对重金属不超标的污泥，可以通过厌氧消化或者好氧堆肥进行土地园林利用，也可以进行高附加值资源提取回收。 资料图片

预计到2020年，我国的污泥产量将达到6000万吨~9000万吨

国外传统的技术工艺还需要进一步研究和提升，才能适合我国的污泥处理处置

总体道路应是污泥和城市有机质废弃物协同厌氧消化，实现规模化生物质燃气回收，生产高品质绿化营养土

下一代污水处理模式应该是基于污染物污泥富集资源回收模式

◆中国环境报见习记者 张蕊

近些年，随着我国不断兴建污水处理厂和配套管网日趋完善，污泥处理成为水务领域关注的重点。

由于不同地区的污泥泥质、经济社会发展水平不同，因此在处理方式、处置路线上也面临着不同的挑战和选择。在日前举行的2014首届珠三角（东莞）水处理创新交流会上，同济大学环境科学与工程学院院长戴晓虎表示，截至2013年，我国污水处理厂有5300座，污水处理能力达到1.63亿立方米/日，年处理污水量450亿立方米，污水处理规模已经接近美国。从资源化利用角度来说，要从污泥的性质和特点考虑处理处置的技术。下一代污水处理模式，应该是基于污染物污泥富集资源回收的模式。

泥质决定技术路线

污泥中60%以上都是蛋白质，此外还含有有机质。从资源化利用角度，要从污泥的性质和特点考虑处理处置技术

记者：请问我国污泥产生的状况如何？

戴晓虎：根据测算，我国每年产生3000万吨~4000万吨含水率在80%左右的污泥。随着“十三五”的到来，污泥量还会增加。预计到2020年，我国的污泥产量将达到6000万吨~9000万吨。

需要强调的是，这里所说的污泥不包括工业废水污泥。如果要加上工业废水污泥，我国的污泥产生量还将更大。

据测算，从污水里转入污泥中的COD比例大概是30%~50%，转入污泥中的氮约为20%~30%，磷约为90%。如果它们得不到有效处理处置，那么我国的节能减排目标将大打折扣。所以不能继续重水轻泥的现状。

记者：和国外相比，我国污泥处理处置处于怎样的水平？

戴晓虎：在污泥处理过程中，国际上的通行标准是“四化”，即稳定化、减量化、无害化、资源化。而我国的现状是80%甚至90%的污水污泥只是简单浓缩脱水。

在稳定化方面，我国污泥普遍没有进行厌氧处理，好氧堆肥也只是局部性进行。污泥处理如果做不到稳定化，那么接下来的无害化和资源化也就无从谈起。特别值得注意的是有些地方推出的高干脱水，添加大量无机材料对污泥进行脱水，其实根本谈不上资源化。

如果污泥没有经过稳定化处理，其中就会含有大量有机物，会给环境带来严重的二次污染。在国际上，在前端对污泥进行浓缩或者厌氧好氧处理，然后脱水，接下来的处置可以在厂区里或者到厂外去进行干化焚烧。

记者：我国污泥有什么特点？如何针对这些特点对污泥加以处理处置？

戴晓虎：围绕污泥泥质，在我国还有争论。总体上，我国污泥的有机质含量比较低。和国外相比，正因为有机质含量低，所以我国污泥中总氮、总磷含量也相对偏低。

另外需要强调的是，通过测算，我们发现污泥中60%以上都是蛋白质，此外还含有有机质。从资源化利用角度来说，要从污泥的性质和特点考虑处理处置的技术。

有观点认为，因为我国污泥含沙量高、有机质含量低，所以污泥厌氧消化的路线较为合适。对此，我认为，一方面，通过提升污泥中有机质含量，进而才能选择更好的处理工艺，对资源加以利用。另一方面，国外的传统的技术工艺在我国还需要进一步研究和提升，才能适合我国的污泥处理处置。

