Current and future solid waste management system in Northern Viet Nam with focus on Ha Noi: climate change effects and landfill management

The contribution investigates the solid waste management system in Ha Noi under consideration of the interrelation between climate change effects and landfill management by means of a cause-and-effect-analysis as well as water balances using the HELP 3.95 model and gas emission data, followed by a Strength, Weakness, Opportunities, Threats (SWOT) analysis. Even landfills are sources of methane (CH₄) emissions they are also impacted by climate change. The main effects on landfill sites are the change of climatic conditions, namely the regional water balance, extreme precipitation and storm events. The results of the water balance model results show that a geomembrane surface sealing can reduce the leachate formation significantly, a fact that is also valid for the climate change scenario with higher precipitation. The risk of flooding and erosion at the landfill sites increases, which will require a customized water management. In parallel landfill gas offers the opportunity for recovery of Greenhouse Gases (GHG) and the generation of renewable energy. Some further management options are wind turbines, photovoltaic systems or biomass for biogas conversion, which was grown on closed landfill sites. The inclusion of climate friendly management options of closed landfills in a “Good Landfill Aftercare Practice” is recommended.     

Suitability of passive sampling for the monitoring of pharmaceuticals in Finnish surface waters

The occurrence of five pharmaceuticals, consisting of four anti-inflammatory and one antiepileptic drug, was studied by passive sampling and grab sampling in northern Lake Päijänne and River Vantaa. The passive sampling was performed by using Chemcatcher® sampler with a SDB-RPS Empore disk as a receiving phase. In Lake Päijänne, the sampling was conducted during summer 2013 at four locations near the discharge point of a wastewater treatment plant and in the years 2013 and 2015 at four locations along River Vantaa. The samples were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The concentrations of carbamazepine, diclofenac, ibuprofen, ketoprofen, and naproxen in Lake Päijänne determined by passive sampling ranged between 1.4–2.9 ng L^?1, 15–35 ng L^?1, 13–31 ng L^?1, 16–27 ng L^?1, and 3.3–32 ng L^?1, respectively. Similarly, the results in River Vantaa ranged between 1.2–40 ng L^?1, 15–65 ng L^?1, 13–33 ng L^?1, 16–31 ng L^?1, and 3.3–6.4 ng L^?1. The results suggest that the Chemcatcher passive samplers are suitable for detecting pharmaceuticals in lake and river waters.     

Does the Temporal Resolution of Precipitation Input Influence the Simulated Hydrological Components Employing the SWAT Model?

This study aimed to evaluate the influence of sub‐daily precipitation time steps on model performance and hydrological components by applying the Green and Ampt infiltration method using the Soil and Water Assessment Tool (SWAT). Precipitation was measured at a resolution of 0.1 mm and aggregated to 5‐, 15‐, 30‐, and 60‐min time steps. Daily discharge data over a 10‐year period were used to calibrate and validate the model. Following a global sensitivity analysis, relevant parameters were optimized through an automatic calibration procedure using SWAT‐CUP for each time step. Daily performance statistics were almost equal among all four time steps (NSE ≈ 0.47). Discharge mainly consisted of groundwater flow (55%) and tile flow (42%), in reasonable proportions for the investigated catchment. In conclusion, model outputs were almost identical, showing simulations responded nearly independently of the chosen precipitation time step. This held true for (1) the selection of sensitive parameters, (2) performance statistics, (3) the shape of the hydrographs, and (4) flow components. However, a scenario analysis revealed that the precipitation time step becomes important when saturated hydraulic conductivities are low and curve numbers are high. The study suggests that there is no need in using precipitation time steps <1 h for lowland catchments dominated by soils with a low surface runoff potential if daily flow values are being considered. Editor's note : This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series.     

