Potential fresh water saving using greywater in toilet flushing in Syria

Greywater reuse is becoming an increasingly important factor for potable water saving in many countries. Syria is one of the most water scarce countries in the Middle East. However, greywater reuse is still not common in the country. Regulations and standards for greywater reuse are not available. Recently, however, several stakeholders have started to plan for greywater reuse. The main objective of this paper is to evaluate the potential for potable water saving by using greywater for toilet flushing in a typical Syrian city. The Sweida city in the southern part of Syria was chosen for this purpose. Interviews were made in order to reflect the social acceptance, water consumption, and the percentage of different indoor water uses. An artificial wetland (AW) and a commercial bio filter (CBF) were proposed to treat the greywater, and an economic analysis was performed for the treatment system. Results show that using treated greywater for toilet flushing would save about 35% of the drinking water. The economic analyses of the two proposed systems showed that, in the current water tariff, the payback period for AW and CBF in block systems is 7 and 52 years, respectively. However, this period will reduce to 3 and 21 years, respectively, if full water costs are paid by beneficiaries. Hence, introducing artificial wetlands in order to make greywater use efficient appears to be a viable alternative to save potable water.     

Quantification of potable water savings by residential water conservation and reuse - A case study

To demonstrate the benefits of water conservation at the household level in regional Victoria in Australia, a family house “Sharland Oasis” was designed and built according to an ecologically sustainable design for improved water and energy efficiency. This study has demonstrated that the combined use of alternative water supplies together with water efficient appliances can save up to 77% of total potable water use compared to the average 1990s household water use in the same region considering the location and differing in water use approach. The use of rainwater inside the home alone saved up to 40% of potable water use. In addition to the water savings, there is a significant wastewater discharge saving achieved through the use of water conservation strategies and greywater reuse. A community survey undertaken in regional Victoria revealed that community receptivity for reusing greywater is highest for uses, such as watering gardens and flushing toilets; but it progressively decreased with increasing personal contact with greywater. Positive perception of greywater reuse needs to be encouraged through programs targeted at developing resources, skills and motivation for new water reuse practices and technologies, across a diverse range of social groups.     

RESIDENTIAL WATER CONSERVATION: CASA DEL AGUA1

ABSTRACT: A single-family residence in Tucson, Arizona, was retrofitted with water-conserving fixtures, rainwater harvesting, and graywater reuse systems. During a four-year study, efficient use of water was shown to significantly decrease demand for domestic water at the house without reducing the residents' quality of life. The use of municipal water was reduced by 66 percent to 148 gallons per day (gpd) and total household use was reduced by 27 percent to 245 gpd. Graywater reuse averaged approximately 77 gpd or 32 percent of the total household water use. Evaporative cooling required about 15 gpd. Water use for toilet flushing was only 9 gallons per capita per day (gpcd) or 14 percent of interior water use.     

Survey of household waste composition and quantities in Abuja,Nigeria

Inadequate management of household solid waste is a serious problem in many developing cities. The study aimed to evaluate the quantities and composition of household solid waste generation in Abuja within different socioeconomic groups. The wastes from 74 households across different socioeconomic levels in Abuja were collected, weighted and classified on a daily basis for seven days in February 2012. The result showed that the average daily per capita household waste generation is 0.634 kg/capita/day. The characteristic of solid waste in Abuja are typical for the developing cities and dominated by organic waste. Households waste consisted of 63.6% organic waste, 9.7% paper, 8.7% plastics, 3.2% metal, 2.6% glass, 1.6% textile and 10.6% others (unclassified) and the bulk density was 240 kg/m³. The evaluation of relationship between income and daily per capita household waste generation showed a positive relationship. The study revealed a statistically significant difference between household size and daily per capita household waste generation in high-income group; a slight significant difference between household size and daily per capita household waste generation in medium income group and no statistically significant difference between household size and daily per capita household waste generation in low-income group.     

CASA DEL AGUA: A RESIDENTIAL WATER CONSERVATION AND REUSE DEMONSTRATION PROJECT IN TUCSON,ARIZONA1

ABSTRACT: A typical single family residence in Tucson, Arizona, was retrofitted to incorporate low-water-use fixtures and water reuse systems. The use of municipal water was reduced by 53 percent to 53 gallons per capita per day (gpcd) and total water use at the home was reduced by 33 percent to 74 gpcd.     

