas purification. The gasified gas has certain impurities, including ash, coke and tar. The impurities need to be removed through a purification system to ensure the normal operation of gas power generation equipment. Third, gas power generation uses gas turbines or gas internal combustion engines for power generation. Some processes can increase waste heat boilers and steam turbines in order to improve power generation efficiency.

Biomass gasification power generation technology is a unique way to use biomass energy that is different from other renewable energy sources. It has three characteristics: First, the technology has sufficient flexibility. Because biomass gasification power generation can use internal combustion engines, it can also Gas turbines are used, and even combined with waste heat boilers and steam power generation systems, so biomass gasification power generation can choose appropriate power generation equipment according to the size of the scale to ensure reasonable power generation efficiency at any scale. The flexible performance of this technology satisfies the characteristics of the decentralized utilization of biomass. Second, it has good cleanliness. Biomass itself is a renewable energy source, which can effectively reduce the emission of harmful gases such as CO2 and SO2. The temperature of the gasification process is generally low (about 700-900 ° C), and the amount of NOx generated is very small, so it can effectively control the NOx emissions; the third is economics, and the flexibility of biomass gasification power generation technology can ensure the The technology is effective and economical at a small scale. At the same time, the gas power generation process is simple and the equipment is compact. It also makes biomass gasification power generation technology smaller than other renewable energy power generation technologies. Therefore, in general, biomass gasification power generation Technology is the most economical power generation technology of all renewable energy technologies, and the comprehensive power generation cost is close to the power generation level of small conventional energy sources.

Floor sludge is an oily solid waste produced during the production or storage of oilfield grounds. The composition is complex, the hydrocarbon components in the oil are volatilized, the asphaltenes and colloidal heavy components increase, and it is difficult to handle. Using thermal analysis as a floor sludge treatment process has important practical significance for the floor sludge produced in oilfield development. The ground oil sludge has a very low oil content after the treatment, which can be directly incinerated or buried, and the crude oil after cleaning can be recycled directly, and the wastewater after cleaning can be recycled.

The ground sludge mainly comes from the oil-water mixture dropped on the well site during oil well workover operations, and the oily sludge at the bottom of the oil storage tank is regularly cleaned. The oil sludge at the well site usually contains impurities such as oil sludge. The oil sludge composition of the oil storage tank is mainly There are mud water and a small amount of crude oil. These sludges can be turned into waste through treatment, but if not treated in time, they will cause secondary pollution to the surrounding environment for a long time. Because its main component is organic matter, it will seriously pollute the soil and it is difficult to degrade. In rainy days, surface runoff will flow into surface water, causing river pollution. Therefore, the timely treatment of ground sludge can not only solve the pollution problem, but also turn waste into treasure, bringing certain economic benefits to the oilfield.
Due to the different types of sludge, the measures taken to treat sludge in different oil fields are also different.

1. Curing treatment
The curing treatment is to mix the floor sludge with a certain amount of chemical additives to cause physical or chemical changes to the two, and perform solid treatment on them. In this way, the harmful substances in the sludge are solidified or blocked in an inert solidified base material to make them It must be stable and harmless, and easy to transport, use or handle. The advantage of this treatment method is that it can greatly reduce the pollution of the soil by various organic substances and harmful ions contained in the ground sludge, thereby reducing the environmental impact and harm. Moreover, the equipment is simple, the processing cost is low, and a certain cost can be saved; the disadvantage is that a large amount of material needs to be added, the curing range is limited, all crude oil is lost, and there is a hidden danger of pollution.

2. Dehydration incineration
Most oil refineries in China have built sludge incineration devices. The sludge is dehydrated before incineration. First, the oily sludge is placed in the sludge concentration tank, and the temperature in the tank is increased. An appropriate amount of flocculant is added. After stirring, gravity After sedimentation, the sludge is separated into layers, and then the equipment is dewatered and dried. The resulting mud cake is sent to an incinerator for incineration. The remaining ash after incineration must be further treated. The advantage of the incineration method is that after the treated sludge is incinerated, almost all kinds of harmful substances are removed, which reduces the harm to the environment. The disadvantage is that secondary pollution is easy to occur during the incineration process, and the resources are wasted because the sludge is not fully utilized.

On January 11, 2020, the awarding ceremony of “Xin’an Zhonglian Outstanding Service Provider of the Year 2019” was held in the office of Xin’an Zhonglian Wanji Cement Co., Ltd. Xin’an Zhonglian Wanji Cement Co., Ltd. has selected four representative supporting service companies after strict selection and voting based on the service attitude, service efficiency and service quality of various suppliers and service providers in recent years, and awarded awards! This is also the first time that various service providers have been selected by Zhonglian. The aim is to improve the management level of the enterprise and the service consciousness of suppliers.

Luoyang Building Materials Architectural Design and Research Institute won the award and award from the “Excellent Service Provider” selected by the owner of Zhonglian for its thoughtful service, superb technology and good style! During the award ceremony, the deputy general manager and chief engineer of Xin’an Zhonglian Wanji Cement Co., Ltd. fully affirmed that Luoyang Building Materials Architectural Design and Research Institute has ensured the company’s normal production operation during the more than one year of production technology transformation. It has made outstanding contributions to the company’s increase in production and efficiency! At the same time, the team of our institute is encouraged to continue to serve the company well, and to escort Xin’an Zhonglian Wanji Cement Co., Ltd. with better service and more advanced technology.

