Siting restrictions and proximity of Concentrated Animal Feeding Operations to surface water

Proximity and connections to surface waters may play significant roles in determining impacts of manure spills. As occurred in many U.S. states, Minnesota adopted in 2000 more stringent regulations on Concentrated Animal Feeding Operations (CAFOs) including restrictions on siting new facilities near surface waters. The objectives of this study were to determine whether CAFO proximity to surface waters decreased following the siting restrictions and to evaluate implications of siting restrictions. Permit dates, locations, and distances to nearest surface water bodies for 111 west central Minnesota CAFOs were determined based on satellite imagery, historical records, and correspondence with regulatory officials. Average distance between surface waters and facilities permitted after 2000 was greater than for facilities permitted before 2000. The increase in average distance between CAFOs and public surface waters was significant for open water (1790 m, p = 0.03), but not for streams (280 m, p = 0.47). Decreased CAFO proximity to surface waters should benefit water quality, but after 2000 facilities continued to be permitted close to hydraulic connections not covered by the siting restriction. Comprehensive manure spill tracking and long term targeted water quality monitoring are needed to evaluate effectiveness of siting restrictions and other strategies for protecting surface waters from manure spills.     

Influence of aeration modes on leachate characteristic of landfills that adopt the aerobic–anaerobic landfill method

As far as the optimal design, operation, and field application of the Aerobic–Anaerobic Landfill Method (AALM) are concerned, it is very important to understand how aeration modes (different combinations of aeration depth and air injection rate) affect the biodegradation of organic carbon and the transformation of nitrogen in landfill solid waste. Pilot-scale lysimeter experiments were carried out under different aeration modes to obtain detailed information regarding the influence of aeration modes on leachate characteristics. Results from these lysimeter experiments revealed that aeration at the bottom layer was the most effective for decomposition of organic carbon when compared with aeration at the surface or middle layers. Moreover, the air injection rate led to different nitrogen transformation patterns, unlike the lesser influence it has on organic carbon decomposition. Effective simultaneous nitrification and denitrification were observed for the aeration mode with a higher air injection rate (=1.0 L/min). On the other hand, the phenomenon of sequenced nitrification and denitrification could be observed when a low air injection rate (=0.5 L/min.) was employed. Finally, it is concluded that, for AALM, air injection with a higher air injection rate at the deepest layer near the leachate collection pipe tends to accelerate the stabilization of landfill waste as defined in terms of the enhancement of denitrification as well as organic carbon decomposition.     

Biodegradation and flushing of MBT wastes

Mechanical–biological treatment (MBT) processes are increasingly being adopted as a means of diverting biodegradable municipal waste (BMW) from landfill, for example to comply with the EU Landfill Directive. However, there is considerable uncertainty concerning the residual pollution potential of such wastes. This paper presents the results of laboratory experiments on two different MBT waste residues, carried out to investigate the remaining potential for the generation of greenhouse gases and the flushing of contaminants from these materials when landfilled. The potential for gas generation was found to be between 8% and 20% of that for raw MSW. Pretreatment of the waste reduced the potential for the release of organic carbon, ammoniacal nitrogen, and heavy metal contents into the leachate; and reduced the residual carbon remaining in the waste after final degradation from ～320 g/kg dry matter for raw MSW to between 183 and 195 g/kg dry matter for the MBT wastes.     

渗滤液回灌在实际应用中应注意的问题

本文介绍了垃圾填埋场渗滤液回灌的机理、优缺点,“干填埋”与“湿填埋”之间的区别。渗滤液回灌可增加填埋废物的含水率,加快垃圾的降解速率,减少渗滤液的处理时间,提高填埋气中甲烷的含量,加速填埋场稳定化进程。鉴于以上这些优点,渗滤液回灌作为一种渗滤液处理方式将会有极大的应用前景。但在实际应用中回灌的渗滤液容易泄漏而导致地下水污染,这是影响渗滤液回灌广泛应用的主要原因。为了避免使地下水受污染,本文总结和分析了渗滤液回灌在实际应用中应注意的问题。     

煤泥水治理技术综述

本文综合评述了目前煤泥水的几种处理措施,比较了它们的优缺点和应用过程中需注意的一些问题,提出应加强对特殊煤泥水治理技术的研究.     