Household solid waste generation and characteristic in a Mekong Delta city,Vietnam

This study was undertaken to evaluate the quantity and composition of household solid waste to identify opportunities for waste recycling in Can Tho city, the capital city of the Mekong Delta region in southern Vietnam. Two-stage survey of 100 households was conducted for dry season and rainy season in 2009. Household solid waste was collected from each household and classified into 10 physical categories and 83 subcategories. The average household solid waste generation rate was 285.28 g per capita per day. The compostable and recyclable shares respectively accounted for 80.02% and 11.73%. The authors also analyzed the relations between some socioeconomic factors and household solid waste generation rates by physical categories and subcategories. The household solid waste generation rate per capita per day was positively correlated with the population density and urbanization level, although it was negatively correlated with the household size. The authors also developed mathematical models of correlations between the waste generation rates of main physical categories and relevant factors, such as household size and household income. The models were proposed by linear models with three variables to predict household solid waste generation of total waste, food waste, and plastic waste. It was shown that these correlations were weak and a relationship among variables existed. Comparisons of waste generation by physical compositions associated with different factors, such as seasonal and daily variation were conducted. Results presented that the significant average differences were found by the different seasons and by the different days in a week; although these correlations were weak. The greenhouse gas baseline emission was also calculated as 292.25 g (CO₂ eq.) per capita per day from biodegradable components.     

Potential for electricity savings by reducing potable water consumption in a city scale

Nowadays, it is very important that water and energy resources are used appropriately as this is a challenge to promote sustainable development. In some sectors, such as water and sewerage utilities, energy consumption depends on water consumption. The main objective of this work is to estimate the potential for electricity savings in a water and sewerage utility by reducing potable water consumption in the residential, commercial and public sectors in the city of Florianópolis, southern Brazil. These three sectors account for 98.9% of the total water consumption in the city. By using data related to energy consumption and costs that apply to the local water utility for water and sewage treatment, and also the potential for potable water savings over the three sectors, it is possible to estimate the potential for energy savings by reducing potable water consumption and sewage treatment. Potable water savings were estimated by using data available in the literature about water end-uses for different types of buildings located in Florianópolis. Three options were considered: installing dual-flush toilets, reusing greywater and using rainwater. The average potential for potable water savings were 30.0%, 53.4% and 60.3%, respectively, for the residential, commercial and public sectors. Thus, the average potable water savings amount to about 10,153,835 m³/year, and the electricity savings amount to 4.4 GW h/year, which would be enough to supply 1217 houses or flats in Florianópolis, with an average energy consumption of 300 kW h/month.     

A decision model for selecting sustainable drinking water supply and greywater reuse systems for developing communities with a case study in Cimahi, Indonesia

Capacity Factor Analysis is a decision support system for selection of appropriate technologies for municipal sanitation services in developing communities. Developing communities are those that lack the capability to provide adequate access to one or more essential services, such as water and sanitation, to their residents. This research developed two elements of Capacity Factor Analysis: a capacity factor based classification for technologies using requirements analysis, and a matching policy for choosing technology options. First, requirements analysis is used to develop a ranking for drinking water supply and greywater reuse technologies. Second, using the Capacity Factor Analysis approach, a matching policy is developed to guide decision makers in selecting the appropriate drinking water supply or greywater reuse technology option for their community. Finally, a scenario-based informal hypothesis test is developed to assist in qualitative model validation through case study. Capacity Factor Analysis is then applied in Cimahi Indonesia as a form of validation. The completed Capacity Factor Analysis model will allow developing communities to select drinking water supply and greywater reuse systems that are safe, affordable, able to be built and managed by the community using local resources, and are amenable to expansion as the community's management capacity increases.     