Being selected as an “excellent service provider” also reflects the company’s corporate purpose of “integrity creates quality, innovation leads the future”, serving the owners and the concept of common development. Mr. Niu Huamin, deputy dean of our hospital, delivered a speech as a representative of outstanding service providers. We thank Xin’an Zhonglian for his recognition of our work. We will provide better services to enterprises with more exquisite technology and a more serious attitude.

“So outstanding because of professionalism”, our institute will always stand on the technical high ground of the cement building materials industry and lead the technological trend. With high-quality and considerate service, we have won the trust of customers!

Soil pollution refers to the phenomenon that pollutants generated by human activities enter the soil and accumulate to a certain extent, causing the quality of the soil to deteriorate and the function to decrease.

After the land is contaminated, topsoil with a high concentration of pollutants easily enters the atmosphere and water bodies under the action of wind and water. These pollutants eventually affect human health through the food chain.

Direct manifestation of soil pollution to human harm

1. Lead to reduced crop production and reduced quality of agricultural products;
2.Contaminated groundwater and surface water;
3.Affect the quality of the atmospheric environment;
4. Endanger human health.

Soil remediation process

1.Physical repair technology

(1) Soil steam extraction and repair technology

Soil steam extraction and repair technology is to introduce clean air into the contaminated soil to generate driving force, and use the concentration gradient between the solid phase, liquid phase and gas phase of the soil to convert it into a gaseous pollutant and discharge it when the air pressure decreases. process.

This technology is suitable for the remediation of soils polluted by high volatile organic compounds and some semi-volatile organic compounds, such as those contaminated by gasoline, stupid and tetrachloroethylene.

(2) Vitrification repair technology

Vitrification repair technology refers to the use of thermal energy to melt solid pollutants into glass-like or glass-ceramic-like substances at high temperatures, and to make the solidified body permanently stable by virtue of the dense crystalline structure of the glass body. After the vitrification of the pollutants, the organic pollutants will be destroyed by pyrolysis or converted into gas to escape, and the radioactive substances and heavy metals in them will be firmly bound in the molten glass. The vitrification repair technology is suitable for both in-situ processing and ex-situ processing.

(3) curing / stabilizing technology

Solidification / stabilization technology refers to the use of physical or chemical methods to fix harmful pollutants in the soil, or to convert pollutants into inactive forms of chemical substances, preventing them from migrating and spreading in the environment, thereby reducing pollution Remediation technology for the degree of substance poisoning.

This technology is usually used for the harmless treatment of soil contaminated by heavy metals and radioactive materials, but subsequent use of the site after repair may cause aging or failure of the solidified material, which affects its curing ability. Contact with water or icing / thawing process will reduce pollution Effects of objects.

(4) Electrodynamic repair technology

Electrokinetic repair technology is to apply direct current (several amperes per square meter) to the soil, under the combined action of point solution, electromigration, diffusion, electroosmosis, electric pulses, etc., to enrich the ions in the soil solution near the electrode, thereby Reach the process of removal.

The target pollutants of this technology include most inorganic pollutants, radioactive materials and organic substances with strong adsorption. The electrokinetic repair speed is fast and the cost is low. It is especially suitable for the repair of contaminated soils with a wide range of viscous metals and soluble organic matter. For insoluble organic sewage, chemical solubilization is required and secondary pollution is easy to occur.

contaminated soil treatment

(5) Thermodynamic repair technology

Thermodynamic repair technology refers to the process of removing or destroying toxic substances in the soil by using some physical and chemical effects generated by high temperature, such as volatilization, combustion, pyrolysis.

This technology is often used to treat organically contaminated soils, such as volatile organics, semi-volatile organics, pesticides, and high-boiling chlorinated compounds. It is also suitable for partially contaminated soils such as volatile metal mercury. But heat treatment technology is not applicable to most inorganic pollutants, corrosive organics, active oxidants and reducing agents.

(6) Guest soil and soil exchange technology

Guest soil refers to covering contaminated soil with non-contaminated soil to prevent pollutants in the contaminated soil from entering the food chain. However, the incoming clean soil layer needs a certain thickness, which can meet the growth of plant roots to prevent it from reaching the polluted soil layer. Soil replacement is to remove some or all of the contaminated soil and replace it with non-contaminated soil. Practice has proved that this is a practical and effective method for controlling soil pollution, especially heavy metal pollution. In general, the greater the thickness of soil replacement, the more significant the reduction of pollutant content in the crop.

2. Chemical repair technology

(1) Chemical leaching technology

Chemical leaching technology refers to the use of eluent or chemical additives to combine with pollutants in the soil, and through the desorption, chelation, dissolution or fixation of the eluent to make the pollutants adsorbed or fixed on the soil particles Desorption, dissolution and removal technology.

Chemical leaching technology can be divided into in situ leaching technology and ectopic leaching technology. In-situ leaching technology is suitable for both inorganic and organic pollutants, especially for the remediation of soil pollution with coarse texture and strong permeability; ectopic leaching technology can be used for radioactive materials, organic or mixed organics, heavy metals Or other inorganic matter contaminated soil before processing.