磷酸氨镁法处理晚期垃圾渗滤液氨氮最佳工艺条件

高浓度氨氮（NH^＋4-N）是造成晚期垃圾渗滤液难以生物处理的重要原因之一,当前物化法处理垃圾渗滤液中氨氮存在不足。磷酸氨镁（MAP）沉淀法可以彻底地去除晚期垃圾渗滤液中NH^＋4-N,而且生成的沉淀物是非常好的缓释肥料,具有较高的经济价值及应用前景。研究结果表明,最佳的工艺条件为：pH=8.5-9.5,n（N）：n（Mg）：n（P）=1：1：1时,处理效果较好,NH^＋4-N去除率大于96％,且残余总磷（TP）浓度小于原水值。     

Particle-facilitated lead and arsenic transport in abandoned mine sites soil influenced by simulated acid rain

The role of acid rain in affecting Pb and As transport from mine tailings was investigated by pumping simulated acid rain at a infiltration rate of 10.2 cm/h through soil columns. Simulated acid rain with pH of 3.0, 4.5 and 5.6 were used as leaching solutions. Results showed that 86.9–95.9% of Pb and 90–91.8% of As eluted from the columns were adsorbed by particles in the leachates. Scanning electron microscopy (SEM) analysis showed that particles released from the columns were mainly composed of flocculated aggregates and plate or rod shaped discrete grains. Transmission electron microscopy (TEM) coupled with energy dispersive X-ray analysis (EDX) showed that these particles were predominantly silicate minerals. Results from our experiments demonstrated that when rapid infiltration conditions or a rainstorm exist, particle-facilitated transport of contaminants is likely to the dominant metal transport pathway influenced by acid rain.     

Leachate from market refuse and biomethanation study

The market place is considered to be an important centre of daily life of campus community. In India, as in Europe and the USA, other forms of shopping have emerged significantly and now predominate, for instance department stores and supermarkets. Though, it is suffered from poor waste management, but the place could be a potential source for obtaining non-conventional energy. The present study examined the quality of market waste management of the Indian Institute of Technology Campus along with the feasibility of biogas production from leachate generated in the waste. Solid wastes from different storage locations of the market place were collected and analyzed. The characteristics of solid wastes were found to be degradable in nature. The wastes, composed of 85% of vegetable origin, were placed in a container and water was added to to generate leachate. The self-purification efficiency of leachate was also studied in the Indian environment and compared with research findings in the USA under an identical moisture application rate. Leachate characterization was investigated both under saturated and submerged conditions. The treatability of leachate was studied in a laboratory-scale up-flow anaerobic filter with hollow burnt clay rings as packing media. It was observed that 4,000–6,000 mg/l would be the optimum range of inlet chemical oxygen demand (COD) concentration for leachate treatment because of the inhibitory effect of ammonia, sulphide, volatile fatty acids and toxic metals in high concentrations at higher strengths of leachate. The gas production rate was found to be at a maximum at 38°C and containing 70–75% methane. From experimental data, it was revealed that 83% COD was removed with input COD concentration of 5,475 mg/l at 2 days hydraulic retention time with biogas yield coefficients of 0.61. The present study also investigated the removal efficiency of chloride, ammonia, sulphide and nitrate.     

不同填埋结构渗滤液回流对填埋场渗滤液水质的影响

通过分析不同填埋结构下渗滤液回灌对填埋垃圾产生的渗滤液水质的影响,进一步验证"生物反应器"的原理,为今后垃圾填埋场合理选择填埋方式及渗滤液回灌的开展提供相应参数。     

Degradation of chlorinated dioxin in denitrifying activated sludge from leachate treatment plant of a landfill

The degradation rate of dioxins added to the activated sludge from a leachate treatment plant of a landfill under denitrification conditions was estimated using six bioreactors. Over 99% of the added dioxins (600ng) were degraded within 7 days. Furthermore, continuous cultivation was carried out for 1 month. The activated sludge degraded 600ng of dioxins (that is, all of the added dioxins) placed in each reactor every 7 days, and this activity was maintained for 35 days. Under aerobic conditions with this sludge, the dioxins were not degraded in 7 days, but 90% of the 600ng of dioxins was degraded in 35 days. The high level of activity observed in the present study may only occur under anaerobic conditions, especially under denitrifying conditions.