稳定是基础，厌氧需重视

厌氧消化和干化焚烧组合，可以显著降低后一个工艺单元的投资和运行费用，并可降低污泥含水率和有机质含量；另外一种技术路线是集中式的城市有机质废弃物和污泥协同处置

记者：为什么污泥在干化焚烧前要进行厌氧消化？如何提高厌氧消化效率？

戴晓虎：厌氧消化和干化焚烧组合，可以显著降低后一个工艺单元的投资和运行费用，并可降低污泥含水率和有机质含量，有助于实现能耗平衡。在德国慕尼黑一个项目中，污泥经过厌氧消化再干化焚烧，产生的能源基本可以实现项目能耗的自给自足，弥补厌氧消化的成本，因此国外有不少城市选择了这样的组合工艺。

在污泥资源和能源回收利用方面，沼气利用是成熟而且经过工程验证的方法。在提升厌氧消化效率方面，上世纪70年代我们关注提高固体负荷或者是提高热转化率及容积负荷。

现在我们谈厌氧消化，还应该包括如何将沼气中的甲烷进行提取分离，这也是提高厌氧消化效率的方法。在2000年以后，第三代厌氧消化池的污泥含固率大于10%，污泥降解率可达50%。

记者：除了厌氧消化，还有哪些技术路线可以考虑？

戴晓虎：另外一种技术路线是集中式的城市有机质废弃物和污泥的协同处置。污泥含固率如果在10%，那么厌氧消化的效率也仅有1.5 kgVss/m3d ~2kgVss/m3d。从游离氨、热值的角度，可以通过协同餐厨垃圾等有机质来提高厌氧消化的效率，大概可以提升到6kgVss/m3d ~10kgVss/m3d。

目前，在高含固污泥/协同厌氧消化技术方面也有一些示范工程。主要包括辽宁省大连夏家河污泥集中处理示范工程、浙江省宁海污泥处理示范工程、湖北省襄阳污泥处理示范工程、湖南省长沙污泥集中处理示范工程等。这些示范工程已经取得良好效果。

我们认为下一代污水处理模式应该是基于污染物污泥富集资源回收的模式。第一阶段最大化利用生物污泥富集污染物，第二阶段回收碳和磷，实现高效高值利用、氮的高效转化和回收。这一模式的目标是能耗输出、氮和磷回收，反应时间为传统活性污泥法的1/3~1/4。

珠三角处置污泥有何药方？

对重金属不超标的污泥，建议通过厌氧消化或者好氧堆肥进行土地园林利用，也可以进行高附加值资源提取回收

记者： 珠三角地区的污泥现状是什么？有何特点？

戴晓虎：截至2014年，珠三角拥有城镇污水处理厂237家，污水处理能力约为0.11亿立方米/日，2013年年产污泥突破200万吨（含水率约为80%）。预计2020年污泥产量将达到400万吨~600万吨/年。

珠三角地区污泥经过脱水后含水率较高，有机质比例偏低，并呈季节性变化。寄生虫卵、病原微生物等致病物质超标较普遍。部分污泥存在铜、铅、铬等重金属超标现象。污泥中还含有多氯联苯等难降解有机物。

珠三角地区的污泥处理现在主要以浓缩脱水为主，还有一部分进行深度脱水，也有一些污水处理厂对污泥进行水泥窑协同处置。例如当地的越堡水泥厂，就对污泥进行水泥窑协同处置。

我对珠三角污泥处理处置提几点建议：围绕资源化循环利用，在珠三角地区尤其是农村地区，重金属如果超标，则可以考虑采用协同焚烧方式。同时，热解气化技术还在开发中。而热能无机物也可以作为建材回收利用。

记者： 您怎么评价直接干化焚烧处理污泥？有哪些技术值得关注？

戴晓虎：我个人不主张直接采用干化焚烧处理污泥，因为我国的污泥泥质还不稳定。如果要单独干化焚烧，就必须采用流化床工艺，整个工艺从资源回收角度来讲做得还不够。

如果污泥的重金属含量超标严重，也可以采用干化焚烧的方式对污泥进行处理。而热解技术和协同技术可能会有市场空间。对重金属不超标的污泥，我强烈建议通过厌氧消化或者好氧堆肥进行土地园林利用，也可以进行高附加值资源提取回收。

