Insight into an Integrated Evaluation of Unmitigated Disposal Options for the Largest Waste Disposal Site in Tehran Using Rapid Impact and Sustainability Assessment Method

This study integrated the rapid impact assessment matrix (RIAM) analysis and the mathematical sustainability modeling to evaluate disposal options so as to find the most appropriate and practical unmitigated option for the main waste disposal site in Tehran, Iran. RIAM analysis was used to assess environmental impacts of five potential disposal options followed by determination of sustainability for each option. RIAM analysis results indicated that option 5 (i.e., composting) had the least negative cumulative impacts on the environmental score value of -481 among the studied options. Incineration of wastes, option 4, was found to be the least favorable option mainly due to the high relevant costs and emission of air pollutants. Option 3, sanitary landfilling, was found to have fewer negative impacts compared to the options 1 (open dumping), 2 (land burial), and 4. It was also found that none of the examined options were sustainable in unmitigated state; however, results indicated that option 5 was the most favorable one in terms of sustainability with an obtained sustainable value of -0.126, which was the lowest value of unsustainability found in the present study. Calculated values of environment for the evaluated options in unmitigated state were not sufficient enough to compensate for the corresponding values of human needs and interests. Finally, option 5 followed by option 3 were suggested as alternative disposal approaches for the current methods in unmitigated state to reduce negative environmental impacts of waste disposal

Temporal and depth variation of water quality due to thermal stratification in Karkheh Reservoir, Iran

Study region: Karkheh Dam Reservoir (KDR) located in western Iran. Study focus: To date, there has been no research in the KDR that investigates the interconnections among thermal stratification (ThS), water quality, and nutrients, based on field measurements. This study explored the temporal trend of ThS in the KDR and its interrelationship with water quality parameters based on data measured from 2005–2006. New hydrological insights for the region: The results showed that a noticeable ThS in the KDR starts in late April and continues until early December. The strongest ThS occurs during late summer when the water temperature difference between the surface and bottom layers in the reservoir exceeds 18 °C. As a result of external forces that generally intensify in December, vertical water circulation occurs, and by January and February there is a minimal temperature gradient between the surface and bottom layers. During ThS, dissolved oxygen (DO) is strongly confined by the metalimnion and does not penetrate into the hypolimnion. However, even during late December to February, there is a large difference between DO concentration in the surface and bottom layers, which indicates limited mixing. Ammonium increasing and nitrate decreasing with depth was observed, likely due to denitrification (in the bottom layers) and nitrification (in the surface layers), respectively. The results of the present study provide new information on the spatio-temporal variation of water quality in large reservoirs, which is important for stakeholders with concerns related to lake and reservoir eutrophication and water quality issues

A critical review on the application of the National Sanitation Foundation Water Quality Index

Many studies have employed the National Sanitation Foundation Water Quality Index (NSFWQI) with non-original rather than originally defined parameters of the model, particularly when incorporating fecal coliform (FC), total solids, and total phosphates as inputs. For this reason, this study aimed to perform a critical review on the application of the NSFWQI to explore the amount of change that can be expected when users employed non-original parameters (such as orthophosphate and total dissolved solids/total suspended solids instead of total phosphorous and total solids, respectively), or different units (FC based on the maximum probable number (FC-MPN) rather than the colony forming unit (FC-CPU)). To demonstrate the influence of originally defined inputs on NSFWQI results, various scenarios were investigated. These scenarios were generated using different possible inputs to the NSFWQI, altering the FC, total solids, and total phosphorous parameters obtained from the monitoring stations of the Sefidroud River in Iran. Considerable differences were observed in the NSFWQI values when using orthophosphate and total suspended solids, instead of the originally defined data (i.e., total phosphorous and total solids), in the model (first scenario). In this case, the number of stations with “good” water quality increased from one to seven when compared with the first scenario results. In addition, unlike the results of the first scenario, none of the stations were classified as class IV (i.e., “bad” water quality status). However, the results of the implemented scenarios presented a more favorable water quality status than those obtained using the first scenario (except the second scenario which included FC-MPN rather than FC-CFU). Using total dissolved solids instead of total solids and FC-MPN rather than FC-CPU, resulted in fewer changes. In both cases, the average of the NSFWQI values in the river classed all stations as “medium” and “bad” water quality for the wet and dry seasons, respectively. Proper application of NSFWQI is important to provide high quality results for evaluation of water bodies, particularly when incorporating total solids and total phosphorous as inputs. The findings showed substantial changes in NSFWQI results when using orthophosphate and total suspended solids instead of total phosphorous and total solids, respectively. Using total dissolved solids instead of total solids and FC-MPN rather than FC-CPU, resulted in fewer changes. Generally, results indicated that the river water quality status in the wet season was better than during the dry season so that none of the scenarios classified the river water quality as “bad” (in terms of water quality status) in the wet season. Meanwhile, the river water quality was classified as “bad” for three scenarios in the dry season

Effect of forest-based biochar on maturity indices and bio-availability of heavy metals during the composting process of organic fraction of municipal solid waste (OFMSW)

Abstract The main objective of this study was to investigate the effect of biochar on the composting process of the organic fraction of municipal solid waste (OFMSW) under real conditions. Different doses of biochar (1%, 3%, and 5%) were mixed with compost piles to evaluate the variation of temperature, moisture content (MC), organic matter (OM), carbon (C), nitrogen (N), C/N ratio, and heavy metal (HM) contents in comparison with the control treatment (with 0% biochar addition). The results of this study showed that the compost piles combined with different doses of biochar had higher MC. The use of biochar as an additive, even at low doses (1%), was able to increase the compost quality through the reduction of N losses during the composting process. The highest reduction of OM during the composting process was observed in the control pile (without biochar addition) by 48.06%, whereas biochar affected the biodegradability of OM and prevented the reduction of nutrients during the composting process under real conditions. The contents of HMs (Pb, Zn, Ni, Cd, and Cu) showed a significant reduction in all of the compost piles combined with biochar in comparison with the control treatment. Considering that in terms of all compost quality indicators, the piles combined with biochar can regarded as high standard product, the composts obtained from combining the OFMSW with different biochar doses have desirable features to be used as an amendment agent to improve agricultural soil quality