Identifying the key factors in increasing recycling and reducing residual household waste: a case study of the Flemish region of Belgium

The competent waste authority in the Flemish region of Belgium created the 'Implementation plan household waste 2003-2007' and the 'Implementation plan sustainable management 2010-2015' to comply with EU regulation. It incorporates European and regional requirements and describes strategies, goals, actions and instruments for the collection and treatment of household waste. The central mandatory goal is to reduce and maintain the amount of residual household waste to 150 kg per capita per year between 2010-2015. In literature, a reasonable body of information has been published on the effectiveness and efficiency of a variety of policy instruments, but the information is complex, often contradictory and difficult to interpret. The objective of this paper is to identify, through the development of a binary logistic regression model, those variables of the waste collection scheme that help municipalities to reach the mandatory 150 kg goal. The model covers a number of variables for household characteristics, provision of recycling services, frequency of waste collection and charging for waste services. This paper, however, is not about waste prevention and reuse. The dataset originates from 2003. Four out of 12 variables in the model contributed significantly: income per capita, cost of residual waste collection, collection frequency and separate curbside collection of organic waste.     

Biomass production for bioenergy using recycled wastewater in a natural waste treatment system

Bioenergy production from biomass is proposed as a method to solve part of the nation's energy problem. However, biomass and bioenergy production is questioned as an environment-friendly approach due to the potential increase of water pollution and the potential decrease of available water resource. A conceptual model of an integrated natural waste treatment system that produces biogas and biomass for bioenergy, treat waste and wastewater, conserve fresh water, and decrease the potential water pollution is presented. The potential biomass production from water hyacinth, duckweed, cattail, and knotgrass was investigated using recycling wastewater from an integrated natural waste treatment system from 2005 to 2008. Although the biomass production from recycling wastewater was not controlled for maximum production, this research identified the large potential impact that could be made if these systems were implemented. The overall average water hyacinth growth rate was high to 0.297 kg wet wt./m²/day during a research period of over 500 days, including both the active and non-active growing seasons. The average daily growth rates of duckweed, cattail, and knotgrass were 0.099-0.127, 0.015, and 0.018 kg wet wt./m², respectively. This research illustrated that water hyacinth was a more promising aquatic plant biomass for bioenergy production when wastewater effluent was recycled as water and nutrient sources from an integrated natural waste treatment system.     

Emergy evaluation of an integrated livestock wastewater treatment system

Wastewater treatment practices should pay more attention to their environmental performances due to their resources consumption and emissions’ impact. While reclaimed water reuse seems to have become a promising practice, is it always feasible in any condition? To address this issue, this study carried out an extended emergy evaluation of a holistic wastewater treatment system. On one hand, this method was extended to include the emissions’ impact. On the other hand, this study integrated a wastewater treatment plant, its excess sludge disposal system and treated water disposal system into an integrated wastewater treatment system (IWTS), so as to evaluate its performances more completely. And then several indicators, including cost per unit pollutant eliminated (CUPE), ratio of positive output (RPO), environmental load ratio (ELR), and sustainability index (SI), were proposed for evaluating the performances of an IWTS. Two scenarios (scenario A: wastewater treatment + sludge landfilling + treated water discharges; scenario B: wastewater treatment + sludge landfilling + reclaimed water reuse) for a livestock wastewater treatment plant in Sichuan Agricultural University located in Ya’an City in Southwest China, as cases, were researched. The results show that scenario B has lower positive output efficiency and greater environmental load than scenario A. Meanwhile, the reclaimed water reuse raises cost per unit pollutant eliminated compared with the treated water being discharged directly; emissions’ impact enhances the environmental load of the two scenarios to different degree; emissions’ impact has decisive effect on the sustainability of the two scenarios. These results mean that the reclaimed water reuse should not be advocated in this case. This study provides some policy implications: (1) wastewater treatment process should be comprehensively evaluated from its resources consumption and impact of emissions; (2) reclaimed water reuse should be carefully evaluated from its pros and cons simultaneously; (3) the local conditions should be considered when implementing reclaimed water reuse, such as local water body conditions, market demands, the related laws and regulations, corporations’ economic conditions, etc.     

WATER REDUCTIONS FROM RESIDENTIAL AUDITS1

ABSTRACT: The water reductions resulting from Contra Costa Water District's 1989 residential audit program are measured using a multivariate regression model. The model explains metered residential water use as a function of both conservation and other household variables. The principle conclusions drawn are that (1) installation of low-flow showerheads reduced indoor water use by 9.7 percent or 7.8 gallons per capita day, (2) the outdoor segment of the audit reduced irrigation needs by 18.7 percent, and (3) irrigation timers are being used inefficiently.     

