Effluent Disposal System Research Articles

Sustainability as an improvement tool: the sinergy between the water capture and effluent disposal system in GNA projects

Sustainability as an improvement tool: the sinergy between the water capture and effluent disposal system in GNA projects

Technical assessment of installed domestic biogas plants in Kavre, Nepal

Domestic biogas technology is a promising source of renewable energy for cooking in developing countries. It is popular in Nepal's rural and peri-urban areas and can be scaled-up to replace solid fuel cookstoves. This study focused on the technical assessment of installed biogas plants such as structural components, pipelines and valves, stove and burner, biogas production and utilization, and effluent disposal system in 303 homes in Kavre district, Nepal. Furthermore, it evaluated the feedstock material's physical and chemical parameters to ascertain their implications on biogas production. The plants' problems were mainly due to faulty components and lack of proper operation and maintenance. About 18% of plants were nonfunctional, out of which 9% of the plants were damaged due to the 2015 mega-earthquake. The highest number of damages was found in the mixture of the inlet structure. About 55% of mixtures were nonfunctional. Almost 77% of users used cow dung and toilet waste either individually or in combination with animal urine as feedstock materials in the digester. The Carbon: Nitrogen (C: N) ratio of feedstock materials ranged from 5:1–24:1, with only 4% of samples measuring C: N greater than 20:1. Similarly, pH (7.7) levels were on the higher side.

Condenser cooling system & effluent disposal system for steam-electric power plants: Improved techniques

In India, the current operation of condenser cooling system & effluent disposal system in existing power plants aims to reduce drawal of seawater and to achieve Zero Liquid Discharge to meet the demands of statutory requirements, water scarcity and ecological system. Particularly in the Steam-Electric power plants, condenser cooling system adopts Once through cooling (OTC) system which requires more drawal of seawater and effluent disposal system adopts sea outfall system which discharges hot water into sea. This paper presents an overview of closed-loop technology for condenser cooling system and to achieve Zero Liquid Discharge plant in Steam-Electric power plants making it lesser drawal of seawater and complete elimination of hot water discharges into sea. The closed-loop technology for condenser cooling system reduces the drawal of seawater by 92% and Zero Liquid Discharge plant eliminates the hot water discharges into sea by 100%. Further, the proposed modification generates revenue out of selling potable water and ZLD free flowing solids at INR 81,97,20,000 per annum (considering INR 60/Cu.m, 330 days/year and 90% availability) and INR 23,760 per annum (considering INR 100/Ton, 330 days/year and 90% availability) respectively. This proposed modification costs INR 870,00,00,000 with payback period of less than 11 years. The conventional technology can be replaced with this proposed technique in the existing and upcoming power plants.

Application of fault tree approach for technical assessment of small-sized biogas systems in Nepal

Biogas technology is becoming increasingly popular throughout the world, particularly in countries where governments promote domestic biogas systems. Despite its popularity, problems exist in biogas technology, such as low-quality construction, leakage of pipelines, low biogas production, and lack of maintenance. These problems should be identified and analyzed for effective implementation and efficient operation of small-sized biogas systems (SBS). This research applies the fault tree approach (FTA) to identify failures, and evaluate their effects on the operation of SBS from a technical point of view, based on a nationwide field study in Nepal. Ninety-four sets of SBS were selected and sampled in targeted areas. Five subsystems of SBS were defined, including structural components, biogas utilization equipment, piping system, biogas production, and effluent disposal system. Based on the statistical analysis of the 94 targeted cases, the fault probabilities of the five subsystems are 0.67, 0.48, 0.73, 0.26, and 0.64, respectively. The weights of five subsystems are determined by Delphi method and fault probability of SBS is calculated. The results show that faults on piping systems happen most frequently, and that proper disposal and reuse of bio-slurry are often neglected. Regardless of the social and economic benefits of SBS, implementation scenarios of SBS throughout Nepal are evaluated under a technical perspective, as follows: (1) the operational status of SBS is not optimal. (2) Based on criteria for failures, well-operation ratio is about 53% in practice. (3) Skilled masons are prerequisites for efficient functioning of SBS. (4) Maintenance plays a key role for efficient functioning. The study results prove that FTA is mostly suitable for SBS evaluation and is an effective analysis tool for technical evaluation in the field of biogas technology.