在高附加值资源提取回收方面，无论是提蛋白、甲烷回收等方法都可以采用。

总体道路还应该是污泥和城市有机质废弃物协同厌氧消化，实现规模化生物质燃气回收，生产高品质绿化营养土。这些模式在我国山东省、福建省厦门市等地都有实践，主要处理工艺就是将餐厨、菜市场垃圾和污泥协同处置。

污泥处理处置还有哪些挑战？

需要技术综合集成示范；提升污泥品质并进行合理的风险评估；污泥处理处置经费需要落实

记者： 现在我国污泥处理处置还需要解决哪些瓶颈问题？为何土地利用的路线没有得到重视？您对此有何建议？

戴晓虎：现在污泥处置的瓶颈问题主要包括：单一技术很多并相对成熟，但是需要技术综合集成示范，研究全流程综合解决方案。目前厌氧、好氧污泥土地利用受到限制，一方面主要是由于我国目前污泥品质还不高，另一方面，污泥土地利用的风险相对被夸大。

同时，国内还存在强制的污泥“稳定化”要求。相关部门应该就此进行协调，提升污泥品质并进行合理的风险评估。

此外，污泥处理处置经费需要落实。建议可以借用德国做法，在后端根据出产的沼气量进行补贴。同时，污泥处理处置费用必须融入污水处理费中，污泥、污水处理分不开。

此外，技术开发和市场的有效结合也很重要，需要开发全产业链可持续发展的商业模式。而我们也可以断定，我国污泥处理机遇和挑战共存，思维理念转变和前瞻性创新需要勇气和担当。同时巨大的市场和需求、大量研发经费的投入，定会引领未来污泥处理处置资源化技术的发展。

污水处理新模式：污染物污泥富集资源回收模式

 

Not excessive sludge of heavy metals, can land garden use by anaerobic digestion or aerobic composting, can also be of high value-added resource extraction recovery. Profile picture 

2020, China's sludge production will reach 60 million tons - 90 million tons 

Foreign traditional craft techniques and further research is needed to improve in order for our sludge treatment and disposal 

Overall sludge and urban roads should be synergistic anaerobic digestion of organic matter waste, chemical and biological substances to achieve scale gas recovery, production of high-quality green nutritive soil 

The next generation of wastewater treatment sludge model should be based on contaminant enrichment resource recovery mode 

◆ China Environment News trainee reporter Zhang Rui 

In recent years, as China continues to build a sewage treatment plant and associated pipeline network maturing, sludge treatment has become the focus of attention in the field of water. 

Due to muddy sludge in different regions, different levels of economic and social development, so the handling, disposal routes are also faced with different challenges and choices. At the recent 2014 inaugural Pearl River Delta (Dongguan) Water Innovation conference, Dean of College of Environmental Science and Engineering, Tongji University Daixiao Hu said that as of 2013, China's sewage treatment plant has a 5300 sewage treatment capacity of 163 million cubic meters / day, the annual amount of 45 billion cubic meters of sewage treatment, sewage treatment capacity has been close to the United States. From the perspective of resource utilization, from a consideration of the nature and characteristics of sludge treatment and disposal technologies. The next generation of wastewater treatment model, it should be enriched sludge recycling of pollutants based mode. 

Argillaceous decision technology roadmap 

More than 60% of sludge are protein, also contains organic matter. From the perspective of resource utilization, the nature and characteristics of the sludge from the treatment and disposal technologies considered 

Reporter: What is the status of sludge how? 

Dai Xiaohu: According to estimates, our country produces 30 million tons - 40 million tons moisture content of about 80% of sludge per year. With the advent of "Thirteen Five", the sludge volume will increase. 2020, China's sludge production will reach 60 million tons to 9,000 tons. 

It should be stressed that the sludge is not mentioned here, including industrial wastewater sludge. If you want to add industrial wastewater sludge, the amount of sludge produced will be greater. 

