Effects of Aspect Ratio on Solar Enhanced Waste Stabilization Ponds

The simulation of solar radiation in waste stabilization ponds is a developing tool worth studying in order to understand its effects on wastewater quality in waste stabilization ponds. Hence, the research is aimed at investigating the effect of length to width ratio (L/W) in solar enhanced waste stabilization ponds (SEWSPs) treatment efficiency. SEWSPs of varying sizes made of metallic tank with inlet and outlet valves, and a solar reflector was constructed to increase the incident sunlight intensity. Wastewater samples collected from the inlet and outlet of the SEWSPs were examined for physico-chemical and biological characteristics for a period of twelve (12) months. The parameters examined were Temperature, pH, detention time, total suspended solids, dissolved oxygen, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), algae count, faecal coliform and E-Coli. The efficiencies of the SEWSPs with respect to these parameters fluctuated with width variation, with the smallest SEWSP in width giving the highest treatment efficiency. The research revealed that with the incorporation of solar radiation in WSPs, a length/ width ratio of 1:0.2 should be used in the design of SEWSPs for maximum treatment efficiency.Keywords: waste stabilization pond, efficiency, solar radiation, aspect ratio, wastewater

Suitability of Saw Dust Ash-Lime Mixture for Production of Sandcrete Hollow Blocks

The use of saw-dust ash (SDA) mixed with 45% slaked lime for production of sandcrete hollow blocks was investigated. The aim was to determine the percentage SDA lime and water-cement ratio that would give the 28-day maximum strength. Saw dust was burnt and the ash sieved using a 150 micrometer sieve. The ash mixed with 45% slake lime was used to partially replace ordinary Portland cement (OPC) in various proportions. Fifteen blocks for each proportion were moulded using the mix of 1:8 and water-cement ratio of 0.50. Sprinkling of water on the blocks commenced after three days. The blocks were cured by complete immersion in water at room temperature. Three blocks were tested for strength at each of the ages of 7, 14 and 28 days for each proportion of OPC/SDA-lime. The 90:10 (cement: SDA-lime) proportion which gave the highest strength was further investigated for various water-cement ratios. It was concluded that for a mix of 1:8, 10% replacement of OPC by SDA-lime gave the maximum strength at water-cement ratio of 0.55 and was recommended for the production of sandcrete hollow blocks. The blocks should be used for low-income housing and non-load bearing walls

Trend Analysis of Raw Water Parameters in River Benue at the Reach of Makurdi, Nigeria

This study ascertained the extent of pollution of the water body of river Benue at the reach of Makurdi. Trend analysis gives an insight to the possible outcome over a period of time in data processing. In this study, available data for twelve points ranging from 1 – 12m distance, and some laboratory analysis were used to estimate the trend of Escherichia Coli (E.coli), Biochemical oxygen Demand (BOD) and chemical oxygen demand (COD) in river Benue at the reach of Makurdi, Benue State. The concentration of E.coli ranged from 584.7 cfu/100ml to 1067.1 cfu/100ml, BOD values ranged from 727.3 mg/l to 870.4mg/l and COD values ranged from 1454.7mg/l to 1758.6mg/l. The values increased with distance with the highest E-coli, BOD and COD at the 12m distance. Three regression models for trend projection were developed. The trend shows that, the water quality of river Benue is not pleasant. Some recommendations are made and if adopted will help to improve the quality of the water for consumption and other recreational purposes.Keywords: Trend Analysis, River Benue, Water Quality, Pollution, Raw Wate