Investigation of the sequestration mechanisms of Cd(II) and 1-naphthol on discharged multi-walled carbon nanotubes in aqueous environment

The increasing exploitation of multi-walled carbon nanotubes (MWCNTs) into many industrial processes has raised considerable concerns as they are likely to be released into the environment. The interactions of the pollutants in water with discharged MWNCTs will further influence the environmental behavior and fate of these contaminants. In this context, our work aims to quantify the sequestration mechanisms and species distribution of Cd(II) and 1-naphthol on discharged MWCNTs by using batch technique. The uptake of Cd(II) on oxidized MWCNTs is greatly enhanced by the coexistent 1-naphthol, whereas the uptake of 1-naphthol on oxidized MWCNTs is not influenced by the coexistent Cd(II) in solution. Based on the experimental results, one can deduce that ion exchange or outer-sphere surface complexation mainly contributes to Cd(II) uptake on oxidized MWCNTs at low pH values, and inner-sphere surface complexation is the main uptake mechanism at high pH values. The uptake of 1-naphthol on oxidized MWCNTs is attributed to the π–π conjugate action between the aromatic ring of 1-naphthol and the graphitic structure of oxidized MWCNTs. The above-mentioned laboratorial results are further verified by the investigation conducted in actual effluent disposal system. The findings in the present study can provide more precise information on the real impact and changes in aqueous environment caused by the simultaneous presence of Cd(II), 1-naphthol and discharged oxidized MWCNTs.

Success Story of Florida County Self-Performing a 6-Million Dollar Wastewater Effluent Disposal System Construction Project – Okaloosa County Florida

Success Story of Florida County Self-Performing a 6-Million Dollar Wastewater Effluent Disposal System Construction Project – Okaloosa County Florida

Assessment of Physical and Chemical Attributes of Sub-Tropical Soil to Predict Long Term Effluent Treatment Potential

On-site wastewater treatment systems aim to assimilate domestic effluent into the environment. Unfortunately failure of such systems is common and inadequate effluent treatment can have serious environmental implications. A research project was undertaken to determine the role of physical and chemical soil properties in the treatment performance of subsurface effluent disposal areas. Monitoring changes in these properties permits improved prediction of the treatment potential of a soil. The changes within soil properties of the disposal area due to effluent application were found to be directly related to the subsurface drainage characteristics, including permeability, clay content and clay type. The major controlling soil physical and chemical attributes were found to be moderate drainage, significant soil cation exchange capacity and dominance of exchangeable Ca or exchangeable Mg over exchangeable Na, low exchangeable Na, clay type and a minimum depth of 0.4 m of potential unsaturated soil before encountering a restrictive horizon. The study confirmed that both the physical properties and chemistry of the soil can be valuable predictive tools for evaluating the long term operation of sewage effluent disposal systems.

An Investigation into the role of site and soil characteristics in onsite sewage treatment

The onsite treatment of sewage is common in all rural and regional areas of the world. Due to the public health and environmental risks that these treatment systems pose, the need for adopting performance-based management strategies is gaining increasing recognition. This demands the establishment of performance objectives for onsite sewage treatment and disposal which are based on stringent scientific analysis. A research project was undertaken to identify and investigate the role of influential site and soil characteristics in the treatment performance of subsurface effluent disposal areas. The treatment performances of a number of septic systems on a range of site and soil conditions were investigated together with detailed soil analysis. The changes to soil physico-chemical characteristics of the disposal area due to effluent application and its effluent renovation capacity were found to be directly related to the subsurface drainage characteristics. Significant changes to exchangeable cations and chemical parameters such as pH, electrical conductivity and cation exchange capacity (CEC) can result due to subsurface effluent application. A relationship exists between chemical parameters such as exchangeable Na and Ca:Mg ratio and CEC. A strong correlation also exists between the depth to the restrictive subsurface horizon and observed treatment performance. The study confirmed that soil chemistry can be a valuable predictive tool for evaluating the long-term performance of sewage effluent disposal systems particularly in poorly drained sites.

