城市污水处理厂污泥农用研究

徐州某污水处理厂主要负责处理徐州市奎河流域排放的生活污水和工业废水,采用普通活性污泥法工艺,污泥处置与利用方式为外运。笔者以该厂脱水压滤后的污泥为对象,分析了其中植物营养素(N,P,K)、重金属等含量的分布特点,并进行了污泥与稻草混合堆肥试验,观测堆肥过程中温度、pH值、有机质、氮磷钾、硝酸盐氮、氨氮及重金属含量等参数的变化情况,结果表明该厂污泥具有很好的农用前景。     

排泥水沉淀物与废弃果渣制备生物肥料的pH值试验

[目的]以排泥水泥淀物和废弃果渣为原料制取生物肥料。[方法]以水厂排泥水沉淀物、废弃果渣为培养基的主要原料,接入酵素菌,通过固体发酵,使其转化为生物肥料。[结果]试验表明,pH值在整个菌种生长繁殖过程中起决定性作用,pH值在6.8以上时,菌种无法生存和繁殖。[结论]排泥水沉淀物、废弃果渣用量对培养基的pH值影响很大。     

重金属对固化污泥强度的影响

[目的]研究污泥中重金属对固化污泥强度的影响。[方法]将加入重金属后的污泥与水泥和石英砂分别按1：2：3、1：3：3、1：5：3的比例进行配制,用不加重金属的污泥配制相应的控制样,将固化后的试样置于养护箱内,在标准养护条件下分别养护7、14、28d后测定其无侧限抗压强度和抗折强度。[结果]养护7、14d时,3种固化方案配制的固化污泥无侧限抗压强度与控制样的差异均小于养护28d时;且养护28d时固化样的抗折强度均小于各自的控制样。[结论]污泥中的重金属对污泥固化体强度的发展具有不利影响。     

城市污水处理厂污泥土地利用的可行性研究

污水污泥产生量大且成份复杂,除少量得到有效处置外,大部分污泥最终出路不明确。污泥处置环节存在潜在环境风险。结合上海某污水处理厂污水污泥性质,对比分析了国内外的污水污泥控制标准及国内外较为成熟实用的土地利用方式的利弊,讨论了污泥土地利用的可行性。认为经过处理后的污水污泥可用于绿化用土、土壤改良,并应加强污泥制片流通环节的管理。     

污水—土壤—植物系统资源再生的关键生态过程及风险控制

综合分析了污水—土壤—植物系统资源再生的关键生态过程、工程风险来源,总结了进行系统结构优化、工艺参数核算、强化布水与集排水以及加强监测等风险控制对策。指出该系统实质是基于生态系统物质循环,以水资源和植物资源再生为主要特征的循环经济模式,是污水生态处理与回用技术和植物资源开发利用技术的有机结合体,兼具低成本、高经济效益和生态效益,可因地制宜,形式多样地促进水污染治理、节约水资源,适合中国国情。     

对环境友好型小区景观设计的几点思考

针对环境友好型小区景观建设的绿化指标、地面保水指标、节水指标以及污水、垃圾处理指标,指出了环境友好型小区景观设计应以植物材料的设计为基础,有效进行垃圾分类和有机垃圾的再利用,建立集雨园,进行地表覆盖、特种绿地的绿化,建立乔灌草的复层立体绿化模式替代单一的草坪绿化模式,同时倡导室内绿化。     

不同种污泥胞外聚合物的提取方法与组成特征

针对废水生物处理系统中各类污泥的功能与结构特点,比较了常用胞外聚合物(EPS)提取方法的效能优劣,并从反应器溶解氧条件、微生物营养类型和污泥空间形态等方面对不同种污泥的EPS组成特征进行了分析,重点强调了EPS组分在培养全自养脱氮颗粒污泥等特殊微生物聚集体中的重要作用。     

Effect of different C/N ratios and hydraulic retention times on denitrification in saline,recirculating aquaculture system effluents

