This study aimed to analyze potential industrial solid waste that can be added to soil-cement blocks. A narrative literature review was conducted in the Scopus academic database, using as the search criteria keywords related to the topic, such as soil-cement, building materials, soil-cement blocks, soil-cement bricks, physical and mechanical properties, solid waste, life cycle analysis, and civil construction. A variety of industrial solid waste that can be incorporated into soil-cement blocks was observed, such as waste rock, sludge from water treatment plants, wood sawdust, polyethylene terephthalate fibers (PET), vegetable fibers from loofah, hemp fibers, rice husks, brachiaria grass, poultry eggshells, sugar cane bagasse, wheat and barley straw, welding slag, foundry sand, waste from quartzite mining, construction, and demolition, mechanical turning, pulp industry grains, and steel mill co-products. Among the investigated wastes, those that improved the physical and mechanical properties of the soil-cement blocks were grains from the cellulose industry, rice husks, Brachiaria grass, steel by-products with granulated soil-cement blocks and blast furnace slag. The waste that produced no satisfactory results was sludge from a water treatment plant, sugarcane bagasse, and vegetable loofah. Through this research, it was possible to verify that the behavior of soil-cement blocks is influenced by several factors in their manufacture, mainly regarding the type and percentage of incorporated waste. However, it is important to be concerned with its application in waste blocks so as not to increase the environmental impacts in the long term.

The construction sector is increasingly seeking sustainable alternatives in its processes worldwide, with a particular focus on the production of eco-friendly materials. Additionally, the improper disposal of solid waste is rapidly increasing, particularly in the agro-industry, including the waste generated from beer processing such as malt bagasse. Therefore, the objective of this study was to incorporate malt bagasse residue into ceramic materials at varying proportions (0, 2.5, 5, 10, and 15%) as a partial substitute for clay, submitted to different sintering temperatures (750, 850, 950, and 1050 °C). The raw materials, namely ceramic mass and malt bagasse, were characterized based on their chemical properties (XRF, loss of fire, and elemental analysis), physical properties (grain size, Atterberg limits), and mineralogical properties (XRD) characteristics. The properties of the ceramics, both with and without the incorporation of waste, were evaluated using dilatometry, apparent density, apparent porosity, water absorption, linear shrinkage, and tensile strength. The compositions that exhibited the best sintering temperatures were subjected to microstructural characterization using optical microscopy and X-ray diffraction (XRD). Significant differences were observed in the properties of the ceramic material, particularly in terms of linear shrinkage and apparent porosity. It was concluded that as the amount of malt bagasse residue incorporated increased, the mechanical properties of the pieces decreased. The incorporation of 15% residue resulted in the lowest performance, primarily due to a greater loss of mass. However, it should be noted that the incorporation of up to 5% malt bagasse for all the studied temperatures can still be considered acceptable, as it meets the minimum recommended value of 1.5 MPa for masonry ceramic components. This incorporation of malt bagasse contributes to both the technological and environmental aspects of civil construction.

Águas residuárias de bovinocultura (ARB) leiteira são alternativas parafornecer os nutrientes minerais, reduzindo o uso de fertilizantes. Assim,avaliaram-se a resposta da atividade fotoquímica e o ganho de biomassa emcitronela sob diferentes doses de nitrogênio aplicadas via lâminas de ARB.O nitrogênio foi o elemento de referência com base no qual se calculou aquantidade de ARB equivalente a ser aplicada. Assim, as doses de nitrogênioaplicadas via ARB foram de 100, 200, 300 e 400% em relação à adubaçãomineral utilizada no controle. Fluorescência da clorofila a, pigmentos emassa seca foram analisados. Verificou-se que a resposta da citronela àsdoses de ARB aplicadas foi tempo-dependente, e a energia absorvida pelosfotossistemas foi utilizada para redução dos aceptores finais na cadeia detransporte de elétrons, promovendo, em todas as doses, melhor eficiênciafotoquímica, mas isso não refletiu no ganho de biomassa, principalmentedas folhas.

Background. Due to the negative impacts caused by the inadequate disposal of dairy cattle wastewater (DCW), alternatives are needed to reduce the environmental impact. Objective. The aim of this study was to evaluate the effects of applying DCW via fertigation on the physical and chemical characteristics of the soil and on the production of citronella essential oil (Cymbopogon nardus (L.) Rendle). Methodology. Nitrogen (N) was adopted as a reference element and DCW equivalent amount to be applied so as to replace this element was calculated. Doses equivalent to 100%, 200%, 300% and 400% of the recommended N concentration were applied. After six months of cultivation, the availability of nutrients for the soil and its relationship to the production of essential oil were evaluated. Results. The results showed that DCW supply for citronella cultivation was effective and, in most parameters, equivalent to the treatment with mineral fertilization. Besides, there was no significant difference between the treatments, regarding the quantity and quality of essential oil production. Implications: DCW does not increase the yield of essential oil, but it is an excellent alternative for the supply of nutrients in degraded soils. Conclusions. Therefore, DCW use for fertigation of citronella cultivation is a valid alternative, helping to mitigate the impacts related to its disposal. However, new studies with a longer evaluation period and other types of soil are suggested.

Water is an asset that is becoming scarce and its reuse is an alternative to preserve it. Social and environmental feasibility motivate the adoption of reuse, but the financial factor can be limited to its use. The objective of this study was to evaluate the economic and financial feasibility for the investment in a domestic wastewater treatment system in which the constructed wetlands could be used aiming at the reuse for irrigation. Instruments such as the minimum attractiveness rate, discounted payback, the internal rate of return and the profitability index were used. The treatment system composed of an equalization tank, a septic tank, horizontal subsurface flow constructed wetland, subsurface flow constructed wetland, and a maturation pond comprising 52 m², demonstrating that it is able to meet the criteria required for reuse. The organic load affluent to the system was projected to 220 mg L-1 at a flow rate of 600 L day-1 of sewage, obtaining removal efficiency above 98% for all parameters, except nitrogen and phosphorus. In the analysis of economic and financial feasibility, it was found that the internal rate of return found for the cash flow considered was 98% and the profitability index according to the present value was 3.28. It was found that the total employed would be recovered in up to two years. With the use of the system, 180 m³ of water would be saved annually, reducing the pressure on the public supply system, in addition to the sewage treatment and the scenic beauty provided by wetlands. Therefore, the system is not limited only to economic gains, but also to social and environmental gains.