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In this work, a low cost six-multipoint temperature data logger was developed. It was designed using LM35 as the sensor, and arduino Uno as the data processing element. The response time of the sensor was observed to be between three and four minutes. The comparative evaluation of the system with other established thermometers show that no two temperature meters gave the same values. However the most important thing is that all the systems recorded the same temperature flow pattern. This indicates that the systems actually senses change in the surrounding effectively. In relation to the alcohol thermometer, the designed system shows an accuracy of +0.4 o C at temperatures below 30 0 C and +1.85 0 C at temperatures above 30 0 C. The system gives room for effective and adjustable temperature data logging procedure. Hence, the system is recommended for use in monitoring low temperature systems.

One of the most popular off-site wastewater treatment plants used in the tropics is the waste stabilization pond (WSP). Although it has several advantages, its use in urban areas is limited because of its large land area requirement. Hence, this research is aimed at investigating if a solar-enhanced WSP (SEWSP) can increase treatment efficiency and consequently reduce the land area requirement. The SEWSPs of varying sizes, made of a metallic tank with inlet and outlet valves and a solar reflector, were constructed to increase the incident sunlight intensity. Wastewater samples collected from the inlet and outlet of the SEWSPs were examined for physio-chemical and biological characteristics for a period of 2 months. The parameters examined were total suspended solids, dissolved oxygen, 5-day biochemical oxygen demand (BOD 5 ), chemical oxygen demand (COD), coliform, and Escherichia coli. The efficiencies of the SEWSPs, with respect to these parameters, fluctuated with temperature variation, with the shallowest SEWSP giving the highest treatment efficiency. The research revealed that the cost of treating wastewater using SEWSPs was approximately 2 times lower than the conventional WSP for the same treatment efficiencies. Water Environ. Res., 81, 540 (2009).