It is estimated that the proportion of COD transferred from the sewage sludge in about 30% to 50% of nitrogen into the sludge is about 20% to 30%, about 90% of phosphorus. If they are not effective treatment and disposal, so our energy reduction targets will be greatly reduced. So the status quo can not continue heavy water light mud. 

Reporter: and abroad compared to sludge treatment and disposal of at what level? 

Dai Xiaohu: In the sludge treatment process, the prevailing international standards is the "four modernizations", ie stabilization, reduction, sound, resource. The current situation in China is 80% or even 90% of sewage sludge dewatering simply. 

In terms of stabilization, our universal no anaerobic treatment of sludge, aerobic composting is only performed locally. If you can not stabilized sludge treatment, then the next harmless and resources does not arise. Of particular note is the introduction of senior cadres in some places dehydration, adding a large number of inorganic materials for sludge dewatering, in fact, not to mention resources. 

If you have not been stabilized sludge treatment, which will contain a lot of organic matter, will give the environment a serious secondary pollution. In the international arena, in front of the concentrated sludge or anaerobic and aerobic treatment, then dehydrated, then disposal in the plant or outside in dry incineration plant go. 

Reporter: What are the characteristics of the sludge? How to deal with these characteristics for the disposal of sludge? 

Dai Xiaohu: around muddy sludge in the country as well as controversy. Overall, the organic content of the sludge is relatively low. And abroad compared because of low organic matter content, so the total nitrogen, total phosphorus content of the sludge is relatively low. 

Also needs to be emphasized is that by calculation, we found that more than 60% of sludge are protein, also contains organic matter. From the perspective of resource utilization, from a consideration of the nature and characteristics of sludge treatment and disposal technologies. 

The idea that, because of the high sediment sludge, low organic matter content, so the anaerobic digestion of the route is more appropriate. In this regard, I think, on the one hand, by increasing the organic matter content of the sludge, and then to choose a better treatment process, the resource to be utilized. On the other hand, the traditional craft of foreign technology requires further research and improvements in our country, in order to fit our sludge treatment and disposal. 

Stability is the basis, anaerobic need attention 

Dry anaerobic digestion and incineration combination can significantly reduce investment and operating costs after a process unit, and reduce the moisture content of the sludge and organic content; another technology route is centralized urban organic waste and sludge together disposal 

Reporter: Why sludge before drying and incineration to anaerobic digestion? How to improve the efficiency of the anaerobic digestion? 

Dai Xiaohu: dry anaerobic digestion and incineration combination, can significantly reduce the capital and operating costs of a process unit, and reduce the moisture content of the sludge and organic matter content, help to achieve energy balance. In Munich, Germany, a project, do it again sludge incineration through anaerobic digestion, energy generated by the project can be basically achieved self-sufficiency in energy consumption to make up for the anaerobic digestion of cost, so there are many cities abroad chose this combination process . 

Sludge recycling of resources and energy, the biogas utilization is mature and proven through engineering methods. In improving the efficiency of anaerobic digestion, 1970s solid load or increase our concern is to improve the thermal conversion rate and volume load. 

Now we are talking about anaerobic digestion, but also should include how to extract methane gas separation, which is to improve the efficiency of the anaerobic digestion method. Later in 2000, the third generation of anaerobic digester sludge solids greater than 10%, the sludge degradation rate of 50%. 

Reporter: In addition to anaerobic digestion, what technology roadmap could be considered? 

Dai Xiaohu: Another technique centralized disposal route is coordinated urban organic waste and sewage sludge. If the sludge solid content of 10%, then the efficiency of the anaerobic digestion is also just 1.5 kgVss / m3d ~ 2kgVss / m3d. From the perspective of free ammonia, calorific value, can improve the efficiency of the anaerobic digestion of food waste and other organic matter through a collaborative, probably can be raised to 6kgVss / m3d ~ 10kgVss / m3d. 

