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New Zealand's Greenhouse Gas Inventory (the NZ Inventory) currently estimates methane (CH4) emissions from anaerobic dairy effluent ponds by: (1) determining the total pond volume across New Zealand; (2) dividing this volume by depth to obtain the total pond surface area; and (3) multiplying this area by an observational average CH4flux. Unfortunately, a mathematically erroneous determination of pond volume has led to an imbalanced equation and a geometry error was made when scaling-up the observational CH4flux. Furthermore, even if these errors are corrected, the nationwide estimate still hinges on field data from a study that used a debatable method to measure pond CH4emissions at a single site, as well as a potentially inaccurate estimation of the amount of organic waste anaerobically treated. The development of a new methodology is therefore critically needed. [ABSTRACT FROM PUBLISHER]

Organic matter from salmon farms has been shown to be assimilated by soft sediment and rocky reef communities within the ecological footprint of salmon farms. Given these findings, another question arises – What other chemicals in salmon feed may be assimilated into wild communities via organic waste from salmon farms? Here we measured a suite of organic contaminants in salmon feed, in organisms used in a controlled feeding experiment, and in reef species collected within the depositional footprint of salmon farms. Gas Chromatography-Tandem Mass Spectrometry was used to quantify trace concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and current-use (CPUs) and historic-use pesticides (HUPs) in salmon feed imported to New Zealand. The effect of assimilation of farm-derived organic matter on contaminant profiles differed among species during the controlled feeding experiment and demonstrated that migration of individuals to a farm-associated site has the potential to increase or decrease organic contaminant concentrations. Concentrations of PCBs in Parapercis colias (blue cod), a highly resident, long-lived fish, were significantly higher at farm sites than at reference sites. While these concentrations were relatively low in a global context, this result presents blue cod as an important candidate for future monitoring of organic contaminants around point sources. PCBs and PBDEs measured in wild marine species were all below limits set by the European Union, whereas concentrations of certain HUPs, specifically dichlorodiphenyltrichloroethane (DDT) and its degradation products and endosulfan, may be of concern as a consequence of alternative anthropogenic activities. Overall, feed imported to New Zealand had relatively low levels of most organic contaminants that, at current levels, are unlikely to result in significant ecological effects to wild communities in adjacent habitats. [Display omitted] • Contaminant concentrations in feed imported to New Zealand akin to alternate feeds. • Sixteen organic contaminants detected across seven feed samples. • Blue cod are key bio accumulators of organic contaminants from points sources. • PCB and PBDE concentrations in farm-associated consumers within specified limits. [ABSTRACT FROM AUTHOR]

Treatment of wastewater generally results in elevated natural 15 N abundance (d 15 N) in the effluent and sludges. For example, high d 15 N values are found in treated sewage effluent, biosolids, and other wastes that are commonly applied to land. In contrast, N deficient coniferous forest soils usually have a low d 15 N. When wastes with high d 15 N values are applied to land, their distinctive d 15 N signature can potentially be used to trace the fate of waste-derived N in the ecosystem. In this paper, we provide an overview of the use of d 15 N in land application of wastes, including New Zealand case studies on tracing nitrogen in forest ecosystems. [ABSTRACT FROM AUTHOR]

The article investigates the levels of pulp mill-sourced organic compounds and sodium in water and sediment samples taken from the Tarawera River in New Zealand. Two pulp mills have for more than thirty five years, discharged effluent waters to the Tarawera River located in the township of Kawerau. The researchers have reported the presence in water samples taken from the lower reaches of the river, of a variety of pulp mill-sourced compounds including, fatty acids, resin acids, and some chlorophenolic compounds. A unique aspect of the effluents was the presence of appreciable quantities of abietan-18-oic acid, a saturated resin acid and four degraded resin hydrocarbons, namely fichtelite, dehydroabietin, tetrahydroretene and retene.

The arsenic concentration is an important issue in compost production. The main inputs of a compost factory, including kerbsides, green wastes, food industry wastes, and river weeds are investigated in this study. Also, this study investigated how treated timbers, ashes, and other contamination can impact arsenic concentration in compost production. The results showed that most treated timbers and all ashes of treated and untreated timbers contained significant amounts of arsenic. These results revealed that the presence of a small amount of treated timber ashes can significantly increase the arsenic concentration in composts. The results of the study show the arsenic concentration in compost increase during cold months, and it dropped during summer, which would be mostly because of high arsenic concentration in ashes of log burners. This study shows ashes of burning timbers can impact arsenic contamination mostly because of using Copper-Chrome-Arsenic wood preservatives (CCA). Also, the lab results show the arsenic level even in ashes of untreated timber is around 96 ppm. The ashes of H3, H4, and H5 treated timbers contain approximately 133,000, 155,000, and 179,000 ppm of arsenic, which one kg of them can increase arsenic concentration around 10 ppm in 13.3, 15.5 and 17.9 tons of dry compost products. The main problem is many people look at ashes and treated timber as organic materials; however, ashes of treated and untreated timbers contained high concentrations of arsenic. Therefore, it was necessary to warn people about the dangers of putting any ashes in organic waste bins. Image 1 • The arsenic concentration in compost increases during cold months, and it dropped during summer. • The arsenic concentration would be mostly because of high arsenic concentration in ashes of log burners. • This study shows ashes of burning timbers can impact arsenic contamination mostly because of using Copper-Chrome-Arsenic wood preservatives (CCA). Main finding: Treated timbers and ashes of burning timbers would be the main source of arsenic contamination in compost products in New Zealand mostly because of using Copper-Chrome-Arsenic wood preservatives (CCA) and. [ABSTRACT FROM AUTHOR]

• Three strategies for enhancing AD of organic wastes are presented. • Balancing biomass composition can ensure the optimum digestion process. • Both macro and microelements adjustment can diminish digestion time. • Carbon source DIET promoting additives improve AD via adsorption potential. • Neutral red can increase biogas generation by promoting DIET potential. Anaerobic digestion (AD) is one of the most promising technologies that can break the complex organic substrate into biogas. However, biogas production from biomass waste and its utilization for energy applications are still challenging due to the complex physical and chemical properties of organic waste, which affect the metabolic pathways and methane content. Consequently, attentions have focused on opportunities for further improvement in biogas yield and quality. This review identified the technical challenges associated with AD and potential solutions for improving biogas production. The critical steps toward improving biogas generation were identified as balancing the waste composition; adjusting nutrient content using trace elements; and using direct interspecies electron transfer (DIET) promoting additives. Direct interspecies electron transfer (DIET) promoting additives such as activated carbon, biochar and phenazine have shown a considerable effect on biogas production. These additives facilitate the electron transfer via direct interspecies electron transfer and improve digestibility via adsorption potential. The last section of the review describes a case study of the potential of using biochar and neutral red (phenazine) additives in one of the commercial landfills in the North Island of New Zealand. The results of this case study indicate that application of "neutral red" in the landfill site can significantly improve biogas generation for a period of 70 years. [ABSTRACT FROM AUTHOR]