(2) In-situ chemical oxidation technology

In-situ chemical oxidation technology refers to the repair technology that injects chemical oxidants into the soil to oxidize the pollutants in it to degrade or convert the pollutants into low-toxicity and low-mobility products. The chemical oxidation technology does not need to excavate all the contaminated soil, but only drills in different plans of the polluted area, and then pumps the oxidant into the soil through a pump.

In situ chemical oxidation technology is often used to repair pollutants such as oils, organic solvents, polycyclic aromatic hydrocarbons, POPs, pesticides, and water-insoluble chlorides that have been in the soil for a long time and are difficult to biodegrade.

Treated soils

(3) Chemical dehalogenation technology

Chemical dehalogenation technology refers to adding reagents to the soil contaminated with halogenated organics to replace or replace halogens in pollutants or to decompose or partially volatilize and remove them. It is one of the ectopic chemical repair technologies.

This technology is suitable for treating volatile or semi-volatile organic pollutants, halogenated organic pollutants, polychlorinated biphenyls, dioxins, furans, etc. It is not suitable for semi-metallic halogenated organic pollutants and heavy metals, polycyclic aromatic hydrocarbons, herbicides, pesticides , Explosives, asbestos, cyanide, corrosive substances, non-halogenated organic pollutants, etc.

(4) Solvent extraction technology

Solvent extraction technology is a technology that uses solvents to extract or remove harmful chemicals from contaminated soil. This technology is mainly applicable to the treatment of volatile and semi-volatile organic pollutants, halogenated or non-halogenated organic pollutants, polychlorinated biphenyls, dioxins, furans, polycyclic aromatic hydrocarbons, herbicides, pesticides, explosives, etc.

(5) Soil performance improvement technology

Soil performance improvement technology refers to engineering techniques that take targeted modifiers or artificially change soil oxidation-reduction potential. Soil performance improvement technology is mainly aimed at heavy metal contaminated soil, and some measures can also be used to improve organic contaminated soil.

3.Microbial repair technology

(1) Principle of microbial remediation of heavy metal contaminated soil

There are many kinds of soil microorganisms, and they are huge in number. They are active organic colloids in the soil, which are larger than the surface, have a strong charge, and have vigorous metabolic activities. Microbes can fix, move, or transform heavy metals in the soil, change their environmental chemical behavior in the soil, and promote the detoxification or reduction of toxicity of toxic and harmful substances, thereby achieving the purpose of bioremediation.

Therefore, the principle of microbial repair of soil contaminated by heavy metals mainly includes biological enrichment (such as bioaccumulation and biosorption) and biotransformation (such as biological redox, methylation and demethylation, and the dissolution of heavy metals and organic complex coordination degradation). ) And other modes of action.

(2) Principles of microbial remediation of organic contaminated soil

Most organic pollutants in the soil can be degraded and transformed by microorganisms, reduce their toxicity or render them completely harmless. The degradation of organic pollutants by microorganisms mainly depends on two modes of action:

① degradation by extracellular enzymes secreted by microorganisms;

② After the pollutants are absorbed into the cells by microorganisms, they are degraded by intracellular enzymes.

Microorganisms degrade and transform organic pollutants in soil, usually rely on the following basic reaction modes to achieve.

Oxidation: alcohol oxidation; aldehyde oxidation; methyl oxidation; oxidative dealkylation; thioether oxidation; peroxidation; benzene ring hydroxylation; aromatic ring cleavage; heterocyclic cleavage; epoxidation, etc.

Reduction: Reduction of vinyl; reduction of ortho alcohol; hydroxylation of aromatic ring, etc.

Gene transfer: decarboxylation; dehalogenation; dehydrocarbonation, etc.

Hydrolysis: mainly includes the types of hydrolysis of esters, amines, phosphates and halogenated hydrocarbons.

4. Phytoremediation technology

Phytoremediation technology refers to an emerging pollution environmental treatment technology that uses the mechanism of absorption, volatilization, transformation, and degradation of plants and their rhizosphere microbial systems to clarify pollutants in the environment.

Tank bottom sludge is mainly derived from oily sludge produced during oil production and gathering and transportation. Among them, the oily sludge produced during oil recovery is mainly produced by trial production, discharge, fracturing, acidification, pipeline perforation, and maintenance operations. Crude oil and oily sludge. The oily sludge of the gathering and transportation system is mainly the sludge, oil sands removed from sewage tanks, oil tanks and sedimentation tanks of transfer stations and joint stations. The solid content of this type of sludge is generally between 15% and 30%. It has the characteristics of large viscosity, strong cohesion, high temperature, low utilization rate of chemicals, complex ingredients, and slow natural sedimentation.

There are several methods to clean up, transfer and treat the bottom of the tank:

1. Draining the bottom oil: The bottom oil of the oil tank is pumped with an explosion-proof oil pump. After being filtered and screened by the stainless steel filter three times, the screened oil is transferred to other oil tanks for storage. After screening, the remaining oily pollutants (such as sediment, oily water, etc.) are confirmed to have no use value by the power plant, and then pumped to the tanker truck for transportation and environmental protection. If there is too much oil sludge at the bottom of the tank, which cannot be pumped safely, it can be cleaned by manual cleaning after it has reached the conditions of manual tank entry and collected in the waste oil recovery vehicle or the recovery container.

