Small-scale Treatment Systems Research Articles

A new perspective on small-scale treatment systems for arsenic affected groundwater

This work provides a new perspective on small-scale treatment systems to remove arsenic from groundwater for potable applications in low-income communities. Data corroborated from the literature highlight a significant challenge to providing potable water in a financially sustainable manner in arsenic affected areas. Analysis of the literature also reveals notable deficiency in the current practice, especially the overfocus on household-scale treatment systems for arsenic affected groundwater without adequate maintenance, monitoring, and a systematic cost–benefit analysis. Accurate and reliable analysis of arsenic in water samples at relevant health guideline values is costly and technologically demanding for low-income communities. Significant discrepancy in the performance of household-scale treatment systems can be attributed to the lack of maintenance and systematic monitoring. Moreover, data on the maintenance and compliance monitoring cost of small-scale arsenic treatment systems are very limited in the literature, and the available data show an exponential increase in maintenance cost per treatment capacity unit as the treatment size decreases. On the other hand, significant opportunities exist to increase performance reliability and reduce water treatment cost by taking advantage of the current digital transformation of the water sector. The analysis in this work suggests the need to reframe current practice towards commune-scale treatment systems as an interim step before centralised water supply is available. • Arsenic contaminated groundwater significantly impacts low-income communities. • Co-contaminants must also be removed to meet drinking water standard. • Inadequate maintenance and monitoring of household-scale systems exists. • Beyond the minimum scale, performance is unreliable or unassessable. • Digitally enabled systems play an interim step before centralised water supply.

The Small-Scale Treatment Plant Industry: Institutional Features of Companies, Problems and Functionality of Small-Scale Treatment Systems.

The purposes of this study is to show the corporate characteristics of companies which have been operating in the fields of small-scale treatment plants' (SSTPs') design, construction, and installation processes, and to exhibit findings/perceptions of company employees on issues such as the initial investment and operating costs, common production and operating problems, the functionality of the small-scale treatment systems and the added value they provide to their customers' facilities. As a result of this study, it was determined that when the personnel participating in the survey were directly trained and recruited by the companies, which is generally the case, their training includes more practical methods and their experiences are shaped by the master-apprentice relationships in the sector. Regarding water treatment in SSTPs, the companies surveyed opted for traditional methods such as reverse osmosis and coagulation-flocculation, and preferred to use traditional biological treatment units-continuous flow or sequencing batch reactors (SBRs)- in wastewater treatment. In favor of businesses in need of water and wastewater management systems, the surveyed company employees have considered SSTPs as a successful, competitive advantage in the industry by maintaining low initial investment and operational costs while fulfilling the relevant environmental legal obligations. After examining the data regarding the opinions of company employees about SSTPs, it was found that there is a very significant relationship between the problems experienced during the installation/construction process and the problems during their operation.

Performance Evaluation of Small-Scale Solar Powered Wastewater and Grey Water Treatment Systems

Onsite wastewater treatment systems are the most economical way of dealing with used water in an isolated environment. And because of the variability normally associated with the operation of these systems is linked to either varying hydraulic loading or the nature of the environment in which the system was installed, the performance of these systems needs to be evaluated to find out the optimum operating condition. In this work, the performance of two small-scale treatment systems used for wastewater and gray water was evaluated. This was done by comparing the measure of some physical, chemical and biological parameters in the effluent to the standards of effluent discharge sets by Dubai Municipality. The performance was also measured from other angles using the proposed Swedish Water and Wastewater Association performance indicators so as to give the analysis a wider coverage of economic and energy consumption. The result shows that the performance of the installed solar-powered treatment systems was enough to meet the requirements set by Dubai municipality for effluent discharge except for Ammonia-Nitrogen. Also, the deployment of solar power energy supply, coupled with a low energy usage of the two systems, has made this particular setting an environmentally sustainable setting for such an isolated site.

The Carrión de los Céspedes Experimental Plant and the Technological Transfer Centre: urban wastewater treatment experimental platforms for the small rural communities in the Mediterranean area

Urban wastewater treatment in small rural communities, where technical and financial resources are usually limited, can pose a problem. Experience has shown that, when treating wastewater in small communities, the solutions used in larger cities are not applicable. In order to solve the problems involved, a number of alternative solutions have been developed, based on small-scale treatment systems which are adapted to the needs of these areas (non-conventional technologies). In Andalusia (Spain), as well as in Morocco, there are a large number of towns with small populations which have insufficient financial resources or management capacity to deal with the problem of their wastewater treatment using the classical treatment systems which, owing to their operational and maintenance costs and the need for qualified personnel, are not feasible in such towns. In Andalusia there is a centre which has become a reference point of urban wastewater treatment in small rural communities both in Europe and in the whole Mediterranean area: the Carrión de los Céspedes Experimental Plant (PECC) in Seville. Here, in a single area covering 35,000 m 2, a number of different treatment systems have been set up, where conventional and non-conventional technologies take pride of place, including combinations of them. On the other hand, in the North of Morocco, the Technological Transfer Centre (CTT) in Tetouan, there is a single area covering 30,000 m 2, with different non-conventional treatments systems. Moreover, there is a cooperation centre where the Andalusian and Moroccan administrations can debate about some subjects related with water in both countries. So in the both PECC and CTT, there is ongoing research to find answers for urban wastewater treatment needs in small communities, which is very important in the Mediterranean area, where the water stress problems and the situation in these population areas need more and more researches and progress in this matter.

Methods for detection of virus in wastewater, applied to samples from small scale treatment systems

Two small scale treatment systems were investigated to evaluate their effect on indigenous viruses in wastewater. In the effluent from an emscher tank system, treating a mixture of outlet from toilet, bath and kitchen, virus was demonstrated rather constantly. Samples were taken from a pasteurization plant where outlet from toilets was treated by addition of formaldehyde and exposure to 76°C for 30 min. A few samples from influent were positive, but no virus was found in the effluent. A comparison was made of four methods to detect viruses in wastewater. Alum precipitation followed by tris elution, acidic precipitation followed by elution with beef extract and two-phase concentration all made it possible to isolate indigenous viruses from wastewater and gave comparable results. No virus was demonstrated by direct inoculation. This corresponds well with the findings that the contents of virus was so low as to require concentration to be demonstrable.