WATER USE REDUCTIONS FROM RETROFIHNG INDOOR WATER FIXTURES1

ABSTRACT: A water use model was developed to estimate water savings from installation of low-flow showerheads and toilet displacement devices in residential housing. The model measures household water use in per capita terms with adjustments for age of occupants, household income, if occupants responsible for direct payment of water bill, and type of water fixtures. Detailed data on 308 single family residences involved with a pilot retrofit program in the Seattle, Washington, area were analyzed. We estimated per capita indoor water use to decline by 6.4 and 2.1 percent from complete installation of low-flow showerheads and toilet displacement devices, respectively.     

Removal of mercury from aqueous solutions using activated carbon prepared from agricultural by-product/waste

Removal of mercury from aqueous solutions using activated carbon prepared from Ceiba pentandra hulls, Phaseolus aureus hulls and Cicer arietinum waste was investigated. The influence of various parameters such as effect of pH, contact time, initial metal ion concentration and adsorbent dose for the removal of mercury was studied using a batch process. The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic models and the equilibrium adsorption data fit the Freundlich isotherm model well. The prepared adsorbents ACCPH, ACPAH and ACCAW had removal capacities of 25.88 mg/g, 23.66 mg/g and 22.88 mg/g, respectively, at an initial Hg(II) concentration of 40 mg/L. The order of Hg(II) removal capacities of these three adsorbents was ACCPH > ACPAH > ACCAW. The adsorption behavior of the activated carbon is explained on the basis of its chemical nature. The feasibility of regeneration of spent activated carbon adsorbents for recovery of Hg(II) and reuse of the adsorbent was determined using HCl solution.     

Sustainable recycling model: A comparative analysis between India and Tanzania

Higher economic growth in developing countries has caused higher amounts of wastes. Local government authorities in these countries usually fail to provide adequate services to dispose the increasing amounts of waste, resulting in threats for both the population and environment health. There is therefore an urgent need for recycling as a form of waste management in order to stop the devastating effects of solid waste in developing countries. Using a qualitative method of analysis, this study presents a model to measure and rank the sustainability of recycling programs in India and Tanzania. The model consists of six main constructs including “production, economic, governmental, social, technological, and international factors”. The results showed that India outperforms Tanzania in sustainable recycling programs: per capita waste generated per day in Delhi is higher than in Dar es Salaam; the government of India focuses more on developing recycling plans and techniques as compared to the government of Tanzania where the country is not actively involved in the recycling process; and the solid waste management planning in India is being performed better than Tanzania.     

Production of lightweight aggregates from mining and industrial wastes

Washing aggregate sludge from a gravel pit, sewage sludge from a wastewater treatment plant (WWTP) and a clay-rich sediment have been physically, chemically and mineralogically characterized. They were mixed, milled and formed into pellets, pre-heated for 5 min and sintered in a rotary kiln at 1150 °C, 1175 °C, 1200 °C and 1225 °C for 10 and 15 min at each temperature. The effects of the raw material characteristics, heating temperatures and dwell times on the loss on ignition (LOI), bloating index (BI), bulk density (ρ_b), apparent and dry particle densities (ρ_a, ρ_d), voids (H), water absorption (WA_24h) and compressive strength (S) were determined. All the mixtures presented a bloating potential taking into consideration the gases released at high temperatures. The products obtained were lightweight aggregates (LWAs) in accordance with Standard UNE-EN-13055-1 (ρ_b ≤ 1.20 g/cm³ or particle density ≤ 2.00 g/cm³). LWAs manufactured with 50% washing aggregate sludge and 50% clay-rich sediment were expanded LWAs (BI > 0) and showed the lowest apparent particle density, the lowest water absorption and the highest compressive strength. It was possible to establish three groups of LWAs on the basis of their properties in comparison to Arlita G3, F3 and F5, commercially available lightweight aggregates manufactured in Spain. Our LWAs may have the same or similar applications as these commercial products, such as horticulture, prefabricated lightweight structures and building structures.     

