Improving sustainability through effective reuse of product returns: minimizing waste in a batch blending process environment

A case study of a successful reuse program in a batch blending production environment is presented. This program involves not only addressing the company's own potential waste, but also working with distributors and customers to take back and reuse product, thus eliminating the customers' burden of disposal. Implications of the program for downstream supply chain partners are identified and a structured approach for implementation is presented. Modification for use in similar production environments is possible, enhancing sustainability, while providing environmental as well as economic benefits.     

化学除磷在中水回用工程中的运用和控制条件

以中水回用工程中总磷的去除为研究对象,考察了化学除磷方法中影响除磷效果的几个因素及其控制条件。结果表明,GT值对化学除磷的效果影响很大;在适当的混凝搅拌条件下聚合硫酸铁对总磷具有良好的去除效果,可使剩余总磷降到0.5 mg/L以下,满足中水回用水质标准。     

稠油采出水回用热采锅炉供水的处理工艺设计

运用混凝沉降、溶气浮选、粗精过滤和弱酸软化方法对稠油采出水进行深度处理。可达到热采锅炉用水指标 ,回用热采锅炉供水 ;生产装置产生的污水、污油、污泥均回收利用。笔者总结了流程选择、工艺配置、新工艺的采用、工艺及自控设计特点 ,为今后污水处理设计提供借鉴。     

城市污水再生与农业再用

概述了我国农业缺水现状和未经处理的城市污水在缺水地区造成的污染问题。以及结合国内外已有实践与经验，阐明了在缺水地区将城市污水再生再用于农业的优点和必要性，并提出了有关的实施对策。     

Evaluating greywater reuse potential for sustainable water resources management in Oman

This study aims to evaluate the potential of greywater availability in Muscat Governorate in the Sultanate of Oman, to establish a methodology for greywater quantity estimation, to test greywater quality in order to assess reuse potential, and to examine public acceptance for reuse.Total fresh water consumption and greywater generation from different household sources were measured by water meters in five selected households during summer and winter. Additionally, a survey was designed and conducted in five administrative areas of Muscat Governorate, with the objective of testing a methodology for estimating greywater generation potential in these areas. Collected data were compared with that used by the Ministry of Housing, Electricity and Water, Sultanate of Oman. The survey covered a total of 169 houses and 1,365 people. Greywater samples were collected and analyzed from showers, laundries, kitchens and sinks in some of these households to determine their water quality parameters. Statistical analysis results indicated that there is no significant variance in the total fresh water consumption between data used by the ministry and those measured and estimated during this study, highlighting the applicability of the tested method. The study concluded that the average per capita greywater generation rate is 151 Lpcd. Greywater production ranged from 80 to 83% of the total fresh water consumption and most of the greywater is generated from showers. Further, 55 to 57% of the greywater generated in a typical Omani household originated from the shower, 28 to 33% originated from the kitchen, 6 to 9% originated from laundry, and 5 to 7% originated from sink, which constitutes approximately 81% of the total fresh water consumption. The physical, chemical, and biological analyses of the grab samples revealed that greywater contains significant levels of suspended solids, inorganic constituents, total organic carbon, chemical and biochemical oxygen demands, total Coliforms and Escherichia Coliform bacteria. The public acceptance survey illustrated that approximately 76% of the respondents accepted the reuse of greywater for gardening, 53% for car washing and 66% for toilet flushing.     

我国城市污水回用现状及前景

通过对我国水资源状况和不处理状况的论述，说明了我国城市污水回用的紧迫性、必要性，分析了我国城市污水利用的现状和回用水利用的模式，提出了下一步应解决的问题的思路，展望了我国城市污水回用的前景，以实现水资源开发利用的可持续性发展。     

Towards a Closed-Loop Materials Economy

Abstract

This paper introduces the recent appearance of a circular economy in such industrialized countries as Germany and Japan and outlines its concept and principles. The author emphasizes that a circular economy should become the breakthrough point for sustainable development and will enable a shift to a sustainable society of “doing less with less” away from the current high-consumption society of “doing more with more”     

Towards a Closed-Loop Materials Economy

This paper introduces the recent appearance of a circular economy in such industrialized countries as Germany and Japan and outlines its concept and principles. The author emphasizes that a circular economy should become the breakthrough point for sustainable development and will enable a shift to a sustainable society of "doing less with less" away from the current high-consumption society of "doing more with more"     

Internal cycle modeling and environmental assessment of multiple cycle consumer products

Dynamic annual flow models incorporating consumer discard and usage loss and featuring deterministic and stochastic end-of-cycle (EOC) return by the consumer are developed for reused or remanufactured products (multiple cycle products, MCPs), including fast and slow cycling, short and long-lived products. It is shown that internal flows (reuse and overall consumption) increase proportionally to the dimensionless internal cycle factor (ICF) which is related to environmental impact reduction factors. The combined reuse/recycle (or cycle) rate is shown capable for shortcut, albeit effective, monitoring of environmental performance in terms of waste production, virgin material extraction and manufacturing impacts of all MCPs, a task, which physical variables (lifetime, cycling frequency, mean or total number of return trips) and conventional rates, via which environmental policy has been officially implemented (e.g. recycling rate) cannot accomplish. The cycle rate is shown to be an increasing (hyperbolic) function of ICF. The impact of the stochastic EOC return characteristics on total reuse and consumption flows, as well as on eco-performance, is assessed: symmetric EOC return has a small, positive effect on performance compared to deterministic, while early shifted EOC return is more beneficial. In order to be efficient, environmental policy should set higher minimum reuse targets for higher trippage MCPs. The results may serve for monitoring, flow accounting and comparative eco-assessment of MCPs. They may be useful in identifying reachable and efficient reuse/recycle targets for consumer products and in planning return via appropriate labelling and digital coding for enhancing environmental performance, while satisfying consumer demand.     

Treatment of domestic wastewater using an anaerobic baffled reactor followed by a duckweed pond for agricultural purposes

The treatment and reuse of domestic wastewater using an anaerobic baffled reactor (ABR) followed by a duckweed pond (DWP) were the main theme of the present study. The ABR was fed continuously with domestic wastewater at four HRTs ranging from 8 to 24 h and corresponds to organic loading rates ranging from 0.67 to 2.1 kg COD/m³/day. The ABR effluent was fed to a DWP operating at 10 and 15 days. The performance of the ABR at the four HRTs gave satisfactory results. Chemical oxygen demand (COD) removal was between 68 and 82%. Fecal coliform removal was between 1 to 2 logs. The 12- and 18-h hydraulic retention times (HRTs) gave close results, as indication of the possible selection of the 12-h HRT as the optimum operation for the ABR based on economic advantage. The ABR compartmentalized structure gave results higher than those produced by the one-stage digester and similar to those produced by the two-phase anaerobic digestion process. Duckweed ponds as post-treatment operated at 10 days and 15 days gave the best results at 15-day HRT, where it was possible to remove 73.4% of nitrogen and 65% of phosphorus and produce protein-rich dry duckweed of 105 kg/ha/day on average. The removal of fecal coliform (FC) in duckweed ponds was 3–4 logs. The final treated domestic sewage characteristics proved its compliance with the Egyptian standards for reuse in restricted irrigation.