Open Access Original Research Article

Bio-Tower Application for Improvement of a Decentralized Waste Water Treatment System for Residential Applications–Reduction of Nonpoint Source Pollution by Nitrogen

K. Dölle, S. Giarrusso

Asian Journal of Environment & Ecology, Page 1-7
DOI: 10.9734/ajee/2021/v14i330206

The application of decentralized wastewater treatment system, also known as septic system is very common in suburban and rural areas with no access to centralized sewage treatment plants. Minimizing water pollution and the effects on wildlife and humans is of specific concern in rural and urban areas.

A packed bio-tower addition to a 1000 gallon septic tank was tested under pilot conditions using municipal residential sewage. The septic tank packed bio-tower pilot system is able to reduce the NH3-N influent level of 16.5 mg/l to 24.0 mg/l by 77.3% to 96.7% at influent flow levels between1060 l/d (280 gal/d) and 3997 l/d (1056 gal/d). 

Biochemical oxygen demand levels reduction was 97.0% from 280 mg/l to 8.5 mg/l. for a flow rate of 1060 l/d (280 gal/d).

Research showed that a bio-tower addition to a septic system has the potential to improve the systems overall performance.

Open Access Original Research Article

Assessment of the Impact of Sawmill Waste on the Environment

H. O. Stanley, J. A. Nnamdi, C. D. Onwukwe

Asian Journal of Environment & Ecology, Page 8-18
DOI: 10.9734/ajee/2021/v14i330207

The aim of this study was to assess the impact of sawmill wastes from selected sawmills in Port Harcourt on the environment. The physicochemical and microbiological features of the air at the sawmill sites were determined using air quality analyzer and settling plate technique respectively. Soil samples were analyzed for their physicochemical and microbiological properties. The study showed that of all the parameters monitored in the air samples at all the sampling sites, only noise level, volatile organic compounds and sulphur (IV) oxide exceeded the Federal Ministry of Environment limits. Results for microbiological analysis of air samples revealed that Total Heterotrophic Bacterial Counts (THBC) ranged from 2.5 x 104 (CFU/m3) to 1.3 x 104 (CFU/m3) while Total Fungal Counts (TFC) ranged between 1.7 x 104 (CFU/m3) and 7.7 x 103 (CFU/m3). The bacteria present in the air samples were identified as species of Staphylococcus, Micrococcus, Klebsiella, Serratia, Pseudomonas, Providencia and Bacillus while the fungi were identified as species of Penicillium, Aspergillus, Geotrichum, Cryptococcus, Rhizopus and Mucor. Results for microbiological analysis of soil samples revealed that THBC ranged from 2.06 x 106 (CFU/g) to 1.1 x 106 (CFU/g) while TFC ranged between 35 (CFU/g) and 1.4 x 102 (CFU/g). The bacterial isolates from the soil were identified as species of Pseudomonas, Salmonella, Aeromonas, Pseudomonas, Serratia and Aeromonas while the fungal isolates were identified as species of Penicillium, Aspergillus, Mucor and candida. The soil physicochemical properties monitored (pH, nitrate, lead, copper arsenic and mercury) where all within normal limits. The study showed that there are inhalable chemical and biological agents in the air at sawmills at the study locations. Measures should be put in place at sawmills to prevent occupational exposure and the waste should be properly managed.

Open Access Original Research Article

Heavy Metal Content and Physico-Chemical Analyses of Soils under the Litter of some Medicinal Taxa in the Luki Biosphere Reserve, Democratic Republic of the Congo

Florent Biduaya Mukeba, Myriam Mukadi Ngondo, Nazaire Kabemba Kadima, Prince Bofati Ilonga, Patrick Kayembe Bibasuya, Patience Mpia Ngelinkoto, Paulin Kapepula Mutwale, Koto-te-Nyiwa Ngbolua, Kalima Nkoma Mwange, Johnny Bopopi Mukoko, Nadège Kabamba Ngombe, Pius T. Mpiana, Théophile Mbemba Fundu

Asian Journal of Environment & Ecology, Page 19-35
DOI: 10.9734/ajee/2021/v14i330208

Aim: The aim of this study was to compare the texture, mineral element and heavy metal content of the soil under the litter of different selected species in relation to the plan of their pedogenesis.

Methods: The granulometric analysis of the various samples based on laser diffraction, measurements of Total Nitrogen and Total Organic Carbon were performed using the Elemental Analyzer, the Organic Matter content is estimated by the loss of ignition method using a Salvis furnace, In order to estimate the CaCO3 content. The same samples were heated in the oven at 1000°C for 60 minutes and reweighed. The carbonate content is estimated by the loss in mass during this second firing, multiplied by 2.274 which is the molecular weight ratio between CaCO3 and CO2. The heavy metal and mineral composition was evaluated by ICP-AES and AAS.

Results: The granulometric analyses show a sandy texture, according to the FAO classification. The organic matter content thus observed in the soils under the litter of these four species did not show any significant difference. The concentration of major mineral elements recorded in soils under the litter of Blighia welwitchii, Oncoba welwitschii, Zanthoxylum gilletii and Harungana madagascariensis did not show any significant difference. However, potassium, phosphorus, and magnesium have a high concentration compared to calcium and sodium. This study showed that the levels of cadmium, lead, arsenic and aluminum in the various samples of litter soils of all plant species including nickel for B. welwitschii are above the standards set by the Canadian Council of Ministers of the Environment for soil quality. Pollution factors for aluminum are the highest. This indicates that aluminum is the most polluting metal. The low pollution factors for lead and nickel are due to the low fixation of these metals by soils.

Conclusions: Our study took place in the Luki Biosphere reserve and showed that the different soils under litter are polluted by very toxic and persistent heavy metals such as cadmium, lead, aluminum, arsenic and nickel. This study has revealed new aspects of heavy metal pollution. This pollution represents a serious threat to the environment in general and to humans in particular through the food chain.