辽西北丘陵地区农村生活污水产污系数测算研究

通过对辽西北丘陵地区农村进行现场调研,测算了农村生活污水产污系数。结果表明,监测农户总生活污水中人均日产污水量为16.42 L,COD、BOD5、NH3-N、TN、TP、动植物油浓度的平均水平分别为696.9,341.83,4.34,36.79,4.32,2.28 mg/L;用水来源对农户生活污水中人均日产污水量和动植物油产污系数无显著影响,可取监测农户的平均值作为统一值;锦州北镇市农户生活污水人均日产量为19.12 L,COD、BOD5、TN、动植物油产污系数分别为0.05,0.11,0.09,0.87 g/(人·d),NH3-N和TP产污系数分别在7.29~7.35 g/(人·d)和14.69~14.83 g/(人·d),朝阳北票市农户生活污水人均日产量为19.12 L,COD、BOD5、NH3-N、TN、TP、动植物油产污系数分别为13.59,6.49,0.09,0.43,0.02,0.87 g/(人·d)。     

Reaching a forest land per capita milestone in the United States

During April 2007, forest land per capita in the United States dropped below 1 ha. This is the result of a rather static area of forest land in the United States for the past 100 years combined with population growth. The US now joins the ranks of most countries (77%) having forest land per capita below 1 ha. The combination of an increasing human population with stable or increasing per capita natural resource utilization may place even more demand on resources derived from forest land in the future. The forest land per capita should be expected to continue its downward trend unless substantive demographic, resource utilization, and land-use changes occur.     

Moving up the waste hierarchy: Car boot sales,reuse exchange and the challenges of consumer culture to waste prevention

Moving up the waste hierarchy is a key priority for UK waste policy. Waste prevention requires policy interventions to promote reuse. The term ‘reuse exchange’ has been adopted by UK policy makers to describe a variety of second-hand trading outlets including car boot sales, charity shops and online exchange sites. As waste policy is based on tonnage diverted from disposal (or landfill), policy interventions to promote reuse exchange will be based on the weight of goods estimated to be flowing through these sites. This paper uses a combination of field survey data and scale-up estimation to quantify and characterise the weight of goods exchanged at car boot sales in England in 2012. This is estimated at 50–60 000 tonnes per annum. The paper emphasises that movement up the waste hierarchy brings waste policy into closer contact with household consumption practices. It draws on qualitative research to show that, for participants, car boot sales are not associated with waste prevention. Instead, car boot sales rely on stocks of surplus household goods and exemplify the culture of thrift, which enables more, not less, consumption. The paper shows the collision between the social values that inform thrift and the environmental values that underpin reuse; and it argues that the policy goal of enhanced recovery for reuse might best be achieved by working with consumer culture. Two ways of achieving this are suggested: interventions that make it easier for consumers to do the right thing, through promoting opportunities for the circulation of stocks of surplus goods, for example, through increasing the frequency of car boot sales; and interventions which recognise that car boot sales also generate waste, which could be recovered for reuse.     

Car wash wastewater reclamation. Full-scale application and upcoming features

Recent features on car wash wastewater reclamation and results obtained in a full-scale car wash wastewater treatment and recycling are reported. The technique employed comprises a new flocculation-column flotation (FCF), sand filtration and final chlorination. Water usage and savings audits (20 weeks) showed that almost 70% reclamation was possible, and less than 40 L of fresh water per wash was attained. Wastewater and reclaimed water were fully characterized by monitoring chemical, physicochemical and biological parameters. Results were discussed in terms of reclamation aesthetic quality (water clarification and odour), health (pathological) and chemical (corrosion and scaling) risks. Noteworthy, this work showed a high count of fecal and total coliforms both in the wastewater and in the treated water, making the need of a final disinfection mandatory. The cost-benefit analysis shows that, for a car wash wastewater reclamation system in Brazil, at least 8 months were needed for the FCF-SC equipment amortization, when considering a demand over 30 washes per day. It is believed that the discussions on car wash wastewater reclamation criteria may assist alerting wash cars units and institutions to create laws in Brazil and elsewhere.