Currently, high solids sludge / synergistic anaerobic digestion technology, there are some aspects of the demonstration project. Including Liaoning Province, Dalian Xiajiahe centralized sludge treatment demonstration project, Ninghai sludge treatment demonstration project, sludge treatment demonstration project Xiangyang, Hubei and Hunan Changsha centralized sludge treatment demonstration projects. These demonstration projects have achieved good results. 

We believe the next generation of wastewater treatment sludge model should be based on contaminant enrichment resource recovery mode. The first stage to maximize the use of biological sludge accumulation of pollutants, the second phase of the recovery of carbon and phosphorus to achieve efficient use of high-value, high-efficiency conversion of nitrogen and recovery. The goal of this model is that energy output, nitrogen and phosphorus recovery, the reaction time is conventional activated sludge process 1/3 to 1/4. 

What sludge disposal PRD prescription? 

For heavy metal sludge is not exceeded recommended by anaerobic digestion or aerobic composting garden land use, also can be high value-added resource extraction recovery 

Reporter: What is the status quo sludge PRD is? What are the characteristics? 

Dai Xiaohu: As of 2014, the PRD has 237 municipal wastewater treatment plants, sewage treatment capacity of approximately 011 million cubic meters / day in 2013 to break 2 million tons annual output of sludge (water content of about 80%). Sludge production in 2020 is expected to reach 4 million tons to 600 million tons / year. 

Pearl River Delta region after dewatering sludge moisture content is high, the low proportion of organic matter, and showed seasonal variation. Parasite eggs, pathogenic microorganisms and other pathogenic substances exceeding more common. Part sludge presence of copper, lead, chromium and other heavy metals exceeded phenomenon. Sludge also contains PCBs and other refractory organics. 

Sludge Treatment PRD is now mainly concentrated mainly dehydration, as well as part of deep dehydration, there are some sewage treatment plant sludge disposal of cement kiln collaboration. For example, the local Fort cement plants, cement kilns on collaborative sludge disposal. 

I PRD sludge disposal a few suggestions: focus on resource recycling, in the Pearl River Delta region, especially in rural areas, heavy metals, if exceeded, you might consider using collaborative incineration. Meanwhile, pyrolysis and gasification technology is still in development. And the thermal energy can be used as the inorganic building materials recycling. 

Reporter: how do you evaluate the direct drying sludge incineration? What are the technical cause for concern? 

Dai Xiaohu: I personally do not advocate the direct use of drying sludge incineration, because our country is not stable muddy sludge. If you want to separate drying and incineration, you must use the fluidized bed process, the entire process of recovering from a resource point of view in terms of not doing enough. 

If the heavy metal content of sludge serious, can also be used for drying and incineration of sludge treatment methods. The pyrolysis technology and collaborative technologies may be market space. Not excessive sludge of heavy metals, and I strongly recommend via anaerobic digestion or aerobic composting garden land use, high value-added resources can also be extracted for recycling. 

In the resource extraction recovery of high-value, whether the protein is to provide the methane recovery and other methods can be used. 

Overall roads should also be coordinated waste sludge and municipal anaerobic digestion of organic matter, chemical and biological substances to achieve scale gas recovery, production of high-quality green nutritive soil. These patterns of Shandong Province, Xiamen City, Fujian Province and other places have practice, the main treatment process is to dining kitchen, vegetable market waste and sludge disposal collaboration. 

Sludge treatment and disposal as well as what are the challenges? 

Requires comprehensive integration technology demonstration; improve sludge quality and reasonable risk assessment; sludge treatment and disposal funds needed to implement 

Reporter: Now sludge treatment and disposal of bottlenecks which need to be addressed? Why route of land use are not taken seriously? What do you recommend? 

Dai Xiaohu: now the bottleneck problem of sludge disposal include: a single lot and relatively mature technology, but requires comprehensive integration technology demonstration study the whole process of integrated solutions. Currently anaerobic, aerobic sludge land-use restrictions, on the one hand is mainly due to China's current sludge quality is not high, on the other hand, the relative risk of sludge land use have been exaggerated. 