2. Tank cleaning: According to environmental protection requirements, tank cleaning should reduce the discharge of oily sewage as much as possible. After the oil impurities in the tank are cleaned up, clean it.

3. For oil tanks with severely corroded tank walls, when the oil and gas concentration drops below 20% of the lower explosion limit, it can be flushed with high-pressure water. Metal parts such as metal pipelines and water line nozzles introduced into the tanks should be electrically connected to the oil tanks. , And should be well grounded.

4. When the oil tank is flushed with high-pressure water, the spraying speed should be controlled not to be too high. During the spraying gap, an oil and gas concentration test should be performed to avoid danger to the flushing operation when the oil and gas concentration exceeds the specified value.

5. For the rust spots in the tank, use a copper brush to further remove rust and dirt, then clean with a metal detergent such as a non-ionic surface active cleaning agent, and wipe it clean with a cotton cloth.

6.Basic requirements for oil tank cleaning: It is required to achieve no obvious rust, impurities, moisture, oil scale, and when it is wiped with a clean cloth, there should be no obvious traces of dirt, sludge and rust, and the natural color of the metal should be exposed.

7. Sewage generated from cleaning oil tanks and sludge are disposed of in accordance with the hazardous waste disposal process and returned to a unit with a hazardous waste business license for recycling.

Biomass is the organic matter contained in all living things. In a broad sense, biomass includes all plants, microorganisms, and the animals that feed on them and the waste they produce. The narrow concept of biomass refers to substances such as lignocellulosic materials such as straw and trees other than grain and fruits during agricultural and forestry production, wastes from agricultural products processing industry, agricultural and forestry waste, and poultry manure and waste during livestock production . Biomass is characterized by renewable, low pollution and widespread distribution. Biomass energy is the form of energy that solar energy stores in biomass in the form of chemical energy, that is, energy that uses biomass as a carrier. It is derived directly or indirectly from photosynthesis of green plants and can be converted into conventional solid, liquid and gaseous fuels. The characteristics of biomass energy are renewable, clean, low-carbon, alternative advantages, and abundant raw materials. Therefore, biomass energy is also called biomass clean energy.

There are four main sources of biomass clean energy:
1. Straw
Some of the fixed solar energy of crops through photosynthesis will remain in the straw and cannot be used by humans. According to statistics, the total straw yield of the nine major crops in China in 2007 was 7.04 × 108t, and the total capacity was 3.55 × 108t standard coal. The top three are corn, wheat and rice. At present, with the exception of a small amount of straw used for traditional fuels, gaskets, livestock feeding, and some for composting, most of it is burned as waste. When the straw is burned on the wood stove, the conversion efficiency is only 10% ~ 20%. Nowadays, the amount of waste straw in many areas has increased year by year, and it has accounted for more than 60% of the straw output. It is imperative to accelerate the conversion and utilization of high-quality straw.

2. Firewood
Fuelwood biomass includes forest harvesting residues, wood processing residues, clear forest afforestation pruning residues, and fuelwood forests that specifically provide fuelwood. The sources of biomass resource use in many countries are mainly forestry wastes and charcoal forests. Formulating long-term forestry planning and rational and planned deforestation and afforestation will help resolve supply-demand contradictions and ecological problems.

3. Poultry manure
Poultry manure is also an important biomass energy. It can be directly burned to supply heat energy after drying, and can also be mixed with straw as raw material for fermentation of biogas. In 2007, the actual amount of livestock and poultry manure was 1.247x109t, and the developable amount was 8.84x108t. The main sources were cattle, pigs, and chickens. The amount of manure can be converted to 1.098x108t standard coal.

4. Urban waste and industrial organic waste
Urban waste is a mixture of household waste, commercial and service waste, and a small amount of construction waste. The composition is relatively complex. Its direct combustion can generate thermal energy, or it can be made into fuel by pyrolysis treatment. The national solid waste removal and transportation volume is 1.52 × 108t (about 30% containing organic waste), and the available rate is 10%. The available resource amount is 1.6 × 107t, and the standard coal is 2.5 × x106t. Organic wastewater and municipal wastewater from the food / agricultural processing industry are important sources of organic pollutants, as well as biomass raw material resources. According to data estimates, organic waste produced and processed by Chinese agricultural products can produce 5.0x1010m3 biogas, which is equivalent to 3.5 × 107t standard coal production capacity. In 2007, the total annual discharge of industrial and urban sewage in China was 5.57 × x1010t, and the total amount of chemical oxygen demand (COD) contained was close to 2.0 × 107t, and biogas could be produced at 1.10x1010m3.

 

In China’s landscaping waste resource reuse industry is still in the early stages of development, and the total amount of landscaping waste is constantly increasing. The development and utilization of landscaping waste is of great significance for improving the urban and rural ecological environment, building a harmonious city, increasing employment, and promoting economic development. Ecological, social and economic benefits.

