With the acceleration of urbanization, the disposal of dewatered sewage sludge (DSS) has become an urgent environmental issue worldwide. Hydrothermal conversion (HC) of DSS is an important method for sludge sustainable utilization due to its combination of efficiency and economic and environmental advantages. This study investigates the product distribution and composition of products during the HC of DSS under subcritical and supercritical water conditions (200–450 °C, 5–90 min), with a particular focus on the formation and conversion mechanisms of steroid compounds. The results indicate that increasing temperature and reaction time leads to a rise in gas-phase products (GPs) and a corresponding decline in solid-phase products (SPs), with phenolic compounds identified as the predominant constituents. In the water-soluble products (WSPs), nitrogen-containing cyclic compounds are the major products. Saturated nitrogen heterocycles dominate at lower temperatures (200 °C), while at elevated temperatures (300–350 °C), saturated azapolycyclic compounds emerge, ultimately transitioning into unsaturated aromatic nitrogen heterocycles at 450 °C. Steroids are primarily concentrated in the oil-phase products (OPs). The conversion process involves the initial conversion of lipids in the DSS to long-chain olefins at 200 °C, which are then converted to steroids at 250–350 °C. At higher temperatures (400–450 °C), these steroids might decompose into gaseous products or undergo polymerization to form char. This suggests the potential for steroids to act as precursor compounds in the process of char formation. This work could contribute to a deeper understanding of the HC mechanism of DSS and provide valuable technical insights for improving bio-oil quality.

It needs to be improved the conversion efficiency and stable operation of conventional pyrolysis with high-temperature flue gas heating (HFH). Herein, a new radiative heating (RH) pyrolysis method is proposed. Experimental studies are carried out on a self-made radiation pyrolysis pilot plant to investigate the effects of different factors (pyrolysis final temperature, residence time, and carrier gas volume) on product distribution. The results show that with the increase of pyrolysis temperature, the yield of the gas phase consistently increases, and the proportion of CH4 and H2 in the pyrolysis gas reaches 62.31

Ultrasonic demulsification treatment is essential to dehydrate refinery sludge with complex composition, high water content, and demulsification difficulty. Herein, the influencing factors and the demulsification mechanism are studied in oily sludge treatment. The effects of initial temperature, ultrasonic amplitude, and time, as well as a diversity of additives on the ultrasonic dehydration rate of oily sludge demulsification, are investigated. The optimal demulsification conditions are confirmed (temperature: 20 °C, ultrasonic amplitude: 100 %, and ultrasonic time: 5 min), based on the effectiveness and economy of dehydration. The combined ultrasonication and pyrolysis of the solid residue of sludge shows a dehydration rate of 60.49 %, beneficial for the green transformation and utilization of subsequent demulsification products. Moreover, the mechanism of ultrasonic emulsification is proposed, as well. This work provides an important reference for the subsequent resource utilization of oily sludge in the industry.

This study aimed to explore the influence of activated carbon, oily sludge pyrolysis residue, and biochar and their contents on the distribution of three-phase products of oily sludge subjected to microwave pyrolysis. A microwave reaction system, refinery gas analyzer, and chromatography-mass spectrometry were used to carry out the experiment and analyze the results. The results showed that all three additives reduced the yield of solid products and increased the yield of gas products. With an increase in the additive content, the volatile matter and moisture content in the pyrolysis residue greatly reduced. The content of CH4 and H-2 in the pyrolysis gas increased with an increase in the additive content. When the amount of activated carbon was 20%, the H-2 content reached a maximum (39.7%), and when the amount of biochar was 20%, the CH4 content reached a maximum (44.5%). All three additives increased the content of small molecules in the pyrolysis oil; when 10% activated carbon was added, the oil recovery rate reached up to 78.5%. The results of this study can guide the industrial application of microwave pyrolysis oily sludge.

