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The recent increase in fish production has resulted in the accumulation of fish pond sediment. This sediment accumulates over time and can lead to a reduction in the depth of ponds and in the living space available for fish, it may also lead to a depletion in dissolved oxygen. Therefore, the removal of sediment from fresh water ponds is crucial for pond maintenance, and thus economical fish production. Fish pond sediment is rich in nutrients and organic matter, and therefore it may have potential as a fertilizer in crop production, nursery pot culture, etc. However, it contains compounds that undergo rapid degradation producing unpleasant odours and posing a threat to the environment, therefore it needs to be managed and handled efficiently in an environmentally sound and sustainable manner. The overall goal of this study was to analyse the current state and management practices of fish pond sediment generated in the existing aquaculture systems, with special reference to organic aquaculture, and the potential for the recovery of nutrients through bioconversion processes to organic fertilizers. K e y w o r d s: fish pond sediment, intensive aquaculture, nutrient recovery, agriculture

Concrete mix design and the determination of concrete performance are not merely engineering studies, but also mathematical and statistical endeavors. The study of concrete mechanical properties involves a myriad of factors, including, but not limited to, the amount of each constituent material and its proportion, the type and dosage of chemical additives, and the inclusion of different waste materials. The number of factors and combinations make it difficult, or outright impossible, to formulate an expression of concrete performance through sheer experimentation. Hence, design of experiment has become a part of studies, involving concrete with material addition or replacement. This paper reviewed common design of experimental methods, implemented by past studies, which looked into the analysis of concrete performance. Several analysis methods were employed to optimize data collection and data analysis, such as analysis of variance (ANOVA), regression, Taguchi method, Response Surface Methodology, and Artificial Neural Network. It can be concluded that the use of statistical analysis is helpful for concrete material research, and all the reviewed designs of experimental methods are helpful in simplifying the work and saving time, while providing accurate prediction of concrete mechanical performance.

Increased fish pond production is associated with the generation of various waste including fish pond sediments. Fish pond sediments could be a valuable source of nutrients for growing plants, however they require further processing in order to be applied to soil. Composting is considered one of the methods for processing fish pond sediments. The aim of this work was to investigate the potential of organic fish pond sediments to be managed through laboratory composting with selected waste materials and evaluate the fertilizing potential of the obtained compost. The scope included: (1) analysis of organic fish pond sediments, (2) laboratory composting of organic fish pond sediments with wheat straw and green grass, (3) analysis of the obtained composts, (4) preparation of growing media with selected additives, (5) analysis of the properties of the prepared growing media and (6) analysis of the effect of the investigated growing media on the growth of Phaseolus vulgaris L. in pot experiments. The addition of cardboard waste and woodchips derived biochar to the obtained compost improved significantly the growth of the roots of Cardamine L. Also, the content of carbon and nitrogen in the compost mixtures increased. The addition of M1 (compost from organic fish pond sediments and 1% of biochar) to the soil had a significant impact on the growth of white beans.