Meanwhile, there are mandatory domestic sludge "stabilization" requirement. In this connection the relevant departments should coordinate and enhance the quality of sludge and reasonable risk assessment. 

In addition, sludge treatment and disposal funds need to be implemented. German practice recommendations can be borrowed at the back end subsidies based on the amount of biogas produced. Meanwhile, sludge treatment and disposal costs must be integrated into the sewage treatment fee, sludge, sewage treatment inseparable. 

In addition, the effective integration of technology development and market is also very important, the need to develop business models for sustainable development of the whole industry chain. And we can conclude that our sludge treatment opportunities and challenges coexist, innovative and forward-thinking concept of change requires courage and play. Meanwhile a huge market and demand, putting in a lot of R & D funding, will lead the future development of sludge treatment and disposal technology resources. 

Sewage new model: the enrichment of pollutants sludge recycling mode 

September 16, 2014 Source: China News NetworkNot excessive sludge of heavy metals, can land garden use by anaerobic digestion or aerobic composting, can also be of high value-added resource extraction recovery. Profile picture 

2020, China's sludge production will reach 60 million tons - 90 million tons 

Foreign traditional craft techniques and further research is needed to improve in order for our sludge treatment and disposal 

Overall sludge and urban roads should be synergistic anaerobic digestion of organic matter waste, chemical and biological substances to achieve scale gas recovery, production of high-quality green nutritive soil 

The next generation of wastewater treatment sludge model should be based on contaminant enrichment resource recovery mode 

◆ China Environment News trainee reporter Zhang Rui 

In recent years, as China continues to build a sewage treatment plant and associated pipeline network maturing, sludge treatment has become the focus of attention in the field of water. 

Due to muddy sludge in different regions, different levels of economic and social development, so the handling, disposal routes are also faced with different challenges and choices. At the recent 2014 inaugural Pearl River Delta (Dongguan) Water Innovation conference, Dean of College of Environmental Science and Engineering, Tongji University Daixiao Hu said that as of 2013, China's sewage treatment plant has a 5300 sewage treatment capacity of 163 million cubic meters / day, the annual amount of 45 billion cubic meters of sewage treatment, sewage treatment capacity has been close to the United States. From the perspective of resource utilization, from a consideration of the nature and characteristics of sludge treatment and disposal technologies. The next generation of wastewater treatment model, it should be enriched sludge recycling of pollutants based mode. 

Argillaceous decision technology roadmap 

More than 60% of sludge are protein, also contains organic matter. From the perspective of resource utilization, the nature and characteristics of the sludge from the treatment and disposal technologies considered 

Reporter: What is the status of sludge how? 

Dai Xiaohu: According to estimates, our country produces 30 million tons - 40 million tons moisture content of about 80% of sludge per year. With the advent of "Thirteen Five", the sludge volume will increase. 2020, China's sludge production will reach 60 million tons to 9,000 tons. 

It should be stressed that the sludge is not mentioned here, including industrial wastewater sludge. If you want to add industrial wastewater sludge, the amount of sludge produced will be greater. 

It is estimated that the proportion of COD transferred from the sewage sludge in about 30% to 50% of nitrogen into the sludge is about 20% to 30%, about 90% of phosphorus. If they are not effective treatment and disposal, so our energy reduction targets will be greatly reduced. So the status quo can not continue heavy water light mud. 

Reporter: and abroad compared to sludge treatment and disposal of at what level? 

Dai Xiaohu: In the sludge treatment process, the prevailing international standards is the "four modernizations", ie stabilization, reduction, sound, resource. The current situation in China is 80% or even 90% of sewage sludge dewatering simply. 

In terms of stabilization, our universal no anaerobic treatment of sludge, aerobic composting is only performed locally. If you can not stabilized sludge treatment, then the next harmless and resources does not arise. Of particular note is the introduction of senior cadres in some places dehydration, adding a large number of inorganic materials for sludge dewatering, in fact, not to mention resources. 