Landscaping waste refers to dead branches, fallen leaves, grass cuttings, flower sap, pruning of trees and shrubs, and other plant debris caused by natural littering or artificial pruning of garden plants. It is also called garden waste or green waste. With the rapid development of urban greening, the total amount of garden greening waste has also increased year by year. In some large cities, garden greening waste has been separated from urban waste, and is centrally absorbed and treated by the gardening and greening department. More methods are reused to form a new class of organic matter.

At present, most cities mainly adopt two methods to deal with urban landscaping waste, that is, most of them are transported to landfills in the suburbs, and a small part is incinerated with domestic garbage. These two methods are not in line with environmental protection requirements and waste money. Therefore, it is of great significance to seek the harmless treatment and resource utilization of garden greening waste, and to solve the problem that the garden greening cultivation substrate relies heavily on peat resources, which saves natural resources, prevents environmental pollution, and realizes a virtuous cycle of ecological economy.

Status of Landscaping Waste Treatment

Because of the many advantages of recycling landscaping waste, countries and local governments around the world have formulated corresponding laws and regulations prohibiting landfilling and incineration of landscaping waste. In addition, according to the overall situation of the country and the city, a series of effective waste collection plans have been formulated to promote the smooth implementation of garden waste resource reduction by reducing costs. Some developed countries have begun to reuse and treat green waste earlier, using modern processing technology systems and supporting equipment, with high scale and industrialization, strong publicity, and wide public awareness. In order to improve the reuse rate of garden waste, some developed countries in the world have invested a lot in technology, policies and aspects. The survey shows that the current scientific treatment mode of garden greening waste is composting, and its technology has matured abroad.

Compared with foreign countries, there are still some gaps in the reuse of garden greening waste in China, and the start is relatively late. The Ministry of Construction pointed out in the opinion on the construction of conservation-oriented urban landscaping that it encourages the development of biomass renewable fuels, organic nutrient substrates, and deep processing through the use of compost technology to treat landscaping waste such as pruning branches, reduce the landfill storage capacity, and Recycling.

Some of these economically developed cities have also launched garden waste recycling projects. Government departments have directly invested in the establishment of a certain scale of garden waste treatment centers to meet the increasing needs of urban garden waste.

Ecological treatment technology of landscaping waste

Landscaping Waste

1. Make feed

Green plants in landscaping waste, such as weeds left after lawn mowing, can be collected, transported, treated, and dried uniformly, and finally made into green hay or processed into feed. The silage is made by using a special cellar to tightly seal the prepared feed, and then fermented with lactic acid bacteria. The feed made by the silage can be stored for a long time and the nutrients are not easy to lose. It is one of the favorite tastes of animals, but as an animal word Because it contains tannins in plant leaves, animals often refuse to eat the feed, and its protein and vitamin content are low, so it has poor availability and cannot be used as a main feed for animals. To eat, only pair it with other feeds.

2. Power generation

Waste-to-energy technology refers to the use of heat generated by the burning or stacking of waste as a kinetic energy to generate electricity. The stacking and burning of landscaping waste can generate a lot of heat that can be used to generate electricity. In the future, with the continuous optimization and popularization of waste-to-energy technology, the skills of using garden green waste development will inevitably be widely used. With the increasing power consumption in China, the demand for biofuels will inevitably increase. In order to better meet this demand, the recycling and utilization of landscaping waste will definitely become more popular and eventually form A relatively complete industry chain.

3. Preparation of biogas

The gas that organic matter undergoes fermentation of various microorganisms in the absence of oxygen to form a mixture is called biogas. The formation of biogas is in an environment without oxygen and sunlight, and it requires a large amount of carbon and nitrogen. Landscaping waste contains a large amount of carbon, so it can be used as a raw material for biogas production. Can provide the necessary microorganisms for biogas production. After the anaerobic fermentation of the biogas digester, the mixed gas can be removed from the system. It is used as a biofuel to generate electricity, which is of great significance to the progress of urban garden construction and resource reuse. Biogas-fermented clinker is usually a liquid. It can be used as a fertilizer to improve sudden fertility. It belongs to a good soil improver.

4. Manufactured into boards and wood chips

The main parts of gardening waste are classified, and they can be divided separately according to the different tree species. The trimmed branches and trunks are transported to the destination, and the thick branches are directly made into boards. After a series of processing, Made into sheet. However, because the smashed particles of landscaping waste are loose, the bearing capacity of the board is relatively weak, and the pressure resistance is not strong, so the scope of its use is more obvious. The remaining branches that cannot be made into boards can be used as raw materials for papermaking.

Landscaping-waste

Ways to reuse landscaping waste

In the process of reusing landscaping waste, pay attention to the nature of the waste, and then apply their properties to practice. The effective ways are: one is organic fertilizer, the other is biomass energy or other types of organic products.

1. Become organic fertilizer

The so-called organic fertilizer is not the so-called organic fertilizer that puts fallen leaves in the soil to make it rot into fertilizer. Organic fertilizer refers to the formation of organic fertilizer only after putting the greenery waste of the garden under certain conditions and subjecting it to fermentation by microorganisms, and a series of processes that completely rot and even deodorize it. Organic fertilizer has the advantages of harmlessness, reduction, and resource conservation. It can play a significant role in soil protection of green space, conservation or cultivation of plants in garden construction, and roof greening.

