In the Niger Delta region of Nigeria, the major anthropogenic source of xenobiotics is petroleum based products. The increasing consumption of petroleum products has led to a significant rise in petroleum industrial waste generation. The petrochemical industry is one of such major source of hazardous waste, produced during manufacture of Petrochemical products. Wastewater from these industries introduced numerous toxic pollutants into the ecosystem, disrupting ecological balance and increasing high health risk in exposed human and wildlife populations. Petrochemical wastewater contains chemical compounds such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), radioactive materials, oil, organic matter that adversely affect biological systems, including microorganisms, plants, animals and humans. These pollutants can impair normal bodily functions and contaminate ecosystem and these compounds must be managed effectively before being discharged into any receiving environments. Treatment of this wastewater involves physical, biological, and chemical processes. This would serve as a bioremediation technique for degradation of petrochemical waste. While physical and chemical methods are commonly employed, they have limitations, including high costs, interference with natural water compositions, and the generation of additional toxins. In contrast, biological methods are environmentally friendly and can effectively mineralize organic pollutants. These methods are cost-effective and rarely produce toxic wastes. Biological approaches employ microorganisms such as bacteria, algae, and fungi under aerobic or anaerobic conditions. These microbial sources offer advantages such as long-term applicability and minimal environmental impact. Typically, petrochemical wastewater treatment occurs in two stages: pre-treatment and advanced treatment. The pre-treatment stage focuses on reducing suspended materials, while the advanced treatment degrade and decrease pollutants to acceptable dischargeable levels. This chapter is focused on treatment methods, xenobiotic composition and health and environmental impacts of petrochemical wastewater discharged in the Niger Delta region in Nigeria.