The response of a mid- and high latitude peat bog to predicted climate change: methane production in a 12-month peat incubation

There are fears that global warming will lead to degradation of peatlands, higher emissions of greenhouse gases from peat, and accelerated warming. Anaerobic decomposition of organic soils produces methane (CH₄), a potent greenhouse gas. Two peat bogs differing in mean annual temperature, Velke Darko (VD, Czech Republic, 7.2 °C), and Stor Åmyran (SA, Sweden, 4.0 °C), were selected for a comparative study of how organic soils in different climatic zones will respond to warmer and drier conditions. Twenty peat cores from each bog were incubated in growth chambers. Under present-day summer conditions, VD produced 14 times more CH₄ than SA. Two different warming scenarios were used. Peat-core replicates were kept at temperatures of 11 versus 16 °C, and 11 versus 22 °C. From 11 to 16 °C, the CH₄ production slightly decreased at SA, and slightly increased at VD. From 11 to 22 °C, the CH₄ production increased 9 times at SA, but slightly decreased at VD. After an 8-month incubation, peat cores under drying conditions (water table at ?14 cm) were compared to samples with original water table (?2 cm). Drying conditions led to a steeper reduction in CH₄ production at VD, compared to SA. The CH₄ production decreased more than 100 times at VD. Then, the combined effect of simultaneous warming and drying at 11 and 22 °C was studied. We did not find any significant effect of interactions between increasing temperature and decreasing water table level. Overall, the warmer site VD responded more strongly to the simulated climate change than the colder site SA.     

Potentials and impacts of short-rotation coppice plantation with aspen in Eastern Germany under conditions of climate change

Woody biomass generated in short-rotation coppice (SRC) plantations with aspen (Populus tremula L.) has good properties for bioenergy crop production: annual yields are high, labour input per year is low, and it is ecologically valuable because of the multi-year rotation periods. Eastern Germany has a special advantage in producing bioenergy crops: the former “agricultural cooperatives” built up quite large farms with, compared to Western Germany, comparatively large fields. Therefore, a modelling study of the potential and the impacts of aspen SRC plantations in the five eastern federal states of Germany under the recent climate and future climate projections was conducted. The ecophysiological forest growth model 4C was used to simulate the growth of aspen SRC plantations and their impacts on carbon in soils, and groundwater recharge, on selected suitable areas currently under crops but with marginal site conditions for cropping. A clear signal to enhanced growth condition over the whole area can be seen in the simulation of the mean annual woody biomass yield under conditions of climate change, which increased from 7.47 t DW ha⁻¹ a⁻¹ under the recent climate to 9.26 t DW ha⁻¹ a⁻¹ at the end of the considered future period 2034–2055 under climate change. The mean soil carbon sequestration rate was 0.81 t C ha⁻¹ a⁻¹ under the recent climate and could rise up to 0.93 t C ha⁻¹ a⁻¹ under the assumption of climate change. On the other hand, the mean annual percolation rate, used as an indicator of impacts on the regional water budget, will diminish under future climatic conditions. The results suggest that aspen SRC plantations are a suitable contribution to regional CO₂ mitigation and carbon sequestration under possible change of climate, but that negative impacts on the regional water budget are possible.     

Toxicological characterization of the landfill leachate prior/after chemical and electrochemical treatment: A study on human and plant cells

In this research, toxicological safety of two newly developed methods for the treatment of landfill leachate from the Piškornica (Croatia) sanitary landfill was investigated. Chemical treatment procedure combined chemical precipitation with CaO followed by coagulation with ferric chloride and final adsorption by clinoptilolite. Electrochemical treatment approach included pretreatment with ozone followed by electrooxidation/electrocoagulation and final polishing by microwave irradiation. Cell viability of untreated/treated landfill leachate was examined using fluorescence microscopy. Cytotoxic effect of the original leachate was obtained for both exposure periods (4 and 24 h) while treated samples showed no cytotoxic effect even after prolonged exposure time. The potential DNA damage of the untreated/treated landfill leachate was evaluated by the comet assay and cytokinesis-block micronucleus (CBMN) assay using either human or plant cells. The original leachate exhibited significantly higher comet assay parameters compared to negative control after 24 h exposure. On the contrary, there was no significant difference between negative control and chemically/electrochemically treated leachate for any of the parameters tested. There was also no significant increase in either CBMN assay parameter compared to the negative control following the exposure of the lymphocytes to the chemically or electrochemically treated landfill leachate for both exposure periods while the original sample showed significantly higher number of micronuclei, nucleoplasmic bridges and nuclear buds for both exposure times. Results suggest that both methods are suitable for the treatment of such complex waste effluent due to high removal efficiency of all measured parameters and toxicological safety of the treated effluent.