Data on operation and performance of cost-effective solutions for end-of-pipe removal of nitrate from land-based saltwater recirculating aquaculture systems (RAS) are scarce but increasingly requested by the aquaculture industry. This study investigated the performance of a (semi)commercial-scale fixed-bed denitrification unit using single sludge for treating effluent from a commercial, saltwater RAS used for production of Atlantic salmon (Salmo salar). A fixed-bed denitrification reactor was fed continuously with 3-days hydrolyzed sludge from the commercial RAS, and was operated at different hydraulic retention times (HRTs; 1.82, 3.64, 5.46, or 7.28 h) or influent C/N ratios (3, 5, 7, or 10). Twenty-four h pooled samples were collected from the inflowing RAS water and the hydrolyzed sludge as well as from the denitrification reactor outlet, and samples were analyzed for nutrients and organic matter content.Nitrate removal rates increased consistently with decreasing HRT (from 64.3 ± 5.2–162.7 ± 22.0 g NO₃-N/m³/d within the HRTs tested) at non-limiting C/N ratios, while nitrate removal efficiencies decreased (from 99.6 ± 0.3–58.2 ± 8.9 %). With increasing influent C/N ratios at constant HRT (3.64 h), nitrate removal rates increased until the removal efficiency was close to 100 % and nitrate concentration in the denitrification reactor became rate-limiting. A maximum nitrate removal rate of 162.7 ± 2.0 g NO₃-N/m³/d was achieved at a HRT of 1.82 h and an influent C/N of 6.6 ± 0.5, while the most efficient use of hydrolyzed sludge (0.19 ± 0.02 g NO₃-N removed/g sCOD supplied) was obtained with a HRT of 3.64 h and a C/N ratio of 2.9. Removal rates of organic matter significantly and consistently increased with decreasing HRT and increasing C/N ratio. In addition, reducing HRT and increasing C/N ratios significantly improved removal of total phosphorus (TP) and PO₄-P.In conclusion, optimal management of the operating parameters (HRT and C/N ratio) in a single-sludge denitrification process can significantly reduce the discharge of nitrogen, organic matter, and phosphorous from land-based saltwater RAS and thus contribute to increased sustainability.     

Anaerobic digestion of solid waste in RAS: effect of reactor type on the biochemical acidogenic potential (BAP) and assessment of the biochemical methane potential (BMP) by a batch assay

Anaerobic digestion is a way to utilize the potential energy contained in solid waste produced in recirculating aquaculture systems (RASs), either by providing acidogenic products for driving heterotrophic denitrification on site or by directly producing combustive methane. In this study the biochemical acidogenic potential of solid waste from juvenile rainbow trout was evaluated by measuring the yield of volatile fatty acids (VFA) during anaerobic digestion by batch or fed-batch reactor operation at hydrolysis time (HT)/hydraulic retention time (HRT) of 1, 5, or 10 days (and for batch additional 14 and 20 days) in continuously stirred tank reactors. Generally, the VFA yield increased with time and no effect of the reactor type used was found within the time frame of the experiment. At 10 days HT or 10 days HRT the VFA yield reached 222.3 ± 30.5 and 203.4 ± 11.2 mg VFA g⁻¹ TVS₀ (total volatile solids at day 0) in batch and fed-batch reactor, respectively. For the fed-batch reactor, increasing HRT from 5 to 10 days gained no significant additional VFA yield. Prolonging the batch reactor experiment to 20 days increased VFA production further (273.9 ± 1.6 mg VFA g⁻¹ TVS₀, n = 2). After 10 days HT/HRT, 16.8–23.5% of total Kjeldahl N was found as TAN and 44.3–53.0% of total P was found as ortho-phosphate. A significant difference between reactor types was detected for the phosphorous dissolution at 5 days HT/HRT as a relatively steep increase (of a factor 2–3) in ortho-P content occurred in fed-batch reactors but similar steep increase was only notable after 10 days HT for batch reactors. No differences between reactor types at the other HT/HRT were recorded for P as well as (for all HT/HRT for) N. Based on this study a HRT of approximately 5 days would be recommended for the design of an acidogenic continuously stirred reactor tank in a RAS single-sludge denitrification set-up. The biochemical methane potential of the sludge was estimated to 318 ± 29 g CH₄ g⁻¹ TVS₀ by a batch assay and represented a higher utility of the solid waste when comparing the methane yield with the VFA yield (in COD units). This points toward a technological challenge of ultimately increase the acidogenic output to match the methane yield as both products are formed from the same source.     

寒地黑土特色生态农业中循环经济模式的应用——以绥化市为例

中国东北的寒地黑土是世界三大黑土资源之一。绥化市处于几块典型黑土地的中心地带,把循环经济模式引入到寒地黑土特色生态农业是必然的选择。从循环经济模式应用在绥化市生态农业建设的视角来看,绥化市农业产业发展战略应定位在发展绿色农作物种植业、资源利用型畜牧业、农产品加工贸易及寒地特色农业观光旅游业等方面。