5597477 Sewage effluent disposal system having sparger in holding tank : Harry David W Olive Branch, MI, Unites States

5597477 Sewage effluent disposal system having sparger in holding tank : Harry David W Olive Branch, MI, Unites States

Ecological Sustainability and On-Site Effluent Treatment Systems

In non-sewered urban and rural residential developments, domestic wastewaters are treated and disposed of on-site. Surveys indicate that the performance of domestic systems needs to be significantly improved to overcome potential public health and nuisance problems caused by failing systems. Many current effluent disposal practices are clearly not sustainable according to the accepted definitions of ecological sustainability. It is essential that the on-site disposal of domestic effluent is considered as an integral part of the land development process. Individual soil and site assessment needs to be undertaken in the design and sizing of effluent disposal systems. An important implication from the consideration of land capability criteria for on-site effluent disposal is that individual lot sizes will need to be larger in future developments of this nature.

Yeasts occurring in the effluent disposal basins of a pulp mill in Saskatchewan.

The numbers of yeasts in the effluent disposal system of the Prince Albert, Saskatchewan Pulp Mill occasionally reached 1 × 106 cells/liter, but were usually below 5 × 105 cells/liter. Rhodotorula species were commonly isolated and sometimes amounted to half of the population, though usually the relative numbers were considerably lower. The highest counts were found in late summer and early autumn. Bacterial counts varied from 20 × 106 to 74 × 106 cells/ml. Chemical O2 demand (COD) reached about 1200 mg/liter at times, and decreased as the effluent moved through the disposal system, about 40% of the total COD being removed during the treatment process. A considerably wider range of yeast species was found in the pulp mill disposal basins than in the Saskatoon sewage treatment plant. Most of the ascosporogenous yeasts found were Hansenula or Pichia species usually occurring in association with trees, as were many of the Candida species isolated.

The combined effects of high salinity and temperature on the survival of young Limanda limanda

Young specimens of the most common inshore flatfish, the dab Limanda limanda (Linnaeus, 1758), in the area of a proposed concentrated brine discharge, off the Yorkshire coast (England) were subjected to high salinities over temperatures corresponding to an annual temperature range. The results of these experiments have been used in the design of a dilution and dispersion system to protect the inshore fisheries. Mortality was found to be size-dependent, smaller dabs being least resistant. Response-surface analyses were utilised, showing mortality in relation to immersion time. The effect of temperature slowly declines with increased immersion time, and salinity becomes increasingly the more dominant effect. A significant salinity-temperature interaction was observed, which reached its peak effect at 3 h immersion. A 3-dimensional response-surface model of the mortality contours, for salinity, temperature, and immersion time, was produced which may be used to set upper limits to the design of the effluent disposal system. It is concluded that, provided salinity does not rise above 55‰, it is unlikely that significant changes in the L. limanda populations will occur.

Studies on Utilization of Organic Manures and Cropping System : II. Effect of the gulle on the yields of the annual forage crops

1. Introducing the gulle system as the effluent disposal system into the experiment farm, authors studied for two years its effect on the yield of the Italian ryegrass (October/1965-June/1966, October/1966-June/1967), and on that of the Rhodes grass (June/1966-October/1966, June/1967-October/1967) which were sown on the same field alternatingly. 2. The excreta of two milch cows were applied to the field of 10a. Nitrogen amount applied to the Italian ryegrass and to the Rhodes grass were estimated as 51 kg/10 a, respectively. The artificial fertilizer was applied only to the Italian ryegrass as the basal dressing. 3. The yield of the Italian ryegrass was 0.9-1.3 t/10 a in the dry weight, and that of the Rhodes grass was 0.8 t/10 a in the dry weight, that is, total yield of both grasses was 1.8-2.1 t/10a/year in the dry weight or 16 t in the flesh weight. Such result shows that the gulle as a grassland fertilizer can be used in place of the artificial one.