Demulsification is usually a necessary step for the treatment of oily sludge, which is also an important and urgent task in the petroleum industry. Since the inefficient and difficult demulsification for the refinery oily sludge by traditional methods, a new method using microwave irradiation to strengthen the demulsification efficiency was proposed in this work. A series of demulsification runs were carried out to investigate the effects of microwave heating temperature and power, upon the droplet-size distribution and the total demulsification efficiency of oily sludge. The demulsification process of the oily sludge heated by microwave irradiation and water bath were compared in terms of demulsification efficiency, demulsification temperature, demulsification time and centrifugal speed. At the same time, characterization tests were performed by viscometer, DSC analyzer, Zeta potentiometer, etc. Results showed that the demulsification temperature of the oily sludge should be kept below 77 degrees C. The demulsification efficiency of oily sludge increased first and then decreased with the increase of microwave heating temperature and power, which reached maximum (67.4%) at 55 degrees C, with the microwave power of 700 W. Compared with conventional heating (55 degrees C), the demulsification efficiency of oily sludge increased by 25.3% under microwave irradiation (700 W, 55 degrees C). Besides, microwave irradiation can simultaneously reduce the demulsification temperature ( 40 degrees C), the demulsification time (> 95%), and the centrifugal speed (similar to 36.7%), which proves that microwave demulsification is a rapid, high-efficiency, low consumption demulsification method.

The combined processed of pretreatment,balance tank,AAO tank,horizontal flow sedimentation tank,flocculation and sedimentation tank,active sand filter and UV tank etc.were used in a wastewater treatment plant in an industrial park of Guizhou.CODcr of the discharged water was below 50 mg/L,and NH3-N was below 5 mg/L,while the other parameters met the first grade A criteria of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002).In this paper,the treatment process flow,general layout,design of the main structures and equipment,construction investment and main economic and technical indicators were introduced in detail.

随着社会经济的快速发展，电能作为在社会发展中的作用越来越显著。同时电力系统也在快速的发展。电厂作为用水量较大的组织，对其产生的废水进行有效、合理的利用，对于水资源的有效利用有着重要的意义。此外，对于社会经济的可持续发展也具有十分重要的意义。本文首先对电厂所产生废水的特性进行了讨论，随后对废水的处理技术等进行了探讨。

Coking wastewater is hard to treat because of its low biodegradability,but pre-oxidation measurements such as Fenton and ozone can elevate its biodegradability. Two processes for improving biodegradability of coking wastewater were compared,and improvement methods of activated carbon catalyzed ozonation for coking wastewater treatment were got. The results show that neither Fenton oxidation nor ozonation can improve the biodegradability,but activated carbon catalyzed ozonation (AC-ozonation)can effectively improve biodegradability better. After AC-ozone,BOD 5 / COD increases from 0. 16 to 0. 25,and rate of COD increases from 72. 5% to 83% .

Chemical companies, food industries usually produce wastewaters with high salinity. In consideration of economy, biological methods are preferred to physicochemical methods to remove organic matters. When sequence batching reactors are applied, aeration rate is of great importance to the COD removal efficiency. In this bench scale experiment, the aeration rate of 0.40 m3/m3.min led to sludge disintegration, poor COD removal efficiency and superfluous foam. After sludge conditioner addition, the aeration rate of 0.19 m3/m3.min led to good sludge flocs, satisfactory COD removal efficiency and few foam. It is the oxidizing environment caused by the high dissolved oxygen that harmed the sludge and made it work with low efficiency.

The advanced treatment of pulp and paper wastewater was carried out by using composite biomimetic enzyme process.The changes of TOC and Fe element,the average molecular weight of reaction products in the wastewater after composite biomimetic enzyme treatment were investigated and the reaction products were analyzed by GC-MS,IR and XPS.The controlling,guiding and terminating paths of free radical reaction in composite biomimetic enzyme process were clarified,and the reaction mechanism of modest oxide-reactive precipitation was proposed.

A combined process of Inverted AAO+Fenton oxidation has been used for treating wastewater from chemical industrial area.The process is characterized by stable treatment effect,excellent compact loading resistance,and less excessive sludge.After two months of trial operation,the effluent CODCr,NH3-N concentration averages were 47 mg/L and 5 mg/L,the effluent can meet the "Cities Sewage treatment plant Pollutant discharge Standard"(GB18918-2002) the level a standard.