If you have not been stabilized sludge treatment, which will contain a lot of organic matter, will give the environment a serious secondary pollution. In the international arena, in front of the concentrated sludge or anaerobic and aerobic treatment, then dehydrated, then disposal in the plant or outside in dry incineration plant go. 

Reporter: What are the characteristics of the sludge? How to deal with these characteristics for the disposal of sludge? 

Dai Xiaohu: around muddy sludge in the country as well as controversy. Overall, the organic content of the sludge is relatively low. And abroad compared because of low organic matter content, so the total nitrogen, total phosphorus content of the sludge is relatively low. 

Also needs to be emphasized is that by calculation, we found that more than 60% of sludge are protein, also contains organic matter. From the perspective of resource utilization, from a consideration of the nature and characteristics of sludge treatment and disposal technologies. 

The idea that, because of the high sediment sludge, low organic matter content, so the anaerobic digestion of the route is more appropriate. In this regard, I think, on the one hand, by increasing the organic matter content of the sludge, and then to choose a better treatment process, the resource to be utilized. On the other hand, the traditional craft of foreign technology requires further research and improvements in our country, in order to fit our sludge treatment and disposal. 

Stability is the basis, anaerobic need attention 

Dry anaerobic digestion and incineration combination can significantly reduce investment and operating costs after a process unit, and reduce the moisture content of the sludge and organic content; another technology route is centralized urban organic waste and sludge together disposal 

Reporter: Why sludge before drying and incineration to anaerobic digestion? How to improve the efficiency of the anaerobic digestion? 

Dai Xiaohu: dry anaerobic digestion and incineration combination, can significantly reduce the capital and operating costs of a process unit, and reduce the moisture content of the sludge and organic matter content, help to achieve energy balance. In Munich, Germany, a project, do it again sludge incineration through anaerobic digestion, energy generated by the project can be basically achieved self-sufficiency in energy consumption to make up for the anaerobic digestion of cost, so there are many cities abroad chose this combination process . 

Sludge recycling of resources and energy, the biogas utilization is mature and proven through engineering methods. In improving the efficiency of anaerobic digestion, 1970s solid load or increase our concern is to improve the thermal conversion rate and volume load. 

Now we are talking about anaerobic digestion, but also should include how to extract methane gas separation, which is to improve the efficiency of the anaerobic digestion method. Later in 2000, the third generation of anaerobic digester sludge solids greater than 10%, the sludge degradation rate of 50%. 

Reporter: In addition to anaerobic digestion, what technology roadmap could be considered? 

Dai Xiaohu: Another technique centralized disposal route is coordinated urban organic waste and sewage sludge. If the sludge solid content of 10%, then the efficiency of the anaerobic digestion is also just 1.5 kgVss / m3d ~ 2kgVss / m3d. From the perspective of free ammonia, calorific value, can improve the efficiency of the anaerobic digestion of food waste and other organic matter through a collaborative, probably can be raised to 6kgVss / m3d ~ 10kgVss / m3d. 

Currently, high solids sludge / synergistic anaerobic digestion technology, there are some aspects of the demonstration project. Including Liaoning Province, Dalian Xiajiahe centralized sludge treatment demonstration project, Ninghai sludge treatment demonstration project, sludge treatment demonstration project Xiangyang, Hubei and Hunan Changsha centralized sludge treatment demonstration projects. These demonstration projects have achieved good results. 

We believe the next generation of wastewater treatment sludge model should be based on contaminant enrichment resource recovery mode. The first stage to maximize the use of biological sludge accumulation of pollutants, the second phase of the recovery of carbon and phosphorus to achieve efficient use of high-value, high-efficiency conversion of nitrogen and recovery. The goal of this model is that energy output, nitrogen and phosphorus recovery, the reaction time is conventional activated sludge process 1/3 to 1/4. 

What sludge disposal PRD prescription? 

For heavy metal sludge is not exceeded recommended by anaerobic digestion or aerobic composting garden land use, also can be high value-added resource extraction recovery 

Reporter: What is the status quo sludge PRD is? What are the characteristics? 