2. Become an organic cover

Organic mulch is generally used to protect the surface of the soil and to improve the coverage of the ground. It uses waste green plants such as wood chips and bark. During the production process, it is crushed first, and then it is covered on the garden green space, the surface of the flower pot and other places. This advantage is that it can effectively save irrigation water, reduce the growth and spread of weeds, and reduce evaporation caused by sun exposure, so that the soil can maintain a certain temperature and increase soil aeration. Although another inorganic cover is relatively low in cost and can be stored for a long time without decay, it has poor air permeability and is generally covered with stones. Therefore, organic mulch has the advantages of effectively preventing soil erosion, improving soil fertility, and promoting the rapid growth of plants.

Landscaping Waste

3. Become biomass energy

In recent years, the demand for new energy has increased, and as an emerging clean energy biomass energy, people have paid more and more attention to it. Facing the declining storage of oil and coal, it is necessary to find solutions to global problems such as air pollution and global warming. Therefore, in view of the hundreds of millions of tons of waste left in China’s landscaping and agriculture each year, the development of biomass energy has great potential.

Concluding remarks

Through the related research on the problem of landscaping waste treatment, we can find that under the current conditions, the design of this work is multi-faceted. The relevant personnel should start from the objective reality of landscaping and make full use of the advantageous conditions to study and formulate The most practical implementation method of waste disposal.

1. Abandoned TV sets, refrigerators, air conditioners, washing machines, computers:
Commonly known as “four machines and one brain”, it belongs to solid waste, waste electrical and electronic products, not hazardous waste. Other electronic wastes, such as discarded mobile phones, iPads, domestic water heaters, microwave ovens, telephones, and other electronic products, are also not hazardous wastes. However, the lead glass, circuit board, compressor, separately collected refrigerant, waste fluorescent powder, waste motor, etc. separated from the waste “four machines and one brain” and other electronic wastes are hazardous wastes, and the waste categories are hw08, hw29, hw31 and hw49 respectively.
2. Button batteries, fluorescent tubes, waste drugs, waste thermometers, sphygmomanometers, etc. produced in daily life of residents:
It belongs to hazardous waste (included in hazardous waste management in classified management of domestic waste). However, according to the list of exemption management of hazardous wastes (2016 Edition), this kind of waste is included in the scope of exemption management at this stage because it comes from the daily life of residents, with small amount, large scope and high management cost.
3. Oily waste fabric, clothing, gloves, cotton yarn mixed with domestic garbage:
It belongs to hazardous waste. However, according to the list of exemption management of hazardous wastes (2016 version), such wastes are included in the exemption management scope because they are also from the daily life of residents. However, there is a situation that needs special explanation. If the enterprises in the mechanical processing and vehicle maintenance industries intentionally throw hazardous wastes such as fabrics, gloves, cotton yarn, etc. containing waste mineral oil into domestic garbage, it belongs to the situation of mixing hazardous wastes into non hazardous waste storage. According to Article 75 of the law of the people’s Republic of China on the prevention and control of environmental pollution by solid wastes, it can be rectified within a time limit And the implementation of administrative penalties.
4. Sludge from domestic sewage treatment plant:
It belongs to solid waste and does not belong to hazardous waste. According to HBO [2010] No. 157 document, in the process of transfer management of this kind of waste, “refer to hazardous waste management, establish sludge transfer joint sheet system.” According to the meaning of hazardous waste management, this kind of sludge does not belong to hazardous waste, but it is necessary to improve the management level, especially to strengthen the management of standing book, so as to prevent leakage and illegal dumping during transportation. However, the sludge produced in the sewage treatment process of industrial enterprises often belongs to the category of hazardous waste due to its leaching toxicity exceeding the standard, or containing other toxic and harmful substances and other hazardous characteristics (the determination method is mainly based on the enterprise environmental assessment, industry rules, source of materials, expert identification, attribute identification, etc.).
5. Fly ash from domestic waste incineration:
It belongs to hazardous waste (hw18). However, after meeting the requirements of article 6.3 of the standard for pollution control of domestic waste landfill (gb16889-2008), entering the domestic waste landfill for landfill is not included in the hazardous waste management; another situation is that if the requirements of the standard for pollution control of collaborative disposal of solid waste by cement kiln (gb30485-2013) are met after pretreatment, the collaborative disposal process is also included in the exemption pipe Rational category.
6. Scrapped cars, battery cars and new energy vehicles:
It belongs to solid waste and does not belong to hazardous waste. However, the following wastes generated in the automobile disassembly and maintenance industry are classified as hazardous wastes after being collected separately: waste battery, waste machine oil drum (kettle, filter element), waste engine oil, waste circuit board, waste exhaust gas purification catalyst (commonly known as ternary multi effect catalyst), unexploded safety airbag, oil-containing gloves (fabric, clothing, etc.), and the waste categories are hw08, hw15, hw49, hw50 respectively And so on.
7. Sludge produced in sewage treatment process of medical institutions:
Most of them are hazardous wastes. According to the regulations on the management of medical wastes (Order No. 380 of the State Council), “medical wastes refer to the wastes with direct or indirect infectivity, toxicity and other hazards produced by medical and health institutions in medical treatment, prevention, health care and other related activities.” According to the national list of hazardous wastes, “medical waste belongs to hazardous waste. The classification of medical waste shall be carried out in accordance with the catalogue of classification of medical waste. ” The “infectious waste” in the catalogue of medical waste classification (WYF [2003] No. 287) includes “other articles polluted by the patient’s blood, body fluid and excreta”. The grid slag, sedimentation sludge and septic tank sludge produced in the sewage treatment process of medical institutions should be included in this category.