A new method for the advanced treatment of pulp and paper wastewater was presented by combining the magnetization with iron-based complex. The iron-based complex was prepared by ferric sulfate and polycarboxylic acid (PA), forming the Fe–PA complex. Effect of magnetization conditions (magnetic intensity and water velocity) on the physical and chemical properties of wastewater were measured. Results indicated that the conductivity and surface tension of wastewater have been greatly changed after the magnetization process, and the optimal magnetizing conditions were determined as magnetic intensity of 750 mT and water velocity of 4.4 m/s. Parameters of the flocs indicated that the properties of flocs formed by Fe–PA complex were enhanced by magnetization. What's more, the pretreatment of wastewater by magnetization accelerated the removal of CODCr and cut down about 7.7% of the Fe–PA complex dosage. In addition, the pilot scale test (1000 m3/d) was designed and the combined use of magnetization and Fe–PA complex demonstrated the excellent performance for the advanced treatment of pulp and paper wastewater, with the cost only 0.84 RMB/m3 (0.13 US$/m3) for the whole pilot scale system.

The iron-based biomimetic compound was used as the mimic enzyme for the delignification of pulp and paper wastewater in this work. It was prepared by ferric sulfate and polycarboxylic acid (PA), forming the Fe–PA complex. The XRD pattern of the Fe–PA complex and its delignification mechanism were discussed. The optimal control conditions of Fe–PA complex on delignification were evaluated by using the Fe–PA complex in practical applications. The XRD pattern reflected the characteristic of a stereochemical cell with iron as the active center in Fe–PA complex, and the delignification mechanism of the Fe–PA complex was based on the complexation and flocculation. The optimal control conditions of Fe–PA complex on delignification were determined and the results showed as the dosage of Fe–PA complex (0.6mmol/L), dosage of H2O2 (60mg/L), pH of the reaction system (5.5) and contact time (30min). In addition, the excellent effect and low cost of Fe–PA complex in practical applications were determined by comparing those of conventional flocculation method, and these results illustrated an effective and economical method in pulp and paper wastewater treatment.

Modified polyurethane filling a bioreactor to remove organic pollutants and ammonia nitrogen in the pilot study.The results showed that at hydraulic retention time of 40 hours with 30% suspended carrier,the effluent concentrations of COD and NH3-N were less than 50 mg·L-1 and 5 mg·L-1 respectively under the influent COD,NH3-N concentrations of 200～100 mg·L-1,200 ～350 mg·L-1,effluent can meet the south along the water pollutant discharge standards(DB 37/599-2006) regional standards for protection.

采用Fenton氧化-电解-水解酸化-固定化微生物组合工艺处理塑料助剂废水，系统经调试试运行后，废水COD从8000mg·L^-1左右降为80mg·L^-1以下，处理效率达到99％，排放水质完全达到国家污水综合排放一级标准。

The combining advanced treatment of magnetization-mimic enzyme catalysis technology researched by Shandong Academy of Environmental Science, one of the drafting units for GB2544-2008 Wastewater Pollutant Discharge Standard for Pulp & Paper Industry, has been applied in many large-scale pulp and paper mills in China and made good results which has been up to the requirement of the new standard. This technology has been proved its technological and economical feasibility.

Plastic Additives Wastewater can be treated by means of Fenton oxidation-electrolysis-hydrolytic acidification-Immobilized microorganisms system, Thought debug. Through the operation of this project, the CODCr of effluent can Pall below 80 mg/L from about 8000 mg/L of influent, and also the removal rate can reach 99 %. Quality of effluent was up to the intregrated wastewater discharge standard of the national.

The paper introduces the major technologies of advanced treatment of pulp and paper effluent at present and analyzes the feature of the technologies and problems in application,then looks forward to the prospect of the technologies in advanced treatment of pulp and paper mill effluent.