Dai Xiaohu: As of 2014, the PRD has 237 municipal wastewater treatment plants, sewage treatment capacity of approximately 011 million cubic meters / day in 2013 to break 2 million tons annual output of sludge (water content of about 80%). Sludge production in 2020 is expected to reach 4 million tons to 600 million tons / year. 

Pearl River Delta region after dewatering sludge moisture content is high, the low proportion of organic matter, and showed seasonal variation. Parasite eggs, pathogenic microorganisms and other pathogenic substances exceeding more common. Part sludge presence of copper, lead, chromium and other heavy metals exceeded phenomenon. Sludge also contains PCBs and other refractory organics. 

Sludge Treatment PRD is now mainly concentrated mainly dehydration, as well as part of deep dehydration, there are some sewage treatment plant sludge disposal of cement kiln collaboration. For example, the local Fort cement plants, cement kilns on collaborative sludge disposal. 

I PRD sludge disposal a few suggestions: focus on resource recycling, in the Pearl River Delta region, especially in rural areas, heavy metals, if exceeded, you might consider using collaborative incineration. Meanwhile, pyrolysis and gasification technology is still in development. And the thermal energy can be used as the inorganic building materials recycling. 

Reporter: how do you evaluate the direct drying sludge incineration? What are the technical cause for concern? 

Dai Xiaohu: I personally do not advocate the direct use of drying sludge incineration, because our country is not stable muddy sludge. If you want to separate drying and incineration, you must use the fluidized bed process, the entire process of recovering from a resource point of view in terms of not doing enough. 

If the heavy metal content of sludge serious, can also be used for drying and incineration of sludge treatment methods. The pyrolysis technology and collaborative technologies may be market space. Not excessive sludge of heavy metals, and I strongly recommend via anaerobic digestion or aerobic composting garden land use, high value-added resources can also be extracted for recycling. 

In the resource extraction recovery of high-value, whether the protein is to provide the methane recovery and other methods can be used. 

Overall roads should also be coordinated waste sludge and municipal anaerobic digestion of organic matter, chemical and biological substances to achieve scale gas recovery, production of high-quality green nutritive soil. These patterns of Shandong Province, Xiamen City, Fujian Province and other places have practice, the main treatment process is to dining kitchen, vegetable market waste and sludge disposal collaboration. 

Sludge treatment and disposal as well as what are the challenges? 

Requires comprehensive integration technology demonstration; improve sludge quality and reasonable risk assessment; sludge treatment and disposal funds needed to implement 

Reporter: Now sludge treatment and disposal of bottlenecks which need to be addressed? Why route of land use are not taken seriously? What do you recommend? 

Dai Xiaohu: now the bottleneck problem of sludge disposal include: a single lot and relatively mature technology, but requires comprehensive integration technology demonstration study the whole process of integrated solutions. Currently anaerobic, aerobic sludge land-use restrictions, on the one hand is mainly due to China's current sludge quality is not high, on the other hand, the relative risk of sludge land use have been exaggerated. 

Meanwhile, there are mandatory domestic sludge "stabilization" requirement. In this connection the relevant departments should coordinate and enhance the quality of sludge and reasonable risk assessment. 

In addition, sludge treatment and disposal funds need to be implemented. German practice recommendations can be borrowed at the back end subsidies based on the amount of biogas produced. Meanwhile, sludge treatment and disposal costs must be integrated into the sewage treatment fee, sludge, sewage treatment inseparable. 

In addition, the effective integration of technology development and market is also very important, the need to develop business models for sustainable development of the whole industry chain. And we can conclude that our sludge treatment opportunities and challenges coexist, innovative and forward-thinking concept of change requires courage and play. Meanwhile a huge market and demand, putting in a lot of R & D funding, will lead the future development of sludge treatment and disposal technology resources. 

Sewage new model: the enrichment of pollutants sludge recycling mode 

September 16, 2014 Source: China News Network