If a medical institution has specially designed the wastewater treatment process during the environmental impact assessment, and has made the attribute judgment for the sludge, if the management department thinks that this kind of sludge should be included in the hazardous waste management, it should make the final judgment through the hazardous waste identification procedure.

1. Basic concept of hazardous waste
Hazardous waste is a kind of special solid waste, which has some characteristics of corrosiveness, toxicity, reactivity, flammability and radioactivity. According to the solid waste law of the people’s Republic of China, hazardous waste is a substance listed in the list of hazardous waste implemented by the state on August 1, 2016, or determined by relevant national departments to meet the relevant standards of hazardous waste.
Harm:
1) Pollution of the atmospheric environment. There may be fine particles and dust in the hazardous waste piled up for a long time, which will drift along with the wind direction and enter the atmosphere, or drift towards the more hazardous waste in the atmosphere, and chemical reactions may occur, causing secondary pollutants and endangering human health. In addition, different degrees of odor pollution may be produced in the accumulated waste.
2) Impact on soil environment. First of all, the random stacking of hazardous waste will occupy a lot of land, destroy vegetation and change the structure of soil properties. In addition, the soil is the place where the micro organism lives, and the environment around the microbial tablet constitutes a complete ecosystem. When the hazardous waste is not treated properly, the heavy metal ions contained in the waste and some of the refractory soil will cause the physiological activities of microorganisms to be affected to death, and eventually destroy the ecological purification capacity of the soil, and the soil will be polluted, with a huge cost and a long time for recovery. Ring. After the hazardous wastes are piled up in disorder, the hazardous substances in the wastes will migrate into rivers and lakes with the precipitation and wind, resulting in no survival of aquatic organisms, and return to the source, endangering human health. During unreasonable storage and filling, the leachate will permeate the soil and enter the groundwater, causing groundwater pollution.
2. Hazardous waste incineration technology
Incineration is a high-temperature treatment technology, which can reduce the volume of hazardous waste after high-temperature incineration, and reduce or remove harmful substances at the same time. The high-temperature flue gas generated by incineration is used for heating and power generation and energy recovery through waste heat boiler steam. The process of hazardous waste incineration and the structure of incinerator are mainly related to the types, properties and combustion characteristics of waste. Furnace type mainly includes grate incinerator, fluidized bed incinerator, vertical incinerator and rotary kiln. Grate incinerator is mainly used for the incineration of domestic waste. The fluidized bed incinerator is mainly used in the vertical incinerator, which is mainly used in the direct combustion of liquid and gas. Rotary kiln is mainly used for the incineration of hazardous wastes and medical wastes, and can handle solid wastes, liquid wastes and gas wastes. The raw materials of hazardous waste in this project include waste liquid, viscous waste liquid and solid waste. It is suitable to select the rotary kiln + second combustion chamber incineration process waste with wide adaptability, mature technology and stable operation for incineration. Hazardous waste incineration process includes pretreatment and feeding system, incineration system, waste heat utilization system, flue gas quench system and flue gas purification system.
3 Existing problems and treatment in the design of hazardous waste treatment
3.1 pretreatment system
Because some inflammable substances are contained in hazardous waste, in order to prevent fire, explosion and other conditions in the process of hazardous waste crushing, the crusher system is equipped with the oxygen content detection function before and after the N2 injection oxygen control system. Once the oxygen content is higher than 6%, the system will automatically close the upper and lower hydraulic gates, and start the button system to complete the functions of N2 injection, oxygen detection, discharge, etc. Reliable operation, crusher system inlet and outlet set hydraulic gate, double protection.
3.2 feed sealing and treatment
The feeding system of kiln head is easy to cause the tempering of kiln head, so it is necessary to design double hydraulic flap door to ensure the safety of operation. When feeding, when the level of the two-stage hydraulic valve does not reach the set value, the upper hydraulic valve will open automatically. After the blanking, the upper hydraulic valve will close, the lower hydraulic valve will open, and the solid waste will enter the rotary kiln through the chute. The intermediate hopper between the feed chute and the two hydraulic doors is cooled by soft water. The whole feeding process operates in sealed and cooled state to ensure safe operation.
3.3 coking problem and treatment of rotary kiln
In the past project operation, coking often occurs at the end of rotary kiln. This is because the combustion machine of the rotary kiln is installed at the kiln head, and the combustion temperature is very high. When the feed contains waste materials with low melting point salts, the ash is easy to become molten state. When these ash are close to the kiln end, the combustion temperature is relatively low, and the molten ash is easy to bond on the refractory. The length of the rotary kiln designed in this project is 11m, which is also prone to coking. This design is directly optimized. The tail of rotary kiln is inserted into the second combustion chamber, sharing a slag outlet with the second combustion chamber, and the bottom of the second combustion chamber is provided with a large opening for slag (3300x800mm), which is convenient for large particle slag to fall. At the same time, a multi-component burner is set at the bottom of the second combustion chamber to ensure that the combustion temperature of the second combustion chamber is higher than 1100 ℃, and the temperature of the rotary kiln tail is raised at the same time. According to the operation parameters, the temperature of the kiln tail can reach more than 1000 ℃, so as to ensure that the molten slag directly falls into the bottom of the water sealed slag extractor. Before the waste is put into the furnace for incineration, the waste into the furnace shall be properly matched. In addition to the calorific value compatibility mentioned above, various waste materials shall be tested. Waste containing low melting point salts must be mixed before entering the furnace. During the operation, it is necessary for the operator to ensure the stable combustion of the rotary kiln and the second combustion chamber by the incineration temperature of the second combustion chamber of the rotary kiln and the reasonable ratio of the primary air and the secondary air. At the same time, operators should regularly patrol. Once coking phenomenon is observed from the kiln end sight glass, waste with high calorific value and without low melting point salt should be replaced for incineration, the temperature of kiln end should be increased, and coking and melting should be carried out slowly as far as possible. Both sides of the second combustion chamber shall be provided with openable observation holes. At present, after the successful commissioning of the project, there is no coking event at the kiln end within half a year of operation guarantee.
3.4 boiler ash corrosion problems and treatment
Ash deposition and corrosion chamber of heating surface of waste heat boiler are common problems in hazardous waste incineration. The common layout of waste heat boiler includes horizontal waste heat boiler and vertical waste heat boiler. Horizontal waste heat boiler is rarely used in hazardous waste combustion, mainly because the horizontal waste heat boiler is easy to accumulate ash and corrosion. This project adopts single drum natural circulation vertical water tube boiler. The boiler is composed of two radiation vertical flue pipes, surrounded by membrane walls, without convection evaporation surface and gas economizer, so as to prevent ash accumulation in the boiler. The way of soot blowing is steam soot blowing, which can effectively remove the accumulated dust. In the design, the flue gas temperature entering the superheater shall not exceed 650 ℃, and the wall temperature of the superheater shall be ensured to be lower than 450 ℃, so as to avoid high temperature chlorine corrosion of the superheater. At the same time, in the long-term operation, the temperature of the second combustion chamber should be controlled below 1200 ℃, so as to avoid the superheater corrosion caused by over temperature operation and the problem of nitrogen oxide exceeding the standard caused by high-temperature combustion.
3.5 corrosion of two stage wet deacidification system
In order to increase the contact area between the flue gas and the reaction alkali and prolong the reaction time of the flue gas and the alkali, the washing tower and the adsorption tower are all equipped with the multi-faceted hollow Bauer ring packing, which is made of polypropylene and has good acid corrosion resistance and alkali corrosion resistance. The washing tower and adsorption tower are made of corrosion-resistant FRP. As the adsorption tower of the washing tower is set before the induced draft fan, in order to ensure the strength of the washing tower and the adsorption tower, the carbon steel lined FRP is selected. The quench section of the upper part of the washing tower adopts regular ceramic packing, and the quench section adopts special high temperature resistant FRP material. All circulation pipelines are made of carbon steel lined FRP to ensure the stable operation of the system.