Variability of Rain Water Quality due to Roof Characteristics

Rainwater harvesting is receiving increased attention worldwide as an alternative source of drinking water. Although, some people typically consume collected rainwater without any type of disinfection, the microbial and other physic-chemical qualities of this water source can be poor. In this paper, the variability of rain water quality due to roof characteristics was investigated using some randomly collected data from both industrialized and rural areas in Gboko, Nigeria. Questionnaires were randomly administered in the rural areas to obtain data on the type of roofing materials and age of the roof. In addition, samples were also collected from both areas and examined for alkalinity, pH, NO3−, SO42−, NH4+, Ca2+, Mg2+, dissolved heavy metals (Fe, Cu, Mn, Zn, Ni and Cr), and total coliform (not detected). The examined parameters gave average values of alkalinity, pH, NO3−, SO42−, NH4+, Ca2+, Mg2+, Fe, Zn as 4.8mg/l, 7.77, 23.9mg/l, 1.2mg/l, 26.1mg/l, 120.3mg/l, 99.6mg/l, 0.12mg/l, 0.13mg/l respectively. It was discovered that, the period of rainfall, environmental factors, type and age of roofing materials have varying effects on the characteristics of rainwater. From the experimental result, the roof drainage water quality in Gboko can be used as grey water for domestic purposes but requires treatment to be used as drinking water.KEYWORDS: Rainwater quality, Water availability, Rainwater harvesting, Variability, Roof drainag

Suitability of Broken Bottles as Fine Aggregate for Production of Concrete

The use of broken bottles as partial replacement of river sand for production of concrete was investigated. The grading of the broken bottles and sand fell in zone II. The specific gravity of the bottles was 2.55 and that of sand was 2.65. Sand was replaced with the broken bottles in the proportions of 0%, 10%, 20%, 30%, 40%, and 50% by weight. The mix of 1:2:4 by weight and watercement ratio of 0.45 were used. Cubes of side 150mm were cast for each proportion, cured by complete immersion in water and tested for density and strength at the ages of 7, 14 and 28 days. The average compressive strength of the cubes was found to increase with curing age but decrease with increase in the proportion of broken bottles in the mix. The proportion of broken bottles to give a minimum strength of 20N/mm2 was 30% at 7 and 14 days, and 40% at 28days. The maximum mean compressive strength of 19.0N/mm2 was obtained at 28days when sand and broken bottles were used in equal proportions. Density did not appear to have a discernible trend. For structural concrete, the proportion of broken bottles should be limited to 30% for early strength concrete and 40% when early strength is not required. For non-structural concrete, proportion greater than 40% can be used

Compressive Strength of Hollow Sandcrete Blocks Made with Rice Husk Ash as a Partial Replacement to Cement

Sandcrete hollow blocks have gained wide publicity and patronage in the construction industry. The cost of cement used in the production of sandcrete blocks is on the increase and unaffordable for the average Nigerian. Waste such as rice husk, which is seen polluting the environment are collected and burnt at 600̊C to produce rice husk ash (RHA), which in turn was used as pozzolana in sandcrete block production. Hollow sandcrete blocks were produced at 0, 10, 20, 30, 40 and 50 percent ash to cement replacement. A total of 120 blocks were produced and cured by water sprinkling at 1, 3, 7, 21 and 28 days. Properties such as compressive strength, density and water absorption were determined. The results showed that blocks made at 30% RHA to cement replacement meet the replacements specified by BS 2028 (1968) and Federal Ministry of Works (FMW), (1979). Finally, the study calls for the use of rice husk ash (RHA) in the production of hollow blocks

Suitability of groundnut shell ash/lime mixture in production of concrete

The suitability of groundnut shell ash (GSA) mixed with 45% slaked lime was investigated. The aim was to determine the percentage GSA/lime and water-cement ratio that would give the 28 – day minimum strength of 20N/mm2. Groundnut shells were burnt and the ash sieved using 150 micrometer sieve. The ash mixed with 45% slaked lime was used to partially replace ordinary Portland cement (OPC) in various proportions. The design mix used was 1:2:4 and water – cement ratios of 0.45, 0.55 and 0.65 by weight. Nine cubes of side 150mm were cast for each proportion and water – cement ratio. The cubes were cured by complete immersion in water at room temperature. Three cubes were tested for density and strength at each of the ages of 7, 14 and 28 days for each proportion of OPC/GSA – lime. It was concluded that for a mix of 1:2:4, the proportion of GSA/lime up to 20% gave the 28-day minimum strength of 20N/mm2 at water-cement ratio of 0.65 and was recommended for use as structural concrete.Keywords: Groundnut shell ash, Cement, Concrete, Water-cement ratio, StrengthNigerian Journal of Technological Research, vol 7(1) 201