Soil remediation refers to the use of physical, chemical, and biological methods to transfer, absorb, degrade and transform pollutants in the soil, reduce its concentration to acceptable levels, or convert toxic and harmful pollutants into harmless substances. Fundamentally speaking, the technical principles of remediation of contaminated soil can include: (1) changing the existing form of pollutants in the soil or the way of combining with the soil, reducing its mobility and bioavailability in the environment; ( 2) Reduce the concentration of harmful substances in the soil.

Soil remediation methods can be classified according to remediation methods and sites. According to the classification of repair methods, it can be roughly divided into biological, physical, and chemical methods; according to the classification of repair sites, it can be divided into two types of repair methods: in situ repair and ectopic repair.

Classification Basis Repair method Specific means Features
 

By repair method

Bioremediation By microorganisms, super enriched plants; Low cost and long cycle;
Physical repair Soil replacement and heat treatment to separate pollutants; Higher cost and more complete repair effect;
Chemical repair Adding chemical substances to passivate pollutants to form more stable substances; Low cost and long repair cycle;
 

By repair site

In situ repair Do not move contaminated soil and repair in situ; Low cost, suitable for simple pollutants and low concentrations;
Ectopic repair Remove contaminated soil for remediation; Higher cost, suitable for complex pollutants and high concentrations;

In-situ repair refers to the method of repairing in situ without moving the soil, which is suitable for simple and low-concentration pollutants. Ex-situ repair refers to the repair method of removing contaminated soil for repair. Higher concentrations. There is a difference in cost between in situ technology and ex situ technology. The cost of in-situ technology is lower than that of ex-situ technology, mainly because it does not require expensive ground facilities, transportation costs, and is relatively simple to operate.